Self-report and behavioural approaches to the measurement of self-control: Are we assessing the same construct?

The capacity for self-control has been consistently linked to successful execution of health behaviour. However, a lack of consensus remains in the conceptualisation and measurement of the construct. Notably, self-report measures relate to behavioural measures of self-control only weakly or not at all. The aim of the current research was to examine the relationship between self-report and behavioural measures of self-control to determine whether these differentially relate to health behaviour. Participants (N = 146) completed questionnaire and behavioural measures of self-control, and reported their physical activity. A direct effect of self-reported self-control on physical activity was observed, qualified by an interaction between self-reported self-control and behavioural measures, whereby greater self-reported self-control was associated with greater engagement in physical activity among those who performed poorly on the stop-signal task and those who performed well on the Stroop task. These results appear to indicate that the combination of trait self-control and behavioural factors leads to facilitative or debilitative effects on behaviour. Self-report and behavioural measures of self-control do not appear to assess the same elements of self-control and should not be used interchangeably. It is suggested that these measurement modes reflect a difference between trait self-control and specific self-control processes.