Imagine being addicted to a substance or an activity and being unable to stop, no matter how hard you try. Imagine your addiction being the only thing you think about all day - from the time you wake up to the time you go to sleep. Imagine how debilitating this would be, and the impact it would have. Addiction can be a consuming part of people's lives, and many theories have been proposed in an attempt to treat addiction. One such theory is the theory of planned behaviour (Ajzen, 1991), a development of the theory of reasoned action by Ajzen and Fishbein (1975).
- First, we will talk about how the theory of reasoned action became the theory of planned behaviour.
- We will then aim to understand what the theory of planned behaviour is.
- Next, we will discuss the three components of the theory of planned behaviour, with respect to addiction.
- Finally, we will evaluate the theory of planned behaviour's strengths and weaknesses and see how it contributes to our understanding of addiction and reducing addiction.
Fig. 1 - The theory of planned behaviour can be used to treat addiction.
Theory of Planned Behaviour Summary
Three key theories of behaviour change for addiction are the theory of reasoned action, the theory of planned behaviour and the transtheoretical model. Since they are all theories which assess how behaviours occur in the first place, they can be further used to derive interventions which can change these behaviours as well.
While these theories may differ in what they suggest, they all operate under the same assumption: intention precedes behaviour.
- Fishbein and Ajzen (1975)¹ wanted to understand the differences between intention and behaviour, which brought about the theory of reasoned action (1975). This theory states that attitude and subjective norms work together to produce intention, which ultimately leads to behaviour.
- After proposing this theory, Ajzen (1985)² realised that there is another factor which can contribute to behaviour; one which the theory of reasoned action does not take into account. This factor was known as perceived behavioural control.
The addition of this factor led to the theory of reasoned action being adapted to the theory of planned behaviour. Let us understand what this theory suggests, and see how it can be applied when talking about addiction.
Theory of Planned Behaviour Model
An extension to the theory of reasoned action, the theory of planned behaviour suggests that an individual's attitudes, subjective norms and perceived behavioural control, are all factors that contribute to the likelihood of whether or not a specific behaviour will be carried out.
The theory of planned behaviour is a cognitive theory that states that in addition to attitudes and subjective norms, individuals must have personal, voluntary control over the behaviour they wish to engage in.
Applied to addiction, the theory of planned behaviour explains drug abstinence by referring to addicts' intention to give up their addictive behaviours, be that drug addiction or gambling.
Such intention arises from three key influences:
- Attitudes - Our personal attitudes.
- Subjective norms - Beliefs about what others think.
- Perceived behavioural control - Beliefs about our ability to change our behaviour.
Theory of Planned Behaviour Constructs
The theory of planned behaviour brings forward two constructs from the earlier version of its theory, i.e., the theory of reasoned action and adds a new one. These three are attitudes, subjective norms and perceived behavioural control, and we will discuss each of these in relation to addiction.
Attitudes
An individual's attitude is how they judge the behaviour under question, in this case, addiction.
Attitude refers to the individual's judgement about whether or not their addiction is good, thereby helping them decide if they should carry it out.
This can be further divided into a positive attitude and a negative attitude. A positive attitude will mean that the individual thinks the behaviour is good, which will lead to an increased intention to continue in the behaviour, thereby resulting in that behaviour.
On the flip side, a negative attitude will mean that the individual thinks the behaviour is bad, which will lead to a decreased intention, thereby not resulting in that behaviour.
Imagine the behaviour under question is gambling. Now imagine someone has a positive attitude towards this behaviour. For them, they may consider gambling to be fun, which will increase their intention to continue gambling, and will ultimately result in them going to a casino.
Now imagine if they had a negative attitude towards this behaviour, and they may consider it to be unhealthy. In this case, they will have decreased intention to stop gambling, resulting in them not going to a casino.
Unfortunately, our attitudes do not solely contribute to our intention; if this were the case, then justifying whether or not we did something would be too easy. Attitudes tend to be affected by subjective norms.
Subjective Norms
Have you ever been in a situation where you don't want to do something, but you do it anyway because you think your friends and family want you to? This is where subjective norms come in.
Subjective norms refer to the individual’s beliefs about their social world; if they think the people important to them (e.g., their family and friends) will view the behaviour in a certain way, motivation to continue these behaviours is affected.
It is the perceived social consequences of engaging in a behaviour.
It is important to note here that subjective norms are not actually what other people think, rather, it is an individual's own perception of their thoughts - this could be true, but it could also not be. Let's understand this better with an example.
We already know that if the behaviour under question is gambling and we have a positive attitude towards it, we are likely to engage in the behaviour, because we will have the intention to.
However, with this attitude, if we believe that people close to us (friends/family/partner) think that gambling is harmful, then our intention towards this behaviour changes, and we are unlikely to go to a casino.
Now that we have understood attitude and subjective norms separately and seen how they can work together, let us look at perceived behavioural control to see how that contributes to the theory of planned behaviour.
Perceived Behavioural Control
Think about this: if you don't believe that you are capable of carrying out a certain behaviour, are you going to make an effort to try? Probably not, right? Welcome to perceived behavioural control.
Perceived behavioural control refers to the extent to which an individual believes they can personally control their behaviours.
Perceived behavioural control is affected directly or indirectly.
If you truly believe it is too hard to stop taking drugs, for instance, if the withdrawal symptoms are particularly devastating, your perceived personal control over your behaviour is low, and your intent to stop taking the drug is affected.
You might now be wondering how all three of these constructs come together to predict whether or not we will carry out a certain behaviour. Let's understand this with yet another example.
