The role of perceived need within the theory of planned behaviour: A comparison of exercise and healthy eating

Objectives: This study examined the effect of perceived need on exercise and healthy eating using the theory of planned behaviour (TPB). In addition, it investigated the determinants of perceived need. Method: Participants completed a questionnaire measuring components of TPB and perceived need. A follow‐up questionnaire 1 week later measured behaviour. The questionnaires were completed by e‐mail. The initial questionnaire was completed by 331 adults, and 286 follow‐up questionnaires were returned. Results: Perceived behavioural control was the main predictor of exercise intention and affective attitude was the main predictor of healthy eating intention. Perceived need significantly contributed to the prediction of healthy eating intention but not to exercise intention. Intention and perceived behavioural control predicted actual behaviour but perceived need did not. Reasons reported for the perception of needing to engage in both behaviours mainly focused on physical health and weight control. Conclusions: Reasons reported for low perceived need suggest that the concept of perceived need may be rather ambiguous, particularly in the case of exercise. Therefore, further research is needed to elucidate the role of perceived need in relation to a variety of health behaviours.     

The theory of planned behaviour and binge drinking: Assessing the moderating role of past behaviour within the theory of planned behaviour

A sample of 398 undergraduate students completed questionnaires assessing the main constructs of the theory of planned behaviour (TPB) in relation to binge drinking, as well as past binge drinking behaviour. Of these, 273 were followed up at 1 week. Regression analyses revealed attitude, self‐efficacy, and perceived control (negative relationship) to be predictive of binge drinking intentions. Intention and self‐efficacy were, in turn, predictive of binge drinking at 1‐week follow‐up. Past behaviour was found to explain additional variance in intention and behaviour. In addition, past behaviour was found to moderate the attitude–intention and intention–behaviour relationships, such that weaker relationships were observed with increasing frequency of past behaviour. The results are discussed in relation to the need to develop and test alternative measures of habit. The implications of the findings for interventions to encourage more appropriate drinking behaviour are outlined.     

Using past behaviour and spontaneous implementation intentions to enhance the utility of the theory of planned behaviour in predicting exercise

Objectives. This study examined the utility of the theory of planned behaviour (TPB), past behaviour, and spontaneous implementation intentions in predicting exercise behaviour. The psychological correlates of spontaneous implementation intentions and the moderating effects of intention, perceived behavioural control, past behaviour, and implementation intentions at various time points were also examined. Design. Data collection occurred over three phases with a 2‐ and 3‐week interval. The attrition rate was 35.97% leaving a total of 162 participants (63 males, 99 females). In the first wave, participants completed measures of TPB, spontaneous implementation intentions, and past behaviour. Behaviour was assessed in the second and third waves, and a follow‐up measure of spontaneous implementation intentions was completed in Phase 3. Results. Several regression analyses were conducted. Attitude towards exercise and perceived behavioural control made a significant contribution to the prediction of intention. Intention made a significant contribution to the prediction of implementation intentions. Spontaneous implementation intentions reduced the effect of intention and past behaviour for behaviour at 2 weeks and when indexed over a 5‐week period. When behaviour was measured for a 3‐week period (following an initial 2‐week period), the variance that intention and past behaviour accounted for in exercise behaviour decreased, and spontaneous implementation intentions were no longer a significant predictor of behaviour. Spontaneous implementation intentions were found to interact with past behaviour, such that implementation intentions predicted exercise behaviour only among participants who did not exercise frequently in the past. Conclusions. Implications and future research directions are discussed.     

Integrating the theory of planned behaviour and self‐determination theory in health behaviour: A meta‐analysis

