Category Archives: Social Psychology

A critique of Stroebe and Strack’s Article “The Alleged Crisis and the Illusion of Exact Replication”

The article by Stroebe and Strack (2014) [henceforth S&S] illustrates how experimental social psychologists responded to replication failures in the beginning of the replicability revolution.  The response is a classic example of repressive coping: Houston, we do not have a problem. Even in 2014,  problems with the way experimental social psychologists had conducted research for decades were obvious (Bem, 2011; Wagenmakers et al., 2011; John et al., 2012; Francis, 2012; Schimmack, 2012; Hasher & Wagenmakers, 2012).  S&S article is an attempt to dismiss these concerns as misunderstandings and empirically unsupported criticism.

“In contrast to the prevalent sentiment, we will argue that the claim of a replicability crisis is greatly exaggerated” (p. 59).  

Although the article was well received by prominent experimental social psychologists (see citations in appendix), future events proved S&S wrong and vindicated critics of research methods in experimental social psychology. Only a year later, the Open Science Collaboration (2015) reported that only 25% of studies in social psychology could be replicated successfully.  A statistical analysis of focal hypothesis tests in social psychology suggests that roughly 50% of original studies could be replicated successfully if these studies were replicated exactly (Motyl et al., 2017).  Ironically, one of S&S’s point is that exact replication studies are impossible. As a result, the 50% estimate is an optimistic estimate of the success rate for actual replication studies, suggesting that the actual replicability of published results in social psychology is less than 50%.

Thus, even if S&S had reasons to be skeptical about the extent of the replicability crisis in experimental social psychology, it is now clear that experimental social psychology has a serious replication problem. Many published findings in social psychology textbooks may not replicate and many theoretical claims in social psychology rest on shaky empirical foundations.

What explains the replication problem in experimental social psychology?  The main reason for replication failures is that social psychology journals mostly published significant results.  The selective publishing of significant results is called publication bias. Sterling pointed out that publication bias in psychology is rampant.  He found that psychology journals publish over 90% significant results (Sterling, 1959; Sterling et al., 1995).  Given new estimates that the actual success rate of studies in experimental social psychology is less than 50%, only publication bias can explain why journals publish over 90% results that confirm theoretical predictions.

It is not difficult to see that reporting only studies that confirm predictions undermines the purpose of empirical tests of theoretical predictions.  If studies that do not confirm predictions are hidden, it is impossible to obtain empirical evidence that a theory is wrong.  In short, for decades experimental social psychologists have engaged in a charade that pretends that theories are empirically tested, but publication bias ensured that theories would never fail.  This is rather similar to Volkswagen’s emission tests that were rigged to pass because emissions were never subjected to a real test.

In 2014, there were ample warning signs that publication bias and other dubious practices inflated the success rate in social psychology journals.  However, S&S claim that (a) there is no evidence for the use of questionable research practices and (b) that it is unclear which practices are questionable or not.

“Thus far, however, no solid data exist on the prevalence of such research practices in either social or any other area of psychology. In fact, the discipline still needs to reach an agreement about the conditions under which these practices are unacceptable” (p. 60).

Scientists like to hedge their statements so that they are immune to criticism. S&S may argue that the evidence in 2014 was not “solid” and surely there was and still is no agreement about good research practices. However, this is irrelevant. What is important is that success rates in social psychology journals were and still are inflated by suppressing disconfirming evidence and biasing empirical tests of theories in favor of positive outcomes.

Although S&S’s main claims are not based on empirical evidence, it is instructive to examine how they tried to shield published results and established theories from the harsh light of open replication studies that report results without selection for significance and subject social psychological theories to real empirical tests for the first time.

Failed Replication of Between-Subject Priming Studies

S&S discuss failed replications of two famous priming studies in social psychology: Bargh’s elderly priming study and Dijksterhuis’s professor priming studies.  Both seminal articles reported several successful tests of the prediction that a subtle priming manipulation would influence behavior without participants even noticing the priming effect.  In 2012, Doyen et al., failed to replicate elderly priming. Schanks et al. (2013) failed to replicate professor priming effects and more recently a large registered replication report also provided no evidence for professor priming.  For naïve readers it is surprising that original studies had a 100% success rate and replication studies had a 0% success rate.  However, S&S are not surprised at all.

“as in most sciences, empirical findings cannot always be replicated” (p. 60). 

Apparently, S&S knows something that naïve readers do not know.  The difference between naïve readers and experts in the field is that experts have access to unpublished information about failed replications in their own labs and in the labs of their colleagues. Only they know how hard it sometimes was to get the successful outcomes that were published. With the added advantage of insider knowledge, it makes perfect sense to expect replication failures, although may be not 0%.

The problem is that S&S give the impression that replication failures are too be expected, but that this expectation cannot be based on the objective scientific record that hardly ever reports results that contradict theoretical predictions.  Replication failures occur all the time, but they remained unpublished. Doyen et al. and Schanks et al.’s articles only violated the code to publish only supportive evidence.

Kahneman’s Train Wreck Letter

S&S also comment on Kahneman’s letter to Bargh that compared priming research to a train wreck.  In response S&S claim that

“priming is an entirely undisputed method that is widely used to test hypotheses about associative memory (e.g., Higgins, Rholes, & Jones, 1977; Meyer & Schvaneveldt, 1971; Tulving & Schacter, 1990).” (p. 60).  

This argument does not stand the test of time.  Since S&S published their article researchers have distinguished more clearly between highly replicable priming effects in cognitive psychology with repeated measures and within-subject designs and difficult to replicate between-subject social priming studies with subtle priming manipulations and a single outcome measure (BS social priming).  With regards to BS social priming, it is unclear which of these effects can be replicated and leading social psychologists have been reluctant to demonstrate replicability of their famous studies by conducting self-replications as they were encouraged to do in Kahneman’s letter.

S&S also point to empirical evidence for robust priming effects.

“A meta-analysis of studies that investigated how trait primes influence impression formation identified 47 articles based on 6,833 participants and found overall effects to be statistically highly significant (DeCoster & Claypool, 2004).” (p. 60). 

The problem with this evidence is that this meta-analysis did not take publication bias into account; in fact, it does not even mention publication bias as a possible problem.  A meta-analysis of studies that were selected for significance produces is also biased by selection for significance.

Several years after Kahneman’s letter, it is widely agreed that past research on social priming is a train wreck.  Kahneman published a popular book that celebrated social priming effects as a major scientific discovery in psychology.  Nowadays, he agrees with critiques that the existing evidence is not credible.  It is also noteworthy that none of the researchers in this area have followed Kahneman’s advice to replicate their own findings to show the world that these effects are real.

It is all a big misunderstanding

S&S suggest that “the claim of a replicability crisis in psychology is based on a major misunderstanding.” (p. 60). 

Apparently, lay people, trained psychologists, and a Noble laureate are mistaken in their interpretation of replication failures.  S&S suggest that failed replications are unimportant.

“the myopic focus on “exact” replications neglects basic epistemological principles” (p. 60).  

To make their argument, they introduce the notion of exact replications and suggest that exact replication studies are uninformative.

 “a finding may be eminently reproducible and yet constitute a poor test of a theory.” (p. 60).

The problem with this line of argument is that we are supposed to assume that a finding is eminently reproducible, which probably means it has been successfully replicate many times.  It seems sensible that further studies of gender differences in height are unnecessary to convince us that there is a gender difference in height. However, results in social psychology are not like gender differences in height.  According to S&S own accord earlier, “empirical findings cannot always be replicated” (p. 60). And if journals only publish significant results, it remains unknown which results are eminently reproducible and which results are not.  S&S ignore publication bias and pretend that the published record suggests that all findings in social psychology are eminently reproducible. Apparently, they would suggest that even Bem’s findings that people have supernatural abilities is eminently reproducible.  These days, few social psychologists are willing to endorse this naïve interpretation of the scientific record as a credible body of empirical facts.   

Exact Replication Studies are Meaningful if they are Successful

Ironically, S&S next suggest that exact replication studies can be useful.

Exact replications are also important when studies produce findings that are unexpected and only loosely connected to a theoretical framework. Thus, the fact that priming individuals with the stereotype of the elderly resulted in a reduction of walking speed was a finding that was unexpected. Furthermore, even though it was consistent with existing theoretical knowledge, there was no consensus about the processes that mediate the impact of the prime on walking speed. It was therefore important that Bargh et al. (1996) published an exact replication of their experiment in the same paper.

Similarly, Dijksterhuis and van Knippenberg (1998) conducted four studies in which they replicated the priming effects. Three of these studies contained conditions that were exact replications.

Because it is standard practice in publications of new effects, especially of effects that are surprising, to publish one or two exact replications, it is clearly more conducive to the advancement of psychological knowledge to conduct conceptual replications rather than attempting further duplications of the original study.

Given these citations it is problematic that S&S article is often cited to claim that exact replications are impossible or unnecessary.  The argument that S&S are making here is rather different.  They are suggesting that original articles already provide sufficient evidence that results in social psychology are eminently reproducible because original articles report multiple studies and some of these studies are often exact replication studies.  At face value, S&S have a point.  An honest series of statistically significant results makes it practically impossible that an effect is a false positive result (Schimmack, 2012).  The problem is that multiple study articles are not honest reports of all replication attempts.  Francis (2014) found that at least 80% of multiple study articles showed statistical evidence of questionable research practices.  Given the pervasive influence of selection for significance, exact replication studies in original articles provide no information about the replicability of these results.

What made the failed replications by Doyen et al. and Shank et al. so powerful was that these studies were the first real empirical tests of BS social priming effects because the authors were willing to report successes or failures.  The problem for social psychology is that many textbook findings that were obtained with selection for significance cannot be reproduced in honest empirical tests of the predicted effects.  This means that the original effects were either dramatically inflated or may not exist at all.

Replication Studies are a Waste of Resources

S&S want readers to believe that replication studies are a waste of resources.

Given that both research time and money are scarce resources, the large scale attempts at duplicating previous studies seem to us misguided” (p. 61).

This statement sounds a bit like a plea to spare social psychology from the embarrassment of actual empirical tests that reveal the true replicability of textbook findings. After all, according to S&S it is impossible to duplicate original studies (i.e., conduct exact replication studies) because replication studies differ in some way from original studies and may not reproduce the original results.  So, none of the failed replication studies is an exact replication.  Doyen et al. replicate Bargh’s study that was conducted in New York city in Belgium and Shanks et al. replicated Dijksterhuis’s studies from the Netherlands in the United States.  The finding that the original results could not be replicate the original results does not imply that the original findings were false positives, but they do imply that these findings may be unique to some unspecified specifics of the original studies.  This is noteworthy when original results are used in textbook as evidence for general theories and not as historical accounts of what happened in one specific socio-cultural context during a specific historic period. As social situations and human behavior are never exact replications of the past, social psychological results need to be permanently replicated and doing so is not a waste of resources.  Suggesting that replications is a waste of resources is like suggesting that measuring GDP or unemployment every year is a waste of resources because we can just use last-year’s numbers.

As S&S ignore publication bias and selection for significance, they are also ignoring that publication bias leads to a massive waste of resources.  First, running empirical tests of theories that are not reported is a waste of resources.  Second, publishing only significant results is also a waste of resources because researchers design new studies based on the published record. When the published record is biased, many new studies will fail, just like airplanes who are designed based on flawed science would drop from the sky.  Thus, a biased literature creates a massive waste of resources.

Ultimately, a science that publishes only significant result wastes all resources because the outcome of the published studies is a foregone conclusion: the prediction was supported, p < .05. Social psychologists might as well publish purely theoretical article, just like philosophers in the old days used “thought experiments” to support their claims. An empirical science is only a real science if theoretical predictions are subjected to tests that can fail.  By this simple criterion, experimental social psychology is not (yet) a science.

Should Psychologists Conduct Exact Replications or Conceptual Replications?

Strobe and Strack’s next cite Pashler and Harris (2012) to claim that critiques of experimental social psychology have dismissed the value of so-called conceptual replications and generalize.

The main criticism of conceptual replications is that they are less informative than exact replications (e.g., Pashler & Harris, 2012).” 

Before I examine S&S’s counterargument, it is important to realize that S&S misrepresented, and maybe misunderstood, Pashler and Harris’s main point. Here is the relevant quote from Pashler and Harris’s article.

We speculate that the harmful interaction of publication bias and a focus on conceptual rather than direct replications may even shed light on some of the famous and puzzling “pathological science” cases that embarrassed the natural sciences at several points in the 20th century (e.g., Polywater; Rousseau & Porto, 1970; and cold fusion; Taubes, 1993).

The problem for S&S is that they cannot address the problem of publication bias and therefore carefully avoid talking about it.  As a result, they misrepresent Pashler and Harris’s critique of conceptual replications in combination with publication bias as a criticism of conceptual replication studies, which is absurd and not what Pashler and Harris’s intended to say or actually said. The following quote from their article makes this crystal clear.

However, what kept faith in cold fusion alive for some time (at least in the eyes of some onlookers) was a trickle of positive results achieved using very different designs than the originals (i.e., what psychologists would call conceptual replications). This suggests that one important hint that a controversial finding is pathological may arise when defenders of a controversial effect disavow the initial methods used to obtain an effect and rest their case entirely upon later studies conducted using other methods. Of course, productive research into real phenomena often yields more refined and better ways of producing effects. But what should inspire doubt is any situation where defenders present a phenomenon as a “moving target” in terms of where and how it is elicited (cf. Langmuir, 1953/1989). When this happens, it would seem sensible to ask, “If the finding is real and yet the methods used by the original investigators are not reproducible, then how were these investigators able to uncover a valid phenomenon with methods that do not work?” Again, the unavoidable conclusion is that a sound assessment of a controversial phenomenon should focus first and foremost on direct replications of the original reports and not on novel variations, each of which may introduce independent ambiguities.

I am confident that unbiased readers will recognize that Pashler and Harris did not suggest that conceptual replication studies are bad.  Their main point is that a few successful conceptual replication studies can be used to keep theories alive in the face of a string of many replication failures. The problem is not that researchers conduct successful conceptual replication studies. The problem is dismissing or outright hiding of disconfirming evidence in replication studies. S&S misconstrue Pashler and Harris’s claim to avoid addressing this real problem of ignoring and suppressing failed studies to support an attractive but false theory.

The illusion of exact replications.

S&S next argument is that replication studies are never exact.

If one accepts that the true purpose of replications is a (repeated) test of a theoretical hypothesis rather than an assessment of the reliability of a particular experimental procedure, a major problem of exact replications becomes apparent: Repeating a specific operationalization of a theoretical construct at a different point in time and/or with a different population of participants might not reflect the same theoretical construct that the same procedure operationalized in the original study.

The most important word in this quote is “might.”   Ebbinghaus’s memory curve MIGHT not replicate today because he was his own subject.  Bargh’s elderly priming study MIGHT not work today because Florida is no longer associated with the elderly, and Disjterhuis’s priming study MIGHT no longer works because students no longer think that professors are smart or that Hooligans are dumb.

