Date of Submission

Spring 2015

Academic Programs and Concentrations

Psychology; Mind, Brain, and Behavior

Project Advisor 1

Sarah Dunphy-Lelii

Abstract/Artist's Statement

One measure that is commonly used to assess a species’ mental complexity is its gesture-following ability, or the ability to follow a human gesture (such as a gaze or a point) to choose between potential food sources. Animals that have demonstrated this ability include dogs and primates. The high-level explanation of gesture following is that it signifies an animal’s ability to understand the human’s knowledge of where the food is and his intent to communicate that knowledge. However, gesture following could also be explained as being a low-level mechanism relying on directional bias. Looking at the eyes of another individual is an extremely adaptive instinct; even if no perspective taking is involved one is still more likely to find objects of universal interest such as food or threats. For my senior project, I investigated the phenomenon of gaze following in black and white ruffed lemurs at the Trevor Zoo in Millbrook, NY. Specifically, I tested the legitimacy of the gaze following paradigm as a measure of social cognition by comparing lemurs' gaze following of a live person versus a photograph of a person versus a photograph of another lemur. The live person is a more reliable social partner reacting to the environment as it changes. The photo, on the other hand, is a static, abstract representation of a social partner and an indirect communicative gesture made by the true social partner, but that happens to correspond visually with the live gaze cue. The photograph of the other lemur is meant to control for possible differences in response to faces of same and other species, as well as to replicate previous findings that lemurs were able to find hidden food based on gaze information from a photograph of a conspecific. I hypothesized that the lemurs would be able to follow gaze to find hidden food, and that this gaze following would be due to perspective taking. Therefore I expected the lemurs to find the food more often than chance in all conditions, and to find food most often in the live gaze condition. My subjects were not able to find the hidden food more often than chance in any of the three conditions, instead favoring the container to their left. This result indicates that black and white ruffed lemurs may not be capable of following gaze.

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