Influence of extended wakefulness on automatic and nonautomatic processing.

We investigated the influence of extended wakefulness on automatic and nonautomatic processes in memory and visual search tasks. Subjects were trained in consistently mapped and variably mapped versions of each task, attaining automatic performance in the consistently mapped versions. We then recorded performance measures and event-related brain potentials for a 14-h period that began during the evening of the last day of training. Overall performance declined with extended wakefulness, but the benefits of consistently mapped training were retained throughout the night. Performance decrements consisted of an increase in nonresponses, increased response latencies, and decreased accuracies. P300 latencies increased, and P300 amplitudes decreased with extended wakefulness. When viewed together, reaction time and event-related brain potentials measures suggest that the locus of extended wakefulness effects was during early perceptual processes.