Off-campus UMass Amherst users: To download campus access theses, please use the following link to log into our proxy server with your UMass Amherst user name and password.

Non-UMass Amherst users: Please talk to your librarian about requesting this thesis through interlibrary loan.

Theses that have an embargo placed on them will not be available to anyone until the embargo expires.

Access Type

Open Access

Degree Program

Neuroscience & Behavior

Degree Type

Master of Science (M.S.)

Year Degree Awarded

January 2007

Month Degree Awarded



Attribution of knowledge refers to equating a shared visual perspective with shared information, a characteristic of human behavior. However, there is considerable debate as to whether nonhuman primates understand the significance of gaze and will select a treat from an experimenter that looks at them as opposed to one that does not. In previous studies, chimpanzees could not differentiate between looking and nonlooking experimenters. However, treats were held in the hands, a considerable distance from the face. We asked whether a group of five rhesus monkeys (Macaca mulatta) could discriminate lookers from nonlookers. We eliminated the problem of focusing on the hands by holding treats in close proximity to the experimenters’ eyes. Monkeys were trained to use an apparatus to select an experimenter. All five subjects were subsequently able to discriminate between experimenters holding different food rewards, even when these rewards were placed out of the monkey’s view. Two of the monkeys could also select the experimenter who initially held a desirable treat after the treat was hidden and that experimenter changed location. On the seeing and knowing task, two probe types of visual occlusion were used: Probe 1- one experimenter turned his head away from the monkey, Probe 2- one experimenter covered his eyes with a blindfold. Position, experimenter, probe trial, and reward type (on standard trials) were block randomized. Data were analyzed using binomial probabilities with &#;=0.05. At the group level, all five monkeys requested food from the experimenter looking at them significantly more than would be expected by chance, but individual subject performance differed depending on probe condition. These data suggest that some rhesus macaques have the ability to understand the connection between seeing and knowing.

First Advisor

Melinda A. Novak