Abstract # 120:

Scheduled for Saturday, June 19, 2010 08:15 AM-09:25 AM: Session 20 (Medallion Ballroom B) Oral Presentation


K. M. Chapman and D. J. Weiss
The Pennsylvania State University, 608 Bruce V. Moore Building, University Park, PA 16802, USA

Cotton-top tamarins have demonstrated sophisticated anticipatory motor planning when performing a single grasp (Weiss et al., 2007). The present study extends this work by investigating a task that requires a coordinated series of manual motor actions. We presented tamarins with a tape measure that contained a food reward located at a near or far distance that could be reeled in. In Experiment 1, subjects viewed the reward as they pulled. In Experiment 2, subjects received no visual feedback during pulling. In Experiment 3, the amount of rope pulled in both near and far conditions was equated. In Experiment 4, the physical forces on the rope were equated and visual feedback was removed. Tamarins typically used a hand-over-hand method to reel in the food and the dependent variable was the distance between grasps (cm) on the tape measure. In Experiment 1, the inter-grasp distance in the near condition was significantly smaller than in the far condition; t(6)=-3.24, P=0.018, an effect evidenced in all subjects. This difference was found in Experiments 2 [P=0.004], 3 [P=0.032] and 4 [P=0.132]. These results demonstrate that tamarins prospectively scale their pulls as a function of goal-distance, representing multiple-action planning. To the best of our knowledge, these results are the first empirical demonstration of nonhuman primates’ ability to plan an untrained sequence of actions without requiring on-going visual feedback.