THE EFFECTS OF EXPECTANCY AND ALCOHOL ON COGNITIVE-MOTOR PERFORMANCE

Previous studies have found equivocal evidence for expectancy effects on cognitive-motor performance. The effects of expectancy and alcohol on a dual tracking reaction-time task analogous to some driving skills , and on choice reaction-time, were studied in a balanced-placebo desi gn (n=90). A dose of alcohol achieving 80 mg/100 ml (high dose) had la rge effects on both tasks, but a low dose (40 mg/100 ml) had no signif icant effects. Expecting alcohol led to subjects who received the high hose performing significantly better on the primary tracking task tha n subjects expecting placebo (but also receiving the high alcohol dose ). By contrast, on a secondary reaction-time task, subjects who had re ceived placebo performed worse 100-130 minutes after drinking, if they had expected alcohol. All groups felt more drunk than baseline and ex pecting alcohol made subjects feel more able to perform, whatever drin k they had received. The implications of these findings for the nature of expectancy effects on performance and the relationship between exp ectations and strategy are discussed.