Just because there is no certainty in inductive inferences doesn’t mean we can just dismiss replication failures because something MIGHT have changed.  It is also possible that the published results MIGHT be false positives because significant results were obtained by chance, with QRPs, or outright fraud.  Most people think that outright fraud is unlikely, but the Stapel debacle showed that we cannot rule it out.  So, we can argue forever about hypothetical reasons why a particular study was successful or a failure. These arguments are futile and have nothing to do with scientific arguments and objective evaluation of facts.

This means that every study, whether it is a groundbreaking success or a replication failure needs to be evaluate in terms of the objective scientific facts. There is no blanket immunity for seminal studies that protects them from disconfirming evidence.  No study is an exact replication of another study. That is a truism and S&S article is often cited for this simple fact.  It is as true as it is irrelevant to understand the replication crisis in social psychology.

Exact Replications Are Often Uninformative

S&S contradict themselves in the use of the term exact replication.  First it is impossible to do exact replications, but then they are uninformative.  I agree with S&S that exact replication studies are impossible. So, we can simply drop the term “exact” and examine why S&S believe that some replication studies are uninformative.

First they give an elaborate, long and hypothetical explanation for Doyen et al.’s failure to replicate Bargh’s pair of elderly priming studies. After considering some possible explanations, they conclude

It is therefore possible that the priming procedure used in the Doyen et al. (2012) study failed in this respect, even though Doyen et al. faithfully replicated the priming procedure of Bargh et al. (1996).  

Once more the realm of hypothetical conjectures has to rescue seminal findings. Just as it is possible that S&S are right it is also possible that Bargh faked his data. To be sure, I do not believe that he faked his data and I apologized for a Facebook comment that gave the wrong impression that I did. I am only raising this possibility here to make the point that everything is possible. Maybe Bargh just got lucky.  The probability of this is 1 out of 1,600 attempts (the probability to get the predicted effect with .05 two-tailed (!) twice is .025^2). Not very likely, but also not impossible.

No matter what the reason for the discrepancy between Bargh and Doyen’s findings is, the example does not support S&S’s claim that replication studies are uninformative. The failed replication raised concerns about the robustness of BS social priming studies and stimulated further investigation of the robustness of social priming effects. In the short span of six years, the scientific consensus about these effects has shifted dramatically, and the first publication of a failed replication is an important event in the history of social psychology.

S&S’s critique of Shank et al.’s replication studies is even weaker.  First, they have to admit that professor probably still primes intelligence more than soccer hooligans. To rescue the original finding S&S propose

“the priming manipulation might have failed to increase the cognitive representation of the concept “intelligence.” 

S&S also think that

another LIKELY reason for their failure could be their selection of knowledge items.

Meanwhile a registered replication report with a design that was approved by Dijksterhuis failed to replicate the effect.  Although it is possible to come up with more possible reasons for these failures, real scientific creativity is revealed in creating experimental paradigms that produce replicable results, not in coming up with many post-hoc explanations for replication failures.

Ironically, S&S even agree with my criticism of their argument.

 “To be sure, these possibilities are speculative”  (p. 62). 

In contrast, S&S fail to consider the possibility that published significant results are false positives, even though there is actual evidence for publication bias. The strong bias against published failures may be rooted in a long history of dismissing unpublished failures that social psychologists routinely encounter in their own laboratory.  To avoid the self-awareness that hiding disconfirming evidence is unscientific, social psychologists made themselves believe that minute changes in experimental procedures can ruin a study (Stapel).  Unfortunately, a science that dismisses replication failures as procedural hiccups is fated to fail because it removed the mechanism that makes science self-correcting.

Failed Replications are Uninformative

S&S next suggest that “nonreplications are uninformative unless one can demonstrate that the theoretically relevant conditions were met” (p. 62).

This reverses the burden of proof.  Original researchers pride themselves on innovative ideas and groundbreaking discoveries.  Like famous rock stars, they are often not the best musicians, nor is it impossible for other musicians to play their songs. They get rewarded because they came up with something original. Take the Implicit Association Test as an example. The idea to use cognitive switching tasks to measure attitudes was original and Greenwald deserves recognition for inventing this task. The IAT did not revolutionize attitude research because only Tony Greenwald could get the effects. It did so because everybody, including my undergraduate students, could replicate the basic IAT effect.

However, let’s assume that the IAT effect could not have been replicated. Is it really the job of researchers who merely duplicated a study to figure out why it did not work and develop a theory under which circumstances an effect may occur or not?  I do not think so. Failed replications are informative even if there is no immediate explanation why the replication failed.  As Pashler and Harris’s cold fusion example shows there may not even be a satisfactory explanation after decades of research. Most probably, cold fusion never really worked and the successful outcome of the original study was a fluke or a problem of the experimental design.  Nevertheless, it was important to demonstrate that the original cold fusion study could not be replicated.  To ask for an explanation why replication studies fail is simply a way to make replication studies unattractive and to dismiss the results of studies that fail to produce the desired outcome.

Finally, S&S ignore that there is a simple explanation for replication failures in experimental social psychology: publication bias.  If original studies have low statistical power (e.g., Bargh’s studies with N = 30) to detect small effects, only vastly inflated effect sizes reach significance.  An open replication study without inflated effect sizes is unlikely to produce a successful outcome. Statistical analysis of original studies show that this explanation accounts for a large proportion of replication failures. Thus, publication bias provides one explanation for replication failures.

Conceptual Replication Studies are Informative

S&S cite Schmidt (2009) to argue that conceptual replication studies are informative.

With every difference that is introduced the confirmatory power of the replication increases, because we have shown that the phenomenon does not hinge on a particular operationalization but “generalizes to a larger area of application” (p. 93).

S&S continue

“An even more effective strategy to increase our trust in a theory is to test it using completely different manipulations.”

This is of course true as long as conceptual replication studies are successful. However, it is not clear why conceptual replication studies that for the first time try a completely different manipulation should be successful.  As I pointed out in my 2012 article, reading multiple-study articles with only successful conceptual replication studies is a bit like watching a magic show.

Multiple-study articles are most common in experimental psychology to demonstrate the robustness of a phenomenon using slightly different experimental manipulations. For example, Bem (2011) used a variety of paradigms to examine ESP. Demonstrating a phenomenon in several different ways can show that a finding is not limited to very specific experimental conditions. Analogously, if Joe can hit the bull’s-eye nine times from different angles, with different guns, and in different light conditions, Joe truly must be a sharpshooter. However, the variation of experimental procedures also introduces more opportunities for biases (Ioannidis, 2005). The reason is that variation of experimental procedures allows researchers to discount null findings. Namely, it is possible to attribute nonsignificant results to problems with the experimental procedure rather than to the absence of an effect.

I don’t know whether S&S are impressed by Bem’s article with 9 conceptual replication studies that successfully demonstrated supernatural abilities.  According to their line of arguments, they should be.  However, even most social psychologists found it impossible to accept that time-reversed subliminal priming works. Unfortunately, this also means that successful conceptual replication studies are meaningless if only successful results are published.  Once more, S&S cannot address this problem because they ignore the simple fact that selection for significance undermines the purpose of empirical research to test theoretical predictions.

Exact Replications Contribute Little to Scientific Knowledge

Without providing much evidence for their claims, S&S conclude

one reason why exact replications are not very interesting is that they contribute little to scientific knowledge.

Ironically, one year later Science published 100 replication studies with the only goal of estimating the replicability of psychology, with a focus on social psychology.  The article has already been cited 640 times, while S&S’s criticism of replication studies has been cited (only) 114 times.

Although the article did nothing else then to report the outcome of replication studies, it made a tremendous empirical contribution to psychology because it reported results of studies without the filter of publication bias.  Suddenly the success rate plummeted from over 90% to 37% and for social psychology to 25%.  While S&S could claim in 2014 that “Thus far, however, no solid data exist on the prevalence of such [questionable] research practices in either social or any other area of psychology,” the reproducibility project revealed that these practices dramatically inflated the percentage of successful studies reported in psychology journals.

The article has been celebrated by scientists in many disciplines as a heroic effort and a sign that psychologists are trying to improve their research practices. S&S may disagree, but I consider the reproducibility project a big contribution to scientific knowledge.

Why null findings are not always that informative

To fully appreciate the absurdity of S&S’s argument, I let them speak for themselves.

One reason is that not all null findings are interesting.  For example, just before his downfall, Stapel published an article on how disordered contexts promote stereotyping and discrimination. In this publication, Stapel and Lindenberg (2011) reported findings showing that litter or a broken-up sidewalk and an abandoned bicycle can increase social discrimination. These findings, which were later retracted, were judged to be sufficiently important and interesting to be published in the highly prestigious journal Science. Let us assume that Stapel had actually conducted the research described in this paper and failed to support his hypothesis. Such a null finding would have hardly merited publication in the Journal of Articles in Support of the Null Hypothesis. It would have been uninteresting for the same reason that made the positive result interesting, namely, that (a) nobody expected a relationship between disordered environments and prejudice and (b) there was no previous empirical evidence for such a relationship. Similarly, if Bargh et al. (1996) had found that priming participants with the stereotype of the elderly did not influence walking speed or if Dijksterhuis and van Knippenberg (1998) had reported that priming participants with “professor” did not improve their performance on a task of trivial pursuit, nobody would have been interested in their findings.

Notably, all of the examples are null-findings in original studies. Thus, they have absolutely no relevance for the importance of replication studies. As noted by Strack and Stroebe earlier

Thus, null findings are interesting only if they contradict a central hypothesis derived from an established theory and/or are discrepant with a series of earlier studies.” (p. 65). 

Bem (2011) reported 9 significant results to support unbelievable claims about supernatural abilities.  However, several failed replication studies allowed psychologists to dismiss these findings and to ignore claims about time-reversed priming effects. So, while not all null-results are important, null-results in replication studies are important because they can correct false positive results in original articles. Without this correction mechanism, science looses its ability to correct itself.

Failed Replications Do Not Falsify Theories

S&S state that failed replications do not falsify theories

The nonreplications published by Shanks and colleagues (2013) cannot be taken as a falsification of that theory, because their study does not explain why previous research was successful in replicating the original findings of Dijksterhuis and van Knippenberg (1998).” (p. 64). 

I am unaware of any theory in psychology that has been falsified. The reason for this is not that failed replication studies are not informative. The reason is that theories have been protected by hiding failed replication studies until recently. Only in recent years have social psychologists started to contemplate the possibility that some theories in social psychology might be false.  The most prominent example is ego-depletion theory, which has been one of the first prominent theories that has been put under the microscope of open science without the protection of questionable research practices in recent years. While ego-depletion theory is not entirely dead, few people still believe in the simple theory that 20 Stroop trials deplete individuals’ will power.  Falsification is hard, but falsification without disconfirming evidence is impossible.

Inconsistent Evidence

S&S argue that replication failures have to be evaluated in the context of replication successes.

Even multiple failures to replicate an established finding would not result in a rejection of the original hypothesis, if there are also multiple studies that supported that hypothesis. 

Earlier S&S wrote

in social psychology, as in most sciences, empirical findings cannot always be replicated (this was one of the reasons for the development of meta-analytic methods). 

Indeed. Unless studies have very high statistical power, inconsistent results are inevitable; which is one reason why publishing only significant results is a sign of low credibility (Schimmack, 2012). Meta-analysis is the only way to make sense of these inconsistent findings.  However, it is well known that publication bias makes meta-analytic results meaningless (e.g., meta-analysis show very strong evidence for supernatural abilities).  Thus, it is important that all tests of a theoretical prediction are reported to produce meaningful meta-analyses.  If social psychologists would take S&S seriously and continue to suppress non-significant results because they are uninformative, meta-analysis would continue to provide biased results that support even false theories.

Failed Replications are Uninformative II

Sorry that this is getting really long. But S&S keep on making the same arguments and the editor of this article didn’t tell them to shorten the article. Here they repeat the argument that failed replications are uninformative.

One reason why null findings are not very interesting is because they tell us only that a finding could not be replicated but not why this was the case. This conflict can be resolved only if researchers develop a theory that could explain the inconsistency in findings.  

A related claim is that failed replications never demonstrate that original findings were false because the inconsistency is always due to some third variable; a hidden moderator.

Methodologically, however, nonreplications must be understood as interaction effects in that they suggest that the effect of the crucial influence depends on the idiosyncratic conditions under which the original experiment was conducted” (p. 64). 

These statements reveal a fundamental misunderstanding of statistical inferences.  A significant result never proofs that the null-hypothesis is false.  The inference that a real effect rather than sampling error caused the observed result can be a mistake. This mistake is called a false positive or a type-I error. S&S seems to believe that type-I errors do not exist. Accordingly, Bem’s significant results show real supernatural abilities.  If this were the case, it would be meaningless to report statistical significance tests. The only possible error that could be made would be false negatives or type-II error; the theory makes the correct prediction, but a study failed to produce a significant result. And if theoretical predictions are always correct, it is also not necessary to subject theories to empirical tests, because these tests either correctly show that a prediction was confirmed or falsely fail to confirm a prediction.

S&S’s belief in published results has a religious quality.  Apparently we know nothing about the world, but once a significant result is published in a social psychology journal, ideally JPSP, it becomes a holy truth that defies any evidence that non-believers may produce under the misguided assumption that further inquiry is necessary. Elderly priming is real, amen.

More Confusing Nonsense

At some point, I was no longer surprised by S&S’s claims, but I did start to wonder about the reviewers and editors who allowed this manuscript to be published apparently with light or no editing.  Why would a self-respecting journal publish a sentence like this?

As a consequence, the mere coexistence of exact replications that are both successful and unsuccessful is likely to leave researchers helpless about what to conclude from such a pattern of outcomes.

Didn’t S&S claim that exact replication studies do not exist? Didn’t they tell readers that every inconsistent finding has to be interpreted as an interaction effect?  And where do they see inconsistent results if journals never publish non-significant results?

Aside from these inconsistencies, inconsistent results do not lead to a state of helpless paralysis. As S&S suggested themselves, they conduct a meta-analysis. Are S&S suggesting that we need to spare researchers from inconsistent results to protect them from a state of helpless confusion? Is this their justification for publishing only significant results?

Even Massive Replication Failures in Registered Replication Reports are Uninformative

In response to the replication crisis, some psychologists started to invest time and resources in major replication studies called many lab studies or registered replication studies.  A single study was replicated in many labs.  The total sample size of many labs gives these studies high precision in estimating the average effect size and makes it even possible to demonstrate that an effect size is close to zero, which suggests that the null-hypothesis may be true.  These studies have failed to find evidence for classic social psychology findings, including Strack’s facial feedback studies. S&S suggest that even these results are uninformative.

Conducting exact replications in a registered and coordinated fashion by different laboratories does not remove the described shortcomings. This is also the case if exact replications are proposed as a means to estimate the “true size” of an effect. As the size of an experimental effect always depends on the specific error variance that is generated by the context, exact replications can assess only the efficiency of an intervention in a given situation but not the generalized strength of a causal influence.

Their argument does not make any sense to me.  First, it is not clear what S&S mean by “the size of an experimental effect always depends on the specific error variance.”  Neither unstandardized nor standardized effect sizes depend on the error variance. This is simple to see because error variance depends on the sample size and effect sizes do not depend on sample size.  So, it makes no sense to claim that effect sizes depend on error variance.

