Choice Under Risk of Gain in Tufted Capuchin Monkeys (Sapajus apella): A Comparison With Young Children (Homo sapiens) and Mangabey Monkeys (Cercocebus torquatus torquatus)

Risk proneness in the gain domain is usually observed in monkeys, apes, and human children. To explore the inhibitory constraints underlying primates' performance on tasks investigating economic risk sensitivity, tufted capuchin monkeys (Sapajus apella) were presented with a gambling task for food reward in which participants have to choose between two options, a certain option and a risky option. Capuchins' attitudes toward risk differed between experimental conditions: Whereas capuchins were indifferent to options in Experiment 1 in which the cover on the safe option was opaque, they preferred the safe option in Experiment 2 in which the cover on the safe option was transparent. We attribute performance differences between opaque and transparent covers to difficulties to inhibit a prepotent response toward the reward that is fully visible. The results are compared with the performances recorded in young children (Homo sapiens) and red-capped mangabeys (Cercocebus torquatus torquatus) under the same paradigm. Our findings point to species differences for how visual access of the reward value controls decision-making under the risk of gain. They suggest distinct attentional mechanisms underlying economic choice behavior in capuchins and mangabeys.