Introduction
Public health is a multi-disciplinary field that aims to 1) prevent disease and death, 2)
promote a better quality of life, and 3) create environmental conditions in which
people can be healthy by intervening at the institutional, community, and societal level.
Whether public health practitioners can achieve this mission depends upon their
ability to accurately identify and define public health problems, assess the fundamental
causes of these problems, determine populationsmost at-risk, develop and implement
theory- and evidence-based interventions, and evaluate and refine those interventions
to ensure that they are achieving their desired outcomes without unwanted negative
consequences.
To be effective in these endeavors, public health practitioners must know how to apply
the basic principles, theories, research findings, andmethods of the social and
behavioral sciences to inform their efforts. A thorough understanding of theories
used in public health, which aremainly derived from the social and behavioral sciences,
allow practitioners to:
● Assess the fundamental causes of a public health problem, and
● Develop interventions to address those problems.
TheHealth BeliefModel
TheHealth BeliefModel (HBM)was developed in the early 1950s by social scientists
at the U.S. Public Health Service in order to understand the failure of people to adopt
disease prevention strategies or screening tests for the early detection of disease.
Later uses of HBMwere for patients' responses to symptoms and compliance with
medical treatments. The HBM suggests that a person's belief in a personal threat of an
illness or disease together with a person's belief in the effectiveness of the
recommended health behavior or action will predict the likelihood the personwill
adopt the behavior.
The HBMderives from psychological and behavioral theory with the foundation that
the two components of health-related behavior are 1) the desire to avoid illness, or
conversely get well if already ill; and, 2) the belief that a specific health action will
prevent, or cure, illness. Ultimately, an individual's course of action often depends on
the person's perceptions of the benefits and barriers related to health behavior. There
are six constructs of the HBM. The first four constructs were developed as the original
tenets of the HBM. The last twowere added as research about the HBMevolved.
1. Perceived susceptibility – This refers to a person's subjective perception of
the risk of acquiring an illness or disease. There is wide variation in a
person's feelings of personal vulnerability to an illness or disease.
2. Perceived severity – This refers to a person's feelings on the seriousness of
contracting an illness or disease (or leaving the illness or disease untreated).
There is wide variation in a person's feelings of severity, and often a person
considers themedical consequences (e.g., death, disability) and social
consequences (e.g., family life, social relationships) when evaluating the
severity.
3. Perceived benefits – This refers to a person's perception of the effectiveness
of various actions available to reduce the threat of illness or disease (or to
cure illness or disease). The course of action a person takes in preventing (or
curing) illness or disease relies on consideration and evaluation of both
perceived susceptibility and perceived benefit, such that the personwould
accept the recommended health action if it was perceived as beneficial.
4. Perceived barriers – This refers to a person's feelings on the obstacles to
performing a recommended health action. There is wide variation in a
person's feelings of barriers, or impediments, which lead to a cost/benefit
analysis. The personweighs the effectiveness of the actions against the
perceptions that it may be expensive, dangerous (e.g., side effects),
unpleasant (e.g., painful), time-consuming, or inconvenient.
5. Cue to action – This is the stimulus needed to trigger the decision-making
process to accept a recommended health action. These cues can be internal
(e.g., chest pains, wheezing, etc.) or external (e.g., advice from others, illness
of family member, newspaper article, etc.).
6. Self-efficacy – This refers to the level of a person's confidence in his or her
ability to successfully perform a behavior. This construct was added to the
model most recently in mid-1980. Self-efficacy is a construct in many
behavioral theories as it directly relates to whether a person performs the
desired behavior.
Limitations of Health BeliefModel
There are several limitations of the HBMwhich limit its utility in public health.
Limitations of themodel include the following:
● It does not account for a person's attitudes, beliefs, or other individual
determinants that dictate a person's acceptance of a health behavior.
● It does not take into account behaviors that are habitual and thusmay
inform the decision-making process to accept a recommended action (e.g.,
smoking).
● It does not take into account behaviors that are performed for non-health
related reasons such as social acceptability.
● It does not account for environmental or economic factors that may prohibit
or promote the recommended action.
