Rudolf Kerschreiter

Who they are

Kerschreiter is the first author of Biased information search in homogeneous groups: Confidence as a moderator for the effect of anticipated task requirements, published in Personality and Social Psychology Bulletin in 2008. His co-authors were Stefan Schulz-Hardt, Andreas Mojzisch and Dieter Frey. The paper reports three experiments with groups of three people whose members had each already chosen the same option before any discussion took place.

Key papers

Kerschreiter, R., Schulz-Hardt, S., Mojzisch, A., & Frey, D. (2008). Biased information search in homogeneous groups: Confidence as a moderator for the effect of anticipated task requirements. Personality and Social Psychology Bulletin, 34(5), 679-691. doi:10.1177/0146167207313934 https://doi.org/10.1177/0146167207313934

Key ideas

The paper asks whether groups that already agree seek out information that backs their view regardless of what they will do next, or whether they adjust their search to the demands of the coming task. In the experiments, each group could request as many as it liked from ten expert statements, five supporting and five opposing its preliminary decision. Some groups were told they would write an essay justifying their decision, and others that they would take part in a debate refuting counterarguments.

Across all three experiments, the groups strongly preferred information that supported what they had already decided. The expected task changed the search only for groups that were not very sure of themselves. Moderately confident groups searched in a balanced way, or even favoured opposing information, when they expected to rebut counterarguments, and searched one-sidedly when they expected to justify. Highly confident groups favoured supporting information whichever task they expected.

In the second experiment confidence was manipulated rather than only measured, and the same split appeared. The paper therefore reports confidence as a moderator of how a group's expected task affects its search, in groups where agreement came before the discussion.

The article What is groupthink? places this result among the experimental tests of the ingredients of Janis's theory. It sits beside the idea of confirmation bias, here observed in groups, and beside Colin Fisher's argument in The Collective Edge that remedies for groupthink lie in how a group is organised.

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