Category Archives: Social Psychology

The Prevalence of Questionable Research Practices in Social Psychology

Introduction

A naive model of science assumes that scientists are objective. That is, they derive hypotheses from theories, collect data to test these theories, and then report the results. In reality, scientists are passionate about theories and often want to confirm that their own theories are right. This leads to conformation bias and the use of questionable research practices (QRPs, John et al., 2012; Schimmack, 2015). QRPs are defined as practices that increase the chances of the desired outcome (typically a statistically significant result) while at the same time inflating the risk of a false positive discovery. A simple QRP is to conduct multiple studies and to report only the results that support the theory.

The use of QRPs explains the astonishingly high rate of statistically significant results in psychology journals that is over 90% (Sterling, 1959; Sterling et al., 1995). While it is clear that this rate of significant results is too high, it is unclear how much it is inflated by QRPs. Given the lack of quantitative information about the extent of QRPs, motivated biases also produce divergent opinions about the use of QRPs by social psychologists. John et al. (2012) conducted a survey and concluded that QRPs are widespread. Fiedler and Schwarz (2016) criticized the methodology and their own survey of German psychologists suggested that QRPs are not used frequently. Neither of these studies is ideal because they relied on self-report data. Scientists who heavily use QRPs may simply not participate in surveys of QRPs or underreport the use of QRPs. It has also been suggested that many QRPs happen automatically and are not accessible to self-reports. Thus, it is necessary to study the use of QRPs with objective methods that reflect the actual behavior of scientists. One approach is to compare dissertations with published articles (Cairo et al., 2020). This method provided clear evidence for the use of QRPs, even though a published document could reveal their use. It is possible that this approach underestimates the use of QRPs because even the dissertation results could be influenced by QRPs and the supervision of dissertations by outsiders may reduce the use of QRPs.

With my colleagues, I developed a statistical method that can detect and quantify the use of QRPs (Bartos & Schimmack, 2020; Brunner & Schimmack, 2020). Z-curve uses the distribution of statistically significant p-values to estimate the mean power of studies before selection for significance. This estimate predicts how many non-significant results were obtained in the serach for the significant ones. This makes it possible to compute the estimated discovery rate (EDR). The EDR can then be compared to the observed discovery rate, which is simply the percentage of published results that are statistically significant. The bigger the difference between the ODR and the EDR is, the more questionable research practices were used (see Schimmack, 2021, for a more detailed introduction).

I merely focus on social psychology because (a) I am a social/personality psychologists, who is interested in the credibility of results in my field, and (b) because social psychology has a large number of replication failures (Schimmack, 2020). Similar analyses are planned for other areas of psychology and other disciplines. I also focus on social psychology more than personality psychology because personality psychology is often more exploratory than confirmatory.

Method

I illustrate the use of z-curve to quantify the use of QRPs with the most extreme examples in the credibility rankings of social/personality psychologists (Schimmack, 2021). Figure 1 shows the z-value plot (ZVP) of David Matsumoto. To generate this plot, the tests statistics from t-tests and F-tests were transformed into exact p-values and then transformed into the corresponding values on the standard normal distribution. As two-sided p-values are used, all z-scores are positive. However, because the curve is centered over the z-score that corresponds to the median power before selection for significance (and not zero, when the null-hypothesis is true), the distribution can look relatively normal. The variance of the distribution will be greater than 1 when studies vary in statistical power.

The grey curve in Figure 1 shows the predicted distribution based on the observed distribution of z-scores that are significant (z > 1.96). In this case, the observed number of non-significant results is similar to the predicted number of significant results. As a result, the ODR of 78% closely matches the EDR of 79%.

Figure 2 shows the results for Shelly Chaiken. The first notable observation is that the ODR of 75% is very similar to Matsumoto’s EDR of 78%. Thus, if we simply count the number of significant and non-significant p-values, there is no difference between these two researchers. However, the z-value plot (ZVP) shows a dramatically different picture. The peak density is 0.3 for Matsoumoto and 1.0 for Chaiken. As the maximum density of the standard normal distribution is .4, it is clear that the results in Chaiken’s articles are not from an actual sampling distribution. In other words, QRPs must have been used to produce too many just significant results with p-values just below .05.

