Abstract

Cotton top tamarins readily share food with family members. To determine whether food sharing is effected by social awareness and actions, 6 pairs of adult tamarins were presented trials requiring them to emit a response simultaneously to receive a reward, and then were presented a bowl of salient food for sharing. The percentage of time spent sharing food was measured, and compared to trials of the same duration and the same food but without cooperation required before them. Four adult pairs spent a significantly larger portion of their time sharing following the cooperative act. The increase could not be accounted for by reward-induced tolerance to share, for in Experiment 2, the same tamarin pairs did not show a significant increase in sharing following free rewards. Like capuchins in a prior study (de Waal & Berger, 2000), tamarins showed increased sharing following acts which were socially synchronized.