Abstract
For centuries scientists have debated whether our brains complete perceptual processing of an object before preparing the appropriate behavioral response to it. To account for behavioral reaction time effects, some models propose that information transmission between perceptual and response selection stages of processing is discrete and that perception is completed before response selection. Other models propose that information flow is cascaded and that information begins to flow between processing stages before perception is complete. We distinguished between these models by simultaneously recording multiple electrophysiological responses that measure when attention is focused on and withdrawn from task-relevant objects and when the appropriate behavioral response to the target object begins being selected. Here we show that perceptual attention is withdrawn from target objects before the response to the stimulus is selected during visual search. This same pattern of neurophysiological results was obtained when we stressed speed over accuracy of the behavioral response. These findings show that during cognitive processing humans complete perceptual processing of target objects before preparing the correct behavioral responses to their appearance.