The comparison of the ODR and EDR shows a large discrepancy of 64 percentage points too many significant results (ODR = 75% minus EDR = 11%). This is clearly not a chance finding because the ODR falls well outside the 95% confidence interval of the EDR, 5% to 21%.

To examine the use of QPSs in social psychology, I computed the EDR and ORDR for over 200 social/personality psychologists. Personality psychologists were excluded if they reported too few t-values and F-values. The actual values can be found and additional statistics can be found in the credibility rankings (Schimmack, 2021). Here I used these data to examine the use of QRPs in social psychology.

Average Use of QRPs

The average ODR is 73.48 with a 95% confidence interval ranging from 72.67 to 74.29. The average EDR is 35.28 with a 95% confidence interval ranging from 33.14 to 37.43. the inflation due to QRPs is 38.20 percentage points, 95%CI = 36.10 to 40.30. This difference is highly significant, t(221) = 35.89, p < too many zeros behind the decimal for R to give an exact value.

It is of course not surprising that QRPs have been used. More important is the effect size estimate. The results suggest that QRPs inflate the discovery rate by over 100%. This explains why unbiased replication studies in social psychology have only a 25% chance of being significant (Open Science Collaboration, 2015). In fact, we can use the EDR as a conservative predictor of replication outcomes (Bartos & Schimmack, 2020). While the EDR of 35% is a bit higher than the actual replication rate, this may be due to the inclusion of non-focal hypothesis tests in these analyses. Z-curve analyses of focal hypothesis tests typically produce lower EDRs. In contrast, Fiedler and Schwarz failed to comment on the low replicability of social psychology. If social psychologists would not have used QRPs, it remains a mystery why their results are so hard to replicate.

In sum, the present results confirm that, on average, social psychologists heavily used QRPs to produce significant results that support their predictions. However, these averages masks differences between researchers like Matsumoto and Chaiken. The next analyses explore these individual differences between researchers.

Cohort Effects

I had no predictions about the effect of cohort on the use of QRPs. I conducted a twitter poll that suggested a general intuition that the use of QRPs may not have changed over time, but there was a lot of uncertainty in these answers. Similar results were obtained in a Facebook poll in the Psychological Methods Discussion Group. Thus, the a priori hypothesis is a vague prior of no change.

The dataset includes different generations of researchers. I used the first publication listed in WebofScience to date researchers. The earliest date was 1964 (Robert S. Wyer). The latest date was 2012 (Kurt Gray). The histogram shows that researchers from the 1970s to 2000s were well-represented in the dataset.

There was a significant negative correlation between the ODR and cohort, r(N = 222) = -.25, 95%CI = -.12 to -.37, t(220) = 3.83, p = .0002. This finding suggests that over time the proportion of non-significant results increased. For researchers with the first publication in the 1970s, the average ODR was 76%, whereas it was 72% for researchers with the first publication in the 2000s. This is a modest trend. There are various explanations for this trend.

One possibility is that power decreased as researchers started looking for weaker effects. In this case, the EDR should also show a decrease. However, the EDR showed no relationship with cohort, r(N = 222) = -.03, 95%CI = -.16 to .10, t(220) = 0.48, p = .63. Thus, less power does not seem to explain the decrease in the ODR. At the same time, the finding that EDR does not show a notable, abs(r) < .2, relationship with cohort suggests that power has remained constant over time. This is consistent with previous examinations of statistical power in social psychology (Sedlmeier & Gigerenzer, 1989).

Although the ODR decreased significantly and the EDR did not decrease significantly, bias (ODR – EDR) did not show a significant relationship with cohort, r(N = 222) = -.06, 95%CI = -19 to .07, t(220) = -0.94, p = .35, but the 95%CI allows for a slight decrease in bias that would be consistent with the significant decrease in the ODR.

In conclusion, there is a small, statistically significant decrease in the ODR, but the effect over the past 40 decades is too small to have practical significance. The EDR and bias are not even statistically significantly related to cohort. These results suggest that research practices and the use of questionable ones has not changed notably since the beginning of empirical social psychology (Cohen, 1961; Sterling, 1959).

