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Abstract:
It is well established that alcohol intoxication impairs a
range of cognitive processes, although the precise nature of
alcohol's effects on information processing remains unclear. A
prominent theory of acute alcohol effects (Steele & Josephs,
1990) posits that alcohol restricts one's focus of attention such
that only the most important or salient information in the
environment is processed. We examined this hypothesis using the
Eriksen flanker task in which target letters are presented among
strings of other letters that are either the same as the target
(i.e., compatible with correct response) or different from the
target (i.e., incompatible with correct response). Forty-two
participants were randomly assigned to either the placebo, moderate
dose (BAC = .04), or high dose (BAC = .08) group. If alcohol
restricts attentional focus, intoxicated participants should be
better able to ignore incompatible flanker letters and thus perform
better in the task. Brain electrical activity (ERPs) and
participants' responses (reaction time and accuracy) were measured
during the task. Alcohol produced a significant and sustained
negativity in the ERP, especially at frontal electrode sites, that
differed monotonically by dose. In addition, the P1 component (an
index of attention) was significantly reduced under high dose
levels. In contrast to our initial hypothesis, alcohol intoxication
decreased response accuracy during incompatible trials, suggesting
that alcohol may not restrict visual attention but instead
increases response competition.
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