Week 5 lecture slides (1 per page).pdf

Lecture 5 – The Health Belief Model & The Theory of Planned Behaviour What we’re going to cover today • The health belief model and the theory of planned behaviour: ØWhat they propose ØEvidence ØStrengths and limitations The benefits of theory • Create a context for understanding, explaining, an...

Lecture 5 – The Health Belief Model & The Theory of Planned Behaviour What we’re going to cover today • The health belief model and the theory of planned behaviour: ØWhat they propose ØEvidence ØStrengths and limitations The benefits of theory • Create a context for understanding, explaining, and ultimately intervening upon, behaviour. • Create a context within which variables under study can be defined and structured. • Allow for study replication and generalisation. • They lay a foundation for the testing and falsification of hypotheses. (e.g., see Rhodes et al., 2018; Psychology of Sport and Exercise) Theories of (health) behaviours • The health belief model (Rosenstock, 1966, 1974) • The theory of planned behaviour (Ajzen, 1991) • Self-determination theory (Deci & Ryan, 1985) • The transtheoretical model (Prochaska & DiClemente, 1983) • The social identity approach (Tajfel & Turner, 1979; Turner et al., 1987) • Self-efficacy theory (Bandura, 1977) • The health action process approach (Schwartzer, 1992) The health belief model • Initially developed to try to explain why people fail to adopt disease prevention strategies or undergo screening tests for the early detection of disease. • Has since been applied to a range of other health behaviours. • Argues that behaviour is a result of a set of core beliefs… The health belief model Perceived susceptibility Perceived severity Behaviour Perceived benefits Perceived barriers Perceived susceptibility • People will be more motivated to act in healthy ways if they believe they are susceptible to a particular negative health outcome. • People will not act to prevent a negative health outcome that they believe is unlikely to afflict them. ØE.g., a woman would be unlikely to get a mammogram if they believe they are unlikely to develop breast cancer. Perceived severity • The stronger a person’s perception of the severity of the negative health outcome, the more motivated they will be to act to avoid that outcome. • If the person believes the undesirable health outcome will not have a large impact on their life, they will not be motivated to act to avoid it. • Severe outcomes include death, physical or mental impairment, and pain. ØE.g., A woman is more likely to get a mammogram if she believes breast cancer has a high likelihood of mortality if it develops undetected. Perceived benefits • The individual is more likely to carry out the target behaviour if they believe it will provide strong positive benefits. • Specifically, they must believe that the target behaviour is likely to prevent the negative health outcome. ØE.g., If a woman believes that mammograms are unlikely to detect cancer accurately, they will be unlikely to schedule an appointment to get one. Perceived barriers • If people perceive there are strong barriers that prevent them adopting the preventative behaviour, they will be unlikely to do so. • The behaviour may be perceived as too expensive, painful, challenging, etc. ØE.g., A woman may not get a mammogram, even if they believe it will accurately detect breast cancer, because the process can be painful. The model predicts that a person is more likely to (try to) quit smoking if… They believe: • Their chances of getting lung cancer are high (perceived susceptibility) • Lung cancer is a life-threatening disease (perceived severity) • Stopping smoking will substantially reduce their risk of lung cancer (perceived benefits) • The withdrawal symptoms won’t be too bad and that they can overcome them (perceived barriers) But are unlikely to (try to) quit smoking if… • They believe lung cancer is something that happens to other people (perceived susceptibility) • They believe that, even if they get it, most people survive lung cancer (perceived severity) • They believe stopping smoking won’t reduce their risk of lung cancer (perceived benefits) • They believe stopping smoking will make them irritable and stressed (perceived barriers) Perceived susceptibility Perceived severity Behaviour Perceived benefits Perceived barriers Cues to action Cues to action • The person is spurred to adopt the behaviour by some additional element. • Could be external cues (e.g., a mass media campaign, a health education leaflet) • Or internal cues (e.g., a negative change in body state) E.g., ØA media breast screening campaign, or the death of someone due to breast cancer (external cues). ØFeeling breathless when walking up stairs (internal cue). Other variables? • Becker (1974) proposed that overall motivation to pursue healthy behaviour should be included. • Rosenstock et al. (1988) proposed that self-efficacy should be added. • However, these variables are rarely included in HBM studies, so it’s difficult to evaluate their impact. Source: Jones et al (2014), Health Psychology Review In a nutshell… The health belief model proposes that behaviour is a result of a set of core beliefs. Specifically, their beliefs about: 1. How susceptible they are to a particular negative health outcome. 2. How severe the negative health outcome would be. 3. To what extent engaging in a preventative behaviour will benefit them (i.e., prevent them experiencing the negative health outcome). 