32 terms

Theory of Reasoned Action & Theory of Planned Behavior


Terms in this set (...)

TRA and TPB founded by
Fishbein & Ajzen and Fishbein
Essence of theories
Health behavior results from intention influenced by attitude, norms, and control
TRA and TPB propose behavior is based on the concept of
the extent to which someone is ready to engage in a certain behavior or the likelihood that someone will engage in a particular behavior
Intention is influenced by the following factors
attitudes, subjective norms, volitional control, and behavioral control
Behavioral Beliefs +
Evaluations of Behavioral Outcomes -->
Attitude Toward Behavior
Attitude toward behavior soy example
if someone believes eating soy is healthier than eating animal protein, is better for the environment, and carries less of a chance of foodborne illness, the individual's attitude toward eating soy products would be favorable
Normative Beliefs +
Motivation to Comply -->
Subjective Norms
Subjective norms
the perceived social pressure to engage or not to engage in a certain behavior
Subjective norms soy example
if a health care provider and family member suggest that an individual eat soy products, and if the person wants to make these others happy, there is a greater willingness to comply and a greater likelihood of soy consumption
Attitude Toward Behavior +
Subjective Norm -->
Behavioral Intention
Behavioral Intention -->
Behavioral Intention
● A person's readiness to perform a given behavior

● Indicated by subjective probability that one will perform the behavior

● Affecting "intent" is the goal of a Theory of Reasoned Action based intervention
Attitude Toward Behavior are a combination of
- Behavioral beliefs: A person's beliefs regarding the
outcomes of a defined behavior


- Evaluation of behavioral outcomes: The person's
evaluation of potential outcomes
Subjective Norms
Perceived overall social pressure
Subjective Norms are a combination of
-Normative Beliefs: A person's beliefs regarding
other people's views of a behavior (belief about
what relevant others think she should do)


- Motivation to comply to other people (The person's
willingness to conform to those views)
The theory of reasoned action has proved to be
most successful when dealing with
purely volitional behaviors
Complications of theory of reasoned action are encountered when the theory is applied to
behaviors that are not fully under volitional control
The theory of planned behavior (TPB) is an
extension of the theory of reasoned action that
the problem of incomplete volitional control
A behavior under volitional control is one
in which the person is able to decide, at will, to engage in or not (such as deciding whether the eat breakfast in the morning)
Control Beliefs +
Perceived Power -->
Perceived Behavioral Control
Perceived Behavioral Control -->
Behavioral Intention & Behavior
Difference between TRA &TPB
- TPB adds one component to the TRA = Perceived Behavioral Control
Perceived Behavioral Control
- Refers to the perceived ease or difficulty to perform behavior

- Refers to people's perceptions of their ability to perform a given behavior

- Account for factors outside the individual's control that may affect intention and behavior
Construct of Behavioral Control is similar to the construct of
self-efficacy in Social Cognitive Theory and the concept of SE theory
How does behavioral control differ from self-efficacy?
SE is concerned with one's perception of ability to perform a behavior, whereas behavioral control is concerned with "perceived control over performance of a behavior"
Perceived behavioral control beliefs
● Reflects past experience & anticipated barriers

● is determined by the total set of accessible control beliefs, i.e., beliefs about the presence of factors that may facilitate or impede performance of the behavior

● perceived power of the control factor

● perceived behavioral control can, together with intention, be used to predict behavior
TPB For example: ➢ predicts that a person will give up smoking if she
1) Has a positive attitude toward quitting

2) Thinks others whom she values believe it would be good for her to quit

3) Perceives that she has control over whether she quits
the importance of the role of perceived
behavioral control came from
Bandura's concept of self-efficacy.

Recently, Fishbein and Cappella (2006) stated that self-efficacy is the same as perceived behavioral control in his model.

it tries to measure the confidence toward the probability, feasibility, or likelihood of executing given behavior
Strengths of TRA and TPB
- TPB can cover people's non-volitional behavior which can't be explained by TRA
- By adding perceived behavioral control, TPB can explain the relationship between behavioral intention and actual behavior
- Several studies found that TPB would help better predict health-related behavioral intention than the TRA
- TPB as well as TRA can explain the individual's social behavior by considering social norm as an important variable
Limitations of TRA and TPB
- the theory of planned behavior is based on cognitive processing and level of behavior change

- compared to affective processing models, the theory of planned behavior overlooks emotional variables such as threat, fear, mood and negative or positive feeling and assessed them in a limited fashion. THis is a limitation since most health behaviors are influenced by personal emotional and affect-laden nature

-poor predictability for health-related behavior in previous health research may be attributed to exclusion of emotion variables
Article at end of chapter
Purpose: assessed the plausability and robustness of Ajzen's TPB in predicting and explaining use, frequency of use and misuse of alcohol among 3946 5th-8th graders in Michigan. Also compared the effectiveness of TPB and TRA in predicting intention to use alcohol

Results: strong support for use of TPB. Intention to use alcohol explained up to 26% variance in use, 38% variance in frequency of use, and 30% variance in misuse of alcohol. up to 76% variance in intention to use alcohol was explained by attitudes, subjective norms, and perceived behavioral control. TPB was more effective in predicting intention to use alcohol than TRA