Self-correction — a key feature distinguishing science from pseudoscience — requires that scientists update their beliefs in light of new evidence. However, people are often reluctant to change their beliefs. We examined belief updating in action by tracking research psychologists’ beliefs in psychological effects before and after the completion of four large-scale replication projects. We found that psychologists did update their beliefs; they updated as much as they predicted they would, but not as much as our Bayesian model suggests they should if they trust the results. We found no evidence that psychologists became more critical of replications when it would have preserved their pre-existing beliefs. We also found no evidence that personal investment or lack of expertise discouraged belief updating, but people higher on intellectual humility updated their beliefs slightly more. Overall, our results suggest that replication studies can contribute to self-correction within psychology, but psychologists may underweight their evidentiary value.
McDiarmid, A.D., Tullett, A.M., Whitt, C.M., Vazire, S., Smaldino, P.E., and Stephens, J.E. 2021. Psychologists update their beliefs about effect sizes after replication studies. Nature Human Behaviour 5, 12, 1663–1673.