Achievement Motivation

Another possibility is that in each generation, QRPs are used more by researches who are more achievement motivated (Janke et al., 2019). After all, the reward structure in science is based on number of publications and significant results are often needed to publish. In social psychology it is also necessary to present a package of significant results across multiple studies, which is nearly impossible without the use of QRPs (Schimmack, 2012). To examine this hypothesis, I correlated the EDR with researchers’ H-Index (as of 2/1/2021). The correlation was small, r(N = 222) = .10, 95%CI = -.03 to .23, and not significant, t(220) = 1.44, p = .15. This finding is only seemingly inconsistent with Janke et al.’s (2019) finding that self-reported QRPs were significantly correlated with self-reported ambition, r(217) = .20, p = .014. Both correlations are small and positive, suggesting that achievement motivated researchers may be slightly more likely to use QRPs. However, the evidence is by no means conclusive and the actual relationship is weak. Thus, there is no evidence to support that highly productive researchers with impressive H-indices achieved their success by using QRPs more than other researchers. Rather, they became successful in a field where QRPs are the norm. If the norms were different, they would have become successful following these other norms.

Impact

A common saying in science is that “extraordinary claims require extraordinary evidence.” Thus, we might expect stronger evidence for claims of time-reversed feelings (Bem, 2011) than for evidence that individuals from different cultures regulate their emotions differently (Matsumoto et al., 2008). However, psychologists have relied on statistical significance with alpha = .05 as a simple rule to claim discoveries. This is a problem because statistical significance is meaningless when results are selected for significance and replication failures with non-significant results remain unpublished (Sterling, 1959). Thus, psychologists have trusted an invalid criterion that does not distinguish between true and false discoveries. It is , however, possible that social psychologists used other information (e.g, gossip about replication failures at conferences) to focus on credible results and to ignore incredible ones. To examine this question, I correlated authors’ EDR with the number of citations in 2019. I used citation counts for 2019 because citation counts for 2020 are not yet final (the results will be updated with the 2020 counts). Using 2019 increases the chances of finding a significant relationship because replication failures over the past decade could have produced changes in citation rates.

The correlation between EDR and number of citations was statistically significant, r(N = 222) = .16, 95%CI = .03 to .28, t(220) = 2.39, p = .018. However, the lower limit of the 95% confidence interval is close to zero. Thus, it is possible that the real relationship is too small to matter. Moreover, the non-parametric correlation with Kendell’s tau was not significant, tau = .085, z = 1.88, p = .06. Thus, at present there is insufficient evidence to suggest that citation counts take the credibility of significant results into account. At present, p-values less than .05 are treated as equally credible no matter how they were produced.

Conclusion

There is general agreement that questionable research practices have been used to produce an unreal success rate of 90% or more in psychology journals (Sterling, 1959). However, there is less agreement about the amount of QRPs that are being used and the implications for the credibility of significant results in psychology journals (John et al., 2012; Fiedler & Schwarz, 2016). The problem is that self-reports may be biased because researchers are unable or unwilling to report the use of QRPs (Nisbett & Wilson, 1977). Thus, it is necessary to examine this question with alternative methods. The present study used a statistical method to compare the observed discovery rate with a statistically estimated discovery rate based on the distribution of significant p-values. The results showed that on average social psychologists have made extensive use of QRPs to inflate an expected discovery rate of around 35% to an observed discovery rate of 70%. Moreover, the estimated discovery rate of 35%is likely to be an inflated estimate of the discovery rate for focal hypothesis tests because the present analysis is based on focal and non-focal tests. This would explain why the actual success rate in replication studies is even lower thna the estimated discovery rate of 35% (Open Science Collaboration, 2015).

The main novel contribution of this study was to examine individual differences in the use of QRPs. While the ODR was fairly consistent across articles, the EDR varied considerably across researchers. However, this variation showed only very small relationships with a researchers’ cohort (first year of publication). This finding suggests that the use of QRPs varies more across research fields and other factors than over time. Additional analysis should explore predictors of the variation across researchers.

Another finding was that citations of authors’ work do not take credibility of p-values into account. Citations are influenced by popularity of topics and other factors and do not take the strength of evidence into account. One reason for this might be that social psychologists often publish multiple internal replications within a single article. This gives the illusion that results are robust and credible because it is very unlikely to replicate type-I errors. However, Bem’s (2011) article with 9 internal replications of time-reversed feelings showed that QRPs are also used to produce consistent results within a single article (Francis, 2012; Schimmack, 2012). Thus, number of significant results within an article or across articles is also an invalid criterion to evaluate the robustness of results.

