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Could cooperation among strangers be facilitated by adaptations that use sparse information from first and second impressions to accurately predict cooperative behavior? If so, does more of this information lead to more accurate predictions? We hypothesize that predictions are influenced by stereotypes, descriptions, appearance, and contextualized behavioral history available for first and second impressions. We also hypothesize that predictions improve when more information is available. We conducted a two-part study. First, we recorded thin-slice videos of university students just before their choices in a repeated Prisoner’s Dilemma (PD) with matched partners. Second, a worldwide sample of raters evaluated each player using either videos, photos, only gender labels, or neither images nor labels. Raters guessed players’ first-round PD choices and then their second-round choices after reviewing first-round behavioral histories. Our design allows us to investigate the incremental effects of gender, appearance, and behavioral history gleaned during first and second impressions. Predictions become more accurate as treatments incrementally add gender, appearance, and behavioral history, but predictions from videos are no more accurate than from photos. These results demonstrate how predictive mind reading abilities function under sparse information conditions, helping explain why conditional cooperation is common among strangers.


ESI Working Paper 22-19



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