To test whether an expectancy challenge (EC) changes implicit and explicit alcohol-related cognitions and binge drinking in young heavy drinkers. This is important for theoretical and practical reasons: the EC presents a critical test for the hypothesized mediational role of alcohol cognitions and the EC has been presented as a promising intervention to counter alcohol problems in heavy drinking youth. SETTING, PARTICIPANTS AND INTERVENTION: Ninety-two heavy drinking college and university students (half women) were assigned randomly to the EC or control condition (a sham alcohol experiment in the same bar-laboratory).