Social Effects on Action Planning

Author:

Santamaria, Joseph Philip

Graduate Program:

Psychology

Degree:

Master of Science

Document Type:

Master Thesis

Date of Defense:

May 14, 2008

Committee Members:

David A. Rosenbaum, Thesis Advisor/Co-Advisor
David A. Rosenbaum, Thesis Advisor/Co-Advisor

Keywords:

mirror neurons
common coding
grasping
reaching

Abstract:

The fields of motor control and social psychology have recently merged, giving rise to studies of mirror neurons, observational facilitation, joint action, and a variety of other topics. Within this spectrum of studies, however, there is a gap at the level of observation-action coupling and joint action. The current study was designed to fill this gap. It did so by making use of a finding in motor control, the grasp height effect (GHE), wherein people take hold of a vertically oriented cylinder high when they plan to bring the cylinder to a low position and low when they plan to bring the cylinder to a high position (Cohen & Rosenbaum, 2004). The experiments make use of a variation of the original GHE study, adding an explicit cue about target location with an implicit cue of grasp height embedded in that explicit cue. The explicit cue related to target height, while the implicit cue was a modeled grasp height that was not related to satisfying the demands of the task but that was related to satisfying the demands of the GHE. Experiment 1 established that the mere cuing of a location on a plunger did not significantly influence the GHE. Experiments 2-4 showed that increasing amounts of observational information significantly affected the GHE, resulting in an attenuation of that effect that increased with the amount of observational information available. Experiment 5 used a simpler version of the experiment that could later be used to assess other potential variables of interest, with the result that individuals were sensitive to modeled grasp-heights. Experiment 5 has promising extensions both in the fields of motor control and social psychology. Briefly discussed are the possibilities for investigating actor-observer differences, such as the role of prejudice and empathy in the action-observation system.