Purpose A meta‐analysis of studies integrating the theory of planned behaviour (TPB) and self‐determination theory (SDT) in health contexts is presented. The analysis aimed to provide cumulative empirical support for a motivational sequence in which self‐determined motivation from SDT predicts the proximal predictors of intentions and behaviour from the TPB. Methods A literature search identified 36 integrated studies providing 45 tests of effects between TPB and SDT variables. Hunter and Schmidt's (1994) methods of meta‐analysis were used to correct the effect sizes across the studies for statistical artifacts. Age (old versus young), publication status (published versus unpublished), study design (correlational versus experimental/intervention), and behaviour type (physical activity versus other health‐related behaviours) were evaluated as moderators of the effects. A path‐analysis using the meta‐analytically derived correlations was conducted to examine the proposed motivational sequence. Results Statistically significant corrected correlations were evident among the perceived autonomy support and self‐determined motivation constructs from SDT and the attitude, subjective norms, perceived behavioural control, intention, and health‐related behaviour constructs from the TPB. Only six of the 28 effect sizes were moderated by the proposed moderators. Path analysis revealed that the significant effects of self‐determined motivation on intentions and behaviour were partially mediated by the proximal predictors from the TPB. Conclusions Evidence from this synthesis supported the theoretical integration and proposed motivational sequence. Results are discussed with reference to the complementary aspects of the TPB and SDT and the need for integrated experimental or intervention studies on a broader range of health behaviours.     

Autonomy and control: augmenting the validity of the theory of planned behaviour in predicting exercise

This study examined the utility of the theory of planned behaviour (TPB) along with additional constructs in predicting exercise, and explored the motivational antecedents of exercise intentions. Participants included 162 Canadian University College students (61% females). Measures of TPB, autonomous and controlling intention, perceived autonomy support and core autonomous intention were completed during phase 1 of data collection. Two and three weeks later behaviour was assessed. Hierarchical regression analyses revealed that: (a) attitude and perceived behavioural control significantly predicted TPB intention and core autonomous intention; (b) subjective norm predicted controlling intention; and (c) perceived autonomy support predicted autonomous and core autonomous intention. TPB intention significantly predicted behaviour. TPB is a fairly useful model for predicting behaviour and important information can be gained when other measures of intention are explored.     

Decision‐making about the use of hormone therapy among perimenopausal women

Objectives. Women reaching menopause must make a controversial decision about whether to use hormone therapy (HT). The theory of planned behaviour (TPB) was the organizing framework. The objectives were to determine if (1) influence of different TPB constructs varied with stage of menopause and HT use, (2) women with diabetes were influenced in significantly different ways from women without, (3) the overall perceived behavioural control (PBC) and self‐efficacy (SE) have independent effects on intention, and (4) physician influence was mediated by subjective norm (SN). Design. Cross‐sectional survey of women from a managed care organization. Methods. Multiple regression analysis was used to analyse 765 responses (230 from women with diabetes) and separately four main subgroups: (1) early menopause stage and never used HT, (2) late menopause stage and never used HT, (3) late menopause stage and previously used HT, and (4) late menopause stage currently using HT. Results. For the entire sample, the model explains 68% of variance in intention, where SE, physicians' influence, self‐identification with menopause as a natural part of ageing, self‐identification as someone who wants to delay menopause, HT status, menopause status, and diabetes were added to the TPB. For the entire sample, SE added 2% to the explained variance and the physician determinant added 7%. Conclusions. An augmented TPB is useful for understanding women's HT use decisions. The theory explains more variance in intention before a behaviour is enacted than after, and decision structure changes over time. PBC and SE have independent effects on intention.     

Psychosocial predictors of rule following in hostels for women experiencing homelessness

This study examined the psychosocial factors impacting upon the rule‐following behaviour of residents of a hostel providing crisis accommodation to women who are homeless. After their arrival, residents of a women's hostel (N=83) completed questionnaires assessing the theory of planned behaviour constructs of attitude, subjective norm, perceived behavioural control (PBC), and intentions related to rule following while residing at the hostel. Perceived resident group norms for rule following were assessed also. Follow‐up staff evaluations of the target behaviour were completed after participants ceased their hostel residence. As expected, attitude, subjective norm, PBC, and group norm significantly predicted intention to follow hostel rules, and intention and PBC predicted rule‐following behaviour. As rule following is a crucial requirement for continuation of their stay, these findings can inform strategies to improve the experiences and outcomes of women's short‐term hostel stays. © 2011 Wiley Periodicals, Inc.     