Second, it is not clear what S&S mean by specific error variance that is generated by the context.  I simply cannot address this argument because the notion of context generated specific error variance is not a statistical construct and S&S do not explain what they are talking about.

Finally, it is not clear why meta-analysis of replication studies cannot be used to estimate the generalized strength of a causal influence, which I believe to mean “an effect size”?  Earlier S&S alluded to meta-analysis as a way to resolve inconsistencies in the literature, but now they seem to suggest that meta-analysis cannot be used.

If S&S really want to imply that meta-analyses are useless, it is unclear how they would make sense of inconsistent findings.  The only viable solution seems to be to avoid inconsistencies by suppressing non-significant results in order to give the impression that every theory in social psychology is correct because theoretical predictions are always confirmed.  Although this sounds absurd, it is the inevitable logical consequence of S&S’s claim that non-significant results are uninformative, even if over 20 labs independently and in combination failed to provide evidence for a theoretical predicted effect.

The Great History of Social Psychological Theories

S&S next present Über-social psychologist, Leon Festinger, as an example why theories are good and failed studies are bad.  The argument is that good theories make correct predictions, even if bad studies fail to show the effect.

“Although their theoretical analysis was valid, it took a decade before researchers were able to reliably replicate the findings reported by Festinger and Carlsmith (1959).”

As a former student, I was surprised by this statement because I had learned that Festinger’s theory was challenged by Bem’s theory and that social psychologists had been unable to resolve which of the two theories was correct.  Couldn’t some of these replication failures be explained by the fact that Festinger’s theory sometimes made the wrong prediction?

It is also not surprising that researchers had a hard time replicating Festinger and Carlsmith original findings.  The reason is that the original study had low statistical power and replication failures are expected even if the theory is correct. Finally, I have been around social psychologists long enough to have heard some rumors about Festinger and Carlsmith’s original studies.  Accordingly, some of Festinger’s graduate students also tried and failed to get the effect. Carlsmith was the ‘lucky’ one who got the effect, in one study p < .05, and he became the co-author of one of the most cited articles in the history of social psychology. Naturally, Festinger did not publish the failed studies of his other graduate students because surely they must have done something wrong. As I said, that is a rumor.  Even if the rumor is not true, and Carlsmith got lucky on the first try, luck played a factor and nobody should expect that a study replicates simply because a single published study reported a p-value less than .05.

Failed Replications Did Not Influence Social Psychological Theories

Argument quality reaches a new low with the next argument against replication studies.

 “If we look at the history of social psychology, theories have rarely been abandoned because of failed replications.”

This is true, but it reveals the lack of progress in theory development in social psychology rather than the futility of replication studies.  From an evolutionary perspective, theory development requires selection pressure, but publication bias protects bad theories from failure.

The short history of open science shows how weak social psychological theories are and that even the most basic predictions cannot be confirmed in open replication studies that do not selectively report significant results.  So, even if it is true that failed replications have played a minor role in the past of social psychology, they are going to play a much bigger role in the future of social psychology.

The Red Herring: Fraud

S&S imply that Roediger suggested to use replication studies as a fraud detection tool.

if others had tried to replicate his [Stapel’s] work soon after its publication, his misdeeds might have been uncovered much more quickly

S&S dismiss this idea in part on the basis of Stroebe’s research on fraud detection.

To their own surprise, Stroebe and colleagues found that replications hardly played any role in the discovery of these fraud cases.

Now this is actually not surprising because failed replications were hardly ever published.  And if there is no variance in a predictor variable (significance), we cannot see a correlation between the predictor variable and an outcome (fraud).  Although failed replication studies may help to detect fraud in the future, this is neither their primary purpose, nor necessary to make replication studies valuable. Replication studies also do not bring world peace or bring an end to global warming.

For some inexplicable reason S&S continue to focus on fraud. For example, they also argue that meta-analyses are poor fraud detectors, which is as true as it is irrelevant.

They conclude their discussion with an observation by Stapel, who famously faked 50+ articles in social psychology journals.

As Stapel wrote in his autobiography, he was always pleased when his invented findings were replicated: “What seemed logical and was fantasized became true” (Stapel, 2012). Thus, neither can failures to replicate a research finding be used as indicators of fraud, nor can successful replications be invoked as indication that the original study was honestly conducted.

I am not sure why S&S spend so much time talking about fraud, but it is the only questionable research practice that they openly address.  In contrast, they do not discuss other questionable research practices, including suppressing failed studies, that are much more prevalent and much more important for the understanding of the replication crisis in social psychology than fraud.  The term “publication bias” is not mentioned once in the article. Sometimes what is hidden is more significant than what is being published.

Conclusion

The conclusion section correctly predicts that the results of the reproducibility project will make social psychology look bad and that social psychology will look worse than other areas of psychology.

But whereas it will certainly be useful to be informed about studies that are difficult to replicate, we are less confident about whether the investment of time and effort of the volunteers of the Open Science Collaboration is well spent on replicating studies published in three psychology journals. The result will be a reproducibility coefficient that will not be greatly informative, because of justified doubts about whether the “exact” replications succeeded in replicating the theoretical conditions realized in the original research.

As social psychologists, we are particularly concerned that one of the outcomes of this effort will be that results from our field will be perceived to be less “reproducible” than research in other areas of psychology. This is to be expected because for the reasons discussed earlier, attempts at “direct” replications of social psychological studies are less likely than exact replications of experiments in psychophysics to replicate the theoretical conditions that were established in the original study.

Although psychologists should not be complacent, there seem to be no reasons to panic the field into another crisis. Crises in psychology are not caused by methodological flaws but by the way people talk about them (Kruglanski & Stroebe, 2012).

S&S attribute the foreseen (how did they know?) bad outcome in the reproducibility project to the difficulty of replicating social psychological studies, but they fail to explain why social psychology journals publish as many successes as other disciplines.

The results of the reproducibility project provide an answer to this question.  Social psychologists use designs with less statistical power that have a lower chance of producing a significant result. Selection for significance ensures that the success rate is equally high in all areas of psychology, but lower power makes these successes less replicable.

To avoid further embarrassments in an increasingly open science, social psychologists must improve the statistical power of their studies. Which social psychological theories will survive actual empirical tests in the new world of open science is unclear.  In this regard, I think it makes more sense to compare social psychology to a ship wreck than a train wreck.  Somewhere down on the floor of the ocean is some gold. But it will take some deep diving and many failed attempts to find it.  Good luck!

Appendix

S&S’s article was published in a “prestigious” psychology journal and has already garnered 114 citations. It ranks #21 in my importance rankings of articles in meta-psychology.  So, I was curious why the article gets cited.  The appendix lists 51 citing articles with the relevant citation and the reason for citing S&S’s article.   The table shows the reasons for citations in decreasing order of frequency.

S&S are most frequently cited for the claim that exact replications are impossible, followed by the reason for this claim that effects in psychological research are sensitive to the unique context in which a study is conducted.  The next two reasons for citing the article are that only conceptual replications (CR) test theories, whereas the results of exact replications (ER) are uninformative.  The problem is that every study is a conceptual replication because exact replications are impossible. So, even if exact replications were uninformative this claim has no practical relevance because there are no exact replications.  Some articles cite S&S with no specific claim attached to the citation.  Only two articles cite them for the claim that there is no replication crisis and only 1 citation cites S&S for the claim that there is no evidence about the prevalence of QRPs.   In short, the article is mostly cited for the uncontroversial and inconsequential claim that exact replications are impossible and that effect sizes in psychological studies can vary as a function of unique features of a particular sample or study.  This observation is inconsequential because it is unclear how unknown unique characteristics of studies influence results.  The main implication of this observation is that study results will be more variable than we would expect from a set of exact replication studies. For this reason, meta-analysts often use random-effects model because fixed-effects meta-analysis assumes that all studies are exact replications.

ER impossible 11
Contextual Sensitivity 8
CR test theory 8
ER uninformative 7
Mention 6
ER/CR Distinction 2
No replication crisis 2
Disagreement 1
CR Definition 1
ER informative 1
ER useful for applied research 1
ER cannot detect fraud 1
No evidence about prevalence of QRP 1
Contextual sensitivity greater in social psychology 1

the most influential citing articles and the relevant citation.  I haven’t had time to do a content analysis, but the article is mostly cited to say (a) exact replications are impossible, and (b) conceptual replications are valuable, and (c) social psychological findings are harder to replicate.  Few articles cite to article to claim that the replication crisis is overblown or that failed replications are uninformative.  Thus, even though the article is cited a lot, it is not cited for the main points S&S tried to make.  The high number of citation therefore does not mean that S&S’s claims have been widely accepted.

(Disagreement)
The value of replication studies.

Simmons, DJ.
“In this commentary, I challenge these claims.”

(ER/CR Distinction)
Bilingualism and cognition.

Valian, V.
“A host of methodological issues should be resolved. One is whether the field should undertake exact replications, conceptual replications, or both, in order to determine the conditions under which effects are reliably obtained (Paap, 2014; Simons, 2014; Stroebe & Strack, 2014).”

(Contextual Sensitivity)
Is Psychology Suffering From a Replication Crisis? What Does “Failure to Replicate” Really Mean?“
Maxwell et al. (2015)
A particular replication may fail to confirm the results of an original study for a variety of reasons, some of which may include intentional differences in procedures, measures, or samples as in a conceptual replication (Cesario, 2014; Simons, 2014; Stroebe & Strack, 2014).”

(ER impossible)
The Chicago face database: A free stimulus set of faces and norming data 

Debbie S. Ma, Joshua Correll, & Bernd Wittenbrink.
The CFD will also make it easier to conduct exact replications, because researchers can use the same stimuli employed by other researchers (but see Stroebe & Strack, 2014).”

(Contextual Sensitivity)
“Contextual sensitivity in scientific reproducibility”
vanBavel et al. (2015)
“Many scientists have also argued that the failure to reproduce results might reflect contextual differences—often termed “hidden moderators”—between the original research and the replication attempt”

(Contextual Sensitivity)
Editorial Psychological Science

Linday,
As Nosek and his coauthors made clear, even ideal replications of ideal studies are expected to fail some of the time (Francis, 2012), and failure to replicate a previously observed effect can arise from differences between the original and replication studies and hence do not necessarily indicate flaws in the original study (Maxwell, Lau, & Howard, 2015; Stroebe & Strack, 2014). Still, it seems likely that psychology journals have too often reported spurious effects arising from Type I errors (e.g., Francis, 2014).

(ER impossible)
Best Research Practices in Psychology: Illustrating Epistemological and Pragmatic Considerations With the Case of Relationship Science

Finkel et al. (2015).
“Nevertheless, many scholars believe that direct replications are impossible in the human sciences—S&S (2014) call them “an illusion”— because certain factors, such as a moment in historical time or the precise conditions under which a sample was obtained and tested, that may have contributed to a result can never be reproduced identically.”

Conceptualizing and evaluating the replication of research results
Fabrigar and Wegener (2016)
(CR test theory)
“Traditionally, the primary presumed strength of conceptual replications has been their ability to address issues of construct validity (e.g., Brewer & Crano, 2014; Schmidt, 2009; Stroebe & Strack, 2014). “

(ER impossible)
“First, it should be recognized that an exact replication in the strictest sense of the term can never be achieved as it will always be impossible to fully recreate the contextual factors and participant characteristics present in the original experiment (see Schmidt (2009); S&S (2014).”

(Contextual Sensitivity)
“S&S (2014) have argued that there is good reason to expect that many traditional and contemporary experimental manipulations in social psychology would have different psychological properties and effects if used in contexts or populations different from the original experiments for which they were developed. For example, classic dissonance manipulations and fear manipulations or more contemporary priming procedures might work very differently if used in new contexts and/or populations. One could generate many additional examples beyond those mentioned by S&S.”

(ER impossible)
“Another important point illustrated by the above example is that the distinction between exact and conceptual replications is much more nebulous than many discussions of replication would suggest. Indeed, some critics of the exact/conceptual replication distinction have gone so far as to argue that the concept of exact replication is an “illusion” (Stroebe & Strack, 2014). Though we see some utility in the exact/conceptual distinction (especially regarding the goal of the researcher in the work), we agree with the sentiments expressed by S&S. Classifying studies on the basis of the exact/conceptual distinction is more difficult than is often appreciated, and the presumed strengths and weaknesses of the approaches are less straightforward than is often asserted or assumed.”

(Contextual Sensitivity)
“Furthermore, assuming that these failed replication experiments have used the same operationalizations of the independent and dependent variables, the most common inference drawn from such failures is that confidence in the existence of the originally demonstrated effect should be substantially undermined (e.g., see Francis (2012); Schimmack (2012)). Alternatively, a more optimistic interpretation of such failed replication experiments could be that the failed versus successful experiments differ as a function of one or more unknown moderators that regulate the emergence of the effect (e.g., Cesario, 2014; Stroebe & Strack, 2014).”

Replicating Studies in Which Samples of Participants Respond to Samples of Stimuli.
(CR Definition)
Westfall et al. (2015).
Nevertheless, the original finding is considered to be conceptually replicated if it can be convincingly argued that the same theoretical constructs thought to account for the results of the original study also account for the results of the replication study (Stroebe & Strack, 2014). Conceptual replications are thus “replications” in the sense that they establish the reproducibility of theoretical interpretations.”

(Mention)
“Although establishing the generalizability of research findings is undoubtedly important work, it is not the focus of this article (for opposing viewpoints on the value of conceptual replications, see Pashler & Harris, 2012; Stroebe & Strack, 2014).“

Introduction to the Special Section on Advancing Our Methods and Practices
(Mention)
Ledgerwood, A.
We can and surely should debate which problems are most pressing and which solutions most suitable (e.g., Cesario, 2014; Fiedler, Kutzner, & Krueger, 2012; Murayama, Pekrun, & Fiedler, 2013; Stroebe & Strack, 2014). But at this point, most can agree that there are some real problems with the status quo.

***Theory Building, Replication, and Behavioral Priming: Where Do We Need to Go From Here?
Locke, EA
(ER impossible)
As can be inferred from Table 1, I believe that the now popular push toward “exact” replication (e.g., see Simons, 2014) is not the best way to go. Everyone agrees that literal replication is impossible (e.g., Stroebe & Strack, 2014), but let us assume it is as close as one can get. What has been achieved?

The War on Prevention: Bellicose Cancer: Metaphors Hurt (Some) Prevention Intentions”
(CR test theory)
David J. Hauser1 and Norbert Schwarz
“As noted in recent discussions (Stroebe & Strack, 2014), consistent effects of multiple operationalizations of a conceptual variable across diverse content domains are a crucial criterion for the robustness of a theoretical approach.”

ON THE OTHER SIDE OF THE MIRROR: PRIMING IN COGNITIVE AND SOCIAL PSYCHOLOGY 
Doyen et al. “
(CR test theory)
In contrast, social psychologists assume that the primes activate culturally and situationally contextualized representations (e.g., stereotypes, social norms), meaning that they can vary over time and culture and across individuals. Hence, social psychologists have advocated the use of “conceptual replications” that reproduce an experiment by relying on different operationalizations of the concepts under investigation (Stroebe & Strack, 2014). For example, in a society in which old age is associated not with slowness but with, say, talkativeness, the outcome variable could be the number of words uttered by the subject at the end of the experiment rather than walking speed.”

