UCL Discovery

Abstract

This paper reports an experiment on the advance planning of actions. Twelve subjects grasped an 8-sided object, and performed a sequence of movements involving juxtaposing a designated face of the object with a designated target. The location of each finger of the right hand on the faces of the 8-sided object was recorded. Results showed that the grip pattern differed significantly from a case where subjects were asked simply to grasp the 8-sided object, without moving it. Further, comparison of sequences of moves involving different target positions showed that subjects did chose grip patterns based on the specific moves they were asked to make. These adjustments were generally more common when the critical item occurred earlier in a sequence than when it occurred later, suggesting a gradient of advance planning comparable to the serial position effect in memory tasks. Further, the grip adjustments observed consisted primarily of reconfigurations of the hand, involving changing the point of contact on the object of a subset of fingers, rather than rotations of the whole hand with respect to the object. (C) 1998 Elsevier Science B.V. All rights reserved.