Modelling the theory of planned behaviour and past behaviour

This paper demonstrated two modelling techniques and three interpretations for the inclusion of past behaviour in a theory of planned behaviour (TPB) framework using structural equation modelling. Model 1 examined past behaviour as either a causal influence or as an autoregressive influence on current behaviour. Model 2 demonstrated a novel approach to including past behaviour and current behaviour while preserving the tenets of the TPB, as it freed the residual correlation between past and present behaviour but not the causal path. Participants were 305 undergraduate students (mean age?=?19.42 years) who completed measures of the TPB, past exercise behaviour and current exercise behaviour at one-month follow-up. Results demonstrated the importance of a priori conceptualization of past behaviour, as the models provide differences between estimated coefficients. Subsequent interpretation and decision to use each modelling strategy depends on the research objective and theory.     

The theory of planned behaviour: reactions and reflections

The seven articles in this issue, and the accompanying meta-analysis in Health Psychology Review [McEachan, R.R.C., Conner, M., Taylor, N., & Lawton, R.J. (2011). Prospective prediction of health-related behaviors with the theory of planned behavior: A meta-analysis. Health Psychology Review, 5, 97-144], illustrate the wide application of the theory of planned behaviour [Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179-211] in the health domain. In this editorial, Ajzen reflects on some of the issues raised by the different authors. Among the topics addressed are the nature of intentions and the limits of predictive validity; rationality, affect and emotions; past behaviour and habit; the prototype/willingness model; and the role of such background factors as the big five personality traits and social comparison tendency.     

From attitudes to behaviour: Basic and applied research on the theory of planned behaviour

The present article traces the development of the theory of planned behaviour, from early research on the attitude-behaviour relationship through the theory of reasoned action. In particular, it is argued that a perceived lack of correspondence between attitude and behaviour led to examination of variables that either moderated (e.g., attitude strength, measurement correspondence) or mediated (behavioural intention) the relationship between attitudes and behaviour. Several meta-analytic reviews provide strong empirical support for the theory of planned behaviour, yet several applied and basic issues need to be resolved. The six papers that make up the remainder of this special issue address several of these issues.     

From attitudes to behaviour: Basic and applied research on the theory of planned behaviour

The present article traces the development of the theory of planned behaviour, from early research on the attitude-behaviour relationship through the theory of reasoned action. In particular, it is argued that a perceived lack of correspondence between attitude and behaviour led to examination of variables that either moderated (e.g., attitude strength, measurement correspondence) or mediated (behavioural intention) the relationship between attitudes and behaviour. Several meta-analytic reviews provide strong empirical support for the theory of planned behaviour, yet several applied and basic issues need to be resolved. The six papers that make up the remainder of this special issue address several of these issues.     

Predictors of smoking cessation in Taiwan: using the theory of planned behavior

This study aimed to explore the factors predicting the intention to quit smoking and the subsequent behavior 6 months later using the theory of planned behavior (TPB). Data were obtained from 145 smokers who attended a smoking cessation clinic in a community hospital. All participants completed a questionnaire which included demographic information, TPB-based items, perceived susceptibility and previous attempts to quit. The actual quitting behavior was obtained by follow-up phone calls 6 months later. The TPB constructs explained 34% of the variance in intention to quit smoking. By adding perceived susceptibility, the explained variance was significantly improved to 40%. The most important predictors were perceived behavior control and perceived susceptibility, followed by attitude. Subjective norm did not contribute to the prediction of intention. Attitude and perceived behavior control contributed to the prediction of actual quitting behavior, but intention, subjective norm and perceived susceptibility did not. Our findings support that the TPB is generally a useful framework to predict the intention to quit smoking in Taiwan. The inclusion of perceived susceptibility improved the prediction of intention. With regards to successfully quitting, attitude and perceived behavior control played more crucial roles than other TPB constructs. Smoking cessation promotion initiatives focusing on reinforcing cessation belief, enhancing a smoker’s perception of their capability to quit smoking, and persuading smokers that they can overcome cessation barriers to cessation could make subsequent interventions more effective.     

