A PSYCHOPHYSIOLOGICAL INVESTIGATION OF THE SELECTION AND THE USE OF PARTIAL STIMULUS INFORMATION IN RESPONSE CHOICE

Two alternative explanations were examined for why selective response activation sometimes starts before stimulus identification is complete (e.g., J. O. Miller & S. A. Hackley, 1992) and sometimes starts only after stimulus identification is complete (e.g., R. De Jong, M. Wierda , G. Mulder, & L. J. M. Mulder, 1988). Distinct psychophysiological me thods related to stimulus identification and response selection provid ed evidence suggesting that partial stimulus information is identified but is or is not used before the stimulus is identified more fully, d epending on task requirements. This result (a) suggests strategic adap tation of task performance, (b) is inconsistent with particular discre te and continuous models of information processing, and (c) shows the existence of a central selection mechanism that can prevent the automa tic activation of responses associated with preliminary available stim ulus information.