Altruism, reciprocity, and probability: Examining relations through a discounting framework.

Probability and reciprocation have been implicated as key variables for understanding altruism and cooperation. Social discounting, which describes the decline in reward value as the recipient increases in social distance, has provided a framework through which to examine altruistic and cooperative choice. A previous study introduced reciprocal discounting as a way of studying perceived altruism from others (termed reciprocal altruism). But probability discounting has not yet been examined in relation to reciprocal discounting. In order to extend research on reciprocal discounting, the present study evaluated correlations between social, reciprocal, and probability discounting as well as relations between standard social distance (used in social discounting) and reciprocal social distance (the participant's perceived social distance placement on someone else's list) among 129 participants. Upon evaluation, the fit of median reciprocal discount rates to the hyperbolic form was replicated. A strong correlation between social and reciprocal discount rates and a moderate correlation between social and probability discount rates were found as well. Additionally, reciprocal and probability discount rates yielded moderate correlations while reciprocal and standard social distance analyses revealed more correspondence between reward values when persons were socially close (i.e., Person 1) or socially distant (i.e., Person 100). This study provides further evidence that reciprocation and probability likely impact altruistic choice while laying groundwork for further investigations into social distance.