The theory of planned behaviour: self-identity, social identity and group norms

Br J Soc Psychol. 1999 Sep;38 ( Pt 3):225-44. doi: 10.1348/014466699164149.


The aim of the present study was to examine further the role that self-identity plays in the theory of planned behaviour and, more specifically, to: (1) examine the combined effects of self-identity and social identity constructs on intention and behaviour, and (2) examine the effects of self-identity as a function of past experience of performing the behaviour. The study was concerned with the prediction of intention to engage in household recycling and reported recycling behaviour. A sample of 143 community residents participated in the study. It was prospective in design: measures of the predictors and intention were obtained at the first wave of data collection, whereas behaviour was assessed two weeks later. Self-identity significantly predicted behavioural intention, a relationship that was not dependent on the extent to which the behaviour had been performed in the past. As expected, there was also evidence that the perceived norm of a behaviourally relevant reference group was related to behavioural intention, but only for participants who identified strongly with the group, whereas the relationship between perceived behavioural control (a personal factor) and intention was strongest for low identifiers.

MeSH terms

  • Adolescent
  • Adult
  • Attitude
  • Female
  • Humans
  • Linear Models
  • Male
  • Middle Aged
  • Motivation*
  • Self Concept*
  • Social Identification*
  • Social Values