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Influences of volitional and forced intentions on physical

activity and effort within the theory of planned behaviour

To cite this Article: Chatzisarantis, Nikos L. D., Frederick, Christina, Biddle, Stuart J. H., Hagger, Martin S. and Smith, Brett , 'Influences of volitional and forced intentions on physical activity and effort within the theory of planned behaviour', Journal of Sports Sciences, 25:6, 699 - 709

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Influences of volitional and forced intentions on physical activity

and effort within the theory of planned behaviour

NIKOS L. D. CHATZISARANTIS

1

, CHRISTINA FREDERICK

2

, STUART J. H. BIDDLE

3

,

MARTIN S. HAGGER

4

, & BRETT SMITH

1

University of Exeter, Exeter, UK,2Embry-Riddle Aeronautical University, Daytona Beach, Florida, USA,3Loughborough University, Loughborough, UK and 4University of Essex, Essex, UK

(Accepted 28 April 2006)

Abstract

In the present study, we examined the utility of volitional and forced intentions in predicting participation in physical activities and effort within the theory of planned behaviour. Four hundred and forty-four participants (184 males, 260 females) aged 19.1+3.3 years (mean+s) completed self-report measures of intentions, attitudes, subjective norms, perceived behavioural control, volitional intentions, forced intentions, and past behaviour in a physical activity context. Six weeks later, they completed self-report measures of physical activity behaviour and effort. Results indicated that volitional intentions and forced intentions contributed to the prediction of effort over and above intentions, attitudes, subjective norms, perceptions of control, past behaviour, and the product terms of attitudes6intentions and subjective norms6intentions. Volitional intentions and forced intentions did not predict participation in physical activities over and above effort. We concluded that volitional intentions and forced intentions assist in the explanation of effort in the context of physical activity behaviour.

Keywords: Physical activity, long-range prediction, meta-cognition

Introduction

The theory of planned behaviour (Ajzen, 1985) proposes a model of intentional behaviour that has led to the successful prediction of social behaviour in several contexts (Ajzen, 1998). The model assumes that the behaviour in question, such as physical activity, is a function of volitional processes (van Ryn, Lytle, & Kirscht, 1996), and hence under the control of a person’s overtly stated intention (Bagozzi, Baumgartner, & Yi, 1992; Bagozzi & Warshaw, 1992). However, while the theory of planned behaviour has received empirical support, research findings cast doubt on the long-term predictive efficacy of the model (Ajzen, 1985; Liska, 1984; Sheeran & Orbell, 1999). One possible reason for this is that intentions do not reflect volition accurately (Meinland, 1970). In the present study, therefore, we examined whether the constructs of volitional and forced intentions assist intentions in indicating volition, and thus improve the long-term predictive efficacy of the theory of planned behaviour model.

Theory of planned behaviour and prediction of social behaviour

The theory of planned behaviour (Ajzen, 1985; Ajzen & Madden, 1986) describes how people process information before engaging in deliberative, voli-tional behaviour. When applied to the domain of physical exercise (or activity), the theory predicts that people process three types of beliefs during delibera-tion. First, there are beliefs (behavioural beliefs) about outcomes associated with physical activity, which guide physical activity intentions through attitudes. Thus, attitudes reflect an overall evaluation towards physical activity captured in attribute di-mensions such as good – bad, harmful – beneficial, or pleasant – unpleasant (Ajzen, 2001, p. 28). Further-more, direct attitudes are formed spontaneously as individuals process their beliefs about physical activity outcomes (Ajzen, 2001). Second, there are beliefs about expectations of others regarding physi-cal activity (normative beliefs). These guide inten-tions through subjective norms. The theory of planned behaviour further enunciates that subjective

Correspondence: N. L. D. Chatzisarantis, School of Health and Sport Sciences, University of Exeter, St. Luke’s Campus, Exeter EX1 2LU, UK. E-mail: [email protected]

ISSN 0264-0414 print/ISSN 1466-447X onlineÓ2007 Taylor & Francis DOI: 10.1080/02640410600818523

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norms reflect the influences that significant others (i.e. parents, teachers, peers, spouse) may exert on decisions to engage in physical activities. Third, according to theory, there are beliefs (control beliefs) about factors that may facilitate or impede participa-tion in physical activities. As such, these control beliefs guide individuals’ intentions to engage in a particular behaviour through perceived behavioural control. That is, an individual’s beliefs relating to control over participation in physical activities shape and frame the intention to undertake this behaviour (Ajzen, 2001).