In conclusion, social psychologists have conducted studies with low statistical power since the beginning of empirical social psychology. The main reason for this is the preference for between-subject designs that have low statistical power with small sample sizes of N = 40 participants and small to moderate effect sizes. Despite repeated warnings about the problems of selection for significance (Sterling, 1959) and the problems of small sample sizes (Cohen, 1961; Sedelmeier & Gigerenzer, 1989; Tversky & Kahneman, 1971), the practices have not changed since Festinger conducted his seminal study on dissonance with n = 20 per group. Over the past decades, social psychology journals have reported thousands of statistically significant results that are used in review articles, meta-analyses, textbooks, and popular books as evidence to support claims about human behavior. The problem is that it is unclear which of these significant results are true positives and which are false positives, especially if false positives are not just strictly nil-results, but also results with tiny effect sizes that have no practical significance. Without other reliable information, even social psychologists do not know which of their colleagues results are credible or not. Over the past decade, the inability to distinguish credible and incredible information has produced heated debates and a lack of confidence in published results. The present study shows that the general research practices of a researcher provide valuable information about credibility. For example, a p-value of .01 by a researcher with an EDR of 70 is more credible than a p-value of .01 by a researcher with an EDR of 15. Thus, rather than stereotyping social psychologists based on the low replication rate in the Open Science Collaboration project, social psychologists should be evaluated based on their own research practices.

References

Cairo, A. H., Green, J. D., Forsyth, D. R., Behler, A. M. C., & Raldiris, T. L. (2020). Gray (Literature) Matters: Evidence of Selective Hypothesis Reporting in Social Psychological Research. Personality and Social Psychology Bulletin, 46(9), 1344–1362. https://doi.org/10.1177/0146167220903896

Janke, S., Daumiller, M., & Rudert, S. C. (2019). Dark pathways to achievement in science: Researchers’ achievement goals predict engagement in questionable research practices.
Social Psychological and Personality Science, 10(6), 783–791. https://doi.org/10.1177/1948550618790227

Personalized P-Values for Social/Personality Psychologists

Last update 8/25/2021
(expanded to 410 social/personality psychologists; included Dan Ariely)

Introduction

Since Fisher invented null-hypothesis significance testing, researchers have used p < .05 as a statistical criterion to interpret results as discoveries worthwhile of discussion (i.e., the null-hypothesis is false). Once published, these results are often treated as real findings even though alpha does not control the risk of false discoveries.

Statisticians have warned against the exclusive reliance on p < .05, but nearly 100 years after Fisher popularized this approach, it is still the most common way to interpret data. The main reason is that many attempts to improve on this practice have failed. The main problem is that a single statistical result is difficult to interpret. However, when individual results are interpreted in the context of other results, they become more informative. Based on the distribution of p-values it is possible to estimate the maximum false discovery rate (Bartos & Schimmack, 2020; Jager & Leek, 2014). This approach can be applied to the p-values published by individual authors to adjust p-values to keep the risk of false discoveries at a reasonable level, FDR < .05.

Researchers who mainly test true hypotheses with high power have a high discovery rate (many p-values below .05) and a low false discovery rate (FDR < .05). Figure 1 shows an example of a researcher who followed this strategy (for a detailed description of z-curve plots, see Schimmack, 2021).

We see that out of the 317 test-statistics retrieved from his articles, 246 were significant with alpha = .05. This is an observed discovery rate of 78%. We also see that this discovery rate closely matches the estimated discovery rate based on the distribution of the significant p-values, p < .05. The EDR is 79%. With an EDR of 79%, the maximum false discovery rate is only 1%. However, the 95%CI is wide and the lower bound of the CI for the EDR, 27%, allows for 14% false discoveries.

When the ODR matches the EDR, there is no evidence of publication bias. In this case, we can improve the estimates by fitting all p-values, including the non-significant ones. With a tighter CI for the EDR, we see that the 95%CI for the maximum FDR ranges from 1% to 3%. Thus, we can be confident that no more than 5% of the significant results wit alpha = .05 are false discoveries. Readers can therefore continue to use alpha = .05 to look for interesting discoveries in Matsumoto’s articles.