***Welcome back Theory
Ap Dijksterhuis
(ER uninformative)
“it is unavoidable, and indeed, this commentary is also about replication—it is done against the background of something we had almost forgotten: theory! S&S (2014, this issue) argue that focusing on the replication of a phenomenon without any reference to underlying theoretical mechanisms is uninformative”

On the scientific superiority of conceptual replications for scientific progress
Christian S. Crandall, Jeffrey W. Sherman
(ER impossible)
But in matters of social psychology, one can never step in the same river twice—our phenomena rely on culture, language, socially primed knowledge and ideas, political events, the meaning of questions and phrases, and an ever-shifting experience of participant populations (Ramscar, 2015). At a certain level, then, all replications are “conceptual” (Stroebe & Strack, 2014), and the distinction between direct and conceptual replication is continuous rather than categorical (McGrath, 1981). Indeed, many direct replications turn out, in fact, to be conceptual replications. At the same time, it is clear that direct replications are based on an attempt to be as exact as possible, whereas conceptual replications are not.

***Are most published social psychological findings false?
Stroebe, W.
(ER uninformative)
This near doubling of replication success after combining original and replication effects is puzzling. Because these replications were already highly powered, the increase is unlikely to be due to the greater power of a meta-analytic synthesis. The two most likely explanations are quality problems with the replications or publication bias in the original studies or. An evaluation of the quality of the replications is beyond the scope of this review and should be left to the original authors of the replicated studies. However, the fact that all replications were exact rather than conceptual replications of the original studies is likely to account to some extent for the lower replication rate of social psychological studies (Stroebe & Strack, 2014). There is no evidence either to support or to reject the second explanation.”

(ER impossible)
“All four projects relied on exact replications, often using the material used in the original studies. However, as I argued earlier (Stroebe & Strack, 2014), even if an experimental manipulation exactly replicates the one used in the original study, it may not reflect the same theoretical variable.”

(CR test theory)
“Gergen’s argument has important implications for decisions about the appropriateness of conceptual compared to exact replication. The more a phenomenon is susceptible to historical change, the more conceptual replication rather than exact replication becomes appropriate (Stroebe & Strack, 2014).”

(CR test theory)
“Moonesinghe et al. (2007) argued that any true replication should be an exact replication, “a precise processwhere the exact same finding is reexamined in the same way”. However, conceptual replications are often more informative than exact replications, at least in studies that are testing theoretical predictions (Stroebe & Strack, 2014). Because conceptual replications operationalize independent and/or dependent variables in a different way, successful conceptual replications increase our trust in the predictive validity of our theory.”

There’s More Than One Way to Conduct a Replication Study: Beyond Statistical Significance”
Anderson & Maxwell
(Mention)
“It is important to note some caveats regarding direct (exact) versus conceptual replications. While direct replications were once avoided for lack of originality, authors have recently urged the field to take note of the benefits and importance of direct replication. According to Simons (2014), this type of replication is “the only way to verify the reliability of an effect” (p. 76). With respect to this recent emphasis, the current article will assume direct replication. However, despite the push toward direct replication, some have still touted the benefits of conceptual replication (Stroebe & Strack, 2014). Importantly, many of the points and analyses suggested in this paper may translate well to conceptual replication.”

Reconceptualizing replication as a sequence of different studies: A replication typology
Joachim Hüffmeier, Jens Mazei, Thomas Schultze
(ER impossible)
The first type of replication study in our typology encompasses exact replication studies conducted by the author(s) of an original finding. Whereas we must acknowledge that replications can never be “exact” in a literal sense in psychology (Cesario, 2014; Stroebe & Strack, 2014), exact replications are studies that aspire to be comparable to the original study in all aspects (Schmidt, 2009). Exact replications—at least those that are not based on questionable research practices such as the arbitrary exclusion of critical outliers, sampling or reporting biases (John, Loewenstein, & Prelec, 2012; Simmons, Nelson, & Simonsohn, 2011)—serve the function of protecting against false positive effects (Type I errors) right from the start.

(ER informative)
Thus, this replication constitutes a valuable contribution to the research process. In fact, already some time ago, Lykken (1968; see also Mummendey, 2012) recommended that all experiments should be replicated  before publication. From our perspective, this recommendation applies in particular to new findings (i.e., previously uninvestigated theoretical relations), and there seems to be some consensus that new findings should be replicated at least once, especially when they were unexpected, surprising, or only loosely connected to existing theoretical models (Stroebe & Strack, 2014; see also Giner-Sorolla, 2012; Murayama et al., 2014).”

(Mention)
Although there is currently some debate about the epistemological value of close replication studies (e.g., Cesario, 2014; LeBel & Peters, 2011; Pashler & Harris, 2012; Simons, 2014; Stroebe & Strack, 2014), the possibility that each original finding can—in principal—be replicated by the scientific community represents a cornerstone of science (Kuhn, 1962; Popper, 1992).”

(CR test theory)
So far, we have presented “only” the conventional rationale used to stress the importance of close replications. Notably, however, we will now add another—and as we believe, logically necessary—point originally introduced by S&S (2014). This point protects close replications from being criticized (cf. Cesario, 2014; Stroebe & Strack, 2014; see also LeBel & Peters, 2011). Close replications can be informative only as long as they ensure that the theoretical processes investigated or at least invoked by the original study are shown to also operate in the replication study.

(CR test theory)
The question of how to conduct a close replication that is maximally informative entails a number of methodological choices. It is important to both adhere to the original study proceedings (Brandt et al., 2014; Schmidt, 2009) and focus on and meticulously measure the underlying theoretical mechanisms that were shown or at least proposed in the original studies (Stroebe & Strack, 2014). In fact, replication attempts are most informative when they clearly demonstrate either that the theoretical processes have unfolded as expected or at which point in the process the expected results could no longer be observed (e.g., a process ranging from a treatment check to a manipulation check and [consecutive] mediator variables to the dependent variable). Taking these measures is crucial to rule out that a null finding is simply due to unsuccessful manipulations or changes in a manipulation’s meaning and impact over time (cf. Stroebe & Strack, 2014). “

(CR test theory)
Conceptual replications in laboratory settings are the fourth type of replication study in our typology. In these replications, comparability to the original study is aspired to only in the aspects that are deemed theoretically relevant (Schmidt, 2009; Stroebe & Strack, 2014). In fact, most if not all aspects may differ as long as the theoretical processes that have been studied or at least invoked in the original study are also covered in a conceptual replication study in the laboratory.”

(ER useful for applied research)
For instance, conceptual replications may be less important for applied disciplines that focus on clinical phenomena and interventions. Here, it is important to ensure that there is an impact of a specific intervention and that the related procedure does not hurt the members of the target population (e.g., Larzelere et al., 2015; Stroebe & Strack, 2014).”

From intrapsychic to ecological theories in social psychology: Outlines of a functional theory approach
Klaus Fiedler
(ER uninformative)
Replicating an ill-understood finding is like repeating a complex sentence in an unknown language. Such a “replication” in the absence of deep understanding may appear funny, ridiculous, and embarrassing to a native speaker, who has full control over the foreign language. By analogy, blindly replicating or running new experiments on an ill-understood finding will rarely create real progress (cf. Stroebe & Strack, 2014). “

Into the wild: Field research can increase both replicability and real-world impact
Jon K. Maner
(CR test theory)
Although studies relying on homogeneous samples of laboratory or online participants might be highly replicable when conducted again in a similar homogeneous sample of laboratory or online participants, this is not the key criterion (or at least not the only criterion) on which we should judge replicability (Westfall, Judd & Kenny, 2015; see also Brandt et al., 2014; Stroebe & Strack, 2014). Just as important is whether studies replicate in samples that include participants who reflect the larger and more diverse population.”

Romance, Risk, and Replication: Can Consumer Choices and Risk-Taking Be Primed by Mating Motives?
Shanks et al.
(ER impossible)
There is no such thing as an “exact” replication (Stroebe & Strack, 2014) and hence it must be acknowledged that the published studies (notwithstanding the evidence for p-hacking and/or publication bias) may have obtained genuine effects and that undetected moderator variables explain why the present studies failed to obtain priming.   Some of the experiments reported here differed in important ways from those on which they were modeled (although others were closer replications and even these failed to obtain evidence of reliable romantic priming).

(CR test theory)
As S&S (2014) point out, what is crucial is not so much exact surface replication but rather identical operationalization of the theoretically relevant variables. In the present case, the crucial factors are the activation of romantic motives and the appropriate assessment of consumption, risk-taking, and other measures.”

A Duty to Describe: Better the Devil You Know Than the Devil You Don’t
Brown, Sacha D et al.
(Mention)
Ioannidis (2005) has been at the forefront of researchers identifying factors interfering with self-correction. He has claimed that journal editors selectively publish positive findings and discriminate against study replications, permitting errors in data and theory to enjoy a long half-life (see also Ferguson & Brannick, 2012; Ioannidis, 2008, 2012; Shadish, Doherty, & Montgomery, 1989; Stroebe & Strack, 2014). We contend there are other equally important, yet relatively unexplored, problems.

A Room with a Viewpoint Revisited: Descriptive Norms and Hotel Guests’ Towel Reuse Behavior
(Contextual Sensitivity)
Bohner, Gerd; Schlueter, Lena E.
On the other hand, our pilot participants’ estimates of towel reuse rates were generally well below 75%, so we may assume that the guests participating in our experiments did not perceive the normative messages as presenting a surprisingly low figure. In a more general sense, the issue of greatly diverging baselines points to conceptual issues in trying to devise a ‘‘direct’’ replication: Identical operationalizations simply may take on different meanings for people in different cultures.

***The empirical benefits of conceptual rigor: Systematic articulation of conceptual hypotheses can reduce the risk of non-replicable results (and facilitate novel discoveries too)
Mark Schaller
(Contextual Sensitivity)
Unless these subsequent studies employ methods that exactly replicate the idiosyncratic context in which the effect was originally detected, these studies are unlikely to replicate the effect. Indeed, because many psychologically important contextual variables may lie outside the awareness of researchers, even ostensibly “exact” replications may fail to create the conditions necessary for a fragile effect to emerge (Stroebe & Strack, 2014)

A Concise Set of Core Recommendations to Improve the Dependability of Psychological Research
David A. Lishner
(CR test theory)
The claim that direct replication produces more dependable findings across replicated studies than does conceptual replication seems contrary to conventional wisdom that conceptual replication is preferable to direct replication (Dijksterhuis, 2014; Neulip & Crandall, 1990, 1993a, 1993b; Stroebe & Strack, 2014).
(CR test theory)
However, most arguments advocating conceptual replication over direct replication are attempting to promote the advancement or refinement of theoretical understanding (see Dijksterhuis, 2014; Murayama et al., 2014; Stroebe & Strack, 2014). The argument is that successful conceptual replication demonstrates a hypothesis (and by extension the theory from which it derives) is able to make successful predictions even when one alters the sampled population, setting, operations, or data analytic approach. Such an outcome not only suggests the presence of an organizing principle, but also the quality of the constructs linked by the organizing principle (their theoretical meanings). Of course this argument assumes that the consistency across the replicated findings is not an artifact of data acquisition or data analytic approaches that differ among studies. The advantage of direct replication is that regardless of how flexible or creative one is in data acquisition or analysis, the approach is highly similar across replication studies. This duplication ensures that any false finding based on using a flexible approach is unlikely to be repeated multiple times.

(CR test theory)
Does this mean conceptual replication should be abandoned in favor of direct replication? No, absolutely not. Conceptual replication is essential for the theoretical advancement of psychological science (Dijksterhuis, 2014; Murayama et al., 2014; Stroebe & Strack, 2014), but only if dependability in findings via direct replication is first established (Cesario, 2014; Simons, 2014). Interestingly, in instances where one is able to conduct multiple studies for inclusion in a research report, one approach that can produce confidence in both dependability of findings and theoretical generalizability is to employ nested replications.

(ER cannot detect fraud)
A second advantage of direct replications is that they can protect against fraudulent findings (Schmidt, 2009), particularly when different research groups conduct direct replication studies of each other’s research. S&S (2014) make a compelling argument that direct replication is unlikely to prove useful in detection of fraudulent research. However, even if a fraudulent study remains unknown or undetected, its impact on the literature would be lessened when aggregated with nonfraudulent direct replication studies conducted by honest researchers.

***Does cleanliness influence moral judgments? Response effort moderates the effect of cleanliness priming on moral judgments.
Huang
(ER uninformative)
Indeed, behavioral priming effects in general have been the subject of increased scrutiny (see Cesario, 2014), and researchers have suggested different causes for failed replication, such as measurement and sampling errors (Stanley and Spence,2014), variation in subject populations (Cesario, 2014), discrepancy in operationalizations (S&S, 2014), and unidentified moderators (Dijksterhuis,2014).

UNDERSTANDING PRIMING EFFECTS IN SOCIAL PSYCHOLOGY: AN OVERVIEW AND INTEGRATION
Daniel C. Molden
(ER uninformative)
Therefore, some greater emphasis on direct replication in addition to conceptual replication is likely necessary to maximize what can be learned from further research on priming (but see Stroebe and Strack, 2014, for costs of overemphasizing direct replication as well).

On the automatic link between affect and tendencies to approach and avoid: Chen and Bargh (1999) revisited
Mark Rotteveel et al.
(no replication crisis)
Although opinions differ with regard to the extent of this “replication crisis” (e.g., Pashler and Harris, 2012; S&S, 2014), the scientific community seems to be shifting its focus more toward direct replication.

(ER uninformative)
Direct replications not only affect one’s confidence about the veracity of the phenomenon under study, but they also increase our knowledge about effect size (see also Simons, 2014; but see also S&S, 2014).

Single-Paper Meta-Analysis: Benefits for Study Summary, Theory Testing, and Replicability
McShane and Bockenholt
(ER impossible)
The purpose of meta-analysis is to synthesize a set of studies of a common phenomenon. This task is complicated in behavioral research by the fact that behavioral research studies can never be direct or exact replications of one another (Brandt et al. 2014; Fabrigar and Wegener 2016; Rosenthal 1991; S&S 2014; Tsang and Kwan 1999).

(ER impossible)
Further, because behavioral research studies can never be direct or exact replications of one another (Brandt et al. 2014; Fabrigar and Wegener 2016; Rosenthal 1991; S&S 2014; Tsang and Kwan 1999), our SPM methodology estimates and accounts for heterogeneity, which has been shown to be important in a wide variety of behavioral research settings (Hedges and Pigott 2001; Klein et al. 2014; Pigott 2012).