Furthermore, the theory of planned behaviour postulates that attitudes in combination with sub-jective norms and perceptions of control lead to the formation of physical activity intentions. These intentions, as Ajzen (1991) suggested, indicate how hard people are willing to try and how much effort people are planning to exert towards participation in physical activities. Moreover, tenets of this theory postulate that when physical activity is perceived not to be under complete volitional control, intentions predict social behaviour indirectly via effort (Ajzen, 1985). The construct of effort does not only indicate how much physical effort people exert when enga-ging in physical activities but, after Bagozzi and Kimmel (1995), how much psychological effort people devote towards engaging in physical activities. For example, in the context of physical exercise, the construct of effort may indicate how much effort people devote towards planning physical activity participation (Bagozzi & Kimmel, 1995). Accord-ingly, the direct effects of physical activity intentions on effort reflect the influences that intentions exert on attempts to participate in physical activities. In addition, the theory predicts that when perceived control is realistic, perceived behavioural control will predict physical activity behaviour directly (Ajzen & Madden, 1986; Hausenblas, Carron, & Mack, 1997; Sheeran & Orbell, 1998; Sheppard, Hartwick, & Warshaw, 1988).

To date, the theory of planned behaviour has been corroborated by numerous meta-analytic reviews across a range of behaviours (Armitage and Conner, 2001; Conner & Armitage, 1998; Kim & Hunter, 1993) and specific health behaviours such as condom use (Albarracı´n, Johnson, Fishbein, & Muellerleile, 2001; Sheeran & Orbell, 1998; Sheeran and Taylor, 1999) and exercise (Hagger, Chatzisarantis, & Biddle, 2002; Hausenblaset al., 1997). There is also evidence to suggest that intentions predict physical activity indirectly via effort (Chatizsarantis, Hagger, Biddle, & Karageorghis, 2002). Notwithstanding this corroborating evidence, the theory has its critics. According to Haggeret al. (2002), it does not explain all variation in physical activity behaviour. Further-more, a meta-analysis by Sheeran and Orbell (1998)

highlighted that intentions become less predictive of it when behaviour is observed over long intervals of time (i.e. more than 4 weeks). Given the small predictive validity of intentions, it would appear that further research is required that attempts to elucidate some of the complexities associated with intentions, prediction, and behaviour. One way to achieve this is to explore a number of the assumptions underlying the theory of planned behaviour and the measure-ment issues that relate to such assumptions.

Some assumptions: Intentions, volition, and the prediction of social behaviour and effort

According to Ajzen (1991, p. 181), ‘‘intentions are assumed to capture the motivational factors that influence behavior; they are indicators of how hard people are willing to try, of how much effort they are planning to exert in order to perform the behavior’’. Building on the work of Meinland (1970), it could be argued that verbal expressions of intentions and experiences of volition are not the same. That is, people may report that they intend to engage in a certain social behaviour because they believe, for example, that it is their duty to do so. To illustrate the point, consider the case of compulsory educa-tion. Would a verbally expressed intention to participate in physical education classes in the upcoming month reflect willingness to participate in physical education classes? If physical education is a compulsory subject, pupils may intend to partici-pate in physical education because they feel that it is their duty to do so. Hence, in some cases, people might well intend to engage in social behaviour without wanting to do so.

The inadequacy of measures of intentions to reflect experiences of volition could be related to the relatively lower predictive validity of intentions observed in previous studies that investigated beha-viour over long intervals of time (Sheeran & Orbell, 1998). It could be argued, for example, that the assumption that intentions can achieve long-range prediction is untenable considering that previous research has differentiated between volition and intentions, and demonstrated deferential effects of volitional and forced decisions on behaviour (Festinger & Carlsmith, 1959). Nearly 47 years of experimental work on cognitive dissonance theory has shown that decisions can be volitional or forced and that volitional decisions exert greater effects on attitudes and overt behaviour than forced decisions (Festinger & Carlsmith, 1959). Using a different conceptual framework, 36 years of experimental investigations of self-determination theory have shown that volitional decisions are associated with effort and prolonged participation in pro-social behaviours, whereas this is not always the case for

