Analysis results from Experiment 1 using mixed-effects logistic regressions of partner condition and temptation level on subject’s choices.

Model 1 is used for inferring the effect of partner condition on altruism rates; it contains a by-subject random coefficient for this variable. Likewise, Model 2 is used for inferring the effect of temptation level on altruism rates; it contains a by-subject random coefficient for this variable.