Effectiveness of experimenter-provided and self-generated implementation intentions to reduce alcohol consumption in...

To test the effectiveness of implementation intentions to decrease alcohol consumption and control for possible demand characteristics by employing an active control condition and contrasting experimenter-provided with self-generated implementation intentions.

Two hundred forty-eight participants were randomly allocated to 1 of 4 conditions: questionnaire-only; questionnaire plus planning instruction; questionnaire, planning instruction plus experimenter-provided implementation intention; or questionnaire, planning instruction plus self-generated implementation intention.

Alcohol intake.

There were clinically and statistically significant decreases in alcohol consumption in the 2 experimental conditions, but not in the 2 control conditions, F(3, 237) = 3.34, p < .05, etap(2) = .04. There were no significant differences between experimenter-provided and self-generated implementation intentions (p = .62). Compliance moderated the effects of self-generated implementation intentions only, such that alcohol intake only significantly decreased in participants who complied with the instructions, F(1, 52) = 4.20, p < .05, etap(2) = .07. However, simply choosing an experimenter-provided implementation intention was just as effective as writing it out in full, implying that implementation intentions work even with minimal information processing.

The findings further support use of implementation intentions to protect against health risk behaviors and are congruent with laboratory research showing that implementation intentions are a case of strategic automaticity.