Theories of health-protective behaviors

 The health belief model – Becker and Rosenstock (Fig 6-2, p173, Sarafino)

• Likelihood of health-related action is sum of perceived threat and assessed sum of benefits minus barriers to action
• Perceived threat is influenced by three factors:
  • Cues to actions (advice, media campaigns, news article, illness in friend or family)
  • Perceived seriousness and perceived susceptibility to health problem
    • The more serious the problem (organic and social consequences) if left untreated, the more threatened
    • The more susceptible to the problem, the more threatened
  • Exogenous factors
    • Demographic variables (age, sex, ethnicity)
    • Sociopsychological variables (SES, peer pressure)
    • Structural variables (prior contact with and knowledge of disease)
• Perceived benefits minus barriers is influenced by the same exogenous factors
  • Benefits – healthier, less likely to develop heart disease if treat EH, treatments work
  • Barriers – costs, time involved to receive treatment, side effects of treatments
  • Note how exogenous factors might influence perceived benefits and barriers

Research on HBM

• Results mixed
  • Higher susceptibility and seriousness of health problems, and perception that benefits outweigh costs related to prevention behaviors (dental visits, breast exams)
  • Same pattern holds, in general, for secondary (early ID and Tx) and tertiary prevention (contain/retard damage, rehab)
  • However, in intervention research (Champion,1994), barriers/benefits more influence than changing perceived susceptibility
  • Cues to action and demographic (sex, race), sociopsychological factors (education) also influence health practice, sometimes more so than attitudes (having a place to go for care)
• Shortcomings
  • Does not account for habitual behaviors well (tooth brushing), because originated out of other reinforcers (parents/family culture)
  • No standard way of measuring components—cross study comparison difficult
  • Rarely accounts for more than 50% of the variance
  • Newer versions enhance prediction by adding elements like self-efficacy, behavioral intentions, and perceived norms (latter two from TRA)

Theory of reasoned action – Azjen and Fishbein, Fig 7-1, p 161

• Assumes people decide rationally, systematically, weighing options, and have freedom to choose among options
• Health behavior is solely predicted by behavioral intention (I intend to smoke a cigarette)
• Intention is sum of:
  • Individual’s attitude toward the behavior
    • Beliefs about outcomes of behavior (if diet I will lose weight)
    • Evaluations of outcomes (losing weight would be good)
  • Subjective norms regarding behavior
    • Normative beliefs (friends and family think I should diet)
    • Motivation to comply (I want to do what family/friends want me to do)

Research on TRA

• Results supportive overall
  • In general, intention is one of best predictors of behavior (I intend to exercise)
  • Both individual attitudes (e.g, about giving blood) and peer attitudes (toward smoking among teenagers) have been associated with health related behaviors, and may add to prediction of intentions
  • At least as useful as HBM, although TRA and HBM rarely tested against each other in same study
• Shortcomings
  • Does not include some important variables
    • prior experience with behavior à among those who intended to give blood those who had given, were more likely to actually give (Past behavior is best predictor of future behavior)
  • Assumes people think about behaviors in detailed/rational way

Theory of Planned Behavior (Ajzen) – addition of perceived control

• Behavioral intention still solely predicts behavior
• Adds third component of perceived control (similar to self-efficacy—I will be able to diet) to subjective norms and individual attitudes toward behavior in predicting intention (Fig 7.2, p 162)
• Two avenues of influence of perceived control
  • Indirect - Those who believe they can are more likely to intend to do so
  • Direct -- Those who perceive control are more likely to have actual control (child’s intention to smoke may be thwarted by lack of control in obtaining cigarettes)

Research on TPB

• Few studies of this new theory
• Most studies support addition of perceived control element
  • Perceived control added to prediction over TRA/HBM
    • in attending health check program
    • in undergrad students health related behaviors
• Indirect evidence à Self-efficacy alone predictive of smoking cessation (belief I can quit – DiClemente et al., 1985), success in dieting (Schifter & Ajzen, 1985), and completing exercise program (Kaplan et al., 1984)