● It assumes that everyone has access to equal amounts of information on the
illness or disease.
● It assumes that cues to action are widely prevalent in encouraging people to
act and that “health” actions are themain goal in the decision-making
process.
The HBM ismore descriptive than explanatory and does not suggest a strategy for
changing health-related actions. In preventive health behaviors, early studies showed
that perceived susceptibility, benefits, and barriers were consistently associated with
the desired health behavior; perceived severity was less often associated with the
desired health behavior. The individual constructs are useful, depending on the health
outcome of interest, but for themost effective use of themodel it should be integrated
with other models that account for the environmental context and suggest strategies
for change.
The Theory of Planned Behavior
The Theory of Planned Behavior (TPB) started as the Theory of Reasoned Action in
1980 to predict an individual's intention to engage in a behavior at a specific time and
place. The theory was intended to explain all behaviors over which people have the
ability to exert self-control. The key component to this model is behavioral intent;
behavioral intentions are influenced by the attitude about the likelihood that the
behavior will have the expected outcome and the subjective evaluation of the risks and
benefits of that outcome.
The TPB has been used successfully to predict and explain a wide range of health
behaviors and intentions including smoking, drinking, health services utilization,
breastfeeding, and substance use, among others. The TPB states that behavioral
achievement depends on bothmotivation (intention) and ability (behavioral control). It
distinguishes between three types of beliefs – behavioral, normative, and control. The
TPB is comprised of six constructs that collectively represent a person's actual control
over the behavior.
1. Attitudes – This refers to the degree to which a person has a favorable or
unfavorable evaluation of the behavior of interest. It entails a consideration
of the outcomes of performing the behavior.
2. Behavioral intention – This refers to themotivational factors that influence a
given behavior where the stronger the intention to perform the behavior,
themore likely the behavior will be performed.
3. Subjective norms – This refers to the belief about whether most people
approve or disapprove of the behavior. It relates to a person's beliefs about
whether peers and people of importance to the person think he or she
should engage in the behavior.
4. Social norms – This refers to the customary codes of behavior in a group or
people or larger cultural context. Social norms are considered normative, or
standard, in a group of people.
5. Perceived power – This refers to the perceived presence of factors that may
facilitate or impede performance of a behavior. Perceived power
contributes to a person's perceived behavioral control over each of those
factors.
6. Perceived behavioral control – This refers to a person's perception of the
ease or difficulty of performing the behavior of interest. Perceived
behavioral control varies across situations and actions, which results in a
person having varying perceptions of behavioral control depending on the
situation. This construct of the theory was added later and created the shift
from the Theory of Reasoned Action to the Theory of Planned Behavior.
Limitations of the Theory of Planned Behavior
There are several limitations of the TPB, which include the following:
● It assumes the person has acquired the opportunities and resources to be
successful in performing the desired behavior, regardless of the intention.
● It does not account for other variables that factor into behavioral intention
andmotivation, such as fear, threat, mood, or past experience.
● While it does consider normative influences, it still does not take into
account environmental or economic factors that may influence a person's
intention to perform a behavior.
● It assumes that behavior is the result of a linear decision-making process,
and does not consider that it can change over time.
● While the added construct of perceived behavioral control was an important
addition to the theory, it doesn't say anything about actual control over
behavior.
● The time frame between “intent” and “behavioral action” is not addressed by
the theory.
The TPB has shownmore utility in public health than the Health BeliefModel, but it is
still limiting in its inability to consider environmental and economic influences. Over
the past several years, researchers have used some constructs of the TPB and added
other components from behavioral theory tomake it a more integratedmodel. This has
been in response to some of the limitations of the TPB in addressing public health
problems.
Diffusion of Innovation Theory
Diffusion of Innovation (DOI) Theory, developed by E.M. Rogers in 1962, is one of the
oldest social science theories. It originated in communication to explain how, over time,
an idea or product gains momentum and diffuses (or spreads) through a specific
population or social system. The end result of this diffusion is that people, as part of a
social system, adopt a new idea, behavior, or product. Adoptionmeans that a person
does something differently thanwhat they had previously (i.e., purchase or use a new
product, acquire and perform a new behavior, etc.). The key to adoption is that the
personmust perceive the idea, behavior, or product as new or innovative. It is through
this that diffusion is possible.
