The Theory of Reasoned Action (Fishbein and Ajzen, 1970, 1980)

This theory assumes behaviour results from the intention to perform that behaviour. People decide their intention in advance of most voluntary behaviours, and intentions are the best predictors of what people will do. A behavioural intention is determined by two factors:

  • An individual’s attitude to the behaviour (a judgement of whether or not the behaviour is a good thing to do). This is determined by two behavioural beliefs – beliefs about the outcome of the behaviour, and evaluations of the expected outcome (is the outcome rewarding?). For example, a person may have the attitude that “exercise is a good thing to do”; which may have developed from the belief that “exercise can help prevent heart disease and make me feel good”, and the evaluation that “I don’t want to develop heart disease” and “I want to feel good”;
  • Subjective norms – a person’s beliefs about their social world. These are basically the perception of and commitment to social standards regarding the behaviour’s acceptability or appropriateness. Subjective norms are based on two normative beliefs: (1) beliefs about others’ opinions about the behaviour, and (2) a person’s motivation to comply with those opinions (i.e. “what do others think I should do?” and “do I want to do what they want?”). For example, a person may think, “exercise is appropriate behaviour”. This subjective norm may have developed from the belief that “my family and friends think I should exercise” and “I value their opinion and want to follow their advice”.

This theory proposes that the two factors outlined above (attitude to the behaviour and subjective norms) combine to produce the intention, which leads to performance of the behaviour. Thus, the attitudes that the person in the examples above has generated from their beliefs are likely to produce the intention to exercise, which will lead them, in turn, to do it. These two factors may be weighted differently in different situations. In some situations attitudes may be more important determinants of behavioural intentions than subjective norms, but in other situations more weight may be given to behaving in a normative way rather than in a way in line with personal attitudes.

Suppose, on the other hand, that this individual had the following beliefs:

  • “Exercise is inconvenient and will probably lead to injury”
  • “I have enough hassle at home and work and I haven’t got time to exercise or get injured”
  • “Nobody I know has suggested I exercise, and most of them don’t exercise anyway”
  • “I value their opinion and want to fit in with them”

This person would almost certainly not generate an intention to exercise, and their behaviour would reflect this.

If people’s behaviour is ultimately a function of their beliefs, what do beliefs actually consist of? This theory proposes beliefs are affected by a variety of factors such as age, gender, education, social class, religion and personality traits. These factors indirectly determine behaviour:
“A person does not perform a given behaviour because she is a woman or educated or altruistic or religious … Instead, she ultimately performs the behaviour because she believes that its performance will lead to more ‘good’ than ‘bad’ consequences and/or because she believes that most of her important others (i.e. the individuals she wants most to comply with) think she should perform that behaviour.” (Fishbein, 1980)

This theory claims intentions precede behaviour. However, other factors may intervene before the intention is realised. For example, a person may intend to go to the gym after work, but gets side-tracked by colleagues going to the pub instead, or he gets caught up in a meeting, or he feels exhausted after a long day at work and goes home instead. Many things can happen to get in the way of a behavioural intention being realised. Two factors seem to be extremely important in the relationship between a behaviour and an intention to carry out that behaviour:

  1. The time gap between the expression of the behavioural intention and the actual behaviour. The bigger the gap, the less likely the intention is to be expressed – the longer the gap, the bigger the variety of other influences and distractions that may cause a change in attitudes, priorities and intentions).
  2. The specificity with which the behavioural intention and actual behaviour are expressed – a person’s attitude towards exercise in general is not likely to be a good basis for predicting participation in a specific exercise class on a specific day at a specific time. The more precisely a behavioural intention is specified, the more likely it is to be predictive of actual behaviour.

Ajzen and Fishbein carried out some research in 1980 looking at a weight loss programme. This study illustrates the importance of specificity. Both diet and exercise/physical activity are important in losing weight, but are both general categories. Ajzen and Fishbein determined specific acts for diet and exercise, as well as a general measure of the intention to lose weight and general measures to engage in dieting and exercise. Examples of specific measures of behavioural intention included participants being asked to rate items such as ‘I intend to avoid snacking between meals and in the evenings for the next two months’ and ‘I intend to do exercises, such as jogging or callisthenics, on a regular basis for the next two months.’

They found that the intention to diet and the intention to engage in exercise were both related to specific behavioural intentions, which in turn were related to actual behaviour. They found that dieting seemed to be quite successful and was a significant predictor of weight loss, although exercise was not.

Although this theory has successfully predicted a wide range of behaviours, people do not always do what they say they intend to do (i.e. there is a weak relationship between attitudes and behaviour). In addition, this theory does not take into account past behaviour (often a good predictor of future behaviour), or take into account the irrational decisions people sometimes make.

Theory of Reasoned Action
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