Objectives. Repeated action can lead to the formation of habits and identification as ‘the kind of person’ that performs the behaviour. This has led to the suggestion that identity-relevance is a facet of habit. This study explores conceptual overlap between habit and identity, and examines where the two constructs fit into an extended Theory of Planned Behaviour (TPB) model of binge-drinking among university students.

Design. Prospective, questionnaire-based correlational design.

Methods. A total of 167 UK university students completed baseline measures of past behaviour, self-identity, the Self-Report Habit Index (SRHI), and TPB constructs. One week later, 128 participants completed a follow-up behaviour measure.

Results. Factor analyses of the SRHI and four identity items revealed two correlated but distinct factors, relating to habit and identity, respectively. Hierarchical regression analyses of intention and behaviour showed that identity contributed over and above TPB constructs to the prediction of intention, whereas habit predicted behaviour directly, and interacted with intentions in predicting behaviour. Habits unexpectedly strengthened the intention–behaviour relation, such that strong intenders were more likely to binge-drink where they also had strong habits.

Conclusions. Identity and habit are conceptually discrete and impact differently on binge-drinking. Findings have implications for habit theory and measurement. Recommendations for student alcohol consumption reduction initiatives are offered.