Theory of planned behaviour and ecstasy use: An analysis of moderator‐interactions

Objective: This study tested potential moderator interactions between components of the Theory of Planned Behaviour (TPB) in relation to ecstasy use, extending previous research. It was expected that attitudes, subjective norms and perceived behavioural control (PBC) would moderate each other in predicting intended use of this drug. Method: A cross‐sectional survey was administered to 200 young adults. Results: In hierarchical multiple regression analysis, past behaviour and attitude independently predicted intention; previous use of ecstasy and more positive attitudes towards ecstasy use were associated with stronger intentions to use this drug in the future. Moreover, there was a significant interaction between attitude and PBC (R²_change = 0.05). Slope analysis revealed that PBC better predicted intention given more positive attitudes towards ecstasy use. Conclusions: This moderator function may help explain predictive inconsistencies reported in the literature. Implications for the TPB are considered.     

Theory of planned behaviour cognitions do not predict self‐reported or objective physical activity levels or change in the ProActive trial

Objective. The objective was to test, in a trial cohort of sedentary adults at risk of Type 2 diabetes, whether theory of planned behaviour (TPB) cognitions about becoming more physically active predicted objective and self‐reported activity levels and change. Design. Participants of a randomized controlled trial underwent measurement at baseline, 6 and 12 months. Methods. Participants (N= 365, 30–50 years) were recruited via their parent or family history registers at 20 general practices in the UK. Energy expenditure was measured objectively at baseline and 1 year. Participants completed questionnaires assessing physical activity and beliefs about becoming more physically active over the next year at baseline, 6 and 12 months. Results. Between baseline and 12 months, objective energy expenditure in the cohort increased by an average of 20 minutes of brisk walking per day. Based on the 252 participants who provided complete data, affective attitude and perceived behavioural control consistently predicted intention, but intention and perceived behavioural control failed to predict physical activity levels or change (p‐values > .05). Conclusions. Failure of the theory to predict behaviour and behaviour change may be due to inapplicability of the theory to this at‐risk population or to trial participation and intensive measurement facilitating behaviour change without affecting measured cognitions, or lack of correspondence between cognitive and behavioural measures. A wide range of potential personal and environmental mediators should be considered when designing physical activity interventions among at‐risk groups. High‐quality experimental tests of the theory are needed in clinical populations.     

Does the easy–difficult item measure attitude or perceived behavioural control?

Objective In order to determine if easy–difficult item measures attitude or perceived behavioural control (PBC), we used structural equation modelling of 10 cross‐sectional data sets. Design Cross‐sectional design was used. Method. Ten studies that examined health‐related behaviours and used the theory of planned behaviour as a theoretical framework were analysed. Samples totalling N = 4,552 participants were employed. All studies involved multi‐item measures of attitude (Aact) and PBC items derived from pilot testing. Results Confirmatory factor analysis confirmed the discriminant validity of Aact and PBC. Structural equation modelling of relevant path indicated that in three studies, easy–difficult item is an indicator of both Aact and PBC. In the other seven studies, easy–difficult item belongs to PBC. The indexes of meta‐analysis suggest that overall, easy–difficult item is an indicator of PBC. Conclusion. Findings from 10 studies converged toward the conclusion that the easy–difficult item is an indicator of perceived PBC. However, since the easy–difficult item is sometimes classified as both Aact and PBC, and only the perceived difficulty dimension of PBC captures a significant increment in the variance of intention, it appears important to develop and validate a set of items devoted to measure the perceived difficulty dimension adequately.     

Predicting alcohol consumption and binge drinking in company employees: an application of planned behaviour and self-determination theories