Figure 3 shows the results for a different type of researcher who took a risk and studied weak effect sizes with small samples. This produces many non-significant results that are often not published. The selection for significance inflates the observed discovery rate, but the z-curve plot and the comparison with the EDR shows the influence of publication bias. Here the ODR is similar to Figure 1, but the EDR is only 11%. An EDR of 11% translates into a large maximum false discovery rate of 41%. In addition, the 95%CI of the EDR includes 5%, which means the risk of false positives could be as high as 100%. In this case, using alpha = .05 to interpret results as discoveries is very risky. Clearly, p < .05 means something very different when reading an article by David Matsumoto or Shelly Chaiken.

Rather than dismissing all of Chaiken’s results, we can try to lower alpha to reduce the false discovery rate. If we set alpha = .01, the FDR is 15%. If we set alpha = .005, the FDR is 8%. To get the FDR below 5%, we need to set alpha to .001.

A uniform criterion of FDR < 5% is applied to all researchers in the rankings below. For some this means no adjustment to the traditional criterion. For others, alpha is lowered to .01, and for a few even lower than that.

The rankings below are based on automatrically extracted test-statistics from 40 journals (List of journals). The results should be interpreted with caution and treated as preliminary. They depend on the specific set of journals that were searched, the way results are being reported, and many other factors. The data are available (data.drop) and researchers can exclude articles or add articles and run their own analyses using the z-curve package in R (https://replicationindex.com/2020/01/10/z-curve-2-0/).

I am also happy to receive feedback about coding errors. I also recommended to hand-code articles to adjust alpha for focal hypothesis tests. This typically lowers the EDR and increases the FDR. For example, the automated method produced an EDR of 31 for Bargh, whereas hand-coding of focal tests produced an EDR of 12 (Bargh-Audit).

And here are the rankings. The results are fully automated and I was not able to cover up the fact that I placed only #188 out of 400 in the rankings. In another post, I will explain how researchers can move up in the rankings. Of course, one way to move up in the rankings is to increase statistical power in future studies. The rankings will be updated again when the 2021 data are available.

Despite the preliminary nature, I am confident that the results provide valuable information. Until know all p-values below .05 have been treated as if they are equally informative. The rankings here show that this is not the case. While p = .02 can be informative for one researcher, p = .002 may still entail a high false discovery risk for another researcher.

Good science requires not only open and objective reporting of new data; it also requires unbiased review of the literature. However, there are no rules and regulations regarding citations, and many authors cherry-pick citations that are consistent with their claims. Even when studies have failed to replicate, original studies are cited without citing the replication failures. In some cases, authors even cite original articles that have been retracted. Fortunately, it is easy to spot these acts of unscientific behavior. Here I am starting a project to list examples of bad scientific behaviors. Hopefully, more scientists will take the time to hold their colleagues accountable for ethical behavior in citations. They can even do so by posting anonymously on the PubPeer comment site.