A Closer Look at Social Psychologists’ Silver Bullet: Inevitable and Evitable Side   Effects of the Experimental Approach
Herbert Bless and Axel M. Burger
(ER/CR Distinction)
Given the above perspective, it becomes obvious that in the long run, conceptual replications can provide very fruitful answers because they address the question of whether the initially observed effects are potentially caused by some perhaps unknown aspects of the experimental procedure (for a discussion of conceptual versus direct replications, see e.g., Stroebe & Strack, 2014; see also Brandt et al., 2014; Cesario, 2014; Lykken, 1968; Schwarz & Strack, 2014).  Whereas conceptual replications are adequate solutions for broadening the sample of situations (for examples, see Stroebe & Strack, 2014), the present perspective, in addition, emphasizes that it is important that the different conceptual replications do not share too much overlap in general aspects of the experiment (see also Schwartz, 2015, advocating for  conceptual replications)

Men in red: A reexamination of the red-attractiveness effect
Vera M. Hesslinger, Lisa Goldbach, & Claus-Christian Carbon
(ER impossible)
As Brandt et al. (2014) pointed out, a replication in psychological research will never be absolutely exact or direct (see also, Stroebe & Strack, 2014), which is, of course, also the case in the present research.

***On the challenges of drawing conclusions from p-values just below 0.05
Daniel Lakens
(no evidence about QRP)
In recent years, researchers have become more aware of how flexibility during the data-analysis can increase false positive results (e.g., Simmons, Nelson & Simonsohn, 2011). If the true Type 1 error rate is substantially inflated, for example because researchers analyze their data until a p-value smaller than 0.05 is observed, the robustness of scientific knowledge can substantially decrease. However, as Stroebe & Strack (2014, p. 60) have pointed out: ‘Thus far, however, no solid data exist on the prevalence of such research practices.’

***Does Merely Going Through the Same Moves Make for a ‘‘Direct’’ Replication? Concepts, Contexts, and Operationalizations
Norbert Schwarz and Fritz Strack
(Contextual Sensitivity)
In general, meaningful replications need to realize the psychological conditions of the original study. The easier option of merely running through technically identical procedures implies the assumption that psychological processes are context insensitive and independent of social, cultural, and historical differences (Cesario, 2014; Stroebe & Strack, 2014). Few social (let alone cross-cultural) psychologists would be willing to endorse this assumption with a straight face. If so, mere procedural equivalence is an insufficient criterion for assessing the quality of a replication.

The Replication Paradox: Combining Studies can Decrease Accuracy of Effect Size Estimates
(ER uninformative)
Michèle B. Nuijten, Marcel A. L. M. van Assen, Coosje L. S. Veldkamp, and Jelte M. Wicherts
Replications with nonsignificant results are easily dismissed with the argument that the replication might contain a confound that caused the null finding (Stroebe & Strack, 2014).

Retro-priming, priming, and double testing: psi and replication in a test-retest design
Rabeyron, T
(Mention)
Bem’s paper spawned numerous attempts to replicate it (see e.g., Galak et al., 2012; Bem et al., submitted) and reflections on the difficulty of direct replications in psychology (Ritchie et al., 2012). This aspect has been associated more generally with debates concerning the “decline effect” in science (Schooler, 2011) and a potential “replication crisis” (S&S, 2014) especially in the fields of psychology and medical sciences (De Winter and Happee, 2013).

Do p Values Lose Their Meaning in Exploratory Analyses? It Depends How You Define the Familywise Error Rate
Mark Rubin
(ER impossible)
Consequently, the Type I error rate remains constant if researchers simply repeat the same test over and over again using different samples that have been randomly drawn from the exact same population. However, this first situation is somewhat hypothetical and may even be regarded as impossible in the social sciences because populations of people change over time and location (e.g., Gergen, 1973; Iso-Ahola, 2017; Schneider, 2015; Serlin, 1987; Stroebe & Strack, 2014). Yesterday’s population of psychology undergraduate students from the University of Newcastle, Australia, will be a different population to today’s population of psychology undergraduate students from the University of Newcastle, Australia.

***Learning and the replicability of priming effects
Michael Ramscar
(ER uninformative)
In the limit, this means that in the absence of a means for objectively determining what the information that produces a priming effect is, and for determining that the same information is available to the population in a replication, all learned priming effects are scientifically unfalsifiable. (Which also means that in the absence of an account of what the relevant information is in a set of primes, and how it produces a specific effect, reports of a specific priming result — or failures to replicate it — are scientifically uninformative; see also [Stroebe & Strack, 2014.)

***Evaluating Psychological Research Requires More Than Attention to the N: A Comment on Simonsohn’s (2015) “Small Telescopes”
Norbert Schwarz and Gerald L. Clore
(CR test theory)
Simonsohn’s decision to equate a conceptual variable (mood) with its manipulation (weather) is compatible with the logic of clinical trials, but not with the logic of theory testing. In clinical trials, which have inspired much of the replicability debate and its statistical focus, the operationalization (e.g., 10 mg of a drug) is itself the variable of interest; in theory testing, any given operationalization is merely one, usually imperfect, way to realize the conceptual variable. For this reason, theory tests are more compelling when the results of different operationalizations converge (Stroebe & Strack, 2014), thus ensuring, in the case in point, that it is not “the weather” but indeed participants’ (sometimes weather-induced) mood that drives the observed effect.

Internal conceptual replications do not increase independent replication success
Kunert, R
(Contextual Sensitivity)
According to the unknown moderator account of independent replication failure, successful internal replications should correlate with independent replication success. This account suggests that replication failure is due to the fact that psychological phenomena are highly context-dependent, and replicating seemingly irrelevant contexts (i.e. unknown moderators) is rare (e.g., Barrett, 2015; DGPS, 2015; Fleming Crim, 2015; see also Stroebe & Strack, 2014; for a critique, see Simons, 2014). For example, some psychological phenomenon may unknowingly be dependent on time of day.

(Contextual Sensitivity greater in social psychology)
When the chances of unknown moderator influences are greater and replicability is achieved (internal, conceptual replications), then the same should be true when chances are smaller (independent, direct replications). Second, the unknown moderator account is usually invoked for social psychological effects (e.g. Cesario, 2014; Stroebe & Strack, 2014). However, the lack of influence of internal replications on independent replication success is not limited to social psychology. Even for cognitive psychology a similar pattern appears to hold.

On Klatzky and Creswell (2014): Saving Social Priming Effects But Losing Science as We Know It?
Barry Schwartz
(ER uninformative)
The recent controversy over what counts as “replication” illustrates the power of this presumption. Does “conceptual replication” count? In one respect, conceptual replication is a real advance, as conceptual replication extends the generality of the phenomena that were initially discovered. But what if it fails? Is it because the phenomena are unreliable, because the conceptual equivalency that justified the new study was logically flawed, or because the conceptual replication has permitted the intrusion of extraneous variables that obscure the original phenomenon? This ambiguity has led some to argue that there is no substitute for strict replication (see Pashler & Harris, 2012; Simons, 2014, and Stroebe & Strack, 2014, for recent manifestations of this controversy). A significant reason for this view, however, is less a critique of the logic of conceptual replication than it is a comment on the sociology (or politics, or economics) of science. As Pashler and Harris (2012) point out, publication bias virtually guarantees that successful conceptual replications will be published whereas failed conceptual replications will live out their lives in a file drawer.  I think Pashler and Harris’ surmise is probably correct, but it is not an argument for strict replication so much as it is an argument for publication of failed conceptual replication.

Commentary and Rejoinder on Lynott et al. (2014)
Lawrence E. Williams
(CR test theory)
On the basis of their investigations, Lynott and colleagues (2014) conclude ‘‘there is no evidence that brief exposure to warm therapeutic packs induces greater prosocial responding than exposure to cold therapeutic packs’’ (p. 219). This conclusion, however, does not take into account other related data speaking to the connection between physical warmth and prosociality. There is a fuller body of evidence to be considered, in which both direct and conceptual replications are instructive. The former are useful if researchers particularly care about the validity of a specific phenomenon; the latter are useful if researchers particularly care about theory testing (Stroebe & Strack, 2014).

The State of Social and Personality Science: Rotten to the Core, Not So Bad, Getting Better, or Getting Worse?
(no replication crisis)
Motyl et al. (2017) “The claim of a replicability crisis is greatly exaggerated.” Wolfgang Stroebe and Fritz Strack, 2014

Promise, peril, and perspective: Addressing concerns about reproducibility in social–personality psychology
Harry T. Reis, Karisa Y. Lee
(ER impossible)
Much of the current debate, however, is focused narrowly on direct or exact replications—whether the findings of a given study, carried out in a particular way with certain specific operations, would be repeated. Although exact replications are surely desirable, the papers by Fabrigar and by Crandall and Sherman remind us that in an absolute sense they are fundamentally impossible in social–personality psychology (see also S&S, 2014).

Show me the money
(Contextual Sensitivity)
Of course, it is possible that additional factors, which varied or could have varied among our studies and previously published studies (e.g., participants’ attitudes toward money) or among the online studies and laboratory study in this article (e.g., participants’ level of distraction), might account for these apparent inconsistencies. We did not aim to conduct a direct replication of any specific past study, and therefore we encourage special care when using our findings to evaluate existing ones (Doyen, Klein, Simons, & Cleeremans, 2014; Stroebe & Strack, 2014).

***From Data to Truth in Psychological Science. A Personal Perspective.
Strack
(ER uninformative)
In their introduction to the 2016 volume of the Annual Review of Psychology, Susan Fiske, Dan Schacter, and Shelley Taylor point out that a replication failure is not a scientific problem but an opportunity to find limiting conditions and contextual effects. To allow non-replications to regain this constructive role, they must come with conclusions that enter and stimulate a critical debate. It is even better if replication studies are endowed with a hypothesis that relates to the state of the scientific discourse. To show that an effect occurs only under one but not under another condition is more informative than simply demonstrating noneffects (S&S, 2014). But this may require expertise and effort.

 

How replicable are statistically significant results in social psychology? A replication and extension of Motyl et al. (in press). 

Forthcoming article: 
Motyl, M., Demos, A. P., Carsel, T. S., Hanson, B. E., Melton, Z. J., Mueller, A. B., Prims, J., Sun, J., Washburn, A. N., Wong, K., Yantis, C. A., & Skitka, L. J. (in press). The state of social and personality science: Rotten to the core, not so bad, getting better, or getting worse? Journal of Personality and Social Psychology. (preprint)

Brief Introduction

Since JPSP published incredbile evidence for mental time travel (Bem, 2011), the credibility of social psychological research has been questioned.  There is talk of a crisis of confidence, a replication crisis, or a credibility crisis.  However, hard data on the credibility of empirical findings published in social psychology journals are scarce.

There have been two approaches to examine the credibility of social psychology.  One approach relies on replication studies.  Authors attempt to replicate original studies as closely as possible.  The most ambitious replication project was carried out by the Open Science Collaboration (Science, 2015) that replicated 1 study from 100 articles; 54 articles were classified as social psychology.   For original articles that reported a significant result, only a quarter replicated a significant result in the replication studies.  This estimate of replicability suggests that researches conduct many more studies than are published and that effect sizes in published articles are inflated by sampling error, which makes them difficult to replicate. One concern about the OSC results is that replicating original studies can be difficult.  For example, a bilingual study in California may not produce the same results as a bilingual study in Canada.  It is therefore possible that the poor outcome is partially due to problems of reproducing the exact conditions of original studies.

A second approach is to estimate replicability of published results using statistical methods.  The advantage of this approach is that replicabiliy estimates are predictions for exact replication studies of the original studies because the original studies provide the data for the replicability estimates.   This is the approach used by Motyl et al.

The authors sampled 30% of articles published in 2003-2004 (pre-crisis) and 2013-2014 (post-crisis) from four major social psychology journals (JPSP, PSPB, JESP, and PS).  For each study, coders identified one focal hypothesis and recorded the statistical result.  The bulk of the statistics were t-values from t-tests or regression analyses and F-tests from ANOVAs.  Only 19 statistics were z-tests.   The authors applied various statistical tests to the data that test for the presence of publication bias or whether the studies have evidential value (i.e., reject the null-hypothesis that all published results are false positives).  For the purpose of estimating replicability, the most important statistic is the R-Index.

The R-Index has two components.  First, it uses the median observed power of studies as an estimate of replicability (i.e., the percentage of studies that should produce a significant result if all studies were replicated exactly).  Second, it computes the percentage of studies with a significant result.  In an unbiased set of studies, median observed power and percentage of significant results should match.  Publication bias and questionable research practices will produce more significant results than predicted by median observed power.  The discrepancy is called the inflation rate.  The R-Index subtracts the inflation rate from median observed power because median observed power is an inflated estimate of replicability when bias is present.  The R-Index is not a replicability estimate.  That is, an R-Index of 30% does not mean that 30% of studies will produce a significant result.  However, a set of studies with an R-Index of 30 will have fewer successful replications than a set of studies with an R-Index of 80.  An exception is an R-Index of 50, which is equivalent with a replicability estimate of 50%.  If the R-Index is below 50, one would expect more replication failures than successes.

Motyl et al. computed the R-Index separately for the 2003/2004 and the 2013/2014 results and found “the R-index decreased numerically, but not statistically over time, from .62 [CI95% = .54, .68] in 2003-2004 to .52 [CI95% = .47, .56] in 2013-2014. This metric suggests that the field is not getting better and that it may consistently be rotten to the core.”

I think this interpretation of the R-Index results is too harsh.  I consider an R-Index below 50 an F (fail).  An R-Index in the 50s is a D, and an R-Index in the 60s is a C.  An R-Index greater than 80 is considered an A.  So, clearly there is a replication crisis, but social psychology is not rotten to the core.

The R-Index is a simple tool, but it is not designed to estimate replicability.  Jerry Brunner and I developed a method that can estimate replicability, called z-curve.  All test-statistics are converted into absolute z-scores and a kernel density distribution is fitted to the histogram of z-scores.  Then a mixture model of normal distributions is fitted to the density distribution and the means of the normal distributions are converted into power values. The weights of the components are used to compute the weighted average power. When this method is applied only to significant results, the weighted average power is the replicability estimate;  that is, the percentage of significant results that one would expect if the set of significant studies were replicated exactly.   Motyl et al. did not have access to this statistical tool.  They kindly shared their data and I was able to estimate replicability with z-curve.  For this analysis, I used all t-tests, F-tests, and z-tests (k = 1,163).   The Figure shows two results.  The left figure uses all z-scores greater than 2 for estimation (all values on the right side of the vertical blue line). The right figure uses only z-scores greater than 2.4.  The reason is that just-significant results may be compromised by questionable research methods that may bias estimates.

Motyl.2d0.2d4

The key finding is the replicability estimate.  Both estimations produce similar results (48% vs. 49%).  Even with over 1,000 observations there is uncertainty in these estimates and the 95%CI can range from 45 to 54% using all significant results.   Based on this finding, it is predicted that about half of these results would produce a significant result again in a replication study.

However, it is important to note that there is considerable heterogeneity in replicability across studies.  As z-scores increase, the strength of evidence becomes stronger, and results are more likely to replicate.  This is shown with average power estimates for bands of z-scores at the bottom of the figure.   In the left figure,  z-scores between 2 and 2.5 (~ .01 < p < .05) have only a replicability of 31%, and even z-scores between 2.5 and 3 have a replicability below 50%.  It requires z-scores greater than 4 to reach a replicability of 80% or more.   Similar results are obtained for actual replication studies in the OSC reproducibilty project.  Thus, researchers should take the strength of evidence of a particular study into account.  Studies with p-values in the .01 to .05 range are unlikely to replicate without boosting sample sizes.  Studies with p-values less than .001 are likely to replicate even with the same sample size.