Adoption of a new idea, behavior, or product (i.e., “innovation”) does not happen
simultaneously in a social system; rather it is a process whereby some people aremore
apt to adopt the innovation than others. Researchers have found that people who
adopt an innovation early have different characteristics than people who adopt an
innovation later.When promoting an innovation to a target population, it is important
to understand the characteristics of the target population that will help or hinder
adoption of the innovation. There are five established adopter categories, and whilethemajority of the general population tends to fall in themiddle categories, it is still
necessary to understand the characteristics of the target population.When promoting
an innovation, there are different strategies used to appeal to the different adopter
categories.
1. Innovators – These are people whowant to be the first to try the innovation.
They are venturesome and interested in new ideas. These people are very
willing to take risks, and are often the first to develop new ideas. Very little,
if anything, needs to be done to appeal to this population.
2. Early Adopters – These are people who represent opinion leaders. They
enjoy leadership roles, and embrace change opportunities. They are already
aware of the need to change and so are very comfortable adopting new
ideas. Strategies to appeal to this population include how-tomanuals and
information sheets on implementation. They do not need information to
convince them to change.
3. EarlyMajority – These people are rarely leaders, but they do adopt new
ideas before the average person. That said, they typically need to see
evidence that the innovation works before they are willing to adopt it.
Strategies to appeal to this population include success stories and evidence
of the innovation's effectiveness.
4. LateMajority – These people are skeptical of change, andwill only adopt an
innovation after it has been tried by themajority. Strategies to appeal to this
population include information on howmany other people have tried the
innovation and have adopted it successfully.
5. Laggards – These people are bound by tradition and very conservative. They
are very skeptical of change and are the hardest group to bring on board.
Strategies to appeal to this population include statistics, fear appeals, and
pressure from people in the other adopter groups.
Source: http://blog.leanmonitor.com/early-adopters-allies-launching-product/
The stages by which a person adopts an innovation, andwhereby diffusion is
accomplished, include awareness of the need for an innovation, decision to adopt (or
reject) the innovation, initial use of the innovation to test it, and continued use of the
innovation. There are fivemain factors that influence adoption of an innovation, andeach of these factors is at play to a different extent in the five adopter categories.
1. Relative Advantage – The degree to which an innovation is seen as better
than the idea, program, or product it replaces.
2. Compatibility – How consistent the innovation is with the values,
experiences, and needs of the potential adopters.
3. Complexity – How difficult the innovation is to understand and/or use.
4. Triability – The extent to which the innovation can be tested or
experimentedwith before a commitment to adopt is made.
5. Observability – The extent to which the innovation provides tangible results.
Limitations of Diffusion of Innovation Theory
There are several limitations of Diffusion of Innovation Theory, which include the
following:
● Much of the evidence for this theory, including the adopter categories, did
not originate in public health and it was not developed to explicitly apply to
adoption of new behaviors or health innovations.
● It does not foster a participatory approach to adoption of a public health
program.
● It works better with adoption of behaviors rather than cessation or
prevention of behaviors.
● It doesn't take into account an individual's resources or social support to
adopt the new behavior (or innovation).
This theory has been used successfully in many fields including communication,
agriculture, public health, criminal justice, social work, andmarketing. In public health,
Diffusion of Innovation Theory is used to accelerate the adoption of important public
health programs that typically aim to change the behavior of a social system. For
example, an intervention to address a public health problem is developed, and the
intervention is promoted to people in a social systemwith the goal of adoption (based
onDiffusion of Innovation Theory). Themost successful adoption of a public health
program results from understanding the target population and the factors influencing
their rate of adoption.
For more on diffusion of innovation theory see “On the Diffusion of Innovations: How
New Ideas Spread” by Leif Singer.