RankNameTestsODREDRERRFDRAlpha
1Robert A. Emmons538789901.05
2Allison L. Skinner2295981851.05
3David Matsumoto3788379851.05
4Linda J. Skitka5326875822.05
5Todd K. Shackelford3057775822.05
6Jonathan B. Freeman2745975812.05
7Virgil Zeigler-Hill5157274812.05
8Arthur A. Stone3107573812.05
9David P. Schmitt2077871772.05
10Emily A. Impett5497770762.05
11Paula Bressan628270762.05
12Kurt Gray4877969812.05
13Michael E. McCullough3346969782.05
14Kipling D. Williams8437569772.05
15John M. Zelenski1567169762.05
16Elke U. Weber3126968770.05
17Hilary B. Bergsieker4396768742.05
18Cameron Anderson6527167743.05
19Rachael E. Jack2497066803.05
20Jamil Zaki4307866763.05
21A. Janet Tomiyama767865763.05
22Benjamin R. Karney3925665733.05
23Phoebe C. Ellsworth6057465723.05
24Jim Sidanius4876965723.05
25Amelie Mummendey4617065723.05
26Carol D. Ryff2808464763.05
27Juliane Degner4356364713.05
28Steven J. Heine5977863773.05
29David M. Amodio5846663703.05
30Thomas N Bradbury3986163693.05
31Elaine Fox4727962783.05
32Miles Hewstone14277062733.05
33Linda R. Tropp3446561803.05
34Rainer Greifeneder9447561773.05
35Klaus Fiedler19507761743.05
36Jesse Graham3777060763.05
37Richard W. Robins2707660704.05
38Simine Vazire1376660644.05
39On Amir2676759884.05
40Edward P. Lemay2898759814.05
41William B. Swann Jr.10707859804.05
42Margaret S. Clark5057559774.05
43Bernhard Leidner7246459654.05
44B. Keith Payne8797158764.05
45Ximena B. Arriaga2846658694.05
46Joris Lammers7286958694.05
47Patricia G. Devine6067158674.05
48Rainer Reisenzein2016557694.05
49Barbara A. Mellers2878056784.05
50Joris Lammers7056956694.05
51Jean M. Twenge3817256594.05
52Nicholas Epley15047455724.05
53Kaiping Peng5667754754.05
54Krishna Savani6387153695.05
55Leslie Ashburn-Nardo1098052835.05
56Lee Jussim2268052715.05
57Richard M. Ryan9987852695.05
58Ethan Kross6146652675.05
59Edward L. Deci2847952635.05
60Roger Giner-Sorolla6638151805.05
61Bertram F. Malle4227351755.05
62Jens B. Asendorpf2537451695.05
63Samuel D. Gosling1085851625.05
64Tessa V. West6917151595.05
65Paul Rozin4497850845.05
66Joachim I. Krueger4367850815.05
67Sheena S. Iyengar2076350805.05
68James J. Gross11047250775.05
69Mark Rubin3066850755.05
70Pieter Van Dessel5787050755.05
71Shinobu Kitayama9837650715.05
72Matthew J. Hornsey16567450715.05
73Janice R. Kelly3667550705.05
74Antonio L. Freitas2477950645.05
75Paul K. Piff1667750635.05
76Mina Cikara3927149805.05
77Beate Seibt3797249626.01
78Ludwin E. Molina1636949615.05
79Bertram Gawronski18037248766.01
80Penelope Lockwood4587148706.01
81Edward R. Hirt10428148656.01
82Matthew D. Lieberman3987247806.01
83John T. Cacioppo4387647696.01
84Agneta H. Fischer9527547696.01
85Leaf van Boven7117247676.01
86Stephanie A. Fryberg2486247666.01
87Daniel M. Wegner6027647656.01
88Anne E. Wilson7857147646.01
89Rainer Banse4027846726.01
90Alice H. Eagly3307546716.01
91Jeanne L. Tsai12417346676.01
92Jennifer S. Lerner1818046616.01
93Andrea L. Meltzer5495245726.01
94R. Chris Fraley6427045727.01
95Constantine Sedikides25667145706.01
96Paul Slovic3777445706.01
97Dacher Keltner12337245646.01
98Brian A. Nosek8166844817.01
99George Loewenstein7527144727.01
100Ursula Hess7747844717.01
101Jason P. Mitchell6007343737.01
102Jessica L. Tracy6327443717.01
103Charles M. Judd10547643687.01
104S. Alexander Haslam11987243647.01
105Mark Schaller5657343617.01
106Susan T. Fiske9117842747.01
107Lisa Feldman Barrett6446942707.01
108Jolanda Jetten19567342677.01
109Mario Mikulincer9018942647.01
110Bernadette Park9737742647.01
111Paul A. M. Van Lange10927042637.01
112Wendi L. Gardner7986742637.01
113Will M. Gervais1106942597.01
114Jordan B. Peterson2666041797.01
115Philip E. Tetlock5497941737.01
116Amanda B. Diekman4388341707.01
117Daniel H. J. Wigboldus4927641678.01
118Michael Inzlicht6866641638.01
119Naomi Ellemers23887441638.01
120Phillip Atiba Goff2996841627.01
121Stacey Sinclair3277041578.01
122Francesca Gino25217540698.01
123Michael I. Norton11367140698.01
124David J. Hauser1567440688.01
125Elizabeth Page-Gould4115740668.01
126Tiffany A. Ito3498040648.01
127Richard E. Petty27716940648.01
128Tim Wildschut13747340648.01
129Norbert Schwarz13377240638.01
130Veronika Job3627040638.01
131Wendy Wood4627540628.01
132Minah H. Jung1568339838.01
133Marcel Zeelenberg8687639798.01
134Tobias Greitemeyer17377239678.01
135Jason E. Plaks5827039678.01
136Carol S. Dweck10287039638.01
137Christian S. Crandall3627539598.01
138Harry T. Reis9986938749.01
139Vanessa K. Bohns4207738748.01
140Jerry Suls4137138688.01
141Eric D. Knowles3846838648.01
142C. Nathan DeWall13367338639.01
143Clayton R. Critcher6978238639.01
144John F. Dovidio20196938629.01
145Joshua Correll5496138629.01
146Abigail A. Scholer5565838629.01
147Chris Janiszewski1078138589.01
148Herbert Bless5867338579.01
149Mahzarin R. Banaji8807337789.01
150Rolf Reber2806437729.01
151Kevin N. Ochsner4067937709.01
152Mark J. Brandt2777037709.01
153Geoff MacDonald4066737679.01
154Mara Mather10387837679.01
155Antony S. R. Manstead16567237629.01
156Lorne Campbell4336737619.01
157Sanford E. DeVoe2367137619.01
158Ayelet Fishbach14167837599.01
159Fritz Strack6077537569.01
160Jeff T. Larsen18174366710.01
161Nyla R. Branscombe12767036659.01
162Yaacov Schul4116136649.01
163D. S. Moskowitz34187436639.01
164Pablo Brinol13566736629.01
165Todd B. Kashdan3777336619.01
166Barbara L. Fredrickson2877236619.01
167Duane T. Wegener9807736609.01
168Joanne V. Wood10937436609.01
169Daniel A. Effron4846636609.01
170Niall Bolger3766736589.01
171Craig A. Anderson4677636559.01
172Michael Harris Bond37873358410.01
173Glenn Adams27071357310.01
174Daniel M. Bernstein40473357010.01
175C. Miguel Brendl12176356810.01
176Azim F. Sharif18374356810.01
177Emily Balcetis59969356810.01
178Eva Walther49382356610.01
179Michael D. Robinson138878356610.01
180Igor Grossmann20364356610.01
181Diana I. Tamir15662356210.01
182Samuel L. Gaertner32175356110.01
183John T. Jost79470356110.01
184Eric L. Uhlmann45767356110.01
185Nalini Ambady125662355610.01
186Daphna Oyserman44655355410.01
187Victoria M. Esses29575355310.01
188Linda J. Levine49574347810.01
189Wiebke Bleidorn9963347410.01
190Thomas Gilovich119380346910.01
191Alexander J. Rothman13369346510.01
192Francis J. Flynn37872346310.01
193Paula M. Niedenthal52269346110.01
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The Diminishing Utility of Replication Studies In Social Psychology

