Auditory evoked potential amplitude and variability: Effects of task and intellectual ability

Studied the effect of stimulus uncertainty, attention, interstimulus interval, and amount of time in the experimental situation on the average auditory evoked potential in 2 groups of 8 19-29 yr old males separated according to differences in intellectual ability. Results indicate that in general, evoked potential amplitude was greater (a) for the 1st part of the experimental test session compared with the later part, (b) for conditions requiring attention compared with nonattending conditions, (c) for the stimulus following the long (rather than short) interstimulus interval, and (d) for conditions of greatest stimulus uncertainty. Also, evoked potential variability was found to increase as amplitude increased. Evoked potential differences between experimental groups suggested divergence both in strategies employed and in effects of experimental conditions on these groups. (26 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).