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forced decisions (Deci, Koestner, & Ryan, 1999; Deci & Ryan, 1985; Williams, Freedman, Ryan, & Deci, 1996). As Ryan, Koestner and Deci (1992) have argued, forced decisions can motivate effort for as along as people are forced to engage in the behaviour. When the external or internal (i.e. feelings of guilt) pressuring forces stop operating, forced decisions do not have an effect on effort or performance of behaviour (Deci et al., 1999). Therefore, a theoretically intriguing proposal is the hypothesis that measures of volitional and forced intentions will increase the utility of intentions and of the theory of planned behaviour in predicting effort. It is important to note here that in this study we do not use the term ‘‘volition’’ to describe the phase that mediates between intentions and performance of behaviour (Gollwiltzer, 1990). Rather, we use the term volition to describe the way that people experience intentions and decisions (Meinland, 1970). The term volition therefore is intended to describe the phenomenology of intentions. In addi-tion, although we use the terms ‘‘intention’’ and ‘‘decision’’ interchangeably, we do recognize that the relationship between decisions and intentions is complex. In the present study, however, we do not consider that there is an additional step of ‘‘decid-ing’’ that occurs between deliberation and formation of intentions which is distinct from the formation of intentions and which brings about formation of intentions (Ajzen, 1991; Meinland, 1970). Having noted these caveats and definitions, in the next sub-section we discuss issues relating to the measurement of volitional and forced intentions.

Measurement of volitional intentions and intentions of duty

One way to measure the volitional quotient of intentions is to ask people to report how they experience their intentions. Perceptions related to how people experience intentions indicate meta-judgemental properties of intentions (Bassili, 1996) and, according to Meinland (1970), such a measure-ment can be obtained by asking people to report why individuals intend to participate in social behaviour. People reporting that they intend to engage in physical activities because they ‘‘have to’’ can be considered as holding intentions that are less volitional in nature because verbal expressions of

have to reflect obligation (Meinland, 1970). In contrast, people reporting that they intend to participate in physical activities because they want tocan be considered as holding volitional intentions given that the verbal expression of ‘‘want to’’ is an expression of volition (Meinland, 1970).

It should also be stressed that verbal expressions of

want tomay not accurately reflect volition, given that

a person may want to do his or her duty (Meinland, 1970). Therefore, it is important to include other indicators of volition that may indicate experiences of volition more accurately in the measurement of volitional intentions. Good indicators of volitional intentions, as Meinland (1970) suggested, include experiences of pleasure and energy that people accrue from their engagement in physical activities. For example, if people state that they want to exercise and they express pleasure at the prospect of exercising, this may serve as a good indicator that people’s physical activity intentions are volitional. Similarly, it can be suggested that the extent to which people try to please significant others’ requests can serve as good indicators of less volitional intentions (Meinland, 1970). For instance, if people indicate that they intend to engage in physical activities to please significant others’ requests, then these may serve as good indicators of forced intentions.

Set against this backdrop, in the present study we tested the proposition that intentions do not indicate willingness to participate in social behaviour and that measures of volitional and forced intentions will increase utility of intentions in indicating experiences of volition (Meinland, 1970). To test this proposi-tion, measures of intentions that represented voli-tional and forced decisions (i.e. volivoli-tional intentions and forced intentions) were obtained and then tested for discriminant and predictive validity. Based on the conceptually informed arguments presented above, we tested three hypotheses. First, it was hypothesized that volitional and forced intentions would display discriminant validity with intentions (H1). This hypothesis was important to test because if volitional and forced intentions did not display discriminant validity with intentions, it could be argued that intentions represented volition satisfactorily, in which case there was no need to incorporate volitional and forced intentions within the theory of planned behaviour.

Second, it was hypothesized that volitional and forced intentions would make an independent contribution to the prediction of measures of effort that reflected willingness to participate in physical activities over and above intentions, perceptions of control, attitudes, and subjective norms (H2). Here we set effort and not actual participation in physical activities as a criterion in evaluating predictive validity of volitional and forced intentions because our central hypothesis posits that volitional and forced intentions assist intentions in indicating will-ingness to participate in social behaviours and not necessarily actual execution of social behaviour. Clearly, willingness to execute a social behaviour and actual execution are not the same. People may be characterized by a strong willingness to exercise but fail to do so because environmental factors that

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people cannot control directly (i.e. transportation) inhibit their attempts to exercise (Ajzen, 1985). However, failure of measures of volitional or forced intentions to predict effort over and above the theory of planned behaviour raise questions about whether measures of volitional and forced intentions improve the utility of intentions in indicating willingness to participate in physical activities.

