Delay choice versus delay maintenance: different measures of delayed gratification in capuchin monkeys (Cebus apella).

Delaying gratification involves 2 components: (1) delay choice (selecting a delayed reward over an immediate one) and (2) delay maintenance (sustaining the decision to delay gratification even if the immediate reward is available during the delay). Two tasks most commonly have explored these components in primates: the intertemporal choice task and the accumulation task. It is unclear whether these tasks provide equivalent measures of delay of gratification. Here, we compared the performance on the intertemporal choice task and the accumulation task of capuchin monkeys (Cebus apella) belonging to 2 study populations. We found only limited evidence of a significant correlation in performance. Consequently, in contrast to what is often assumed, our data provide only partial support for the hypothesis that these tasks provide equivalent measures of delay of gratification.