Behavioural automaticity moderates and mediates the relationship of trait self-control and physical activity behaviour.

OBJECTIVES: Trait self-control has been shown to be associated with physical activity behaviour. However, in contrast with the theoretical assumption underlying the strength model of self-control, self-control seems to be more important for automatic compared with controlled behaviours. It is argued that self-control might facilitate the formation of adaptive habits (behavioural automaticity) and therefore enhance health behaviour through an indirect effect. The credibility of this hypothesis was empirically assessed in a proof-of-concept study.
METHODS: In a prospective design study with two laboratory sessions, participants (N = 124) completed standardised questionnaires assessing trait self-control and behavioural automaticity as predictors (1st session) and actual physical activity behaviour (after one week) as the dependent variable (2nd session).
RESULTS: The predictive power of self-control was stronger for participants with high behavioural automaticity compared with participants with low behavioural automaticity. Furthermore, automaticity mediated the relationship between self-control and behaviour. DISCUSSION: Behavioural automaticity appears to be a helpful construct for specifying the relationship between self-control and physical activity. Our results support the approach of effortless self-control and self-control success, an extension of the strength model of self-control which assumes that self-control is helpful in creating effective routines. In future studies, causal relationships should be examined using more robust and rigorous research designs.