Theory of Planned Behaviour
Intention and expectation
Intention - a person's plans about their future. Expectation - perceived likelihood of performing a behaviour. A smoker may think it likely they will have given up smoking in 5 years (expectation) without having a definite plan to give up (intention).
Self report techniques
Research tends to rely on self-report techniques despite evidence to suggest the vulnerability of such data to self-presentational biases. Attitudes and intentions that are assessed by questionnaires may turn out to be a poor representation of those that eventually exist in the behavioural situation. E.g. a smoker may develop a negative attitude toward smoking because of the health threat. They may intend to give them up, but this may change when with a group of smokers with the associated sights and smells.
Ignores other factors
There are many other influential factors that are ignored by the TPB. For example, Topa and Moriano (10) suggest group variables, such as identification with peers, could play a mediating role in the relation with relation to any addictive behaviour. Another element missing is motivation. Klag (06) studied 350 substance abusers in Australia and found that recovery was more successful in individuals who had decided themselves to give up rather than people who were coerced (e.g. because of a court sentence). Self determination theory is preferable to the TPB because it emphasises the importance of self motivation.
Behavioural Attitude
A product of personal views; the individual's attitude towards the behaviour. This attitude is formed on the basis of beliefs about the consequences (feel good, lose weight, etc.), and whether they will be good or bad. E.g. smoking will affect their running ability, thinks it will help them relax.
Subjective Norms
A product of social influence; the individual's subjective awareness of social norms relating to that behaviour (what we think is the right thing to do ('injunctive norm') and what other people are doing ('descriptive norm'). E.g. most of their friends don't smoke, their parents smoke.
Influence of alcohol and drugs
Attitudes and intentions tend to be measured when sober, whereas risky behaviours such as gambling or unprotected sex may be performed under the influence of alcohol or drugs. MacDonald et al (96) found that alcohol increased measured intention to engage in unprotected sex and other risky behaviours.
AO1
Changing or preventing risky or unhealthy behaviour, such as addiction, has become a major concern of health professionals and governments. One way to approach change or prevention is to consider the factors that contribute to a person's intention to change an unhealthy behaviour. Also, any model must consider how that intention might be transformed into an actual behaviour.
White et al (08)
Examined the sun protection intentions and behaviours of young people in a high risk cancer area in Queensland, Australia. Over 1,000 participants, aged between 12 and 20, completed a questionnaire assessing TPB predictors. Two weeks later, participants reported their sun protection behaviours for the previous fortnight. Results showed that the TPB predictors of attitude, subjective norms and perceived behavioural control were significant predictors of intentions to engage in sun protection, and these intentions were significant predictors of actual sun protection behaviour.
Majer et al (04)
Investigated role of cognitive factors, including self-efficacy, on abstinence. Encouraging an addicts belief in their ability to abstain was related to optimism and ultimately a positive outcome. It was concluded that enhancing self-efficacy should form a primary goal of treatment plans.
Correlational analysis
Research on the TPB is almost entirely correlational, linking outcomes to certain behaviours. This means it is not clear that attitudes and expectations have caused any change.
Main Assumptions
The TPB (Ajzen, 89) is one of several cognitive theories about the factors that lead to a person's decision to engage in a particular behaviour. In this theory, an individual's decision to engage in a behaviour can be directly predicted by their intention to engage in that behaviour. Intention is a function of three factors.
Too rational
The TPB fails t take into account emotions, compulsions or other irrational determinants of human behaviour. (Armitage et al, 99). When filling in a questionnaire, people mau find it impossible to anticipate the strong desires and emotions that compel their behaviour in real life. The presence of strong emotions may explain why people act irrationally by failing to carry out an intended behaviour even when it is in their best interest (Albarracin, 08).
Self-efficacy
The TPB proposes that intentions to change behaviour will be stronger in people that have an increased sense of control (perceived behavioural control). This has been shown to be important in many aspects of addiction prevention, such as relapse prevention programmes.
Webb et al (10)
The internet is being increasingly used to promote health behaviour change, such as stopping smoking and gambling. Webb analysed 85 studies of such interventions and concluded that those based on a theoretical model, especially the TPB, tended to have greater success. This suggests that the TPB can have an important role in the development of internet prevention programmes.
Perceived Behavioural Control
The more control people believe themselves to have, the stronger their intention to actually perform that behaviour will be. An individual with higher perceived control is likely to try harder and persevere for longer. E.g. it is their choice, impossible for her to say no.
