Effects of an implementation intention-based intervention on fruit consumption

Implementation intentions represent a potentially powerful means to increase fruit consumption, yet no studies have demonstrated their effects in this domain. The aim of the present study was to test the effectiveness of an implementation intention intervention to increase fruit consumption and to control for some possible demand characteristics by measuring cognition and behaviour immediately following the manipulation. A total of 120 participants were recruited and randomly allocated to a questionnaire-only control condition or an implementation intention-plus-questionnaire experimental condition. Findings revealed significant increases in fruit consumption in the experimental condition, but not in the control condition, F(1, 80) = 4.47, p < 0.05, eta(2)(p) = 0.06. These effects were independent of motivation and two possible demand characteristics. The findings provide further support for Gollwitzer's model of action phases and demonstrate that successful behaviour change interventions should target both motivation and volition.