The Social Cognitive Theory
Social Cognitive Theory (SCT) started as the Social Learning Theory (SLT) in the 1960s
by Albert Bandura. It developed into the SCT in 1986 and posits that learning occurs in
a social context with a dynamic and reciprocal interaction of the person, environment,
and behavior. The unique feature of SCT is the emphasis on social influence and its
emphasis on external and internal social reinforcement. SCT considers the uniqueway
in which individuals acquire andmaintain behavior, while also considering the social
environment in which individuals perform the behavior. The theory takes into account
a person's past experiences, which factor into whether behavioral action will occur.
These past experiences influences reinforcements, expectations, and expectancies, all
of which shapewhether a personwill engage in a specific behavior and the reasons
why a person engages in that behavior.
Many theories of behavior used in health promotion do not consider maintenance of
behavior, but rather focus on initiating behavior. This is unfortunate as maintenance of
behavior, and not just initiation of behavior, is the true goal in public health. The goal of
SCT is to explain how people regulate their behavior through control and
reinforcement to achieve goal-directed behavior that can bemaintained over time. The
first five constructs were developed as part of the SLT; the construct of self-efficacy
was addedwhen the theory evolved into SCT.
1. Reciprocal Determinism – This is the central concept of SCT. This refers to
the dynamic and reciprocal interaction of person (individual with a set of
learned experiences), environment (external social context), and behavior
(responses to stimuli to achieve goals).
2. Behavioral Capability – This refers to a person's actual ability to perform a
behavior through essential knowledge and skills. In order to successfully
perform a behavior, a personmust knowwhat to do and how to do it. People
learn from the consequences of their behavior, which also affects the
environment in which they live.
3. Observational Learning – This asserts that people canwitness and observe a
behavior conducted by others, and then reproduce those actions. This is
often exhibited through “modeling” of behaviors. If individuals see
successful demonstration of a behavior, they can also complete the behavior
successfully.
4. Reinforcements – This refers to the internal or external responses to a
person's behavior that affect the likelihood of continuing or discontinuing
the behavior. Reinforcements can be self-initiated or in the environment,
and reinforcements can be positive or negative. This is the construct of SCT
that most closely ties to the reciprocal relationship between behavior and
environment.
5. Expectations – This refers to the anticipated consequences of a person's
behavior. Outcome expectations can be health-related or not health-related.
People anticipate the consequences of their actions before engaging in the
behavior, and these anticipated consequences can influence successful
completion of the behavior. Expectations derive largely from previous
experience. While expectancies also derive from previous experience,
expectancies focus on the value that is placed on the outcome and are
subjective to the individual.
6. Self-efficacy – This refers to the level of a person's confidence in his or her
ability to successfully perform a behavior. Self-efficacy is unique to SCT
although other theories have added this construct at later dates, such as the
Theory of Planned Behavior. Self-efficacy is influenced by a person's specific
capabilities and other individual factors, as well as by environmental factors
(barriers and facilitators).
Limitation of Social Cognitive Theory
There are several limitations of SCT, which should be consideredwhen using this
theory in public health. Limitations of themodel include the following:
● The theory assumes that changes in the environment will automatically lead
to changes in the person, when this may not always be true.
● The theory is loosely organized, based solely on the dynamic interplay
between person, behavior, and environment. It is unclear the extent to
which each of these factors into actual behavior and if one is more
influential than another.
● The theory heavily focuses on processes of learning and in doing so
disregards biological and hormonal predispositions that may influence
behaviors, regardless of past experience and expectations.
● The theory does not focus on emotion ormotivation, other than through
reference to past experience. There is minimal attention on these factors.
● The theory can be broad-reaching, so can be difficult to operationalize in
entirety.
Social Cognitive Theory considers many levels of the social ecological model in
addressing behavior change of individuals. SCT has beenwidely used in health
promotion given the emphasis on the individual and the environment, the latter of
which has become amajor point of focus in recent years for health promotion
activities. As with other theories, applicability of all the constructs of SCT to one public
health problemmay be difficult especially in developing focused public health
programs.
