Effects of graded doses of alcohol on speed-accuracy tradeoff in choice reaction time

The inconsistency of previous results concerning the effects of alcohol on reaction time (RT) may be related to possible tradeoffs between speed and accuracy. In the present experiment, complete speed-accuracy tradeoff functions were generated for each of five doses of alcohol (0-1.33 ml/kg) t'f1 a choiceRT task. Such functions permit RT differences resulting from changes in performance efficiency to be distinguished from those due to changes in subjects' speed accuracy criteria. Increasing doses ofalcohol produced a progressive decrease in the slope parameter of linear equations fit to the speed-accuracy data, but did not significantly alter the intercept of the functions with the RT axis. Thus, alcohol reduced performance efficiency by decreasing the rate of growth of accuracy per unit time. A change in speed-accuracy criterion was combined with the decrease in efficiency at the highest alcohol dose.