We've discussed how attitudes and subjective norms work together to result in the individual going to a casino. Now, let's look at perceived behavioural control. If someone believes they are capable of controlling how much they gamble, then, of course, they are likely to gamble.
However, if they believe that are not capable of controlling how much they gamble, then they are unlikely to gamble for fear of losing money.
Perceived behavioural control is further dependent on two additional factors, (a) internal factors, i.e., one's ability and determination towards a specific behaviour and (b) external factors, i.e., the resources and support available to the individual so that they can perform the behaviour.
When discussing gambling, internal factors could be things like 'I want to gamble' or 'gambling is fun', and external factors could be things like 'the casino is five minutes away' or 'everyone around me gambles'.
Additionally, there are two more ways perceived behavioural control can impact one's behaviour:
- If we believe we have greater control over our behaviour, we will form a stronger intention to engage in it.
- If we believe we have greater control over our behaviour, then we will work longer and harder to succeed.
Thus, in addition to feeding intention for a specific behaviour, perceived behavioural control can also impact behaviour directly.
Fig. 2 - Perceived behavioural control was added as a third aspect to the original theory of reasoned action
Evaluation of the Theory of Planned Behaviour
As with any theory, the theory of planned behaviour comes with its own set of strengths and weaknesses, which we will discuss in more detail below.
Strengths and Weaknesses of the Theory of Planned Behaviour
Let's explore the various strengths and weaknesses of the theory of planned behaviour.
- Hagger et al. (2012)³ tested the theory of planned behaviour for alcohol-related addictions. They found that personal attitudes, subjective norms and perceived behavioural control affected an addict’s intention to quit using the substance they were addicted to.
- Further, in a study conducted by Alanazi et al. (2017)4, they found that the strongest predictors of intentions were attitudes and perceived behavioural control; results showed that attitudes towards smoking cigarettes (negative or positive) and the perception of how easy/difficult it was to smoke cigarettes directly influenced adults' intention to smoke. This shows how important perceived behavioural control is when it comes to one's intentions towards certain behaviours, and supports the theory of planned behaviour.
- However, McEachan et al. (2011)5 found that intention only predicted that an addict would give up their addiction if the space between intention and giving up (behaviour) was small. They conducted a meta-analysis of 206 addiction-related health behaviour articles and how they linked to the theory of planned behaviour. Upon analysis, they found that the strength of the correlation between intentions and behaviour varied according to the length of time between the two; the smaller the period in between, the stronger the intention to quit their addictive behaviour. Therefore, it can be said that intention is only a valid explanation for giving up addiction in the short term.
- Moreover, Miller and Howell (2005)6 studied gambling in underage teens and found a strong correlation between attitudes, norms, perceived control and intention but no link between this intention and behaviour. This may explain why the research evidence on the theory of planned behaviour is not an entirely valid explanation of drug-related behaviour.
A substantial amount of research into the theory of planned behaviour uses self-report techniques and is therefore liable to social desirability bias.
Social desirability bias is a type of response bias wherein individuals responding to a survey answer questions in a manner that will make them 'look good' in front of others, rather than being honest.
The emphasis on perception means that researchers have to ask addicts about their attitudes and perceptions. According to social desirability bias then, individuals may try to answer these questions in a manner that is viewed favourably by others, meaning that they are not being 100% truthful.
Due to the discrepancies evidenced by research, many psychologists now question whether the theory of planned behaviour is a model of behavioural change at all. It focuses on intention, which makes it challenging to create drug-related interventions that could connect this intention to behaviour.
Theory of planned behaviour - Key takeaways
- The theory of planned behaviour is a cognitive theory that states that in addition to attitudes and subjective norms, individuals must have personal, voluntary control over the behaviour they wish to engage in.
- The theory of planned behaviour explains addiction treatment by referring to addicts' intention to give up addiction-related behaviours which arises from three key influences: our attitudes, subjective norms, and perceived behavioural control.
Attitude refers to the individual's judgement about whether or not their addiction is good, thereby helping them decide if they should carry it out.
Subjective norms refer to the individual’s beliefs about their social world and the perceived social consequences of engaging in the behaviours.
Perceived behavioural control refers to the extent to which an individual believes they can control their addictive behaviour.
References
- Fishbein, M. & Ajzen, Icek. (1975). Belief, attitude, intention and behaviour: An introduction to theory and research.
- Ajzen, I. (1985). From intentions to actions: A theory of planned behavior. In J. Kuhi & J. Beckmann (Eds.), Action-control: From cognition to behavior (pp. 11ó39). Heidelberg: Springer.
- Hagger, M. S., Lonsdale, A., & Chatzisarantis, N. L. (2012). A theory-based intervention to reduce alcohol drinking in excess of guideline limits among undergraduate students. British journal of health psychology, 17(1), 18–43. https://doi.org/10.1111/j.2044-8287.2010.02011.x
- Alanazi, N.H., Lee, J.W., Dos Santos, H. et al. The use of planned behavior theory in predicting cigarette smoking among Waterpipe smokers. Tob. Induced Dis. 15, 29 (2017). https://doi.org/10.1186/s12971-017-0133-z
- Rosemary Robin Charlotte McEachan, Mark Conner, Natalie Jayne Taylor & Rebecca Jane Lawton (2011) Prospective prediction of health-related behaviours with the Theory of Planned Behaviour: a meta-analysis, Health Psychology Review, 5:2, 97-144, DOI: 10.1080/17437199.2010.521684
- Miller, R., & Howell, G. (2005). A test of the theory of planned behavior in underage lottery gambling. Paper presented at the Consumer Behavior.
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