theory of planned behaviour

• the theory of planned behaviour is a behavioural change model that has three interacting components: personal attitudes, subjective norms and perceived behavioural control which combines to create a behavioural intention leading to behavioural change
• personal attitudes


  an individual's personal view towards the given behaviour e.g., cigarettes help me cope with stress or cigarettes are damaging my body
• subjective norms


  the individual's opinion of what is normal, primarily informed by family and peers, but also teachers, doctors and government campaigns etc

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  how motivated the individual is to comply e.g., uninterested in giving up as their friends aren't either or the desire to prevent harm to their family
• perceived behavioural control


  self-efficacy - the belief that someone has the ability to give up their addiction

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  perceived external barriers e.g., peer pressure, inability to cope without addictive substance/behaviour
• theory of planned behaviour in changing behavioural intention (and ideally their actual behaviour)

  changing personal attitudes by providing information about health risks/other costs of behaviour e.g., financial

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  change subjective norms by sharing statistics about the wider population e.g., teenage overestimation of alcohol consumption in peer group, to normalise healthy behaviour

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  change perceived behavioural control by increasing self-efficacy (sharing success stores) and change perceived barriers by creating alternative coping strategies
• Martin et al. (2010)

  used TPB to predict gambling behaviours in uni students through questionnaires to assess different elements of TPB and a calculated coefficient between the two variables e.g., attitudes towards gambling and how often they gambled

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  findings consistent with TPB - students with a positive attitude towards gambling, believed their friends/family did not disapprove of them gambling, and believed they had little control over gambling, they gambled more frequently

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  practical applications for prediction and intervention, large sample (over 700), issues with self-report
• ao3 - Martin's research evidence

  questionnaires lead to a high possibility of social desirability bias -> reduces reliable as correlation coefficients misleading -> provides less support than originally perceived
• ao3 - practical applications

  health professionals can use TPB to pick the most appropriate intervention e.g., if a smoker has positive attitudes towards smoking, prescribing NRT may be pointless, saving wasting money and time on inappropriate treatments

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  this then means a shift in personal attitudes, subject norms and perceived behavioural control to create more engagement in treatment e.g., laying out long-term health risks -> implications for less people with addiction (reduced criminality, reduced cost to NHS for health problems etc)
• ao3 - focus on planned behaviour


  planned behaviour is rational but when addicts engage in addictive substance/behaviour their state of mind is often irrational due to high stress or emotion - TPB does not help predict behaviour in this kind of irrational state - differences in reporting behaviour to professionals when of clear mind and real-life decisions in high-risk situations

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  issues with conscious awareness/articulation/understanding of each element and self-reporting techniques - subjective interpretation by researcher
• ao3 - highlights importance between narrowing gap of intention and action


  meta-analysis of many TPB studies found a correlation between variation of intention and behaviour according to the length of time between to two - a strong correlation if gap less than 5 weeks, weak correlation if more

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  the then emphasises the importance of encouraging addicts to act promptly on their intentions of e.g., quitting an addictive substance