The TranstheoreticalModel (Stages of Change)
The Transtheoretical Model (also called the Stages of ChangeModel), developed by
Prochaska andDiClemente in the late 1970s, evolved through studies examining the
experiences of smokers who quit on their ownwith those requiring further treatment
to understandwhy some people were capable of quitting on their own. It was
determined that people quit smoking if they were ready to do so. Thus, the
Transtheoretical Model (TTM) focuses on the decision-making of the individual and is a
model of intentional change. The TTMoperates on the assumption that people do not
change behaviors quickly and decisively. Rather, change in behavior, especially habitual
behavior, occurs continuously through a cyclical process. The TTM is not a theory but a
model; different behavioral theories and constructs can be applied to various stages of
themodel where theymay bemost effective.
The TTMposits that individuals move through six stages of change: precontemplation,
contemplation, preparation, action, maintenance, and termination. Termination was
not part of the original model and is less often used in application of stages of change
for health-related behaviors. For each stage of change, different intervention
strategies aremost effective at moving the person to the next stage of change and
subsequently through themodel tomaintenance, the ideal stage of behavior.
1. Precontemplation – In this stage, people do not intend to take action in the
foreseeable future (defined as within the next 6months). People are often
unaware that their behavior is problematic or produces negative
consequences. People in this stage often underestimate the pros of
changing behavior and place toomuch emphasis on the cons of changing
behavior.
2. Contemplation – In this stage, people are intending to start the healthy
behavior in the foreseeable future (defined as within the next 6months).
People recognize that their behavior may be problematic, and amore
thoughtful and practical consideration of the pros and cons of changing the
behavior takes place, with equal emphasis placed on both. Evenwith this
recognition, people may still feel ambivalent toward changing their behavior.
3. Preparation (Determination) – In this stage, people are ready to take action
within the next 30 days. People start to take small steps toward the behavior
change, and they believe changing their behavior can lead to a healthier life.
4. Action – In this stage, people have recently changed their behavior (defined
as within the last 6months) and intend to keepmoving forward with that
behavior change. People may exhibit this bymodifying their problem
behavior or acquiring new healthy behaviors.
5. Maintenance – In this stage, people have sustained their behavior change for
a while (defined asmore than 6months) and intend tomaintain the behavior
change going forward. People in this stage work to prevent relapse to earlier
stages.
6. Termination – In this stage, people have no desire to return to their
unhealthy behaviors and are sure they will not relapse. Since this is rarely
reached, and people tend to stay in themaintenance stage, this stage is
often not considered in health promotion programs.
To progress through the stages of change, people apply cognitive, affective, and
evaluative processes. Ten processes of change have been identifiedwith some
processes beingmore relevant to a specific stage of change than other processes.
These processes result in strategies that help people make andmaintain change.
1. Consciousness Raising – Increasing awareness about the healthy behavior.
2. Dramatic Relief – Emotional arousal about the health behavior, whether
positive or negative arousal.
3. Self-Reevaluation – Self reappraisal to realize the healthy behavior is part of
who they want to be.
4. Environmental Reevaluation – Social reappraisal to realize how their
unhealthy behavior affects others.
5. Social Liberation – Environmental opportunities that exist to show society is
supportive of the healthy behavior.
6. Self-Liberation – Commitment to change behavior based on the belief that
achievement of the healthy behavior is possible.
7. Helping Relationships – Finding supportive relationships that encourage the
desired change.
8. Counter-Conditioning – Substituting healthy behaviors and thoughts for
unhealthy behaviors and thoughts.
9. ReinforcementManagement – Rewarding the positive behavior and
reducing the rewards that come from negative behavior.
10.Stimulus Control – Re-engineering the environment to have reminders and
cues that support and encourage the healthy behavior and remove those
that encourage the unhealthy behavior.
Limitations of the TranstheoreticalModel
There are several limitations of TTM, which should be consideredwhen using this
theory in public health. Limitations of themodel include the following:
● The theory ignores the social context in which change occurs, such as SES
and income.
● The lines between the stages can be arbitrary with no set criteria of how to
determine a person's stage of change. The questionnaires that have been
developed to assign a person to a stage of change are not always
standardized or validated.