Independent Replication Study 

Schimmack and Brunner (2016) applied z-curve to the original studies in the OSC reproducibility project.  For this purpose, I coded all studies in the OSC reproducibility project.  The actual replication project often picked one study from articles with multiple studies.  54 social psychology articles reported 173 studies.   The focal hypothesis test of each study was used to compute absolute z-scores that were analyzed with z-curve.

OSC.soc

The two estimation methods (using z > 2.0 or z > 2.4) produced very similar replicability estimates (53% vs. 52%).  The estimates are only slightly higher than those for Motyl et al.’s data (48% & 49%) and the confidence intervals overlap.  Thus, this independent replication study closely replicates the estimates obtained with Motyl et al.’s data.

Automated Extraction Estimates

Hand-coding of focal hypothesis tests is labor intensive and subject to coding biases. Often studies report more than one hypothesis test and it is not trivial to pick one of the tests for further analysis.  An alternative approach is to automatically extract all test statistics from articles.  This makes it also possible to base estimates on a much larger sample of test results.  The downside of automated extraction is that articles also report statistical analysis for trivial or non-critical tests (e.g., manipulation checks).  The extraction of non-significant results is irrelevant because they are not used by z-curve to estimate replicability.  I have reported the results of this method for various social psychology journals covering the years from 2010 to 2016 and posted powergraphs for all journals and years (2016 Replicability Rankings).   Further analyses replicated the results from the OSC reproducibility project that results published in cognitive journals are more replicable than those published in social journals.  The Figure below shows that the average replicability estimate for social psychology is 61%, with an encouraging trend in 2016.  This estimate is about 10% above the estimates based on hand-coded focal hypothesis tests in the two datasets above.  This discrepancy can be due to the inclusion of less original and trivial statistical tests in the automated analysis.  However, a 10% difference is not a dramatic difference.  Neither 50% nor 60% replicability justify claims that social psychology is rotten to the core, nor do they meet the expectation that researchers should plan studies with 80% power to detect a predicted effect.

replicability-cog-vs-soc

Moderator Analyses

Motyl et al. (in press) did extensive coding of the studies.  This makes it possible to examine potential moderators (predictors) of higher or lower replicability.  As noted earlier, the strength of evidence is an important predictor.  Studies with higher z-scores (smaller p-values) are, on average, more replicable.  The strength of evidence is a direct function of statistical power.  Thus, studies with larger population effect sizes and smaller sampling error are more likely to replicate.

It is well known that larger samples have less sampling error.  Not surprisingly, there is a correlation between sample size and the absolute z-scores (r = .3).  I also examined the R-Index for different ranges of sample sizes.  The R-Index was the lowest for sample sizes between N = 40 and 80 (R-Index = 43), increased for N = 80 to 200 (R-Index = 52) and further for sample sizes between 200 and 1,000 (R-Index = 69).  Interestingly, the R-Index for small samples with N < 40 was 70.  This is explained by the fact that research designs also influence replicability and that small samples often use more powerful within-subject designs.

A moderator analysis with design as moderator confirms this.  The R-Indices for between-subject designs is the lowest (R-Index = 48) followed by mixed designs (R-Index = 61) and then within-subject designs (R-Index = 75).  This pattern is also found in the OSC reproducibility project and partially accounts for the higher replicability of cognitive studies, which often employ within-subject designs.

Another possibility is that articles with more studies package smaller and less replicable studies.  However,  number of studies in an article was not a notable moderator:  1 study R-Index = 53, 2 studies R-Index = 51, 3 studies R-Index = 60, 4 studies R-Index = 52, 5 studies R-Index = 53.

Conclusion 

Motyl et al. (in press) coded a large and representative sample of results published in social psychology journals.  Their article complements results from the OSC reproducibility project that used actual replications, but a much smaller number of studies.  The two approaches produce different results.  Actual replication studies produced only 25% successful replications.  Statistical estimates of replicability are around 50%.   Due to the small number of actual replications in the OSC reproducibility project, it is important to be cautious in interpreting the differences.  However, one plausible explanation for lower success rates in actual replication studies is that it is practically impossible to redo a study exactly.  This may even be true when researchers conduct three similar studies in their own lab and only one of these studies produces a significant result.  Some non-random, but also not reproducible, factor may have helped to produce a significant result in this study.  Statistical models assume that we can redo a study exactly and may therefore overestimate the success rate for actual replication studies.  Thus, the 50% estimate is an optimistic estimate for the unlikely scenario that a study can be replicated exactly.  This means that even though optimists may see the 50% estimate as “the glass half full,” social psychologists need to increase statistical power and pay more attention to the strength of evidence of published results to build a robust and credible science of social behavior.

 

 

2016 Replicability Rankings of 103 Psychology Journals

Update: October 24, 2017.
The preliminary 2017 rankings are now available. They provide information for the years 2010-2017, updated analyses, and a correction in the estimates due to a computational error that lowered estimates by about 10 percentage points, on average.  Please check the newer rankings for the most reliable information.

—————————————————————————————————————————————–


I post the rankings on top.  Detailed information and statistical analysis are provided below the table.  You can click on the journal title to see Powergraphs for each year.

Rank   Journal Change 2017 2016 2015 2014 2013 2012 2011 2010
1 Social Indicators Research 10 90 70 65 75 65 72 73 73
2 Psychology of Music -13 81 59 67 61 69 85 84 72
3 Journal of Memory and Language 11 79 76 65 71 64 71 66 70
4 British Journal of Developmental Psychology -9 77 52 61 54 82 74 69 67
5 Journal of Occupational and Organizational Psychology 13 77 59 69 58 61 65 56 64
6 Journal of Comparative Psychology 13 76 71 77 74 68 61 66 70
7 Cognitive Psychology 7 75 73 72 69 66 74 66 71
8 Epilepsy & Behavior 5 75 72 79 70 68 76 69 73
9 Evolution & Human Behavior 16 75 57 73 55 38 57 62 60
10 International Journal of Intercultural Relations 0 75 43 70 75 62 67 62 65
11 Pain 5 75 70 75 67 64 65 74 70
12 Psychological Medicine 4 75 57 66 70 58 72 61 66
13 Annals of Behavioral Medicine 10 74 50 63 62 62 62 51 61
14 Developmental Psychology 17 74 72 73 67 61 63 58 67
15 Judgment and Decision Making -3 74 59 68 56 72 66 73 67
16 Psychology and Aging 6 74 66 78 65 74 66 66 70
17 Aggressive Behavior 16 73 70 66 49 60 67 52 62
18 Journal of Gerontology-Series B 3 73 60 65 65 55 79 59 65
19 Journal of Youth and Adolescence 13 73 66 82 67 61 57 66 67
20 Memory 5 73 56 79 70 65 64 64 67
21 Sex Roles 6 73 67 59 64 72 68 58 66
22 Journal of Experimental Psychology – Learning, Memory & Cognition 4 72 74 76 71 71 67 72 72
23 Journal of Social and Personal Relationships -6 72 51 57 55 60 60 75 61
24 Psychonomic Review and Bulletin 8 72 79 62 78 66 62 69 70
25 European Journal of Social Psychology 5 71 61 63 58 50 62 67 62
26 Journal of Applied Social Psychology 4 71 58 69 59 73 67 58 65
27 Journal of Experimental Psychology – Human Perception and Performance -4 71 68 72 69 70 78 72 71
28 Journal of Research in Personality 9 71 75 47 65 51 63 63 62
29 Journal of Child and Family Studies 0 70 60 63 60 56 64 69 63
30 Journal of Cognition and Development 5 70 53 62 54 50 61 61 59
31 Journal of Happiness Studies -9 70 64 66 77 60 74 80 70
32 Political Psychology 4 70 55 64 66 71 35 75 62
33 Cognition 2 69 68 70 71 67 68 67 69
34 Depression & Anxiety -6 69 57 66 71 77 77 61 68
35 European Journal of Personality 2 69 61 75 65 57 54 77 65
36 Journal of Applied Psychology 6 69 58 71 55 64 59 62 63
37 Journal of Cross-Cultural Psychology -4 69 74 69 76 62 73 79 72
38 Journal of Psychopathology and Behavioral Assessment -13 69 67 63 77 74 77 79 72
39 JPSP-Interpersonal Relationships and Group Processes 15 69 64 56 52 54 59 50 58
40 Social Psychology 3 69 70 66 61 64 72 64 67
41 Achive of Sexual Behavior -2 68 70 78 73 69 71 74 72
42 Journal of Affective Disorders 0 68 64 54 66 70 60 65 64
43 Journal of Experimental Child Psychology 2 68 71 70 65 66 66 70 68
44 Journal of Educational Psychology -11 67 61 66 69 73 69 76 69
45 Journal of Experimental Social Psychology 13 67 56 60 52 50 54 52 56
46 Memory and Cognition -3 67 72 69 68 75 66 73 70
47 Personality and Individual Differences 8 67 68 67 68 63 64 59 65
48 Psychophysiology -1 67 66 65 65 66 63 70 66
49 Cognitve Development 6 66 78 60 65 69 61 65 66
50 Frontiers in Psychology -8 66 65 67 63 65 60 83 67
51 Journal of Autism and Developmental Disorders 0 66 65 58 63 56 61 70 63
52 Journal of Experimental Psychology – General 5 66 69 67 72 63 68 61 67
53 Law and Human Behavior 1 66 69 53 75 67 73 57 66
54 Personal Relationships 19 66 59 63 67 66 41 48 59
55 Early Human Development 0 65 52 69 71 68 49 68 63
56 Attention, Perception and Psychophysics -1 64 69 70 71 72 68 66 69
57 Consciousness and Cognition -3 64 65 67 57 64 67 68 65
58 Journal of Vocactional Behavior 5 64 78 66 78 71 74 57 70
59 The Journal of Positive Psychology 14 64 65 79 51 49 54 59 60
60 Behaviour Research and Therapy 7 63 73 73 66 69 63 60 67
61 Child Development 0 63 66 62 65 62 59 68 64
62 Emotion -1 63 61 56 66 62 57 65 61
63 JPSP-Personality Processes and Individual Differences 1 63 56 56 59 68 66 51 60
64 Schizophrenia Research 1 63 65 68 64 61 70 60 64
65 Self and Identity -4 63 52 61 62 50 55 71 59
66 Acta Psychologica -6 63 66 69 69 67 68 72 68
67 Behavioral Brain Research -3 62 67 61 62 64 65 67 64
68 Child Psychiatry and Human Development 5 62 72 83 73 50 82 58 69
69 Journal of Child Psychology and Psychiatry and Allied Disciplines 10 62 62 56 66 64 45 55 59
70 Journal of Consulting and Clinical Psychology 0 62 56 50 54 59 58 57 57
71 Journal of Counseling Psychology -3 62 70 60 74 72 56 72 67
72 Behavioral Neuroscience 1 61 66 63 62 65 58 64 63
73 Developmental Science -5 61 62 60 62 66 65 65 63
74 Journal of Experimental Psychology – Applied -4 61 61 65 53 69 57 69 62
75 Journal of Social Psychology -11 61 56 55 55 74 70 63 62
76 Social Psychology and Personality Science -5 61 42 56 59 59 65 53 56
77 Cognitive Therapy and Research 0 60 68 54 67 70 62 58 63
78 Hormones & Behavior -1 60 55 55 54 55 60 58 57
79 Motivation and Emotion 1 60 60 57 57 51 73 52 59
80 Organizational Behavior and Human Decision Processes 3 60 63 65 61 68 67 51 62
81 Psychoneuroendocrinology 5 60 58 58 56 53 59 53 57
82 Social Development -10 60 50 66 62 65 79 57 63
83 Appetite -10 59 57 57 65 64 66 67 62
84 Biological Psychology -6 59 60 55 57 57 65 64 60
85 Journal of Personality Psychology 17 59 59 60 62 69 37 45 56
86 Psychological Science 6 59 63 60 63 59 55 56 59
87 Asian Journal of Social Psychology 0 58 76 67 56 71 64 64 65
88 Behavior Therapy 0 58 63 66 69 66 52 65 63
89 Britsh Journal of Social Psychology 0 58 57 44 59 51 59 55 55
90 Social Influence 18 58 72 56 52 33 59 46 54
91 Developmental Psychobiology -9 57 54 61 60 70 64 62 61
92 Journal of Research on Adolescence 2 57 59 61 82 71 75 40 64
93 Journal of Abnormal Psychology -5 56 52 57 58 55 66 55 57
94 Social Cognition -2 56 54 52 54 62 69 46 56
95 Personality and Social Psychology Bulletin 2 55 57 58 55 53 56 54 55
96 Cognition and Emotion -14 54 66 61 62 76 69 69 65
97 Health Psychology -4 51 67 56 72 54 69 56 61
98 Journal of Clinical Child and Adolescence Psychology 1 51 66 61 74 64 58 54 61
99 Journal of Family Psychology -7 50 52 63 61 57 64 55 57
100 Group Processes & Intergroup Relations -5 49 53 68 64 54 62 55 58
101 Infancy -8 47 44 60 55 48 63 51 53
102 Journal of Consumer Psychology -5 46 57 55 51 53 48 61 53
103 JPSP-Attitudes & Social Cognition -3 45 69 62 39 54 54 62 55

Notes.
1. Change scores are the unstandardized regression weights with replicabilty estimates as outcome variable and year as predictor variable.  Year was coded from 0 for 2010 to 1 for 2016 so that the regression coefficient reflects change over the full 7 year period. This method is preferable to a simple difference score because estimates in individual years are variable and are likely to overestimate change.
2. Rich E. Lucas, Editor of JRP, noted that many articles in JRP do not report t of F values in the text and that the replicability estimates based on these statistics may not be representative of the bulk of results reported in this journal.  Hand-coding of articles is required to address this problem and the ranking of JRP, and other journals, should be interpreted with caution (see further discussion of these issues below).

Introduction

I define replicability as the probability of obtaining a significant result in an exact replication of a study that produced a significant result.  In the past five years, it has become increasingly clear that psychology suffers from a replication crisis. Even results that are replicated internally by the same author multiple times fail to replicate in independent replication attempts (Bem, 2011).  The key reason for the replication crisis is selective publishing of significant results (publication bias). While journals report over 95% significant results (Sterling, 1959; Sterling et al., 1995), a 2015 article estimated that less than 50% of these results can be replicated  (OSC, 2015).

The OSC reproducibility made an important contribution by demonstrating that published results in psychology have low replicability.  However, the reliance on actual replication studies has a a number of limitations.  First, actual replication studies are expensive or impossible (e.g., a longitudinal study spanning 20 years).  Second, studies selected for replication may not be representative because the replication team lacks expertise to replicate some studies. Finally, replication studies take time and replicability of recent studies may not be known for several years. This makes it difficult to rely on actual replication studies to rank journals and to track replicability over time.

