Testing an extended theory of planned behavior to predict young people's intentions to join a bone marrow donor registry

An extended theory of planned behavior (TPB) was used to understand the factors, particularly control perceptions and affective reactions, given conflicting findings in previous research, informing younger people's intentions to join a bone marrow registry. Participants (N = 174) completed attitude, subjective norm, perceived behavioral control (PBC), moral norm, anticipated regret, self‐identity, and intention items for registering. The extended TPB (except PBC) explained 67.2% of variance in intention. Further testing is needed as to the volitional nature of registering. Moral norm, anticipated regret, and self‐identity are likely intervention targets for increasing younger people's bone marrow registry participation.     

To Be a Donor or Not to Be? Applying an Extended Theory of Planned Behavior to Predict Posthumous Organ Donation Intentions

Using a theory of planned behavior (TPB) perspective, individual intentions to register and discuss the decision of organ donation with significant others were examined. In addition to standard TPB variables (attitude, subjective norm, and perceived behavioral control [PBC]), self-identity and moral norm were incorporated into the TPB as predictors. Australian university students ( N  = 303) completed a survey comprising standard and additional TPB constructs. Separate analyses were conducted for both registered and nonregistered participants. In general, results provide support for the extended TPB model in predicting intentions to register and discuss the donation decision, with the exceptions that self-identity did not predict discussion intentions for either registered or nonregistered participants, and PBC did not predict discussion intentions for nonregistered participants.     

Predicting People’s Intention to Donate Their Body to Medical Science and Research

Predictors of people’s intention to register with a body bequest program for donating their deceased body to medical science and research were examined using standard theory of planned behavior (TPB) predictors (attitude, subjective norm, perceived behavioral control) and adding moral norm, altruism, and knowledge. Australian students (N = 221) at a university with a recently established body bequest program completed measures of the TPB’s underlying beliefs (behavioral, normative, and control beliefs) and standard and extended TPB predictors, with a sub-sample reporting their registration-related behavior 2 months later. The standard TPB accounted for 43.6%, and the extended predictors an additional 15.1% of variance in intention. The significant predictors were attitude, subjective norm, and moral norm, partially supporting an extended TPB in understanding people’s body donation intentions. Further, important underlying beliefs can inform strategies to target prospective donors.     

Identifying Beliefs and Cognitions Underpinning Commuters' Travel Mode Choices

Interventions to reduce car use have shown limited success, in part due to limitations in models of transport choices. The theory of planned behavior (TPB) has provided a useful predictive model of car use but the specific beliefs that underpin TPB‐specified cognitions are less well understood. In this study, 229 university employees responded to a questionnaire and then reported their commuting choices 1 week later. Intention and perceived behavioral control (PBC) predicted car use (R² = .79). Intention was predicted by attitude, subjective norm, PBC, and moral norm (R² = .56). Beliefs could not be differentiated into attitudinal and PBC constructs, but seven beliefs predicted TPB cognitions. A similar model was tested for public transport use. The results identify key targets for future interventions.     

Antecedents of children's physical activity intentions and behaviour: Predictive validity and longitudinal effects

Abstract

This study examined the predictive validity and time-lagged relationships in a model of children's physical activity intentions, attitudes, perceived behavioural control (PBC), behaviour and past behaviour using the Theory of Planned Behaviour (TPB; Ajzen, 1985) as a framework. In Study 1, 386 children aged 12–14 years completed measures of intentions, attitudes, subjective norm, PBC and past behaviour. Their physical activity behaviour was assessed one week later. Structural equation analyses supported the construct and predictive validity of the TPB with the exception of subjective norms which did not predict intentions. In Study 2,70 children completed measures of their physical activity attitudes, intentions, PBC and past behaviour. Attitudes, intentions, PBC and recent behaviour were re-assessed five weeks later. The cognitions demonstrated a moderate degree of stability over time and there were some cross-lagged effects between attitudes and PBC. Past behaviour demonstrated additive rather than attenuating effects. These results support the use of the TPB cognitions and past behaviour as a framework to examine children's physical activity behaviour.     

Alcohol Consumption and the Theory of Planned Behavior: An Examination of the Cognitive Mediation of Past Behaviorid

This study examined the predictive power of the theory of planned behavior (TPB) in explaining alcohol consumption in 3 prospective samples of students ( Ns = 178. 176. and 159). Generally, the TPB performed well. with attitudes, subjective norms and perceived behavioral control (PBC) explaining between 28% and 46% of the variability in intentions. Intentions and PBC explained between 12% and 50% of the variability in behavior. Measures of self-identity as a "drinker" and past behavior contributed to predictions of intentions over and above the contribution of attitudes. subjective norms. and PBC. Measures of past behavior but not self-identity consistently contributed to predictions of behavior over and above the contributions from intentions and PBC. The direct relationship between past behavior and intention and between past behavior and behavior (independent of the TPB variables or self-identity) could not be attributed to common method variance.     

