What's the Deal with Replication?

Wondering what the fun and fascinating stories were in the world of Psychology on Twitter this week? Let me tell you! The Psychology Twittersphere has been full of thoughts about a very important topic lately: Replication.

If you remember back to your first science classes, replication is a key part of the scientific method! In science, we develop hypotheses, or guesses, about a given phenomenon. Then we make predictions based on our hypotheses which can be tested by conducting experiments and analyzing the results of those experiments. After an experiment is conducted once and produces a set of results, it is important to repeat it and see if the results are replicated.

In some physical sciences, replication is simply a matter of running a chemical reaction a second time or repeating a DNA sequencing. In the psychological sciences, our experiments and methods can be very complex and replicating results can be time-consuming, so replication studies are rarely conducted.

In recent years, many psychological scientists have called for a revival of replication, pointing to the importance of replication for the advancement of our science. The Association for Psychological Science holds replication projects which encourage psychologists across the country to run previously published studies in their own labs and see if others’ results can be replicated. In their upcoming replication project, APS has called for replications of the famous “ego depletion effect,” the idea that one’s ability to exercise self-control limited, and is depleted as self-control is exerted (Baumeister, Bratslavsky, Muraven, & Tice, 1998).

The first APS replication project resulted in a Registered Replication Report which was published in September of this year. This project focused on the “verbal overshadowing” effect, which suggests that recalling or describing a visual memory (specifically of a crime) can impair later recognition of an image (Schooler & Engstler-Schooler, 1990). One of the psychological scientists behind the experiment that first showed this effect, Jonathan Schooler, wrote in nature that he welcomed the APS replication project, whether it supported or disconfirmed his results. In the end, The APS replication project confirmed the original finding, though the replicating labs found smaller effects than were originally reported (Alogna et al., 2014).

These replication projects are an important advancement for Psychological Science. Not only do they offer a way to explore our field’s most important findings, they also raise the profile of replication and remind us all of its importance.


For further reading:

Alogna, V. K., Attaya, M. K., Aucoin, P., Bahnik, S., Birch, S., Birt, A. R., ...Zwaan, R. A. (2014). Registered replication report: Schooler & Engstler-Schooler (1990). Perspectives on Psychological Science, 9, 556–578.

Baumeister, R. F., Bratslavsky, E., Muraven, M., & Tice, D. M. (1998). Ego depletion: Is the active self a limited resource? Journal of Personality and Social Psychology, 74, 1252-1265. doi: 10.1037/0022-3514.74.5.1252

Schooler, J. W. (2014). Turning the lens of science on itself: Verbal overshadowing, replication, and metascience. Perspectives on Psychological Science, 9, 579–584.

Schooler, J. W., & Engstler-Schooler, T. Y. (1990). Verbal overshadowing of visual memories: Some things are better left unsaid. Cognitive Psychology, 22, 36–71. doi:10.1016/B0-08-043076-7/01599-0

Simons, D. J., Holcombe, A. O., & Spellman, B. A. (2014). An introduction to registered replication reports at Perspectives on Psychogical Science. Perspectives on Psychological Science, 9, 552–555.

Simone Schnall on replication projects and replies to and discussions on her post.