What is chosen first, the hand used for reaching or the target that is reached?

Abstract

Models of information processing generally assume that stimuli are processed before actions are selected, at least in typical laboratory experiments where stimuli are presented and responses follow. In everyday life, however, there are generally fewer constraints on the ordering of decisions pertaining to stimuli and actions. This raises the question of which sorts of decisions normally precede which others. To address this question, we asked participants to aim for either of two targets with either hand on the basis of whichever combination seemed easiest. We analyzed the choices made in this free condition with choices made when the hand was specified or when the target was specified. We found that a model assuming similar selection processes in the hand-specified condition and the free condition provided the best account for the data. The data accord with the hypothesis that hand was generally chosen first in the free-choice condition.