Contact sports, moral functioning and planned behaviour theory

The goal was to test the psychometric properties of the Moral Functioning Scale in a Greek athletic context, and to investigate any possible relation between moral functioning and planned behaviour. The sample comprised 384 athletes, 103 from the sport of football (soccer), 97 from basketball, and 184 from water polo. To measure moral functioning the researchers used a scale developed by Gibbons, Ebbeck, and Weiss. Planned Behaviour was assessed with a questionnaire based on Planned Behaviour Theory. Hierarchical regression analysis indicated strong association for Attitudes, Intention, Role Identity, and Perceived Behavioural Control with the four dilemmas of the moral functioning scale. The moral reasoning measure is a promising tool for measuring athletes' moral dilemmas in Greece.     

Promoting drivers' compliance with speed limits: Testing an intervention based on the theory of planned behaviour

The efficacy of a theory of planned behaviour (TPB)‐based intervention to promote drivers' compliance with speed limits was tested. Participants (N=300) were randomly assigned to an experimental condition, and received persuasive messages designed to change beliefs as specified in the TPB, or a control condition. Baseline and follow‐up (1 month post‐baseline) measures of TPB variables and behaviour were collected using postal questionnaires. Results showed that the intervention had a significant effect on one control belief, and significantly increased perceived behavioural control and reported behaviour. Mediation analyses confirmed that the control belief change generated the perceived behavioural control change and that the perceived behavioural control change generated the behaviour change. Implications for promoting road safety are discussed.     

Statistical guidelines for studies of the theory of reasoned action and the theory of planned behaviour

Abstract

We identify potential problems in the statistical analysis of social cognition model data, with special emphasis on the theories of reasoned action (TRA) and planned behaviour (TPB). Some statistical guidelines are presented for empirical studies of the TRA and the TPB based upon multiple linear regression and structural equation modelling (SEM). If the model is tested using multiple regression, the assumptions of this technique must be considered and variables transformed if necessary. Adjusted R² (not R²) should be used as a measure of explained variance and semipartial correlations are useful in assessing each component's unique contribution to explained variance. R² is not an indicator of model adequacy and residuals should be examined. Expectancy-value variables that are the product of expectancy and value measures represent the interaction term in a multiple regression and should not be used. SEM approaches make explicit the assumptions of unidimensionality of constructs in the TRA/TPB, assumptions that might usefully be challenged by competing models with multidimensional constructs. Finally, statistical power and sample size should be considered for both approaches. Inattention to any of these aspects of analysis threatens the validity of TRA/TPB research.     

Sleep hygiene behaviours: an application of the theory of planned behaviour and the investigation of perceived autonomy support, past behaviour and response inhibition

This study investigated the sleep hygiene behaviour of university students within the framework of the Theory of Planned Behaviour (TPB [Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179-211.]), and examined the predictive validity of additional variables including perceived autonomy support, past behaviour and response inhibition. A total of 257 undergraduate students from an Australian university were administered two online questionnaires at two time points. At time 1, participants completed the TPB questionnaire and the Go/NoGo task as a measure of response inhibition. A week later at time 2, participants completed a questionnaire measuring the performance of sleep hygiene behaviours. Multiple and hierarchical regression analyses showed that the TPB model significantly predicted intention and behaviour. Although intention and perceived behavioural control were statistically significant in predicting behaviour, past behaviour and response inhibition accounted for more variance when added to the TPB model. Subjective norm was found to be the strongest predictor of intention implying the importance of normative influences in sleep hygiene behaviours. Response inhibition was the strongest predictor of behaviour, reinforcing the argument that the performance of health protective behaviours requires self-regulatory ability. Therefore, interventions should be targeted at enhancing self-regulatory capacity.     

Predictive validity of the theory of planned behaviour: the role of questionnaire format and social desirability

The present study was designed to assess the predictive validity of a theory of planned behaviour extended to include self‐identity, in the context of health‐related food choice. Following criticism of the use of questionnaires in social cognitive research, the impact of questionnaire format (random vs structured) and social desirability on questionnaire responses was assessed. Findings indicated that intention was the principal determinant of food choice; attitude, subjective norm and self‐identity were independently predictive of intention. There was only weak evidence to suggest effects of social desirability or questionnaire format on component relationships. The present study indicates that the impact of questionnaire format and social desirability on models such as the theory of planned behaviour is minimal, and that such models are robust predictors of food choice. Copyright © 1999 John Wiley & Sons, Ltd.     