Schimmack and Brunner (2016) developed a statistical method (z-curve) that makes it possible to estimate average replicability for a set of published results based on the original results in published articles.  This statistical approach to the estimation of replicability has several advantages over the use of actual replication studies.  Replicability can be assessed in real time, it can be estimated for all published results, and it can be used for expensive studies that are impossible to reproduce.  Finally, it has the advantage that actual replication studies can be criticized  (Gilbert, King, Pettigrew, & Wilson, 2016). Estimates of replicabilty based on original studies do not have this problem because they are based on published results in original articles.

Z-curve has been validated with simulation studies and can be used when replicability varies across studies and when there is selection for significance, and is superior to similar statistical methods that correct for publication bias (Brunner & Schimmack, 2016).  I use this method to estimate the average replicability of significant results published in 103 psychology journals. Separate estimates were obtained for the years from 2010, one year before the start of the replication crisis, to 2016 to examine whether replicability increased in response to discussions about replicability.  The OSC estimate of replicability was based on articles published in 2008 and it was limited to three journals.  I posted replicability estimates based on z-curve for the year 2015 (2015 replicability rankings).  There was no evidence that replicability had increased during this time period.

The main empirical question was whether the 2016 rankings show some improvement in replicability and whether some journals or disciplines have responded more strongly to the replication crisis than others.

A second empirical question was whether replicabilty varies across disciplines.  The OSC project provided first evidence that traditional cognitive psychology is more replicable than social psychology.  Replicability estimates with z-curve confirmed this finding.  In the 2015 rankings, The Journal of Experimental Psychology: Learning, Memory and Cognition ranked 25 with a replicability estimate of 74, whereas the two social psychology sections of the Journal of Personality and Social Psychology ranked 73 and 99 (68% and 60% replicability estimates).  For this post, I conducted more extensive analyses of disciplines.

Journals

The 103 journals that are included in these rankings were mainly chosen based on impact factors.  The list also includes diverse areas of psychology, including cognitive, developmental, social, personality, clinical, biological, and applied psychology.  The 2015 list included some new journals that started after 2010.  These journals were excluded from the 2016 rankings to avoid missing values in statistical analyses of time trends.  A few journals were added to the list and the results may change when more journals are added to the list.

The journals were classified into 9 categories: social (24), cognitive (12), development (15), clinical/medical (19), biological (8), personality (5), and applied(IO,education) (8).  Two journals were classified as general (Psychological Science, Frontiers in Psychology). The last category included topical, interdisciplinary journals (emotion, positive psychology).

Data 

All PDF versions of published articles were downloaded and converted into text files. The 2015 rankings were based on conversions with the free program pdf2text pilot.  The 2016 program used a superior conversion program pdfzilla.  Text files were searched for reports of statistical results using my own R-code (z-extraction). Only F-tests, t-tests, and z-tests were used for the rankings. t-values that were reported without df were treated as z-values which leads to a slight inflation in replicability estimates. However, the bulk of test-statistics were F-values and t-values with degrees of freedom.  A comparison of the 2015 rankings using the old method and the new method shows that extraction methods have an influence on replicability estimates some differences (r = .56). One reason for the low correlation is that replicability estimates have a relatively small range (50-80%) and low retest correlations. Thus, even small changes can have notable effects on rankings. For this reason, time trends in replicability have to be examined at the aggregate level of journals or over longer time intervals. The change score of a single journal from 2015 to 2016 is not a reliable measure of improvement.

Data Analysis

The data for each year were analyzed using z-curve Schimmack and Brunner (2016).  The results of individual analysis are presented in Powergraphs. Powergraphs for each journal and year are provided as links to the journal names in the table with the rankings.  Powergraphs convert test statistics into absolute z-scores as a common metric for the strength of evidence against the null-hypothesis.  Absolute z-scores greater than 1.96 (p < .05, two-tailed) are considered statistically significant. The distribution of z-scores greater than 1.96 is used to estimate the average true power (not observed power) of the set of significant studies. This estimate is an estimate of replicability for a set of exact replication studies because average power determines the percentage of statistically significant results.  Powergraphs provide additional information about replicability for different ranges of z-scores (z-values between 2 and 2.5 are less replicable than those between 4 and 4.5).  However, for the replicability rankings only the replicability estimate is used.

Results

Table 1 shows the replicability estimates sorted by replicability in 2016.

The data were analyzed with a growth model to examine time trends and variability across journals and disciplines using MPLUS7.4.  I compared three models. Model 1 assumed no mean level changes and variability across journals. Model 2 assumed a linear increase. Model 3 tested assumed no change from 2010 to 2015 and allowed for an increase in 2016.

Model 1 had acceptable fit (RMSEA = .043, BIC = 5004). Model 2 increased fit (RMSEA = 0.029, BIC = 5005), but BIC slightly favored the more parsimonious Model 1. Model 3 had the best fit (RMSEA = .000, BIC = 5001).  These results reproduce the results of the 2015 analysis that there was no improvement from 2010 to 2015, but there is some evidence that replicability increased in 2016.  Adding a variance component to slope in Model 3 produced an unidentified model. Subsequent analyses show that this is due to insufficient power to detect variation across journals in changes over time.

The standardized loadings of individual years on the latent intercept factor ranged from .49 to .58.  This shows high variabibility in replicability estimates from year to year. Most of the rank changes can be attributed to random factors.  A better way to compare journals is to average across years.  A moving average of five years will provide reliable information and allow for improvement over time.  The reliability of the 5-year average for the years 2012 to 2016 is 68%.

Figure 1 shows the annual averages with 95%CI as well relative to the average over the full 7-year period.

rep-by-year

A paired t-test confirmed that average replicability in 2016 was significantly higher (M = 65, SD = 8) than in the previous years (M = 63, SD = 8), t(101) = 2.95, p = .004.  This is the first evidence that psychological scientists are responding to the replicability crisis by publishing slightly more replicable results.  Of course, this positive result has to be tempered by the small effect size.  But if this trend continuous or even increases, replicability could reach 80% in 10 years.

The next analysis examined changes in replicabilty at the level of individual journals. Replicability estimates were regressed on a dummy variable that contrasted 2016 with the previous years.  This analysis produced only 7 significant increases with p < .05 (one-tailed), which is only 2 more significant results than would be expected by chance alone. Thus, the analysis failed to identify particular journals that contribute to the improvement in the average.  Figure 2 compares the observed distribution of t-values to the predicted distribution based on the null-hypothesis (no change).

t-value Distribution.png

The blue line shows the observed density distribution, which is slightly moved to the right, but there is no set of journals with notably larger t-values.  A more sustained and larger increase in replicability is needed to detect variability in change scores.

The next analyses examine stable differences between disciplines.  The first analysis compared cognitive journals to social journals.  No statistical tests are needed to see that cognitive journals publish more replicable results than social journals. This finding confirms the results with actual replications of studies published in 2008 (OSC, 2015). The Figure suggests that the improvement in 2016 is driven more by social journals, but only 2017 data can tell whether there is a real improvement in social psychology.

replicability.cog.vs.soc.png

The next Figure shows the results for 5 personality journals.  The large confidence intervals show that there is considerable variability among personality journals. The Figure shows the averages for cognitive and social psychology as horizontal lines. The average for personality is only slightly above the average for social and like social, personality shows an upward trend.  In conclusion, personality and social psychology look very similar.  This may be due to considerable overlap between the two disciplines, which is also reflected in shared journals.  Larger differences may be visible for specialized social journals that focus on experimental social psychology.

replicability-personality

The results for developmental journals show no clear time trend and the average is just about in the middle between cognitive and social psychology.  The wide confidence intervals suggest that there is considerable variability among developmental journals. Table 1 shows Developmental Psychology ranks 14 / 103 and Infancy ranks 101/103. The low rank for Infancy may be due to the great difficulty of measuring infant behavior.

replicability-developmental

The clinical/medical journals cover a wide range of topics from health psychology to special areas of psychiatry.  There has been some concern about replicability in medical research (Ioannidis, 2005). The results for clinical are similar to those for developmental journals. Replicability is lower than for cognitive psychology and higher than for social psychology.  This may seem surprising because patient populations and samples tend to be smaller. However, a randomized controlled intervention study uses pre-post designs to boost power, whereas social and personality psychologists use comparisons across individuals, which requires large samples to reduce sampling error.

replicability-clinical

The set of biological journals is very heterogeneous and small. It includes neuroscience and classic peripheral physiology.  Despite wide confidence intervals replicability for biological journals is significantly lower than replicabilty for cognitive psychology. There is no notable time trend. The average is slightly above the average for social journals.

replicability.biological.png

The last category are applied journals. One journal focuses on education. The other journals focus on industrial and organizational psychology.  Confidence intervals are wide, but replicabilty is generally lower than for cognitive psychology. There is no notable time trend for this set of journals.

replicability.applied.png

Given the stability of replicability, I averaged replicability estimates across years. The last figure shows a comparison of disciplines based on these averages.  The figure shows that social psychology is significantly below average and cognitive psychology is significantly above average with the other disciplines falling in the middle.  All averages are significantly above 50% and below 80%.

Discussion

The most exciting finding is that repicability appears to have increased in 2016. This increase is remarkable because averages in the years before consistently tracked the average of 63.  The increase by 2 percentage points in 2016 is not large, but it may represent a first response to the replication crisis.

The increase is particularly remarkable because statisticians have been sounding the alarm bells about low power and publication bias for over 50 years (Cohen, 1962; Sterling, 1959), but these warnings have had no effect on research practices. In 1989, Sedlmeier and Gigerenzer (1989) noted that studies of statistical power had no effect on the statistical power of studies.  The present results provide the first empirical evidence that psychologists are finally starting to change their research practices.

However, the results also suggest that most journals continue to publish articles with low power.  The replication crisis has affected social psychology more than other disciplines with fierce debates in journals and on social media (Schimmack, 2016).  On the one hand, the comparisons of disciplines supports the impression that social psychology has a bigger replicability problem than other disciplines. However, the differences between disciplines are small. With the exception of cognitive psychology, other disciplines are not a lot more replicable than social psychology.  The main reason for the focus on social psychology is probably that these studies are easier to replicate and that there have been more replication studies in social psychology in recent years.  The replicability rankings predict that other disciplines would also see a large number of replication failures, if they would subject important findings to actual replication attempts.  Only empirical data will tell.

Limitations

The main limitation of replicability rankings is that the use of an automatic extraction method does not distinguish theoretically important hypothesis tests and other statistical tests.  Although this is a problem for the interpretation of the absolute estimates, it is less important for the comparison over time.  Any changes in research practices that reduce sampling error (e.g., larger samples, more reliable measures) will not only strengthen the evidence for focal hypothesis tests, but also increase the strength of evidence for non-focal hypothesis tests.

Schimmack and Brunner (2016) compared replicability estimates with actual success rates in the OSC (2015) replication studies.  They found that the statistical method overestimates replicability by about 20%.  Thus, the absolute estimates can be interpreted as very optimistic estimates.  There are several reasons for this overestimation.  One reason is that the estimation method assumes that all results with a p-value greater than .05 are equally likely to be published. If there are further selection mechanisms that favor smaller p-values, the method overestimates replicability.  For example, sometimes researchers correct for multiple comparisons and need to meet a more stringent significance criterion.  Only careful hand-coding of research articles can provide more accurate estimates of replicability.  Schimmack and Brunner (2016) hand-coded the articles that were included in the OSC (2015) article and still found that the method overestimated replicability.  Thus, the absolute values need to be interpreted with great caution and success rates of actual replication studies are expected to be at least 10% lower than these estimates.

Implications

Power and replicability have been ignored for over 50 years.  A likely reason is that replicability is difficult to measure.  A statistical method for the estimation of replicability changes this. Replicability estimates of journals make it possible for editors to compete with other journals in the replicability rankings. Flashy journals with high impact factors may publish eye-catching results, but if this journal has a reputation of publishing results that do not replicate, they are not very likely to have a big impact.  Science is build on trust and trust has to be earned and can be easily lost.  Eventually, journals that publish replicable results may also increase their impact because more researchers are going to build on replicable results published in these journals.  In this way, replicability rankings can provide a much needed correction to the current incentive structure in science that rewards publishing as many articles as possible without any concerns about the replicability of these results. This reward structure is undermining science.  It is time to change it. It is no longer sufficient to publish a significant result, if this result cannot be replicate in other labs.

Many scientists feel threatened by changes in the incentive structure and the negative consequences of replication failures for their reputation. However, researchers have control over their reputation.  First, researchers often carry out many conceptually related studies. In the past, it was acceptable to publish only the studies that worked (p < .05). This selection for significance by researchers is the key factor in the replication crisis. The researchers who are conducting the studies are fully aware that it was difficult to get a significant result, but the selective reporting of these successes produces inflated effect size estimates and an illusion of high replicability that inevitably lead to replication failures.  To avoid these embarrassing replication failures researchers need to report results of all studies or conduct fewer studies with high power.  The 2016 rankings suggest that some researchers have started to change, but we will have to wait until 2017 to see whether 2017 can replicate the positive trend in the 2016 rankings.

Replicability Report No.2: Do Mating Primes have a replicable effects on behavior?

In 2000, APA declared the following decade the decade of behavior.  The current decade may be considered the decade of replicability or rather the lack thereof.  The replicability crisis started with the publication of Bem’s (2011) infamous “Feeling the future” article.  In response, psychologists have started the painful process of self-examination.

Preregistered replication reports and systematic studies of reproducibility have demonstrated that many published findings are difficult to replicate and when they can be replicated, actual effect sizes are about 50% smaller than reported effect sizes in original articles (OSC, Science, 2016).

To examine which studies in psychology produced replicable results, I created ReplicabilityReports.  Replicability reports use statistical tools that can detect publication bias and questionable research practices to examine the replicability of research findings in a particular research area.  The first replicability report examined the large literature of ego-depletion studies and found that only about a dozen studies may have produced replicable results.

This replicability report focuses on a smaller literature that used mating primes (images of potential romantic partners / imagining a romantic scenario) to test evolutionary theories of human behavior.  Most studies use the typical priming design, where participants are randomly assigned to one or more mating prime conditions or a control condition. After the priming manipulation the effect of activating mating-related motives and thoughts on a variety of measures is examined.  Typically, an interaction with gender is predicted with the hypothesis that mating primes have stronger effects on male participants. Priming manipulations vary from subliminal presentations to instructions to think about romantic scenarios for several minutes; sometimes with the help of visual stimuli.  Dependent variables range from attitudes towards risk-taking to purchasing decisions.

Shanks et al. (2015) conducted a meta-analysis of a subset of mating priming studies that focus on consumption and risk-taking.  A funnel plot showed clear evidence of bias in the published literature.  The authors also conducted several replication studies. The replication studies failed to produce any significant results. Although this outcome might be due to low power to detect small effects, a meta-analysis of all replication studies also produced no evidence for reliable priming effects (average d = 00, 95%CI = -.12 | .11).

This replicability report aims to replicate and extend Shanks et al.’s findings in three ways.  First, I expanded the data base by including all articles that mentioned the word mating primes in a full text search of social psychology journals.  This expanded the set of articles from 15 to 36 articles and the set of studies from 42 to 92. Second, I used a novel and superior bias test.  Shanks et al. used Funnel plots and Egger’s regression of effect sizes on sampling error to examine bias. The problem with this approach is that heterogeneity in effect sizes can produce a negative correlation between effect sizes and sample sizes.  Power-based bias tests do not suffer from this problem (Schimmack, 2014).  A set of studies with average power of 60% cannot produce more than 60% significant results (Sterling et al., 1995).  Thus, the discrepancy between observed power and reported success rate provides clear evidence of selection bias. Powergraphs also make it possible to estimate the actual power of studies after correcting for publication bias and questionable research practices.  Finally, replicability reports use bias tests that can be applied to small sets of studies.  This makes it possible to find studies with replicable results even if most studies have low replicability.

