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