Finally, we used measures of past behaviour to control statistically for the effects of unmeasured variables on effort and on physical activity behaviour (Bagozzi, 1981). Specifically, previously research has shown that past behaviour is a strong predictor of intentions and of social behaviour (Ajzen, 2002; Hagger et al., 2002). It has also been suggested that the main effects from past behaviour to future behaviour reflected effects from psychological vari-ables that have not been taken into consideration by the theory of planned behaviour (Ajzen, 2002; Bagozzi, 1981). Therefore, through measures of past behaviour, we iexamined whether the effects from volitional intentions and forced intentions on effort and social behaviour were independent from deter-minants of social behaviour that the theory of planned behaviour omits. It was hypothesized that if the effects from volitional and forced intentions to effort and behaviour were independent from antecedents of social behaviour that the theory of planned behaviour omits, volitional or forced intentions would predict effort over and above past behaviour (H3).

Overall, in this study we tested effects of volitional intentions and forced intentions on effort and physical activity participation in a manner presented in Figure 1. According to this diagram, volitional intentions and forced intentions exert direct effects on effort but not on physical activity participation. In addition, components of the theory of planned behaviour and past behaviour exert effects on effort and physical activity participation. One ramification of the present study is that intentions do not reflect volition accurately and that the constructs of

volitional and forced intentions assist intentions in indicating experiences of volition.

Methods

Research participants and procedure

A total of 444 individuals (184 males, 260 females) aged 19.1+3.3 years (mean+s) were recruited from comprehensive schools and universities in the Midlands, UK. Participants were volunteers and informed consent was obtained from each individual and from the head teachers of the schools. A letter explaining the procedures and risks associated with our study was also delivered to the parents via their children, and parents were provided with the option to decline participation by their child by returning the letter. None of the parents declined participation. The participants took 20 minutes to complete the questionnaires in groups of less than 20 in quite classroom settings. Four researchers were responsi-ble for implementing, distributing, and collecting the questionnaires. Teachers were also present during data collection. The participants were separated to prevent them from copying one another. They were not asked to report their name in the questionnaire. Response attrition was over 10.2%.

A prospective design was employed with psycholo-gical variables being assessed at two instants in time. In the first wave of data collection, participants were provided with a definition of vigorous physical activity performed during leisure time, developed by Godin and Shephard (1985). This definition described vigorous physical activity as activities performed at vigorous intensity for at least 30 minutes, 3 days per week for the next 6 weeks, during leisure time. To ensure that the definition of leisure time physical activity was understood, the participants were asked to report examples of vigorous physical activities and of leisure time. Next, the questionnaire assessed vari-ables specified by the theory of planned behaviour, past behaviour, and volitional and forced intentions. The participants were also instructed to use this definition when answering questions related to the theory of planned behaviour, past behaviour, voli-tional intentions, and forced intentions. After 6 weeks, actual participation in physical activities during leisure time and effort were assessed (Bagozzi & Kimmel, 1995; Godin & Shephard, 1985). Prospective re-sponses were matched with baseline rere-sponses using dates of birth and sex as matching indices.

Measures

The theory of planned behaviour and past behaviour.

The development of the theory of planned behaviour questionnaire followed the procedures

Figure 1. A model presenting hypothesized relationships between components of the theory of planned behaviour, past behaviour, forced intentions, and volitional intentions.

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recommended by Ajzen and Fishbein (1980) and Ajzen and Madden (1986). Three items drawn from Ajzen and Fishbein (1980) and Ajzen and Madden (1986) were used to measure behavioural intentions. An example was: ‘‘I intend to do active sports and/or vigorous physical activities, for at least 30 minutes, three days per week, during my leisure time, over the next six weeks’’. All items were rated on 7-point Likert scales ranging from ‘‘strongly disagree’’ (1) to ‘‘strongly agree’’ (7). Subjective norms were mea-sured through two items, on a 7-point scale ranging from ‘‘strongly disagree’’ (1) to ‘‘strongly agree’’ (7). An example was: ‘‘Others who are important to me think that I should do active sports and/or vigorous physical activities for at least 30 minutes, three days per week, during my leisure time, over the next six weeks’’. Attitudes were assessed through three bipolar adjectives. One adjective was intended to reflect moral evaluations (bad – good). An additional adjective echoed instrumental evaluations (harmful – beneficial), while the third reflected affective evalua-tions (interesting – boring). All adjectives were mea-sured on 7-point semantic differential scales (Ajzen & Driver, 1991; Ajzen & Fishbein, 1980). An example was: ‘‘For me, doing active sports and/or vigorous physical activities for at least 30 minutes, three days per week, during my leisure time, over the next six weeks . . .’’.