Self-regulation theory - Bandura

• Behavior is self-regulated
  • Monitor determinants (internal or external) and effects of our behavior
  • Judge behavior relative to internal standards in context (environmental conditions – church vs. basketball court)
  • Respond to behavior (regulate/modify) relative to how it corresponds to standards
• Likelihood of behavior influenced by self-efficacy – belief in ability to carry out specific behavior
  • Influences on self-efficacy
    • Performance (I really can do it)
    • Modeling, vicarious experience (If Joe can do it, I can)
    • Social influence (advice, persuasion—you can do it)
    • Arousal (anxiety may inhibit belief in ability to perform)
• Research shows positive relationship between self-efficacy and many behaviors (changing behavior related to CVD, smoking cessation)

Stages of change theory (transtheoretical model) – Prochaska & DiClemente

• Models readiness to change as critical to explain behavior
• 5 stages
  • Pre-contemplation – not considering change, never thought of it or decided against
  • Contemplation – aware of problem, not ready yet, but seriously thinking about change within few months
  • Preparation – ready to change, make specific plans to change, to achieve goal, within month
  • Action – overt changes to behavior to achieve goal, usually lasting about 6 months
  • Maintenance – sustain changes, resist relapse, indefinite period
• Move through stages in spiral, not linear fashion
• Interventions should be matched to stage (info on risk during pre-contemplation)
• Research is limited
  • Stages seem to apply in general across variety of health behaviors (BSE, smoking cessation, weight)
  • Those in later stages more likely to be performing target behavior (eating low fat diet) than those in early stages
  • Ability to predict behavior change modest

 Precaution-adoption process model – Weinstein

• Explains change via changes in belief about susceptibility
• 7 stages
  • Stage 1 - Unaware of risk
  • Stage 2 - Aware of risk, personal invulnerability (optimistic bias)
  • Stage 3 - Personal susceptibility, precaution good idea, not ready yet
  • Stage 4 – decide to act
  • Stage 5 – decide action unnecessary
  • Stage 6 – action, already taking precautions
  • Stage 7 – maintenance, if needed
• Research limited
  • Those changing behavior report more susceptibility
  • Those not changing behavior report less susceptibility, consistent with optimistic bias (smokers not thinking of quitting saw their personal risk as small)

 Critique of health related theories

• None explain a majority of the variance consistently
• TRA/TPB may be slightly better than HBM, primarily because intention is a good predictor
• Self-efficacy helpful in explaining action initiation, but less helpful in predicting maintenance
• All theories suffer from restrictions in variable sets examined
  • Vanity may be more predictive of behavior than health-related decision making
  • Variety of external factors restrict explanatory power (availability, public policy)
  • Although all postulate barriers, number is nearly uncountable and likely vary for different subgroups (African American vs. European American)
• Valid and comparable instruments to assess components not available
• Models may not explain all health related variables equally well
  • May vary for different disorders, primary vs secondary prevention
  • May vary for types of people (children often not involved in health decisions)

The role of non-rational processes

• Motivated reasoning (Kunda, 1990)
  • Our desires and preferences influence judgments of accuracy/usefulness of info
  • Example: want to continue smoking—look for reasons to accept supportive info and reject nonsupportive info
    • Smokers give lower estimates of risk vs nonsmokers
• Conflict theory (Janis & Mann, 1977)
  • Decisions create decisional conflict—deciding between two or more options
  • Factors affecting how we cope with decisional conflict
    • Risks – how risky the situation/problem
    • Hope – how likely we believe the situation/problem is modifiable
    • Time – how much time we believe we have
  • Different combinations of factors produce different coping patterns, some more "rational" than others
  • EXAMPLES:
    • Hypervigilance – serious risks in current behavior, serious risks in contemplated solutions, running out of time à high stress, frantic search, not well considered decision
    • Vigilance – serious risks in current behavior, serious risk to contemplated solutions, optimistic that lower risk alternative available, time still available à moderate stress, rational choice