The role of goal representations in moving to temporal and spatial targets

Abstract

Traditionally, movement kinematics are thought to reflect physical properties (e.g., position and time) of movement targets. However, targets may also evoke intentional goals like “to be in a certain position at a given time”. Therefore, kinematics may be viewed not as a reaction to stimuli, but rather as the means to attain intended goals. In the present study participants performed continuous reversal movements. It was first shown that kinematics towards temporal and spatial targets differ from kinematics away from those targets. Further, kinematics are different for movements to temporal (relatively short movement times, high and late peak velocity) and spatial (relatively long movement times, early peak velocity) targets (Experiments 1 and 2). In order to obtain evidence for the influence of goal representations on kinematics, combinations of temporal and spatial targets were investigated in Experiments 3 and 4. Specifically, the conditions were: spatial targets always present with varying temporal targets, temporal targets always present with varying spatial targets, and combined and separate spatial and temporal targets. Not only the physical features, but also how the targets were represented as movement goals, were important. Thus, movement kinematics do not simply reflect stimulus properties, but rather the representation of the intended goal.

I want to thank Dirk Kerzel and Lothar Knuf for providing helpful computer routines. Further thanks go to Christian Ginglseder, Jana Hiller, and Ursula Weber for their help with collecting the data. I also thank Fiorello Banci for building the cover for the writing pad and Assja Metzger for improving the English. Thanks go also to Wolfgang Prinz, who supported this study. Last but not least I thank Werner Helsen, Howard Zelaznik, and one anonymous reviewer for the helpful comments on the manuscript.