Studies have shown that social drinkers are poor estimators of alcohol-induced impairment. Underestimates of blood alcohol concentration and other indices of intoxication are associated with decisions to perform risky behaviors, such as operating a motor vehicle. It is possible that self-evaluations of impaired functioning under alcohol might be particularly compromised in the presence of other sources of impairment. A common source of impairment that co-occurs with alcohol is visual degradation.