Evaluation of Decision-Making Behavior Under Uncertainty in Capuchin Monkeys (Sapajus apella) and Humans (Homo sapiens) Using a Modified Balloon Analogue Risk Task

Many animals, including humans, must make decisions when outcomes involve risk and/or ambiguity. To explore the evolutionary roots of decision making when outcomes are unknown, we modified the Balloon Analogue Risk Task (BART) for use with tufted capuchin monkeys (Sapajus [Cebus] apella), creating the Primate Analogue Risk Task (PART). Using both the BART and the PART, we first compared human performance across the two tasks using analogous parameters. Humans' performance on the two tasks was positively correlated. Next, we tested capuchin monkeys' performance on the PART to assess their decision-making strategies in the context of ambiguity. Secondarily, although it was not the main goal of the study, this allowed us to look at species differences between capuchins' and humans' performance. Finally, we investigated the influence of prior experience on human and capuchin decision-making behavior. Neither capuchins nor humans behaved differently following an unsuccessful trial compared to a successful trial. We found individual differences in capuchin monkeys' choice behavior, though as a whole they demonstrated a pattern of reward maximization over time. Finally, as a species, capuchins had lower PART risk scores than humans. This paradigm presents a useful way to assess behavior in a context with uncertain outcomes using a comparative approach.

Automated summary

This study modified the Balloon Analogue Risk Task to test decision-making strategies in tufted capuchin monkeys. The results showed differences in performance between capuchins and humans, with capuchins scoring lower in risk assessment as a species.