The theory of planned behaviour and breast self-examination: assessing the impact of past behaviour, context stability and habit strength

This study applied the theory of planned behaviour (TPB) to the prediction of breast self-examination (BSE) intentions and behaviour, and tested whether the frequency of past behaviour and context stability moderates intention-behaviour and habit-behaviour relations. Seventy-seven females completed measures of the TPB, frequency of past behaviour, context stability and habit strength (Self-Report Habit Index). BSE behaviour was assessed at 1-month follow-up (n?=?66). The TPB explained 33% of the variance in BSE intentions and 11% of the variance in time 2 BSE. The frequency of past behaviour moderated the intention-behaviour relationship such that the intention was only positively related to time 2 BSE behaviour when the frequency of past behaviour was low. Context stability and the combination of the frequency of past behaviour?×?context stability moderated the habit-behaviour relationship such that habit strength was only positively related to time 2 BSE behaviour when context stability and the combination of frequency of past behaviour?×?context stability were high. The results are consistent with the proposal that behaviours that are performed frequently in stable contexts are predominantly under the control of habitual processes, whereas behaviours that are performed infrequently in unstable contexts are predominantly under the control of intentional processes.     

Predicting sun-protective intentions and behaviours using the theory of planned behaviour: a systematic review and meta-analysis

Objective: To synthesise theory of planned behaviour (TPB) relationships, using meta-analysis, and test the predictive utility of the model for sun protection behaviour.

Design: Thirty-eight samples were identified via database/manual searches and academic society posts based on the criteria: measuring sun-protective intentions and/or prospective behaviour; using the TPB/theory of reasoned action as a basis of measurement; and providing bivariate correlations for at least one relevant TPB association.

Main outcome measures: Sun-protective intentions and behaviours.

Results: The sample-weighted average effects were moderate-to-strong with attitudes showing the strongest association with intention (r+ = 0.494), followed by perceived behavioural control (PBC; r+ = 0.451), and subjective norm (r+ = 0.419). Intentions showed a stronger association with prospective behaviour (r+ = 0.486) compared to PBC (r+ = 0.314). A total of 39% of variance in intentions and 25% of variance in behaviour were explained. Publication bias was not evident. Moderator analyses showed that TPB associations were stronger when measures specified the Target, Action, Context and Time; in non-student samples; and when follow-up exceeded two weeks.

Conclusion: Despite recent criticism, this review shows that the TPB explains a large amount of variance in sun protection and that TPB associations are robust across different populations.     

Predicting uptake of housing services: The role of self-categorization in the theory of planned behaviour

The theory of planned behaviour (TPB) and self-categorization theory (SCT) were used to predict homeless people’s (n = 80) uptake of housing support services. Homeless people’s uptake behaviour was measured one year after a TPB/SCT-based interview schedule was administered. Congruent with previous research, TPB variables were influential predictors of both intention and behaviour. However, the addition of self-categorization variables, such as friendship group norms and identification as a housing support service user, significantly increased the rate prediction for both intention and behaviour, respectively. The implications of the research are firstly, that social cognition models are useful for understanding uptake of housing support services; and secondly, the addition of self-categorization variables aids in exploring the central role that social norms play in understanding the uptake of these services. These findings are discussed in terms of their impact on theory and practice.     

The theory of planned behaviour and exercise: An investigation into the role of prior behaviour,behavioural intentions and attitude variability

This paper reports a prospective study which applied the Theory of Planned Behaviour (TPB) to the prediction of exercise behaviour over a six-month period. The study addressed a number of issues which have been identified in the literature on the TPB; these being the role of prior behaviour in the TPB, the distinction between desires and self-predictions, and the question of attitude variability. The findings showed prior behaviour to be the strongest predictor of exercise behaviour at six months. Contrary to expectations, the self-prediction measure was not found to be a better predictor of behaviour than the desire measure. Attitude variability was found to be related to perceptions of control. However, attitude variability was not found to moderate relationships between components of the TPB. The implications of the results for the development of the TPB are discussed.     

