THEORETICAL FRAMEWORK
2.2 Individual-level behaviour change theories
2.2.2. Theory of reasoned action (TRA) and theory of planned behaviour (TPB)
Intention: The intent to perform behaviour is the best predictor that a desired behaviour will
actually occur. To measure the intent accurately and effectively, it should be defined using the same components used to define behaviour: action, context and time.
Attitude: A person’s positive or negative feelings toward performing the defined behaviour.
Behavioural beliefs: Behavioural beliefs are a combination of a person’s beliefs regarding the outcomes of a defined behaviour and the person’s evaluation of potential outcomes. These beliefs will differ from population to population depending on the norm.
Norms: A person’s perception of other people’s opinions regarding the defined behaviour.
o Normative beliefs are a combination of a person’s beliefs regarding other people’s views of behaviour and the person’s willingness to conform to those views. Normative beliefs play a central role in TRA, and generally focus on individual’s perception of other people, particularly influential people, would expect him/her to do. These other people may be his/her peer, family members, parents, church leaders or the society at large.
Normative beliefs also vary from population to population.
Unlike the Stages of Change model, the TRA model supports a linear process in which the individual’s actual behaviour is ultimately affected by changes in individual’s behavioural and normative beliefs (i.e., cognitive structures). It is strongly taken that a person’s intention remains the best indicator that the desired behaviour will occur.
A framework reflecting how the variables are linked up is presented in Figure 1.2. The cognitive structures (i.e., the behavioural and normative beliefs) influence an individual’s attitude and
subjective norms. Consequently, attitudes and norms shape a person’s intention to perform behaviour. The influence of attitude and norm variables, and their underlying cognitive structures, on a person’s intention vary. VanLandingham, Suprasect, Grandjean & Sittitiai (1995), in a study on Thai males, revealed that men’s perceptions of peer norms were the best predictor of condom use. In an earlier study carried out on college females in the USA, attitudinal beliefs exerted greater influence on the intent to use condoms. TRA has been explored in a number of behaviours including smoking, dieting, drinking, treatment programmes, contraception, wearing seatbelts or safety helmets, regular exercising, breastfeeding and voting.
Table 1.2: Theory of planned behaviour
Concept Definition Measurement approach
Behavioural intention Perceived likelihood of performing behaviour
Are you likely or unlikely to perform the bahaviour?
Attitude Personal evaluation of the behaviour Do you see the behaviour as good, neutral, or bad
Subjective norm Beliefs about whether key people approve or disapprove of the behaviour; motivation to behave in a way that gains their approval
Do you agree or disagree that most people approve of/disapprove of the behaviour?
Perceived behavioural control
Belief that one has, and can exercise, control over performing the behaviour
Do you believe performing the behaviour is up to you, or not up to you?
Adopted from: Ajen, I., Fishbein, M. (1980): Understanding attitudes and predicting social behaviour. New Jersey: Prentice-Hall, Inc.
Figure 1.2: Schematic representation of the Theory of Reasoned Action
2.2.2.2 The theory of planned behaviour
Like TRA, the TPB posits that behavioural intention is influenced by a person’s attitude toward performing behaviour and by beliefs about possible approval or disapproval from individuals who are important to the person (subjective norm). Both theories also assume other factors, like culture and the environment, operate through the models’ constructs, and do not independently explain the possibility that an individual will behave in a certain way. However, the TPB incorporates additional construct, perceived behavioural control (Figure 1.3), which has to do with people’s beliefs that they can control a particular behaviour. The inclusion of this construct was to account for situations where individual’s behaviour is influenced by factors beyond his/her control. It was then suggested that individual’s perceptions about
The person’s beliefs that the behaviour leads to certain outcomes and his/her evaluations of these outcomes
The person’s beliefs that specific individuals or groups think he/she should or should not perform the behaviour and his/her motivation to comply with the specific reference
Subjective norm Attitude toward behaviour
Relative importance of attitudinal and normative considerations
Behaviour
Intention Behaviour
controllability might have an important influence on behaviour. Table 1.3 presents a summary of the TPB along with a scheme that combines TRA and TPB in Figure 1.3 (NIH, 2005).
Behavioural beliefs
Evaluation of behavioural outcomes
Normative beliefs
Motivation to comply
Attitude toward behaviour
Subjective norm
Behaviour
intention Behaviour
Control beliefs
Perceived power
Perceived behaviour control
Source: NIH, 2005 (The blue boxes represent the improvement of TPB on TRA)
Figure 1.3: Theory of reasoned action (black) and theory of planned behaviour (the entire figure) combined
The TPB explains how behavioural intention determines behaviour, and how attitude toward behaviour, subjective norm and perceived behavioural control influence behavioural intention.
It also shows that attitudes toward behaviour are shaped by beliefs about what performing the behaviour entails and the outcomes of the behaviour. Compliance with subjective norms is
affected by social standards and motivation to comply with them. The existence of negative or positive factors that make it easier or difficult to perform or reject the behaviour influence perceived behavioural control. One could then conclude that the existence of a chain of beliefs, attitudes, and intentions drives behaviour.