Theory of Planned Behaviour

The Theory of Planned Behavior (TPB) is a social psychological theory that explains human behaviour by considering the interplay of behavioural, normative, and control beliefs. It was first proposed by Icek Ajzen in 1991, and has been widely used in various fields to understand and predict human behaviour.

According to the TPB, behaviour is determined by three types of beliefs:

1. Behavioural beliefs: the perceived consequences of a behaviour, and the evaluation of those consequences.

2. Normative beliefs: the perceived social pressure to engage or not engage in a behaviour, and the evaluation of that pressure.

3. Control beliefs: the perceived barriers or facilitators to engaging in a behaviour, and the evaluation of those barriers and facilitators.

The TPB posits that these three types of beliefs determine a person's attitude towards a behaviour, which in turn determines their subjective norm, and ultimately their behavioural intentions and behaviour.

The theory has been applied in various fields such as health promotion, environmental conservation, and marketing to understand and predict behaviour. Studies have shown that the TPB can be a useful tool for predicting intentions and behaviour in a wide range of contexts, and that it can be useful for designing interventions to change behaviour.

One of the key strengths of the TPB is its ability to predict and explain a wide range of behaviours. Studies have found that the TPB can be used to predict behaviours such as recycling, physical activity, and healthy eating, as well as intentions to engage in behaviours such as condom use, taking medication, and visiting the dentist.

Additionally, the TPB has been used to understand and predict behaviour in a variety of different cultural contexts. Research has found that the TPB can be applied cross-culturally, and that the three types of beliefs (behavioural, normative, and control) are consistent across different cultures.

The TPB can also be used as a guide for designing interventions to change behaviour. By identifying the specific beliefs that influence a particular behaviour, interventions can be tailored to target those beliefs and increase the likelihood of behavior change. For example, if the control beliefs are identified as a barrier to a behavior, interventions can be designed to reduce or remove those barriers.

Finally, it is worth noting that the TPB is a relatively parsimonious theory. It can be understood and applied with minimal technical training and has a relatively small number of concepts and variables, which makes it a useful tool for researchers, practitioners and practitioners-researchers.

In summary, the TPB is a widely accepted and widely used theory in the field of psychology, as well as other fields such as public health, marketing and management. Its key strength is its ability to predict and explain human behaviour. It is cross-cultural and can be used as a guide for designing interventions to change behaviour. And it is relatively simple to understand and apply.

Limitations: One limitation of the TPB is that it may not fully capture the complexity of human behaviour. The theory assumes that behaviour is determined by a person's attitudes, subjective norms, and perceived behavioural control. However, in reality, behaviour is influenced by a variety of factors, including emotions, past experiences, and situational factors. Another limitation is that the TPB assumes that people have the ability to plan and control their behaviour, which may not always be the case. Some individuals may not have the necessary resources or opportunities to engage in certain behaviours, or may be constrained by their physical or mental health. Another limitation is that the TPB assumes that attitudes, subjective norms, and perceived behavioural control are stable across different situations, which may not always be the case. People's attitudes, norms, and perceived control can vary depending on the context in which the behaviour is taking place. Additionally, the TPB does not take into account the possible influence of unconscious or implicit processes on behaviour. Research on Implicit Association Test (IAT) and Implicit Motivation Test (IMT) shows that people may act in ways that are inconsistent with their conscious attitudes, subjective norms, and perceived behavioural control. Finally, the TPB relies on self-reported data, which may not always be accurate. People may not always be aware of their true attitudes, norms, and perceived control, or may be unwilling or unable to report them accurately.