Capuchins (Cebus apella) can solve a means-end problem

Three capuchin monkeys (Cebus apella) were tested on a 2-choice discrimination task designed to examine their knowledge of support, modeled after Hauser, Kralik, and Botto-Mahan's (1999) experiments with tamarins. This task involved a choice between 2 pieces of cloth, including 1 with a food reward placed on its surface, and a second cloth with the food reward next to its surface. After reliably solving the basic problem, the capuchins were tested with various alternations of the original food reward and cloth. The capuchins were able to solve the initial task quickly, and generalize their knowledge to additional functional and nonfunctional variations of the problem. In comparison to the tamarins previously tested on this problem (Hauser et al., 1999), the capuchins were able to reach criterion faster during the training and food size conditions and showed a greater ability to inhibit reaching toward larger food rewards that were unavailable.