4. How strong the barriers are to them engaging in the preventative behaviour. • It further proposes that people can be spurred to adopt a behaviour by internal/external cues. Empirical evidence – can the model be used to predict behaviour? Carpenter (2010) • Meta analysis of 18 longitudinal studies examining whether the 4 focal beliefs predict behaviour. Perceived susceptibility r = .05 Perceived severity r = .15 Behaviour r = .27 Perceived benefits r = .30 Perceived barriers Additional findings and interpretations • Suggested that the comparatively weaker effects of susceptibility and severity may be because they have indirect effects on behaviour through perceived threat (as Janz & Becker, 1984; Jones et al., 2014 proposed). • Time between measures was a moderator: The longer the time between when susceptibility, severity, and benefits were measured and when behaviour was measured, the weaker the effects. ØBeliefs change over time, meaning the Time 1 measure becomes increasingly invalid the longer the interval. ØThe longer the interval, the more likely it is that a cue to action will arise that causes someone who does not perceive the disease to be severe or themselves susceptible to adopt the behaviour, despite their original perceptions. Can the model be used to help change behaviour? Tola et al. (2016) • Examined whether the HBM could help guide efforts to reduce non-adherence to tuberculosis (TB) treatment in Ethiopia. • Cluster randomized control trial (N=698). • Patients in 16 health care centres received routine anti-TB therapy (N=330). • Patients in 14 different health care centres received routine therapy plus the intervention (N=368). • Assessed non-adherence to treatment and each of the HBM variables at baseline (1-2 months after commencing the treatment) and four months later. Intervention • Beginning from the 2nd month of treatment initiation, and lasting 4 months, health education was provided by health professionals on: ØTB disease acquisition. ØThe risks and consequences associated with non-adherence. ØMethods to help overcome psychological barriers to follow the treatment. ØBenefits of TB medication and treatment adherence. ØMethods to develop self-efficacy. (7 x 30-minute sessions in total) *Also an anxiety and depression counselling component of the intervention. Results “How many of your schedule or medication did you miss in the last 30 days?” 0% (not a single dose or schedule missed) 100% (not a single dose taken) Results Jones et al. (2014) • Systematic review of 18 studies that used the HBM as the basis for an intervention designed to improve adherence to health behaviours. • Focused on studies where the intervention aimed to improve adherence to a medical regime. E.g., Increasing vaccine uptake, participating in screening, seeking referral to assess stroke risk. • Most common technique used to change behaviour was providing information about health consequences to participants. • Others included using a prompt to change behaviour, teaching a new behaviour (instruction), and providing a comparison of outcomes (e.g., for those who do/don’t engage in the given behaviour). Results • 14 of the 18 studies found that the intervention significantly improved adherence. • Effect sizes varied a lot (d = 0.02 to d = 1.00). ØSix studies produced moderate to large effect sizes (d = 0.5 – 0.8) ØThe rest reported only small to moderate effects (d = 0.2 – 0.5). • The strongest results tended to be in studies that used healthprofessional-led interventions. • Findings consistent with other reviews which have found that the effects of the 4 variables on behaviour are generally small (e.g., Abraham & Sheeran, 2015; Harrison et al., 1992) Source: Abraham and Sheeran (2015), p.60 Strengths • The model focuses on modifiable psychological influences on behaviour. • It has provided a basis for practical interventions across a range of behaviours. • The model’s common-sense constructs are easy for non-psychologists to grasp and can be readily and inexpensively operationalized in selfreport questionnaires. Criticisms/limitations • There remains limited consensus about how to operationalize the model variables and the links between them (reliability of the results across studies therefore low). • Mediation analyses have rarely been conducted in intervention studies. • High quality evidence limited. ØMost studies have assessed behaviour via self-report rather than using objective behavioural measures. ØSome interventions have lacked appropriate control groups. ØLots of research has been cross sectional. The theory of planned behaviour The theory of planned behaviour Attitude Subjective Norms Perceived Behavioural Control Behavioural Intention Behaviour The theory of planned behaviour Behavioural beliefs Attitude Normative beliefs Subjective Norms Control beliefs Perceived Behavioural Control Behavioural Intention Behaviour An example… Attitude: ‘I believe this will help me maintain my fitness and mean I can continue playing with my grandchildren.’ I’m too old to play with my grandchildren, going for walk isn’t going to make any difference’ An example… Subjective norm: ‘I believe my family think it’s important that I stay active.’ ‘My family don’t care if I stay active or not.’ An example… Perceived behavioural control: ‘I believe I’m capable of walking 5kms and can do it even though the weather is going to be warm.’ ‘I’m not sure I’m fit enough to walk 5kms and the warm weather will make it almost impossible.’ Example theory of planned behaviour measures Attitudes: For me, participating in regular physical activity would be… Dull ® interesting Unpleasant ® pleasant Unhealthy ® healthy Subjective norms: People who are close to me think I should participate in regular physical activity (disagree ® agree) Perceived behavioural control: To what extent do you see yourself as being capable of participating in regular physical activity (incapable ® capable) Intentions: How often do you intend to take part in regular physical activity (Never ® frequently) In a nutshell… The theory of planned behaviour proposes that the most proximal predictor of our engagement in a given behaviour is our intention to engage in that behaviour. It further proposes that 3 factors predict our behavioural intentions: 1. Our beliefs about the outcomes the behaviour will lead to (attitude). 2. Our beliefs about whether others think we should engage in the behaviour (subjective norm). 3. Our beliefs about whether we’re capable of carrying out the behaviour, given the potential barriers (perceived behavioural control). Empirical evidence • Lots of it! ØE.g., over 200 studies applying the theory to physical activity alone had been conducted in 2011 (Rhodes & Nigg, 2011). • Some influential reviews… McEachan et al. (2011) • Meta analysis of 237 prospective tests of the theory. • Found that, overall, the TPB variables accounted for 19.3% of variation in health behaviour and 44.3% of the variation in intention. • The model was a better predictor of some behaviours (e.g., physical activity and diet) than others (e.g., safe sex, risky behaviours). • The TPB variables were less predictive of behaviour when: ØStudies used shorter follow-up periods. ØParticipants were not university students. ØOutcome measures were objective, rather than obtained via selfreport. Steinmetz et al. (2016) Meta analysis of 82 papers containing 123 interventions aimed at improving: • Physical activity • Nutrition • Behaviour at work or school • Drug use • Adherence to medical regimens • Sexual behaviour • Hygiene Intervention content • Interventions aim at changing behavioral, normative, and/or control beliefs. So, a successful intervention could, for example: ØIncrease beliefs about positive outcomes (e.g., provide information, persuasion, encourage self-monitoring). ØIncrease the perception that important others approve of the behaviour (e.g., provide information, persuasion). ØIncrease skills or knowledge to perform the behaviour and overcome barriers (e.g., modelling of the behaviour, encourage rehearsal of skills, planning/setting goals) or decrease actual barriers/generate actual facilitators (e.g., through social support). Results • Overall, the interventions were effective in changing the theory’s variables and the target behaviour. • But considerable variation in effect sizes across studies. • Intervention effectiveness varied as a function of context, target behaviour, and behaviour change strategy used. E.g., ØInterventions delivered to a group of people superior to interventions focusing on individuals. ØRelatively strong and consistent effects for interventions focused on physical activity and sexual behaviour. ØIncreasing skills effective for changing attitudes, persuasion effective for changing perceived behavioural control and intentions. Is it really any good? 1. The theory has limited utility as a model of behaviour change? ØPositive changes in attitudes, subjective norms, and perceived behavioural control but no effect on intentions or behaviour (Sniehotta et al., 2009). ØInconsistent evidence from interventions – effects vary by context and as a function of target behaviour (Steinmetz et al., 2016). Counterargument: Interventions that haven’t worked have been poorly designed or inadequate. Sniehotta et al. (2009) • Assigned 579 university students to receive a behavioural belief intervention or not, a normative belief intervention or not, and a control belief intervention or not (i.e., to one of six conditions). • Primary outcome was the number of weeks that participants attended the university’s sport and recreation facilities over 2 months between baseline measurement and the university’s Christmas break, based on objective attendance records. Intervention Behavioural belief intervention emphasised things like: • The positive effects of regular physical activity on health, fitness, mood etc. • The safety and low injury risk of physical activity in the university facilities. Normative belief intervention emphasised things like: • Most friends and family approve of involvement in physical activity which is safe, secure, and healthy. • That perceptions of regular facility users as fit, well-trained super-athletes who look down on regular people trying to get fitter are not accurate. Control belief intervention addressed four key barriers to participation: • Costs, time, access, feelings of discomfort and embarrassment about exercising in public. Results Post-intervention: • Participants who received the behavioural belief intervention demonstrated more favourable attitudes than those who did not. • Participants who received the normative belief intervention demonstrated more favourable subjective norms than those who did not. • Participants who received the control belief intervention did not differ in their perceived behavioural control to those who did not. But only the control belief intervention exerted a significant effect on objectively-assessed attendance (and this effect was very