ETHANOL AND NEGATIVE PRIMING

In order to investigate the effect of ethanol on negative priming, 18 subjects aged 18-24 took part in a three-period crossover study in whi ch they received placebo (PL), and two doses of ethanol in random orde r. The higher dose (E2) produced peak breath alcohol concentrations eq uivalent to 62.7 mg/100 mi blood, the lower dose (El) 36.4 mg/100 mi. Subjects performed a negative priming task in which they detected the larger of two circles which could appear in any of four positions on a monitor. A prime trial was rapidly followed by a probe trial in which either both circles were in previously unoccupied positions (C), or t he non-target was in a previously unoccupied position and the target i n the same location and the same size as the previous non-target (IR). Negative priming (IR-C) was increased by alcohol, the effect being si gnificant for the lower dose (PL: 13.1 ms; El: 25.2 ms; E2: 21.6 ms). Other performance tasks showed an impairment to divided attention at t he higher dose. Subjective drunkenness was significantly increased for both ethanol doses. These results indicate that negative priming is s ensitive to the effects of ethanol in doses that do not produce major disruption to performance. These results are in the same direction as those previously noted for drugs acting upon catecholamine systems, an d suggest that the specificity of the previous findings may need to be re-evaluated.