Action selection and likelihood ratio estimation by individuals and groups

Abstract

This study investigates the shifts between individual and group performance in a choice dilemma, a gambling, and a Bayesian likelihood ratio estimation task. Twenty seven male subjects performed each task alone. Six four-man leaderless groups were formed and repeated the each task. Three subjects performed the task alone a second time. Finally, all 27 subjects repeated each task again alone. The choice dilemma task decisions reproduced previously found patterns of shifts. Groups preferred higher variance gambles than did the average of pregroup individuals. The post-group likelihood ratio estimates of 22 of the 24 test subjects resembled their group's estimates more closely than they resembled their own pregroup estimates. Both group and individual correlations between measures of performance in all three tasks were low.