Ethanol, errors, and the speed-accuracy trade-off

Ethanol has been shown to have a relatively greater effect on error rates i n speeded tasks than temazepam, and this may be due to a differential effec t on the speed-accuracy trade-off (SATO). This study used different instruc tion sets to influence the SATO. Forty-nine healthy volunteers (24 males, a ged 18-41 years) were allocated at random to one of three instruction condi tions - emphasising accuracy, neutral, and emphasising speed. After familia risation, they took part in two sessions spaced at least 4 days apart in wh ich they received either ethanol (0.8 g/kg, max 60 g males, 50 g females) o r placebo in randomised order. Tests were administered starting at 30 and 7 5 min postdrug. Instructions significantly affected performance. In two maz e tasks, one on paper, the other on a pen computer, the pattern of instruct ion effects was as expected. A significant increase in errors with ethanol was seen for both maze tasks, and there was a tendency to speed up with eth anol (significant only for the pen computer task). Responses to fixed stimu lus sequences on the Four-Choice Reaction Test also showed a tendency to sp eed up and an increase in errors with ethanol, while all other tests showed both slowing and increases in errors with ethanol compared to placebo. Err or scores are consistently increased by ethanol in all test situations, whi le the effects of ethanol on speed are variable across tests. (C) 2001 Else vier Science Inc. All rights reserved.