Combining Self-Affirmation and Implementation Intentions: Evidence of Detrimental Effects on Behavioral Outcomes

Background There is limited evidence that self-affirmation\ud manipulations can promote health behavior change.\ud Purpose The purpose of this study was to explore whether the\ud efficacy of a self-affirmation manipulation at promoting exercise\ud could be enhanced by an implementation intention\ud intervention.\ud Methods Participants (Study 1N =120, Study 2N =116) were\ud allocated to one of four conditions resulting from the two\ud (self-affirmation manipulation: no affirmation, affirmation)\ud by two (implementation intention manipulation: no implementation intention, implementation intention) experimental design. Exercise behavior was assessed 1 week post intervention.\ud Results Contrary to prediction, those participants receiving both manipulations were significantly less likely to increase\ud the amount they exercised compared to those receiving only the self-affirmation manipulation.\ud Conclusion Incorporating an implementation intention manipulation alongside a self-affirmation manipulation had a\ud detrimental effect on exercise behavior; participants receiving both manipulations exercised significantly less in the week\ud following the intervention