Attitudes, norms, and self-efficacy are construed as the key predictors of action in the dominant theories of social and health behaviour, including the theory of reasoned action (Fishbein, 1980), the theory of planned behaviour (Ajzen, 1991), the model of interpersonal behaviour (Triandis, 1980), the health belief model (Rosenstock, 1974), protection motivation theory (Rogers, 1983), the transtheoretical model (Prochaska et al., 1992), the prototype/willingness model (Gibbons et al., 1998), goal-setting theory (Locke & Latham, 1990), the model of action phases (Heckhausen, 1991), and social cognitive theory (Bandura, 1999). Attitude refers to people’s overall evaluation of what it would be like to perform a behaviour (e.g., “Smoking cigarettes is enjoyable/not enjoyable”), and motivate behaviour because people wish to approach good outcomes and avoid bad outcomes. Social norms refer both to people’s perceptions of social pressure to engage (or not) in a behaviour (e.g., “Most people who are important to me think that I should not smoke cigarettes”) and to perceptions of other people’s behaviour in the domain (e.g., “Most of my friends and family smoke cigarettes”). Self-efficacy refers to people’s appraisals of their ability to perform a behaviour (e.g., “I am confident that I am able to quit smoking cigarettes”). One additional factor is also important for understanding the prediction of behaviour, namely, the concept of intention. Intentions are people’s decisions or self-instructions to perform particular behaviours or achieve certain goals (e.g., “I intend to quit smoking cigarettes this week”) and are thought to mediate the impact of attitude, social norm, and self-efficacy on behaviour (Azjen, 1991). Numerous primary studies and meta-analyses support the validity of attitudes, norms, self-efficacy as predictors of intentions and behaviour (e.g., Sheppard et al, 1988). However, because the vast majority of research is correlational, it does not provide a clear answer to the question, “Does changing attitudes, norms, and self-efficacy cause changes in intentions and behaviour?” A definitive answer to this question can only be provided by experimental tests. That is, a causal relationship between, e.g., attitude and behaviour can only be established by randomly assigning one-half of a sample to an intervention or treatment that succeeds in changing attitude compared to the other half of the sample that did not receive this treatment (the control group). Subsequent behaviour of the treatment group versus control group must then be compared. If the treatment group exhibit a significant difference in behaviour compared to the control group, this would indicate that attitude change has a causal impact on behaviour change. The present research aimed to answer the question “Does changing attitudes, norms, and self-efficacy cause changes in intentions and behaviour?” by using metaanalysis to integrate experimental studies that met the three criteria of (1) random assignment of participants, (2) significant change in attitude, social norm, or self-efficacy among treatment compared to control participants, and (3) comparison of subsequent intention or behaviour by condition. In addition, the research aimed to design and test a behaviour change intervention based on findings from the metaanalysis. (Author/publisher)
Samenvatting