● There is no clear sense for howmuch time is needed for each stage, or how
long a person can remain in a stage.
● Themodel assumes that individuals make coherent and logical plans in their
decision-making process when this is not always true.
The Transtheoretical Model provides suggested strategies for public health
interventions to address people at various stages of the decision-making process. This
can result in interventions that are tailored (i.e., a message or program component has
been specifically created for a target population's level of knowledge andmotivation)
and effective. The TTM encourages an assessment of an individual's current stage of
change and accounts for relapse in people's decision-making process.
Social Norms Theory
The Social Norms Theory was first used by Perkins and Berkowitz in 1986 to address
student alcohol use patterns. As a result, the theory, and subsequently the social norms
approach, is best known for its effectiveness in reducing alcohol consumption and
alcohol-related injury in college students. The approach has also been used to address
a wide range of public health topics including tobacco use, driving under the influence
prevention, seat belt use, andmore recently sexual assault prevention. The target
population for social norms approaches tends to be college students, but has recently
been usedwith younger student populations (i.e., high school).
This theory aims to understand the environment and interpersonal influences (such as
peers) in order to change behavior, which can bemore effective than a focus on the
individual to change behavior. Peer influence, and the role it plays in individual
decision-making around behaviors, is the primary focus of Social Norms Theory. Peer
influences and normative beliefs are especially important when addressing behaviors
in youth. Peer influences are affectedmore by perceived norms (what we view as typical
or standard in a group) rather than on the actual norm (the real beliefs and actions of
the group). The gap between perceived and actual is amisperception, and this forms the
foundation for the social norms approach.
The Social Norms Theory posits that our behavior is influenced bymisperceptions of
how our peers think and act. Overestimations of problem behavior in our peers will
cause us to increase our own problem behaviors; underestimations of problem
behavior in our peers will discourage us from engaging in the problematic behavior.
Accordingly, the theory states that correctingmisperceptions of perceived normswillmost likely result in a decrease in the problem behavior or an increase in the desired
behavior.
Social norms interventions aim to present correct information about peer group norms
in an effort to correct misperceptions of norms. In particular, many social norms
interventions are social normsmedia campaignswheremisperceptions are addressed
through community-wide electronic and print media that promote accurate and
healthy norms about the health behavior. The phases of a social normsmedia campaign
include:
● Assessment or collection of data to inform themessage.
● Selection of the normativemessage that will be distributed.
● Testing themessage with the target group to ensure it is well-received.
● Selection of themode in which themessage will be delivered.
● Amount, or dosage, of themessage that will be delivered.
● Evaluation of the effectiveness of themessage
Social normsmedia campaigns are currently being funded bymany federal agencies,
state agencies, foundation grants, and non-profit organizations. Sometimes social
normsmedia campaigns are funded by industry. There has been a good deal of
evaluations conducted on social norms campaigns.
There are several limitations of Social Norms Theory that need to be considered prior
to using the theory. Limitations of the theory include the following:
● Participants of an intervention focused on social norms are likely to
question the initial message being presented to them due tomisperceptions
they hold. Informationmust be presented in a reliable way to correct those
misperceptions.
● Poor data collection in the initial stages can lead to unreliable data and poor
choice of normativemessage. This can undermine the campaign and
reinforcemisperceptions.
● Unreliable sources, or sources that are not credible to the target population,
can result in an unappealingmessage that undermines the campaign, even if
themessage is correctly chosen.
● The dose, or amount, of themessage received by the target populationmust
be enough tomake an impact, but not toomuch that it becomes
commonplace.
Although these limitations exist, when used correctly Social Norms Theory can be very
effective in changing individual behavior by focusing on changingmisperceptions at
the group level. Social norms interventions can be used alone or in conjunction with
other types of intervention strategies. Themost effective social norms interventions
are those that havemessages targeted to the at-risk population that are correct and
influential. To target messages, a substantial amount of research and data collection
has to be invested to understand the norms that exist in the group of interest. Social
norms interventions are alsomost effective when presented in interactive formats that
actively engage the target audience.
