The stage-specific effect of alcohol on human information processing.
BACKGROUND
Research on the limits of information processing shows that when a dual task is performed in quick succession, performance on the second task is increasingly degraded as the temporal gap between task 1 and task 2 decreases. The carry-over effect on task 2 is assumed to occur because the central cognitive stage of processing must be completed before the processing of task 2 can begin. This creates a bottleneck when the tasks are performed in close succession, but with longer delays task 2 is no longer affected by task 1.


OBJECTIVE
It was predicted that if alcohol disturbs (slows) the central stage of processing, shorter delays between task 1 and task 2 should reveal more intense disruption in the performance of task 2.


METHODS
Two groups (n=16) of healthy male social drinkers performed a baseline test on a dual task. On each trial, task 1 was followed by task 2 at one of four delays (50, 200, 500, and 1100 ms). The groups then received either 0.65 g alcohol/kg or a placebo and performed the task again.


RESULTS
The RT of the alcohol and placebo groups did not differ on the baseline test. In accord with the hypothesis, the alcohol group performed task 2 more slowly on the treatment test than did the placebo group at the three shortest delays (P<0.02). At the longest delay, the RT of the groups did not differ (P>0.15).


CONCLUSIONS
This pattern of task 2 RTs indicates that a moderate dose of alcohol can significantly impair (slow) the central, cognitive stage of information processing.
Schweizer
Tom A
TA
Department of Psychology, University of Waterloo, Waterloo, ON, Canada. tschweizer@rotman-baycrest.on.ca
Vogel-Sprott
M
M
Dixon
Michael J
MJ
Jolicoeur
Pierre
P
D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects*; D003071:Cognition / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008606:Mental Processes / Q000187:drug effects*; D011930:Reaction Time / Q000187:drug effects; D013997:Time Factors
D000431:Ethanol