Theory of Planned Behaviour and Physical Activity

1. Theory of Planned Behaviourand Physical Activity EPHE 348

2. Origins • Attitudes were a major focus in psychology during the 1930s • Evidence was often not supportive of attitude-behaviour relations

3. Problems with earlier research • Aggregate assessment • Specificity (action, context, time-frame, target)

4. Theory of Reasoned Action • Fishbein & Ajzen (1975) postulated a theoretical model for understanding behaviour centered around the attitude construct • Remains the most influential attitude model 30 years later

5. TRA • Attitudes – overall evaluation of a behaviour • Subjective norm – overall perceived expectation to perform the behaviour from others • Intention – summary motivation to enact the behavior

6. TRA Principles • Attitude and subjective norm influence behaviour through intention • Importance of attitude and subjective norm can differ by behavior or target group

7. But what makes up an attitude? • Attitudes are a function of underlying beliefs about the behavior • Weighted Expectancy x Value • Norms are a function of normative beliefs (norm x value of referent)

8. Theory of Planned Behaviour • Due to the popularity and demonstrated importance of self-efficacy, the TRA was extended to include a control construct • Perceived behavioural control – ability of the individual to carry out the behaviour (skills, opportunity, resources)

9. Perceived Behavioural Control • Also an E x V construct: • Belief of capability to overcome an obstacle x the probability that the obstacle will occur • Ajzen (1991) argues that PBC influences intention and, to the extent that it represents real control, behaviour directly

10. Theory of Planned Behavior (Ajzen, 1985) Attitude Intention Behavior Subjective Norm Perceived behavioral control Figure 14.1

11. What causes the beliefs? • Ajzen and Fishbein leave this open but include personal and observational experience, personality, demographics, environment, culture among others…

12. TPB and PA • Over 100 studies with various populations • Intention related to PA large effect size • Attitude and PBC are related to PA with a medium to large effect size and related to intention with a large effect size • Subjective norm related to behaviour and intention with a small effect size

13. PA Beliefs • Most important behavioural beliefs: • Stress relief, takes too much time, fun thing to do • Most important behavioural value: • Health, physical appearance/weight control • Most important normative beliefs and values: • friends, family, spouse/romantic partner • Most important control beliefs and values • Time • Fatigue

14. Multi-Component TPB • Attitude, subjective norm, and PBC are multi-faceted: • Attitude = affect, instrumental • Subjective norm = injunctive, descriptive • PBC = skills, opportunity, resources • Rhodes, R.E., Blanchard, C.M. & Matheson, D.H. (2006). A multi-component model of the theory of planned behaviour. British Journal of Health Psychology, 11, 119-137. • Rhodes, R.E. & Courneya, K.S. (2003). Investigating multiple components of attitude, subjective norm, and perceived control: An examination of the theory of planned behavior in the exercise domain. British Journal of Social Psychology, 42, 129-146.

15. Intention behavior relations • Intention-behavior asymmetry is from intenders not acting and not from nonintenders acting • The more one intends to exercise, the more likely one is to fail at achieving one’s intentions (>3 becomes very problematic) • Rhodes, R.E., Courneya, K.S. & Jones, L.W. (2003). Translating exercise intentions into behaviour: Personality and social cognitive correlates. Journal of Health Psychology, 8, 449-460.

17. TPB in intervention • Few studies have focused on TPB-based intervention • Basic premise is that behaviour can be changed three ways: • Increase or decrease a belief • Create a belief • Increase or decrease a value

18. Belief Tests • Chatzisarantis & Hagger (2005) • Study of Adolescents and modal vs non beliefs showed differences in intention via attitude

19. Properties of Physical Activity Attitude Boring Affective Unpleasant Physical Activity Instrumental

20. Attitude Tests • Conner & Rhodes (2008) • Undergraduate samples given either completely affective message or completely instrumental message • Examined effect on attitudes, intention, and behaviour (2 weeks later)

21. Effect on Behaviour

22. Attitude Tests • Parrott et al. (2008) • Persuasive Messages sent to Undergraduates (3 week follow-up) • Focused on Instrumental followed by Affective Attitude compared to no message • RESULTS – Dependent on baseline status.

23. Making an Enemy an Ally • Can the reinforcing and distracting properties of video games be used to facilitate exercise?

24. UVIC/UBC Gamebike Study • 27 sedentary young men randomly assigned to a stationary bike or video game bike • Advised to attend 30 min sessions 3xweek • 6 weeks • Measured on fitness and psychological variables

25. Physiological Effects (Warburton et al., 2007) Fitness results were better in the video game condition

26. Why? Attendance

27. Fitness Attendance Gamebike

28. What is going on with Attendance? • Participants report lower exertion in the videobike condition than controls despite higher power output (Sarkany et al., 2006) • Participants report greater affective attitude (i.e., enjoyment) in the videobike condition (Rhodes et al., in press)

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30. Mechanism AffectiveAttitude Gamebike Attendance Fitness