small; η2= .007). • Sniehotta et al. (2009) argued that the findings: “question the TPB’s leading role in behavioral science” • Ajzen (2015) disagreed… The wrong focus? • Ajzen argued that when the TPB is used as the basis for designing an intervention, it is first necessary to establish whether the problem is one of (a) insufficient motivation or of (b) a failure to carry out existing favourable intentions. • In the case of Sniehotta et al.’s (2009) study he argued that, even without any intervention, participants’ attitudes, subjective norms and intentions with respect to participating in the university’s sports and recreation programme were generally favourable (based on the descriptive statistics reported). Øi.e., the intervention should have focused on making sure participants were able to carry out their intentions, not increasing motivation. Issues with the intervention? • Argued the behavioural belief messages emphasising the positive effects of regular physical activity on health, fitness, mood etc. were too broad. ØDon’t deal with the specific goal of getting students to participate in the university’s sports and recreation program. ØPlus, most students were probably already familiar with these benefits of regular exercise. These messages therefore unlikely to produce much change in beliefs or attitudes. ØA better intervention would have emphasised positive outcomes of participating in the university’s program and/or negative outcomes of not participating that were not part of already existing beliefs supporting the behaviour. 2. Intention — behaviour gap • Lots of studies fall short of measuring actual behaviours. Among those that do, results have shown: • Medium-sized changes in intention lead to trivial changes in behaviour (Rhodes & Dickau, 2012) • Half the sample fell into the intention-behaviour gap – ‘unsuccessful intenders’ (Rhodes & de Bruijn, 2013) Counterargument: Events occurring between the assessment of intentions and when behaviour occurs can lead to changes in intentions. Closing the gap – a role for implementation intentions? • Developing simple but specific plans, after intentions, about what to do. • The ‘what’ and ‘when’ of a behaviour. • E.g., Someone who intends to stop smoking is more likely to do so if they if they make the implementation intention: “I intend to stop smoking tomorrow at midday when I have finished my last packet” • Implementation intentions can increase the correlation between intentions and behaviour for behaviours including increasing fruit and vegetable consumption and reducing/quitting smoking, alcohol intake, and dietary fat (e.g., Armitage, 2004, 2007; Conner & Higgins, 2010; Gratton et al., 2007). 3. The model’s hypotheses are just common sense statements that can’t be falsified? Won’t find that people are more likely to: • Engage in behaviours that they don’t intend to. • Intend to engage in behaviours that they feel incapable of. “If we are not careful, our discipline very quickly descends into the science of the blatantly obvious and we test our common sense hypotheses only to discover what the rest of world knew already.” (Ogden, 2015, p.165) Counterargument: You can’t claim that the theory isn’t open to falsification when the overall claim of your article is that it has been falsified! Summary Sniehotta et al. (2014): • “The TPB has become an empty gesture to tick the box that science should be theory-based.” • “The TPB is no longer a plausible theory of behaviour or behaviour change and should be allowed to enjoy its well-deserved retirement.” Ajzen (2015): • “Sniehotta et al. have failed to make a case for retiring the TPB. They display a profound misunderstanding of the theory itself, they fail to appreciate the work needed to properly apply the theory in efforts to change behaviour and they misinterpret negative findings of poorly conducted studies as evidence against the theory.” • “Contrary to their claims, the TPB is alive and well and gainfully employed in the pursuit of a better understanding of human behaviour.” Summary • The theory of planned behaviour is one of the most popular theories of human behaviour in psychology. • Thousands of studies have sought to test its usefulness. • But psychology still can’t decide if it’s any good! Over to you… • In your labs – the big debate! Reading Debate: Ajzen, I. (2015). The theory of planned behaviour is alive and well, and not ready to retire: A commentary on Sniehotta, Presseau, and Araújo-Soares. Health Psychology Review, 9(2), 131-137. Ogden, J. (2015). Time to retire the theory of planned behaviour?: One of us will have to go! A commentary on Sniehotta, Presseau and Araújo-Soares. Health Psychology Review, 9(2), 165-167. Sniehotta, F. F., Presseau, J., & Araújo-Soares, V. (2014). Time to retire the theory of planned behaviour. Health Psychology Review, 8(1), 1-7. Reviews: Hagger, M., Chatzisarantis, N., & Biddle, S. (2002). A meta-analytic review of the theories of reasoned action and planned behavior in physical activity: Predictive validity and the contribution of additional variables. Journal of Sport & Exercise Psychology, 24(1), 3-32. Steinmetz, H., Knappstein, M., Ajzen, I., Schmidt, P., & Kabst, R. (2016). How effective are behavior change interventions based on the theory of planned behavior? A three-level metaanalysis. Zeitschrift für Psychologie, 224(3), 216-233. Topa, G., & Moriano, J. A. (2010). Theory of planned behavior and smoking: Meta-analysis and SEM model. Substance Abuse and Rehabilitation, 1, 23.