Abstract # 2247 Event # 186:

Scheduled for Saturday, June 23, 2007 09:30 AM-09:45 AM: Session 17 (North Main Hall E) Oral Presentation

Orienting by Prosimian Primates in Naturalistic Conditions

S. V. Shepherd and M. L. Platt
Duke University, Box 3209, Bryan Research Bldg, Research Dr, Durham, NC 27710, USA
     Orienting reflects the integration of sensory, motor, and motivational variables with behavioral goals, and certain stimuli may thus have intrinsic salience for visual orienting during natural behavior. We used telemetric infrared video gaze-tracking technology to quantitatively measure gaze in freely-moving, social primates (Lemur catta). Eye and scene video data broadcast via mobile transmitter were analyzed at 0.216 x 33.3ms resolution in a custom-designed Matlab environment. We habituated 2 socially-housed adult males to the gear; measured pupil position and size during hand restraint and free movement; and recorded visual orienting during interaction and locomotion. Permutations tests [a=0.05] showed all categories were fixated more often than chance; subjects systematically gazed toward lemurs and humans significantly more than food rewards, and food rewards significantly more than high-contrast environmental features. During locomotion this pattern reversed, with gaze toward environmental features significantly enhanced; and toward food rewards, lemurs or humans significantly suppressed. Chi-squared tests [a=0.05] also showed significant evidence of gaze-following behavior (during and after fixations), which has not been previously reported in prosimian primates. These experiments provided the first precise measurements of visual orienting in freely-moving nonhuman animals and the first quantitative measurement of eye movements in prosimian primates. Support contributed by the Alfred P. Sloan Foundation and Duke Lemur Center.