ABSTRACT
Information processing is generally assumed to involve both automatic/preattentive and controlled/attentional processes, and research has been concerned with what reactions to stimuli reflect which type of processing, and how and when preattentive and attentional processes interact. However, much of the research has inferred preattentive effects from voluntary behavioral responses that occur relatively late in the processing stream. In contrast, psychophysiological methods permit observation of physiological reactions that occur both automatically and relatively early in time, and have the further advantage of being measurable across the life span and across species.