Dorthy Bishop writes on her blog.

“As was evident from my questions after the talk, I was less enthused by the idea of doing a large, replication of Darryl Bem’s studies on extra-sensory perception. Zoltán Kekecs and his team have put in a huge amount of work to ensure that this study meets the highest standards of rigour, and it is a model of collaborative planning, ensuring input into the research questions and design from those with very different prior beliefs. I just wondered what the point was. If you want to put in all that time, money and effort, wouldn’t it be better to investigate a hypothesis about something that doesn’t contradict the laws of physics?”


I think she makes a valid and important point. Bem’s (2011) article highlighted everything that was wrong with the research practices in social psychology. Other articles in JPSP are equally incredible, but this was ignored because naive readers found the claims more plausible (e.g., blood glucose is the energy for will power). We know now that none of these published results provide empirical evidence because the results were obtained with questionable research practices (Schimmack, 2014; Schimmack, 2018). It is also clear that these were not isolated incidents, but that hiding results that do not support a theory was (and still is) a common practice in social psychology (John et al., 2012; Schimmack, 2019).

A large attempt at estimating the replicability of social psychology revealed that only 25% of published significant results could be replicated (OSC). The rate for between-subject experiments was even lower. Thus, the a-priori probability (base rate) that a randomly drawn study from social psychology will produce a significant result in a replication attempt is well below 50%. In other words, a replication failure is the more likely outcome.

