Abstract # 53:

Scheduled for Thursday, August 17, 2006 04:30 PM-04:45 PM: Session 6 (Regency East #3) Oral Presentation


ELDERLY RHESUS MACAQUES (Macaca mulatta) USE DIFFERENT STRATEGIES TO SOLVE INVISIBLE DISPLACEMENT TASKS WITH VARYING AMOUNTS OF VISUAL INFORMATION

P. K. Prunty1 and M. A. Novak1,2
1Neuroscience and Behavior Program, University of Massachusetts , Amherst, MA 01003, USA, 2Department of Psychology, University of Massachusetts, Amherst, MA 01003
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     Preliminary data with three rhesus macaques (Macaca mulatta) hinted at an age difference in how macaques solve an invisible displacement task with varied visual information. For older, but not the younger, animals, visual information was important. To explore this possible age effect, we tested 11 subjects which fell into three age categories: elderly (17+ years; 2 males and 2 females), young adults (4 to 6 years; 1 male and 2 females), and juveniles (2 to 4 years; 2 males and 2 females). During testing, an object fell through one of three clear tubes and disappeared behind an occluding panel with three upside-down cups at the bottom. In Condition 1, the animals were tested on a descending series in which the object’s visible trajectory started at 15-cm and was increased (until 35-cm) and decreased (until 15-cm) using 5-cm increments. In Condition 2, we tested whether or not the animals based their search patterns on the available visible trajectory or on the object’s proximity to the cup when it disappeared. Elderly animals solved the task by choosing the location where the object was last seen whereas younger animals were able to solve the task at lower trajectory amounts (p < 0.05, binomial distribution). These results demonstrate that macaques are able to solve invisible displacement tasks although the skill with which this is accomplished may vary with age.