The effects of alcohol intoxication on accuracy and the confidence-accuracy relationship in photographic simultaneous lineups

Acute alcohol intoxication during encoding can impair subsequent identification accuracy, but results across studies have been inconsistent, with studies often finding no effect. Little is also known about how alcohol intoxication affects the identification confidence-accuracy relationship. We randomly assigned women (n=153) to consume alcohol (dosed to achieve a 0.08% BAC) or tonic water, controlling for alcohol expectancy. Women then participated in an interactive hypothetical sexual assault scenario and, twenty-four hours or seven days later, attempted to identify the assailant from a perpetrator present or a perpetrator absent simultaneous lineup and reported their decision confidence. Overall, levels of identification accuracy were similar across the alcohol and tonic water groups. However, women who had consumed tonic water as opposed to alcohol identified the assailant with higher confidence on average. Further, calibration analyses suggested confidence is predictive of accuracy regardless of alcohol consumption. The theoretical and applied implications of our results are discussed.