Interpersonal forgiveness is a burgeoning area of research in psychology and has been linked to lower levels of depression and perseverative cognitive states such as rumination.As much of the extant research employs self-reported assessments of forgiveness, the aims of the present work are to test a novel operational definition of forgiveness using behavioral outcomes from economic games-specifically, the Ultimatum Game (UG) and Dictator Game (DG)-and to explore how such behavior corresponds with phasic heart rate (HR), heart rate variability (HRV), individual differences, and psychosocial variables.Participants (n = 89; age M = 19 years; 46% female) were instrumented with continuous electrocardiogram and were seated for a 5minute resting baseline, a pre-post adaptation of the DG and UG with digital opponents, randomization to forgiveness or rumination imagery, and a 5-minute recovery period.Participants reported affective ratings as a manipulation check as well as questionnaires on state and trait forgiveness, hostility, and rumination.Forgiving behavior was operationalized as more generous monetary offers to previously unfair, provoking opponents (positive value for post-minus pre-manipulation DG offer).As hypothesized, individuals who imagined forgiving previously unfair, provoking opponents showed more behavioral forgiveness in their return offers and reported less negative affect