PLANNING A COORDINATED SEQUENCE OF ACTIONS: COTTON-TOP TAMARINS (SAGUINUS OEDIPUS) STICK TO THE PLAN

Open Access
Author:
Chapman, Kate M
Graduate Program:
Psychology
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
None
Committee Members:
  • Daniel J Weiss, Thesis Advisor
Keywords:
  • comparative cognition
  • nonhuman primates
  • motor planning
  • cotton-top tamarins
Abstract:
Cotton-top tamarins have demonstrated sophisticated anticipatory motor planning when performing a single grasp (Weiss, Wark & Rosenbaum, 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, an effect evidenced in all subjects. This significant difference was found in Experiments 2, 3, and the trend, although not significant, appeared in Experiment 4 as well. 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.