Effects of the motivation focus on manual grasping.

Abstract

We have shown before that grasping movements from a given starting position to a given object differ substantially when performed as a typical laboratory task (L) and when they are embedded in an everyday-like context (E). The present study investigates whether this context-dependence is related to the subjects' motivation focus. We manipulated subjects' motivation focus and observed significant effects of Context on performance, as in previous work, but also significant effects of Motivation and Context x Motivation on performance. The interaction term could not be interpreted as generally higher or lower motivation sensitivity in L than in E, and therefore it doesn't support the hypothesis that context-dependence of grasping can be reduced to motivation-dependence. We conclude that some brain areas contribute differently to L and to E, thus producing contextdependence, and that those areas are differently sensitive to motivation.