Prosociality Beyond Big Five Agreeableness and HEXACO Honesty-Humility: Is Openness/Intellect Associated With Cooperativeness in the Public Goods Game?

Who is cooperative? Although Big Five (B5) Agreeableness and HEXACO Honesty-Humility are correlates of charitable prosociality, distinctions between “charity” and “cooperation” suggest that additional traits could be associated with cooperative prosociality. Echoing prior theoretical and empirical indications that B5 Openness/Intellect may play a role in cooperation, Study 1 ( N = 119; exploratory) revealed a significant correlation between Openness/Intellect and cooperativeness in the one-shot Public Goods Game that did not generalize to charitableness in the Dictator Game. We therefore conducted three preregistered replications to discern the robustness of this Openness/Intellect–cooperativeness link. As expected, Openness/Intellect showed no consistent correlation with charitable behavior. Surprisingly, the predicted correlation between Openness/Intellect and cooperative behavior was also inconsistent, partially replicating in Study 3 ( N = 304) but not Studies 2 or 4 ( Ns = 131; 552). Across our replications, cooperative behavior was most strongly correlated with Honesty-Humility (internal meta-analytic [Formula: see text] = .15, p = .005). The correlation between Openness/Intellect and cooperative behavior across our replications was significant and identical in magnitude to that between Agreeableness and cooperative behavior, though this effect-size was weak (internal meta-analytic [Formula: see text] = .08, p < .001). We therefore conclude that Openness/Intellect is a nonnull but very modest correlate of cooperativeness.