Humans were required to space taps on a response key at least 55 seconds apart, but not more than 60 seconds apart (interresponse time, or IRT, equals 55-60 seconds). One group (no feedback group) was not given any information about the durations of their IRT's during the experimental sessions. A second group (low feedback group) was given visual and auditory stimuli when IRT's were between 55 and 60 seconds. A third group (high feedback group) was given the visual and auditory stimuli when IRT's were between 55 and 60 seconds, was given a second visual stimulus when IRT's were less than 55 seconds and was given a third visual stimulus when IRT's were more than 60 seconds. Changes in the pattern of IRT durations after ethyl alcohol were largest in the no feedback group, less in the low feedback group and smallest in the high feedback group. Ethyl alcohol increased the proportion of long IRT's of subjects in the no feedback group. In the low feedback group, ethyl alcohol usually increased the proportion of long IRT's, but in some subjects other changes in the pattern of IRT durations were observed. Ethyl alcohol occasionally increased the proportion of both long and short IRT's of subjects in the high feedback group, although this effect was small. During control sessions first order sequential dependencies of IRT durations occurred in all groups, but the sequential dependencies were more pronounced in the no feedback and low feedback groups than in the high feedback group. Ethyl alcohol had little tendency to disrupt these IRT sequential dependencies.
Abstract