Using the theory of planned behaviour to predict screening uptake in two contexts

Given current policy that decisions about screening should be based on informed choice, such decisions should reflect people's values and attitudes. This prospective study compares the attitudes and other cognitive predictors of screening uptake in two contexts: when conducted as part of a routine visit and when it is conducted at a separate, test-specific visit. It was conducted in two hospitals in England, differing in method of screening organisation. 1499 pregnant women offered serum screening for Down Syndrome completed a questionnaire assessing theory of planned behaviour constructs: attitude towards undergoing the test, subjective norms of others, perceived behavioural control and intention to undergo the test.

Intention predicted screening uptake in both screening settings, but more strongly when screening was part of a routine visit. Perceived behavioural control was not predictive of uptake, and only weakly predictive of intention in both settings. Subjective norm predicted intention more strongly when it referred to partner and friends than when it referred to health professionals, in both settings.

Attitude was more strongly predictive of intention to attend screening when screening was organised as a part of routine screening, rather than requiring a separate visit. These results suggest that offering a screening test at a routine visit compared with a separate visit is more likely to facilitated uninformed choices, given the stronger association between attitudes and intention and the absence of an association with the perceived influence of health professionals.     

Predicting uptake of housing services: The role of self-categorization in the theory of planned behaviour

The theory of planned behaviour (TPB) and self-categorization theory (SCT) were used to predict homeless people’s (n = 80) uptake of housing support services. Homeless people’s uptake behaviour was measured one year after a TPB/SCT-based interview schedule was administered. Congruent with previous research, TPB variables were influential predictors of both intention and behaviour. However, the addition of self-categorization variables, such as friendship group norms and identification as a housing support service user, significantly increased the rate prediction for both intention and behaviour, respectively. The implications of the research are firstly, that social cognition models are useful for understanding uptake of housing support services; and secondly, the addition of self-categorization variables aids in exploring the central role that social norms play in understanding the uptake of these services. These findings are discussed in terms of their impact on theory and practice.     

Depression and medication adherence among breast cancer survivors: Bridging the gap with the theory of planned behaviour

Evidence suggests that more depressed breast cancer patients will less likely adhere to treatment plans. This study presents evidence that the theory of planned behaviour mediates the relation between depression and intentions to adhere to treatment plans and between depression and lack of adherence to medication regime. Two hundred and thirteen women undergoing breast cancer treatment participated in this study. Measures of depressive symptoms and planned behaviour variables were collected at the first time point; measures of medication adherence were collected at the second time point. Structural equation models were utilised to fit the data to the proposed models. Depressive symptoms were significantly correlated to both intentions and medication adherence. In support of hypotheses, the relation between depressive symptoms and treatment intention was mediated by attitudes towards health maintenance plans. The relation between depressive symptoms and medication adherence was fully mediated by the planned behaviour process. Conditions under which treatment intentions and perceptions of control in adhering to treatment were most related to medication adherence were elucidated. The results point to avenues for interventions to increase medication adherence among breast cancer patients. Manipulating attitudes and perceptions of control towards treatment plans will potentially serve to increase medication adherence.     

Intentions to participate in counselling among front-line,at-risk Irish government employees: an application of the theory of planned behaviour

ABSTRACT

The study set out to examine intentions to engage in counselling among at-risk Irish government employees and the differential utility of two alternative theory of planned behaviour (TPB) models of behaviour to explain intentions to participate in counselling. Individuals (N=259) employed in a front-line, at-risk occupation for the Irish government completed a TPB-based questionnaire. Quantitative analyses revealed that participants held positive to neutral intentions to participate in counselling, irrespective of gender. The original TPB model explained 49.9% of variance in intentions whereas an alternative TPB model, splitting the perceived behavioural control (PBC) construct between its internal and external control components, explained a further 8.9% of variance. Furthermore, self-efficacy was found to be the strongest predictor of intentions. This study therefore supports the use of the TPB in understanding counselling-seeking behaviour.