Objectives. This study tested an integrated model of the psychosocial determinants of alcohol‐related behaviour among company employees from four nations. A motivational sequence was proposed in which motivational orientations from self‐determination theory influenced intentions to consume alcohol within guideline limits and alcohol‐related behaviour via the mediation of the theory of planned behaviour variables of attitude, subjective norms, and perceived behavioural control (PBC). Design. A three‐wave prospective design using self‐reported psychological and behavioural measures. Methods. Company employees (N= 486, males = 225, females = 261; M age = 30.41, SD= 8.31) from four nations (Estonia, Finland, Sweden, and UK) completed measures of autonomous and controlled motivation from self‐determination theory, attitudes, subjective norms, PBC, intentions from the theory of planned behaviour, and self‐reported measures of past alcohol consumption and binge‐drinking occasions at the first time point (time 1). Follow‐up psychological and behavioural measures were taken one month later (time 2) and follow‐up behavioural measures taken a further 2 months later (time 3). Results. Path analyses supported the motivational sequence with identified regulation (time 1), predicting intentions (time 1), and alcohol units consumed (time 2). The effects were indirect via the mediation of attitudes and PBC (time 1). A similar pattern of effects was found for the effect of time 2 psychological variables on time 3 units of alcohol consumed. There was little support for the effects of the psychological variables on binge‐drinking behaviour. Conclusions. Findings provide new information on the psychosocial determinants of alcohol behaviour in company employees and the processes involved. Results may provide impetus for the development of interventions to reduce alcohol consumption.     

Habit, identity, and repetitive action: a prospective study of binge-drinking in UK students

Objectives. Repeated action can lead to the formation of habits and identification as ‘the kind of person’ that performs the behaviour. This has led to the suggestion that identity‐relevance is a facet of habit. This study explores conceptual overlap between habit and identity, and examines where the two constructs fit into an extended Theory of Planned Behaviour (TPB) model of binge‐drinking among university students. Design. Prospective, questionnaire‐based correlational design. Methods. A total of 167 UK university students completed baseline measures of past behaviour, self‐identity, the Self‐Report Habit Index (SRHI), and TPB constructs. One week later, 128 participants completed a follow‐up behaviour measure. Results. Factor analyses of the SRHI and four identity items revealed two correlated but distinct factors, relating to habit and identity, respectively. Hierarchical regression analyses of intention and behaviour showed that identity contributed over and above TPB constructs to the prediction of intention, whereas habit predicted behaviour directly, and interacted with intentions in predicting behaviour. Habits unexpectedly strengthened the intention–behaviour relation, such that strong intenders were more likely to binge‐drink where they also had strong habits. Conclusions. Identity and habit are conceptually discrete and impact differently on binge‐drinking. Findings have implications for habit theory and measurement. Recommendations for student alcohol consumption reduction initiatives are offered.     

Role of anticipated regret,intentions and intention stability in adolescent smoking initiation

Objectives To examine the impact of anticipated regret within the theory of planned behaviour (TPB) on intentions of adolescents to initiate smoking. To examine the moderating role of anticipated regret and intention stability on the relationship between intentions and smoking initiation in adolescents. Methods We conducted two studies measuring anticipated regret within the TPB applied to adolescent smoking initiation. In the first study, 347 non‐smoking adolescents (between 11 and 12 years of age) completed the TPB and anticipated regret measures about smoking initiation. In the second study, 675 non‐smoking adolescents (between 11 and 12 years of age) completed the TPB, anticipated regret, and intention stability measures in relation to smoking initiation. Smoking was assessed objectively by carbon monoxide breath monitor 9 months later. Results In Studies 1 and 2, regret significantly added to predictions of intentions over and above components of the TPB (p <.001). In Study 2, smoking behaviour was predicted by intentions and the relationship of intentions to behaviour was moderated by regret and intention stability. Conclusions Regret and intention stability were shown to be important variables within the TPB in understanding intentions and behaviour of smoking initiation in adolescents.     

Does perceived behavioural control mediate the relationship between power beliefs and intention?

Objectives: In order to determine whether the relationship between power beliefs (Σp) and health‐related behavioural intentions is mediated by perceived behavioural control (PBC) we used structural equation modelling of eight cross‐sectional data sets. Method: Eight studies that examined health‐related behaviours and employed representative samples totallingN = 4663 participants were analysed. All studies involved power belief items derived from pilot testing and employed standard multiitem measures of power beliefs, PBC and intention that were highly reliable. Results: Confirmatory factor analysis confirmed the discriminant validity of power beliefs, PBC and intention. Structural equation modelling of relevant paths indicated that PBC only partially mediated the relationship between power beliefs and intention (Z_Sobel = 5.15,p < .001;Z_Baron&Kenny = 5.16,p < .001). Power beliefs had a significant direct relationship with intention even after PBC had been taken into account. Conclusion: The findings undermine Ajzen's contention that PBC mediates the power beliefs‐intention relationship and suggests that it is important to employ measures of power beliefsin addition to measures of PBC in order to enhance the prediction of intentions to perform health‐risking, or health‐promoting, behaviours.     

