EEG correlates of signal rate, time in task and individual differences in reaction time during a five-stage sustained attention task.

Abstract

Abstract The EEG of 20 subjects was monitored continuously while they performed a sustained attention task in which each subject performed five conditions in different order. All conditions involved regular presentation of digits (stimuli) at the rate of one per two seconds. Subjects were required to respond to particular digits (signals) and signal ratios varied between 10 and 50% over the five conditions. There was a brief rest between each condition, and total task time (including periods of rest) was approximately 112 min. The Results were: (i) Mean reaction time to wanted signals increased following the first condition (independent of signal ratio) and was also longest for the 50% signal ratio condition (independent of order of presentation), (ii) Errors (false positives and misses) increased as a function of signal ratio but not as a function of order of presentation. Subjects with faster mean reaction time committed more errors. However overall absolute error rate was low (3.2% under the most extre...