Replication studies: Bad copy

Nature:

For many psychologists, the clearest sign that their field was in trouble came, ironically, from a study about premonition. Daryl Bem, a social psychologist at Cornell University in Ithaca, New York, showed student volunteers 48 words and then abruptly asked them to write down as many as they could remember. Next came a practice session: students were given a random subset of the test words and were asked to type them out. Bem found that some students were more likely to remember words in the test if they had later practised them. Effect preceded cause.

Bem published his findings in the Journal of Personality and Social Psychology (JPSP) along with eight other experiments1 providing evidence for what he refers to as “psi”, or psychic effects. There is, needless to say, no shortage of scientists sceptical about his claims. Three research teams independently tried to replicate the effect Bem had reported and, when they could not, they faced serious obstacles to publishing their results. The episode served as a wake-up call. “The realization that some proportion of the findings in the literature simply might not replicate was brought home by the fact that there are more and more of these counterintuitive findings in the literature,” says Eric-Jan Wagenmakers, a mathematical psychologist from the University of Amsterdam.

Read the whole story: Nature