Extending the Theory of Planned Behavior: A Review and Avenues for Further Research

This paper describes and reviews the theory of planned behavior (TPB). The focus is on evidence supporting the further extension of the TPB in various ways. Empirical and theoretical evidence to support the addition of 6 variables to the TPB is reviewed: belief salience measures, past behavior/habit, perceived behavioral control (PBC) vs. self-efficacy, moral norms, self-identity, and affective beliefs. In each case there appears to be growing empirical evidence to support their addition to the TPB and some understanding of the processes by which they may be related to other TPB variables, intentions, and behavior. Two avenues for expansion of the TPB are presented. First, the possibility of incorporating the TPB into a dual-process model of attitude–behavior relationships is reviewed. Second, the expansion of the TPB to include consideration of the volitional processes determining how goal intentions may lead to goal achievement is discussed.     

Application of the theory of planned behaviour to the prediction of objectively assessed breaking of posted speed limits

In two studies the Theory of Planned Behaviour (TPB) including moral norms, anticipated regret and past behaviour was applied to predicting intention to exceed the posted speed limit across different roads and objectively assessed speeding behaviour. All measures except behaviour were taken by self‐report questionnaires referring to different driving scenarios. The behaviour measures were based on performance in a simulator (Study 1) or unobtrusive on‐road speed camera assessment taken without driver awareness (Study 2) across roads with varying posted speed limits. Results are reported averaged across road types in both studies. In Study 1 (N = 83), 82% of the variance in intentions to speed was explained, with attitudes, subjective norms, perceived behavioural control (PBC), moral norms, anticipated regret and past behaviour being significant predictors. A total of 35% of the variance in speed as assessed on a driving simulator was accounted for with intentions, PBC, moral norms and previous accidents being significant predictors. In Study 2 (N = 303), 76% of the variance in intentions to speed was explained with attitudes, moral norms, anticipated regret and past behaviour being significant predictors. A total of 17% of the variance in speed as assessed on‐road was accounted for with intentions and moral norms being significant. Practical implications of the findings for road safety are discussed.     

Having Casual Sex: Additive and Interactive Effects of Alcohol and Condom Availability on the Determinants of Intentions

The impact of alcohol, condom availability, and gender on intentions to engage in casual sex and its antecedents was investigated. Students ( N = 384) who were or were not intoxicated with alcohol completed measures based on the theory of planned behavior (TPB) in relation to having casual sex in a scenario. The scenario described sex between 2 individuals not in a relationship and manipulated the consumption of alcohol of the sexual partners and availability of condoms. The data were supportive of the TPB: Intentions were predictable from attitudes, subjective norms, and perceived behavioral control (PBC). Results also support the inclusion of measures of past behavior and anticipated affective reactions, but not self-identity or moral norms as predictors of intentions. Alcohol in the scenario and condom availability increased intentions to have sex. There were also several interaction effects. Implications for using the TPB to understand sexual behaviors under the influence of alcohol are discussed.     

Theory of planned behaviour and parasuicide: An exploratory study

Recent evidence suggests that parasuicide (deliberate self-harm) should be considered in terms of ‘normal’ rather than ‘abnormal’ behaviour. This study aimed to address this assertion by applying a social cognition model, for the first time, to parasuicidal behaviour. An extended theory of planned behaviour (TPB) model was tested on 55 individuals drawn from hospital and non-hospital populations. Thirty-eight percent of the sample (n=21) reported a history of deliberate self-harm. Findings supported the utility of the TPB: attitudes, subjective norm, self-efficacy, moral norm and anticipated affect discriminated significantly between those with and without a history of parasuicide. The extended TPB explained more than 50% of the variance associated with intentions to deliberately self-harm. These findings have considerable theoretical and practical implications for intervention. Future research should investigate the utility of the TPB employed within a prospective framework.     

Predicting Psychologists' Intentions to Integrate Complementary and Alternative Therapies Into Their Practice

Drawing on an extended Theory of Planned Behaviour (TPB) framework, we employed a cross‐sectional design study to investigate psychologists' intentions to integrate complementary and alternative therapies (CAT) into their practice via recommending CAT to clients or referring clients to CAT practitioners. Participants were registered practicing psychologists from a range of therapeutic orientations (e.g., narrative, cognitive behavioural, psychodynamic). The psychologists were either recruited by phone, following a search of the Internet, or were contacted through their place of employment (hospitals, university counselling service). Those who agreed to participate (N = 122; n = 88 females, n = 34 males) completed a questionnaire that included standard TPB items of attitude, subjective norm, and perceived behavioural control, along with items measuring perceived risk, past behaviour, CAT knowledge, and gender. The outcome variables of interest were (a) intention to recommend CAT to clients and (b) intention to refer clients to CAT practitioners. Structural equation modelling revealed that the extended model was a good fit, explaining 69% (recommending CAT) and 51% (referring to CAT practitioners) of the variance in intentions. For both behaviours, direct paths from attitude and subjective norm to intentions were observed, with perceived risk and past behaviour influencing the TPB predictors of attitudes, subjective norm, and perceived behavioural control. The findings illustrate the role that cognitive and risk factors have on psychologists' decisions to integrate CAT into their practice. Understanding psychologists' cognitions and decisions about CAT integration forms an important basis on which to consider future changes in policy or practice.     

