Conditional Copying Fidelity in Capuchin Monkeys (Cebus apella)

In the last two decades, it became largely accepted that monkeys show little, if any, copying fidelity. However, some recent studies have begun to challenge this notion. To explore reasons for such contrary findings, we designed a foraging apparatus so that in each of two experiments with capuchin monkeys (Cebus apella), a model would demonstrate one of two alternative methods to obtain food. The apparatus had a V-shaped track on which a panel could be slid up left or right from the center to reveal food. In Experiment 1, food was located in a cup directly behind the center panel. In Experiment 2, sliding the panel left or right revealed food either in left or right ends of the V-track. Since this sliding movement led directly to one food location exclusive of the other, we predicted capuchins would show greater copying fidelity in this second Experiment. Instead, subjects were significantly more faithful to the model's method in Experiment 1, which provided strong evidence of capuchins copying what they had observed. We suggest that the contrasting results of Experiment I may have occurred because capuchins prioritize exploratory behavior when alternative foraging locations are accessible.