2.3 Theory of Planned Behaviour (TPB)
2.3.1 Perceived Behavioural Control
The introduction of Perceived Behavioural Control (PBC) as the third determinant of behaviour, in addition to attitude and subjective norm, is a key component of TPB (Ajzen, 1991; 1985). It helps to understand and explain non-volitional elements of behaviour. PBC refers to the degree to which an individual feels that the performance of the behaviour in question is or is not under his or her volitional control. It is concerned with the actor’s perception of his ability or of potential constraints to perform the behaviour (Conner & Armitage, 1998; Fishbein & Ajzen 2010:64).Thus a high level of PBC should intensify the individual’s possibility to perform the behaviour and a low level of PBC is likely to affect an intention negatively. Generally, the more favourable the attitude and subjective norm and the greater the perceived behavioural control, the stronger a person’s intention and possibility to perform a behaviour. Figure 2.2 below illustrates how perceived behavioural control (PBC) explains behaviour in cases where the actor does not have volitional control.
Figure 2.2: The TPB Model (adapted from Fishbein & Ajzen, 2010:22)
Background Factors Individual Personality Mood, EmotionValues,
Stereotypes General Attitudes
Perceived risk Past behavior
Social Education Age, gender
Income Religion Race, ethnicity
Culture
Information Knowledge Media Intervention
Behavioral Beliefs
Normative Beliefs
Control Beliefs
Attitude Toward the Behavior (A)
Perceived Behavioral Control
(PBC) Subjective
Norm (SN)
Behaviour (B) Intention
(I)
Based on our framework depicted in Figure 2.2, behavioural control can influence intention to perform behaviour and behaviour in two different ways. The first is the PBC-intention relationship. The magnitude of this relationship between perceived behavioural control and intention is dependent on the type of behaviour and the situation (Ajzen, 1991). The second is the effect actual behavioural control can have on the relationship between intention and behaviour.
In the first instance, perceived behavioural control takes into consideration how difficult a behaviour is perceived to be and the perception of how successfully the individual can or cannot perform the behaviour. When one believes that one has manageable obstacles to encounter (thus exhibit a high degree of perceived behavioural control), one should have confidence in the ability to perform the behaviour (Bandura, 1991:169). On the other hand if, one thinks obstacles are not manageable, then it might affect the intention to perform a behaviour.
PBC takes consideration of control factors which can be both internal and external and could inhibit or facilitate the performance of a behaviour. The presence of strong control beliefs about the existence of factors that will facilitate a behaviour makes the individual to have high perceived control over a behaviour. Internal controls are personal and include factors such as skills, abilities, information and even emotions. It has been argued that even with a positive attitude and subjective norm, one may not perform a behaviour if one believes not to have the skills, ability or adequate information needed to perform the behaviour (Yzer, 2012). External controls are situational factors or organizational dynamics which influence people’s perception of the ease or difficulty of performing a behaviour and as a result of that affect intention (Ajzen, 1991; Barr & Gilg, 2007). Situationalism views people’s behaviors as more influenced by situational or external factors than by internal traits. It sees behaviour to be socially determined by context, influenced by circumstances, external expectations, and societal environment and by norms and values of the society in which one is born and raised (Jensen & Meckling, 1994:15).
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In the second instance, actual behavioural control can have a mediating role on the relationship between intention and behaviour. The inclusion of behavioural controls strengthen the relationship between intentions and behaviours. Intentions would be expected to lead to the performance of a behaviour to the extent that the person has actual behavioural control. When actual control is high then it is much more likely that the actor will perform the behaviour (i.e. execute the intention). People’s behaviours are largely seen to be dependent on the actual ability to perform that behaviour. This refers to the moderating role of actual behavioural control regarding the intention-behaviour relation such that intentions will predict behaviour worse when actual control is low (Fishbein & Ajzen, 2010:65). People are less likely to perform a behaviour if they do not have control, resources, and abilities to perform the behaviour (Sheppard, Hartwick, & Warshaw, 1998).
It is only when there is control over behavioural performance that intentions are good predictors of behaviours (Fishbein & Ajzen, 2010:65). Actual control improves the prediction of behaviour as it considers the degree to which the individual actually has control over performing the behaviour. Just like with the other constructs, perceived behavioural control has to be conceptualized and assessed in accordance with the principle of compatibility involving target, action, context, and time elements (Fishbein & Ajzen, 2010:155). The TPB brings in the assumption that with greater perceived behavioural control in addition to a favourable attitude and subjective norm, there would be more likelihood of performing the behaviour. TPB does not negate the tenets of TRA but further strengthens it. On its own, TRA cannot fully account for behaviours where one does not have volitional control. In such cases, this weakness of TRA is addressed by adding PBC to the model, for a more comprehensive explanation of behaviour.