Figure 3.

Social information is a valuable resource for macaque monkeys. (a) A rhesus macaque on Cayo Santiago assumes a vulnerable posture (left) to drink from a puddle, but periodically interrupts this posture in order to visually scan the surrounding region for potential threats (right). There are no predators on the island, but aggressive social interactions are commonplace. (b) Values determined for different image classes for two male monkey subjects (open and closed bars), in ms of fluid delivery time. Positive deflections indicate the subject was willing to forgo fluid to view that image class. Negative deflections indicate the subject required fluid overpayment to choose that image class. Hindquarters refers to the perineal sexual signals of familiar females. Dominant and subordinate refer to the faces of familiar dominant and subordinate males. Gray refers to a plain gray square matched for size and luminance to the other image classes. Behavioral data depicted here corresponds to neural data depicted in Figure 4, below. Photographs by K. K. Watson.