AN EFFECT OF ALCOHOL ON THE DISTRIBUTION OF SPATIAL ATTENTION

Objective: Previous research on the effects of alcohol on visual perfo rmance led us to the prediction that alcohol should interfere with the distribution of visual spatial attention. This prediction was examine d in two experiments that measured the effect of alcohol on reaction t ime (RT) for tasks that differed in visual spatial attention requireme nts. Method: In the first experiment, 48 adult volunteers (33 female) responded to either the onset or offset of one of five potential targe ts without alcohol to determine the relative demands on attention of s timulus onset and offset. The spatial extent of the five-target displa y was also varied. In the second experiment, the effect of alcohol was determined for both the onset and the offset tasks in 12 adult volunt eers (nine female). Results: The offset task was found to place greate r demands on spatial attention as the increase in display area resulte d in relatively greater increases in RT. Alcohol increased RT in the o ffset task for the larger, but not the smaller, display, and there wer e no significant effects of alcohol for the onset task. Conclusions: T he results indicate that alcohol impairs performance on tasks that pla ce greater demands on visual spatial attention and likely disrupts the ability to shift attention from one spatial locus to another during s erial search.