The low success rate of these replication studies was a shock. However, it is sometimes falsely implied that the low replicability of results in social psychology was not recognized earlier because nobody conducted replication studies. This is simply wrong. In fact, social psychology is one of the disciplines in psychology that required researchers to conduct multiple studies that showed the same effect to ensure that a result was not a false positive result. Bem had to present 9 studies with significant results to publish his crazy claims about extrasensory perception (Schimmack, 2012). Most of the studies that failed to replicate in the OSC replication project were taken from multiple-study articles that reported several successful demonstrations of an effect. Thus, the problem in social psychology was not that nobody conducted replication studies. The problem was that social psychologists only reported replication studies that were successful.

The proper analyses of the problem also suggests a different solution to the problem. If we pretend that nobody did replication studies, it may seem useful to starting doing replication studies. However, if social psychologists conducted replication studies, but did not report replication failures, the solution is simply to demand that social psychologists report all of their results honestly. This demand is so obvious that undergraduate students are surprised when I tell them that this is not the way social psychologists conduct their research.

In sum, it has become apparent that questionable research practices undermine the credibility of the empirical results in social psychology journals, and that the majority of published results cannot be replicated. Thus, social psychology lacks a solid empirical foundation.

What Next?

It is implied by information theory that little information is gained by conducting actual replication studies in social psychology because a failure to replicate the original result is likely and uninformative. In fact, social psychologists have responded to replication failures by claiming that these studies were poorly conducted and do not invalidate the original claims. Thus, replication studies are both costly and have not advanced theory development in social psychology. More replication studies are unlikely to change this.

A better solution to the replication crisis in social psychology is to characterize research in social psychology from Festinger’s classic small-sample, between-subject study in 1957 to research in 2017 as exploratory and hypotheses generating research. As Bem suggested to his colleagues, this was a period of adventure and exploration where it was ok to “err on the side of discovery” (i.e., publish false positive results, like Bem’s precognition for erotica). Lot’s of interesting discoveries were made during this period; it is just not clear which of these findings can be replicated and what they tell us about social behavior.

Thus, new studies in social psychology should not try to replicate old studies. For example, nobody should try to replicate Devine’s subliminal priming study with racial primes with computers and software from the 1980s (Devine, 1989). Instead, prominent theoretical predictions should be tested with the best research methods that are currently available. Thus, the way forward is not to do more replication studies, but rather to use open science (a.k.a. honest science) that uses experiments to subject theories to empirical tests that may also falsify a theory (e.g., subliminal racial stimuli have no influence on behavior). The main shift that is required is to get away from research that can only confirm theories and to allow for empirical data to falsify theories.

This was exactly the intent of Danny Kahneman’s letter, when he challenged social priming researchers to respond to criticism of their work by going into their labs and to demonstrate that these effects can be replicated across many labs.

Kahneman makes it clear that the onus of replication is on the original researchers who want others to believe their claims. The response to this letter speaks volumes. Not only did social psychologists fail to provide new and credible evidence that their results can be replicated, they also demonstrated defiant denial in the face of replication failures by others. The defiant denial by prominent social psychologists (e.g., Baumeister, 2019) make it clear that they will not be convinced by empirical evidence, while others who can look at the evidence objectively do not need more evidence to realize that the social psychological literature is a train-wreck (Schimmack, 2017; Kahneman, 2017). Thus, I suggest that young social psychologists search the train wreck for survivors, but do not waste their time and resources on replication studies that are likely to fail.

A simple guide through the wreckage of social psychology is to distrust any significant result with a p-value greater than .01 (Schimmack, 2019). Prediction markets also suggest that readers are able to distinguish credible and incredible results (Atlantic). Thus, I recommend to build on studies that are credible and to stay clear of sexy findings that are unlikely to replicate. As Danny Kahneman pointed out, young social psychologists who work in questionable areas face a dilemma. Either they have to replicate the questionable methods that were used to get the original results, which is increasingly considered unethical, or they end up with results that are not very informative. On the positive side, the replication crisis implies that there are many important topics in social psychology that need to be studied properly with the scientific method. Addressing these important questions may be the best way to rescue social psychology.