We knew it all along: Hindsight bias in groups

Two studies investigated the occurrence of hindsight distortion in groups as compared to individuals. Competing predictions were derived from four theoretical positions: Memory impairment, response bias, self-presentation, and group polarization. In Experiment 1, small groups vs individuals made hypothetical predictions with or without outcome information. Both individuals and groups were found to distort their predictions in the direction of the alleged outcome. Experiment 2 employed a memory design in which individuals vs groups made a series of predictions for which they subsequently received outcome information which was either above or below their prediction or for which they received no outcome information. Subjects had to recall their initial prediction. Results indicated that (a) hindsight bias was slightly attenuated in groups compared to individuals, (b) groups were more likely to recall their original predictions correctly than individuals, (c) this recall advantage of groups disappeared when time taken to make the initial prediction was held constant, and (d) outcome information affected hindsight bias but not hit rates. Results were interpreted as supporting the response bias perspective.