Managing exercise with another highly valued and conflicting leisure time goal

Research has identified concurrent self‐regulatory efficacy as a consistent exercise predictor when adults pursue another non‐exercise leisure time goal. Although intergoal conflict is an inconsistent exercise predictor, prior research did not ensure that goals were sufficiently highly valued to truly conflict. Other possible exercise predictors have not been examined among concurrent goals. The purpose was to examine whether intergoal conflict and outcome expectations (likelihood; value) predicted moderate‐vigorous exercise over 1 month, beyond concurrent self‐regulatory efficacy, when adults held highly valued, conflicting exercise and non‐exercise goals concurrently. Eighty‐seven adult exercisers pursuing highly valued and conflicting exercise and non‐exercise goals completed online surveys assessing (1) concurrent self‐regulatory efficacy, intergoal conflict, and outcome expectations at Time 1 and (2) exercise over the prior month at Time 2. A hierarchical multiple regression (R² adjusted = 0.24, p < .001) revealed intergoal conflict and outcome expectations accounted for a significant additional 13% of exercise variance, beyond self‐regulatory efficacy. Future research should examine these social cognitions across adults who vary in their exercise levels (i.e., beginner, irregular, regular exercisers). Valuable information about which social cognitions should be targeted to improve exercise levels among each group to that of regular exercisers would result.     

Deciding to exercise: The role of anticipated regret

Objectives: Two studies tested (a) whether anticipated regret (AR) qualifies as an additional predictor of intentions to engage in a health‐enhancing behaviour (exercise) after variables from the Theory of Planned Behaviour (TPB) and past behaviour have been controlled, and (b) whether a manipulation that induces participants to focus on AR causes stronger intentions to exercise. Design: Study 1 employed a cross‐sectional questionnaire design; Study 2 employed a between‐participants experimental design (AR focus vs. no AR focus). Method: Participants (N = 385) completed standard, multi‐item, reliable measures of TPB constructs and AR and also reported their past behaviour (Study 1). Participants in Study 2 (N = 70) completed measures of AR and intention; salience of AR was manipulated by means of item order. Results: Study 1 showed that even though TPB variables and past behaviour were reliable predictors of intention, and explained 51% of the variance, AR contributed a substantial increment in the variance (5%) even after these predictors had been taken into account. Study 2 showed that participants who were induced to focus on AR prior to intention formation had significantly stronger intentions to exercise compared to controls. Conclusion: The findings indicate that AR predicts a health‐enhancing behaviour (as well as the health‐risk behaviours examined in previous research) and that effects of AR are independent of TPB variables and past behaviour. The findings also indicate that a simple and inexpensive manipulation of the salience of AR can be used to promote exercise intentions.     

Sample size for regression analyses of theory of planned behaviour studies: Case of prescribing in general practice

Objectives. Interest has been growing in the use of the theory of planned behaviour (TBP) in health services research. The sample sizes range from less than 50 to more than 750 in published TPB studies without sample size calculations. We estimate the sample size for a multi‐stage random survey of prescribing intention and actual prescribing for asthma in British general practice. To our knowledge, this is the first systematic attempt to determine sample size for a TPB survey. Methods. We use two different approaches: reported values of regression models' goodness‐of‐fit (the λ method) and zero‐order correlations (the variance inflation factor or VIF method). Intra‐cluster correlation coefficient (ICC) is estimated and a socioeconomic variable is used for stratification. We perform sensitivity analysis to estimate the effects of our decisions on final sample size. Results. The VIF method is more sensitive to the requirements of a TPB study. Given a correlation of .25 between intention and behaviour, and of .4 between intention and perceived behavioural control, the proposed sample size is 148. We estimate the ICC for asthma prescribing to be around 0.07. If 10 general practitioners were sampled per cluster, the sample size would be 242. Conclusions. It is feasible to perform sophisticated sample size calculations for a TPB study. The VIF is the appropriate method. Our approach can be used with adjustments in other settings and for other regression models.