DESCRIPTIVE STATISTICS

The dataset consists of 36 articles and 92 studies. The median sample size of a study was N = 103 and the total number of participants was N = 11,570. The success rate including marginally significant results, z > 1.65, was 100%.  The success rate excluding marginally significant results, z > 1.96, was 90%.  Median observed power for all 92 studies was 66%.  This discrepancy shows that the published results are biased towards significance.  When bias is present, median observed power overestimates actual power.  To correct for this bias, the R-Index subtracts the inflation rate from median observed power.  The R-Index is 66 – 34 = 32.  An R-Index below 50% implies that most studies will not replicate a significant result in an exact replication study with the same sample size and power as the original studies.  The R-Index for the 15 studies included in Shanks et al. was 34% and the R-Index for the additional studies was 36%.  This shows that convergent results were obtained for two independent samples based on different sampling procedures and that Shanks et al.’s limited sample was representative of the wider literature.

POWERGRAPH

For each study, a focal hypothesis test was identified and the result of the statistical test was converted into an absolute z-score.  These absolute z-scores can vary as a function of random sampling error or differences in power and should follow a mixture of normal distributions.  Powergraphs find the best mixture model that minimizes the discrepancy between observed and predicted z-scores.

Powergraph for Romance Priming (Focal Tests)

 

The histogram of z-scores shows clear evidence of selection bias. The steep cliff on the left side of the criterion for significance (z = 1.96) shows a lack of non-significant results.  The few non-significant results are all in the range of marginal significance and were reported as evidence for an effect.

The histogram also shows evidence of the use of questionable research practices. Selection bias would only produce a cliff to the left of the significance criterion, but a mixture-normal distribution on the right side of the significance criterion. However, the graph also shows a second cliff around z = 2.8.  This cliff can be explained by questionable research practices that inflate effect sizes to produce significant results.  These questionable research practices are much more likely to produce z-scores in the range between 2 and 3 than z-scores greater than 3.

The large amount of z-scores in the range between 1.96 and 2.8 makes it impossible to distinguish between real effects with modest power and questionable effects with much lower power that will not replicate.  To obtain a robust estimate of power, power is estimated only for z-scores greater than 2.8 (k = 17).  The power estimate is 73% based. This power estimate suggests that some studies may have reported real effects that can be replicated.

The grey curve shows the predicted distribution for a set of studies with 73% power.  As can be seen, there are too many observed z-scores in the range between 1.96 and 2.8 and too few z-scores in the range between 0 and 1.96 compared to the predicted distribution based on z-scores greater than 2.8.

The powergraph analysis confirms and extends Shanks et al.’s (2016) findings. First, the analysis provides strong evidence that selection bias and questionable research practices contribute to the high success rate in the mating-prime literature.  Second, the analysis suggests that a small portion of studies may actually have reported true effects that can be replicated.

REPLICABILITY OF INDIVIDUAL ARTICLES

The replicability of results published in individual articles was examined with the Test of Insufficient Variance (TIVA) and the Replicability-Index.  TIVA tests bias by comparing the variance of observed z-scores against the variance that is expected based on sampling error.  As sampling error for z-scores is 1, observed z-scores should have at least a variance of 1. If there is heterogeneity, variance can be even greater, but it cannot be smaller than 1.  TIVA uses the chi-square test for variances to compute the probability that a variance less than 1 was simply due to chance.  A p-value less than .10 is used to flag an article as questionable.

The Replicability-Index (R-Index) used observed power to test bias. Z-scores are converted into a measure of observed power and median observed power is used as an estimate of power.  The success rate (percentage of significant results) should match observed power.  The difference between success rate and median power shows an inflated success rate.  The R-Index subtracts inflation from median observed power.  A value of 50% is used as the minimum criterion for replicability.

Articles that pass both tests are examined in more detail to identify studies with high replicability.  Only three articles passed this test.

1   Greitemeyer, Kastenmüller, and Fischer (2013) [R-Index = .80]

The article with the highest R-Index reported 4 studies.  The high R-Index for this article is due to Studies 2 to 4.  Studies 3 and 4 used a 2 x 3 between subject design with gender and three priming conditions. Both studies produced strong evidence for an interaction effect, Study 3: F(2,111) = 12.31, z = 4.33, Study 4: F(2,94) = 7.46, z = 3.30.  The pattern of the interaction is very similar in the two studies.  For women, the means are very similar and not significantly different for each other.  For men, the two mating prime conditions are very similar and significantly different from the control condition.  The standardized effect sizes for the difference between the combined mating prime conditions and the control conditions are large, Study 3: t(110) = 6.09, p < .001, z = 5.64, d = 1.63; Study 4: t(94) = 5.12, d = 1.30.

Taken at face value, these results are highly replicable, but there are some concerns about the reported results. The means in conditions that are not predicted to differ from each other are very similar.  I tested the probability of this event to occur using TIVA and compared the means of the two mating prime conditions for men and women in the two studies.  The four z-scores were z = 0.53, 0.08, 0.09, and -0.40.  The variance should be 1, but the observed variance is only Var(z) = 0.14.  The probability of this reduction in variance to occur by chance is p = .056.  Thus, even though the overall R-Index for this article is high and the reported effect sizes are very high, it is likely that an actual replication study will produce weaker effects and may not replicate the original findings.

Study 2 also produced strong evidence for a priming x gender interaction, F(1,81) = 11.23, z = 3.23.  In contrast to studies 3 and 4, this interaction was a cross-over interaction with opposite effects of primes for males and females.  However, there is some concern about the reliability of this interaction because the post-hoc tests for males and females were both just significant, males: t(40) = 2.61, d = .82, females, t(41) = 2.10, d = .63.  As these post-hoc tests are essentially two independent studies, it is possible to use TIVA to test whether these results are too similar, Var(z) = 0.11, p = .25.  The R-Index for this set of studies is low, R-Index = .24 (MOP = .62).  Thus, a replication study may replicate an interaction effect, but the chance of replicating significant results for males or females separately are lower.

Importantly, Shanks et al. (2016) conducted two close replication of Greitemeyer’s studies with risky driving, gambling, and sexual risk taking as dependent variables.  Study 5 compared the effects of short-term mate primes on risky driving.  Although the sample size was small, the large effect size in the original study implies that this study had high power to replicate the effect, but it did not, t(77) = = -0.85, p = .40, z = -.85.  The negative sign indicates that the pattern of means was reversed, but not significantly so.  Study 6 failed to replicate the interaction effect for sexual risk taking reported by Greitemeyer et al., F(1, 93) = 1.15, p = .29.  The means for male participants were in the opposite direction showing a decrease in risk taking after mating priming.  The study also failed to replicate the significant decrease in risk taking for female participants.  Study 6 also produced non-significant results for gambling and substance risk taking.   These failed replication studies raise further concerns about the replicability of the original results with extremely large effect sizes.

Jon K. Maner, Matthew T. Gailliot, D. Aaron Rouby, and Saul L. Miller (JPSP, 2007) [R-Index = .62]

This article passed TIVA only due to the low power of TIVA for a set of three studies, TIVA: Var(z) = 0.15, p = .14.  In Study 1, male and female participants were randomly assigned to a sexual-arousal priming condition or a happiness control condition. Participants also completed a measure of socio-sexual orientation (i.e., interest in casual and risky sex) and were classified into groups of unrestricted and restricted participants. The dependent variable was performance on a dot-probe task.  In a dot-probe task, participants have to respond to a dot that appears in the location of two stimuli that compete for visual attention.  In theory, participants are faster to respond to the dot if appears in the location of a stimulus that attracts more attention.  Stimuli were pictures of very attractive or less attractive members of the same or opposite sex.  The time between the presentation of the pictures and the dot was also manipulated.  The authors reported that they predicted a three-way way interaction between priming condition, target picture, and stimulus-onset time.  The authors did not predict an interaction with gender.  The ANOVA showed a significant three-way interaction, F(1,111) = 10.40, p = .002, z = 3.15.  A follow-up two-way ANOVA showed an interaction between priming condition and target for unrestricted participants, F(1,111) = 7.69, p = .006, z = 2.72.

Study 2 replicated Study 1 with a sentence unscrambling task which is used as a subtler priming manipulation.  The study closely replicated the results of Study 1. The three way interaction was significant, F(1,153) = 9.11, and the follow up two-way interaction for unrestricted participants was also significant, F(1,153) = 8.22, z = 2.75.

Study 3 changed the primes to jealousy or anxiety/frustration.  Jealousy is a mating related negative emotion and was predicted to influence participants like mating primes.  In this study, participants were classified into groups with high or low sexual vigilance based on a jealousy scale.  The predicted three-way interaction was significant, F(1,153) = 5.74, p = .018, z = 2.37.  The follow-up two-way interaction only for participants high in sexual vigilance was also significant, F(1,153) = 8.13, p = .005, z = 2.81.

A positive feature of this set of studies is that the manipulation of targets within subjects reduces within-cell variability and increases power to produce significant results.  However, a problem is that the authors also report studies for specific targets and do not mention that they used reaction times to other targets as covariate. These analyses have low power due to the high variability in reaction times across participants.  However, surprisingly each study still produced the predicted significant result.

Study 1: “Planned analyses clarified the specific pattern of hypothesized effects. Multiple regression evaluated the hypothesis that priming would interact with participants’ sociosexual orientation to increase attentional adhesion to attractive opposite-sex targets. Attention to those targets was regressed on experimental condition, SOI, participant sex, and their centered interactions (nonsignificant interactions were dropped). Results confirmed the hypothesized interaction between priming condition and SOI, beta = .19, p < .05 (see Figure 1).”
I used r = .19 and N = 113 and obtained t(111) = 2.04, p = .043, z = 2.02.

Study 2: “Planned analyses clarified the specific pattern of hypothesized effects. Regression evaluated the hypothesis that the mate-search prime would interact with sociosexual orientation to increase attentional adhesion to attractive opposite-sex targets. Attention to these targets was regressed on experimental condition, SOI score, participant sex, and their centered interactions (nonsignificant interactions were dropped). As in Study 1, results revealed the predicted interaction between priming condition and sociosexual orientation, beta = .15, p = .04, one-tailed (see Figure 2)”
I used r = .15 and N = 155 and obtained t(153) = 1.88, p = .06 (two-tailed!), z = 1.86.

Study 3: “We also observed a significant main effect of intrasexual vigilance, beta = .25, p < .001, partial r = .26, and, more important, the hypothesized two-way interaction between priming condition and level of intrasexual vigilance, beta = .15, p < .05, partial r = .16 (see Figure 3).”
I used r = .16 and N = 155 and obtained t(153) = 2.00, p = .047, z = 1.99.

The problem is that the results of these three independent analyses are too similar, z = 2.02, 1.86, 1.99; Var(z) < .001, p = .007.

In conclusion, there are some concerns about the replicability of these results and even if the results replicate they do not provide support for the hypothesis that mating primes have a hard-wired effect on males. Only one of the three studies produced a significant two-way interaction between priming and target (F-value not reported), and none of the three studies produced a significant three-way interaction between priming, target, and gender.  Thus, the results are inconsistent with other studies that found either main effects of mating primes or mating prime by gender interactions.

3. Bram Van den Bergh and Siegfried Dewitte (Proc. R. Soc. B, 2006) [R-index = .58]

This article reports three studies that examined the influence of mating primes on behavior in the ultimatum game.

Study 1 had a small sample size of 40 male participants who were randomly assigned to seeing pictures of non-nude female models or landscapes.  The study produced a significant main effect, F(1,40) = 4.75, p = .035, z = 2.11, and a significant interaction with finger digit ratio, F(1,40) = 4.70, p = .036, z = 2.10.  I used the main effect for analysis because it is theoretically more important than the interaction effect, but the results are so similar that it does not matter which effect is used.

Study 2 used rating of women’s t-shirts or bras as manipulation. The study produced strong evidence that mating primes (rating bras) lead to lower minimum acceptance rates in the ultimatum game than the control condition (rating t-shirts), F(1,33) = 8.88, p = .005, z = 2.78.  Once more the study also produced a significant interaction with finger digit ratio, F(1,33) = 8.76, p = .006, z = 2.77.

Study 3 had three experimental conditions, namely non-sexual pictures of older and young women, and pictures of young non-nude female models.  The study produced a significant effect of condition, F(2,87) = 5.49, p = .006, z = 2.77.  Once more the interaction with finger-digit ratio was also significant, F(2,87) = 5.42.

This article barely passed the test of insufficient variance in the primary analysis that uses one focal test per study, Var(z) = 0.15, p = .14.  However, the main effect and the interaction effects are statistically independent and it is possible to increase the power of TIVA by using the z-scores for the three main effects and the three interactions.  This test produces significant evidence for bias, Var(z) = 0.12, p = .01.

In conclusion, it is unlikely that the results reported in this article will replicate.

CONCLUSION

The replicability crisis in psychology has created doubt about the credibility of published results.  Numerous famous priming studies have failed to replicate in large replication studies.  Shanks et al. (2016) reported problems with the specific literature of romantic and mating priming.  This replicability report provided further evidence that the mating prime literature is not credible.  Using an expanded set of 92 studies, analysis with powergraphs, the test of insufficient variance, and the replicability index showed that many significant results were obtained with the help of questionable research practices that inflate observed effect sizes and provide misleading evidence about the strength and replicability of published results.  Only three articles passed the test with TIVA and R-Index and detailed examination of these studies also showed statistical problems with the evidence in these articles.  Thus, this replicability analysis of 36 articles failed to identify a single credible article.  The lack of credible evidence is consistent with Shanks et al.’s failure to produce significant results in 15 independent replication studies.

Of course, these results do not imply that evolutionary theory is wrong or that sexual stimuli have no influence on human behavior.  For example, in my own research I have demonstrated that sexually arousing opposite-sex pictures capture men’s and women’s attention (Schimmack, 2005).  However, these responses occurred in response to specific stimuli and not as carry-over effects of a priming manipulation. Thus, the problem with mating prime studies is probably that priming effects are weak and may have no notable influence on unrelated behaviors like consumer behavior or risk taking in investments.  Given the replication problems with other priming studies, it seems necessary to revisit the theoretical assumptions underlying this paradigm.  For example, Shanks et al. (2016) pointed out that behavioral priming effects are theoretically implausible because these predictions contradict well-established theories that behavior is guided by the cognitive appraisal of the situation at hand rather than unconscious residual information from previous situations. This makes evolutionary sense because behavior has to respond to the adaptive problem at hand to ensure survival and reproduction.

I recommend that textbook writers, journalists, and aspiring social psychologists treat claims about human behavior based on mating priming studies with a healthy dose of skepticism.  The results reported in these articles may reveal more about the motives of researchers than their participants.