Social Distance and Delay Exert Multiple Control over Altruistic Choices


We evaluated the degree to which delay to reinforcement and social distance concurrently influenced altruistic choices within a discounting paradigm. Forty participants completed two discounting tasks in a repeated measures design. In the SELF task, delay was parametrically imposed on the participant; in the OTHER task, delay was parametrically imposed on the hypothetical other. Results of a multilevel analysis of indifference data supported a hyperbolic discount rate for social distance in both conditions and delay in the OTHER condition. Results also suggested a statistically significant difference in the discount rate between the two discounting tasks (t = -4.53, p <.001 and t = -4.03, p <.001, respectively). Due to a poor fit of the hyperbolic delay discount rate for the SELF task, we compared the hyperbolic fit to a logarithmic model that described an increase in subjective value as a function of delay to reinforcement for the participant. Given support of these models at the individual and group level, we developed multiplicative models for the SELF and OTHER tasks that provided strong fits for the obtained median indifference values. Results are discussed in terms of interpreting human behavior believed to be altruistic as well as potential implications for influencing social policy.



Document Type





Altruism, Choice, Delay discounting, Social discounting

Publication Date


Journal Title

Psychological Record