Combining implementation intentions and monetary incentives to reduce alcohol use: a failed generalization to a public bar context

Background: Implementation intentions have been demonstrated to reduce alcohol use in retrospective self-report measures. It remains unclear, however, whether they can moderate drinking in a challenging naturalistic context. We examined this by studying the effects of implementation intentions on alcohol use in a bar. Methods: One hundred and twenty-one participants visiting a local bar were randomized over three conditions: control, motivational trigger, and motivational trigger plus implementation intentions. Those in the motivational trigger group were motivated to reduce drinking, and the combined intervention group made additional alcohol-related implementation intentions. We assessed participants’ pre- and post-intervention breath alcohol concentrations, their post-intervention drinking behavior over one hour, and measures of trait impulsivity and reward sensitivity. To predict post-intervention drinking, multiple hierarchical regression was used. Results: Neither the motivational trigger nor the added implementation intentions reduced drinking. Across treatment groups, trait impulsivity predicted alcohol consumption. Conclusions: The present study showed that motivational trigger and implementation intentions failed to reduce alcohol use in a naturalistic setting. Potential reasons, implications, and limitations are discussed. This first attempt demonstrates that implementation intentions aimed at moderation are not as easily implemented in a public high-risk context.