Theory of planned behaviour and parasuicide: An exploratory study

Recent evidence suggests that parasuicide (deliberate self-harm) should be considered in terms of ‘normal’ rather than ‘abnormal’ behaviour. This study aimed to address this assertion by applying a social cognition model, for the first time, to parasuicidal behaviour. An extended theory of planned behaviour (TPB) model was tested on 55 individuals drawn from hospital and non-hospital populations. Thirty-eight percent of the sample (n=21) reported a history of deliberate self-harm. Findings supported the utility of the TPB: attitudes, subjective norm, self-efficacy, moral norm and anticipated affect discriminated significantly between those with and without a history of parasuicide. The extended TPB explained more than 50% of the variance associated with intentions to deliberately self-harm. These findings have considerable theoretical and practical implications for intervention. Future research should investigate the utility of the TPB employed within a prospective framework.     

The role of self-efficacy in predicting rule-following behaviors in shelters for homeless youth: a test of the theory of planned behavior

Through a prospective study of 70 youths staying at homeless-youth shelters, the authors tested the utility of I. Ajzen's (1991) theory of planned behavior (TPB), by comparing the constructs of self-efficacy with perceived behavioral control (PBC), in predicting people's rule-following behavior during shelter stays. They performed the 1st wave of data collection through a questionnaire assessing the standard TPB components of attitudes, subjective norms, PBC, and behavioral intentions in relation to following the set rules at youth shelters. Further, they distinguished between items assessing PBC (or perceived control) and those reflecting self-efficacy (or perceived difficulty). At the completion of each youth's stay at the shelter, shelter staff rated the rule adherence for that participant. Regression analyses revealed some support for the TPB in that subjective norm was a significant predictor of intentions. However, self-efficacy emerged as the strongest predictor of intentions and was the only significant predictor of rule-following behavior. Thus, the results of the present study indicate the possibility that self-efficacy is integral to predicting rule adherence within this context and reaffirm the importance of incorporating notions of people's perceived ease or difficulty in performing actions in models of attitude-behavior prediction.     

Interaction Effects in the Theory of Planned Behavior: The Interplay of Self-Identity and Past Behavior

This research used a revised theory of planned behavior (TPB) model, which incorporated self-identity and past behavior—and the interaction between these constructs—in order to improve the model's predictive power in relation to consumer behavior (purchasing one's preferred beer). At Time 1, respondents ( N  = 108) completed measures of attitudes, perceived behavioral control, subjective norm, self-identity, past behavior, and intentions. Behavior was assessed 1 week later. All predictors were positively related to intentions. Self-identity and past behavior interacted to influence intentions: Self-identity had a stronger influence on intentions at low, rather than high, levels of past behavior. Intentions and past behavior were predictive of Time 2 behavior. These findings emphasize the need to consider identity issues in the TPB.     

Predicting Intentions to Conserve Water From the Theory of Planned Behavior,Perceived Moral Obligation,and Perceived Water Right1

This study tested the explanatory power of Ajzen's (1991) theory of planned behavior (TPB), and a modified TPB model including perceived moral obligation (PMO) and perceived water right (PWR), to predict people's intentions to conserve water. The study had 244 government employees who participated. The TPB variables improved the prediction of intention to use less water, but were less successful in predicting intention to install water-efficient appliances. A significant interaction was found between attitude and subjective norm, suggesting that past studies have overlooked moderating effects in the TPB model. In addition to the TPB variables, PWR further improved the prediction of intention to install water-efficient appliances. Results also suggest that water-saving procedures should be differentiated into curtailment and efficiency procedures.     

How well can the theory of planned behavior account for occupational intentions?

We tested the capacity of an extended version of the theory of planned behavior (TPB) to account for intentions to work for the UK’s National Health Service (NHS) as a nurse, physiotherapist or radiographer amongst three groups: professionally unqualified (N = 507), in professional training (N = 244), and professionally qualified (N = 227). We found strong support for the three core TPB variables attitude, subjective norm and perceived behavioral control as predictors of behavioral intention, and limited support for two additional variables: moral obligation and identification. There were some differences in the relative importance of TPB variables between groups. We conclude that the TPB has utility for more complex behaviors as well as simpler ones that are more frequently researched. However, more attention should be paid to differences in people’s circumstances, particularly regarding past vocational decisions and behavior, and to obstacles to implementing an intention.