Perceived behavioural control was assessed on 7-point scales (Ajzen & Madden, 1986). Examples included: ‘‘I feel in complete control over whether I do active sports and/or vigorous physical activities for at least 30 minutes, 3 days per week, during my leisure time, over the next six weeks’’; ‘‘How much control do you have over doing active sports and/or vigorous physical activities for at least 30 minutes, 3 days per week, during your leisure time, over the next six weeks’’. Average scores ranging from 1 to 7 were used to represent attitudes, intentions, sub-jective norms, and perceived behavioural control.

Volitional and forced intentions. The questionnaire developed to measure volitional and forced inten-tions asked why the respondents intended to participate in active sports and/or vigorous physical activities for at least 30 minutes, 3 days per week, over the next six weeks, during their leisure time, and then provided six reasons that have been pre-selected by us to represent volitional and forced intentions. Indicators of volitional intentions reflected an expression of volition (e.g. ‘‘because I really want to exercise’’), feelings of enjoyment (e.g. ‘‘because I enjoy physical activity’’), and feelings of energy (e.g. ‘‘because physical activity makes me feel energetic’’). Indicators of forced intentions reflected feelings of obligation (e.g. ‘‘because I have to exercise’’), a tendency to satisfy important others’ requests (e.g.

‘‘in order to please important others’ requests’’), and a tendency not to disappoint important others (e.g. ‘‘because I would disappoint others if I do not exercise’’). All items were measured on 7-point Likert scales ranging from ‘‘strongly disagree’’ (1) to ‘‘strongly agree’’ (7). As with components of the theory of planned behaviour, mean scores ranging from (1) to (7) were used to represent volitional intentions and forced intentions.

Physical activity and effort. At the first (past beha-viour) and second wave (future behabeha-viour) of data collection, vigorous physical activity was assessed using Godin and Shephard’s (1985) Leisure-Time Exercise Questionnaire. The instrument contains three open-ended questions capturing the frequency of mild, moderate, and vigorous physical activity. The present study targeted vigorous physical activity. Independent evaluations of the Leisure-Time Ex-ercise Questionnaire found it to be valid, reliable, easy to administer, and to display concurrent validity with objective activity and fitness indices (Jacobs, Ainsworth, Hartman, & Leon, 1993). The measure of physical activity that was administered during the first wave of data collection represents past beha-viour, whereas the measure of physical activity that was administered at the second wave of data collection represents future behaviour. Measures of physical activity behaviour could range from 1 to 7.

Perceived effort was measured during the second wave of data collection. The participants reported the effort they had exerted in a sense of maintaining willpower, planning, energy, trying, and discipline in the past five weeks (e.g. ‘‘How hard did you try in a sense of maintaining your willpower to exercise the last 6 weeks, during your leisure time?’’). This measure of effort is considered to reflect strength of will or desire to participate in physical activities more accurately than measures of physical activity given that indicators of effort indicate willpower whereas measures of physical activity participation indicate actual participation in physical activities. All types of effort were measured on 7-point scales ranging from ‘‘tried not at all’’ (1) to ‘‘tried very hard’’ (7) (Bagozzi & Kimmel, 1995). Mean scores ranging from 1 to 7 were used to represent effort.

Data analysis

A series of confirmatory factor analyses was used to examine discriminant validity between volitional intentions, forced intentions, and intentions (H1) (Mulaik & Millsap, 2000). Discriminant validity was examined by evaluating the utility of a three-factor model (Model 1) in explaining the covariance between indicators of intentions, forced intentions, and volitional intentions (Bagozzi, 1981; Bentler,

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1989). Model 1 was compared with two competing models that hypothesized lack of discriminant validity either between intentions and volitional intentions (Model 2) or between intentions and forced intentions (Model 3). Model 2 tested lack of discriminant validity between intentions and voli-tional intentions because it examined the utility of a single factor in explaining the covariance between measures of intentions and volitional intentions. Model 3 tested lack of discriminant validity between intentions and forced intentions because it examined the utility of a single factor in explaining the covariance between measures of intentions and forced intentions. Parameters of all confirmatory models were estimated with the maximum likelihood estimation method using the EQS statistical software (Bentler, 1989). In addition, in all models, variances of factors were fixed at 1.0 (Bentler, 1989), while cross-loadings and residual correlations were fixed at zero. Results from the confirmatory factor analysis were considered to support discriminant validity if (a) Model 1 explained the observed covariance matrix more satisfactorily than Models 2 and 3 did, and (b) the confidence interval of the correlation between constructs that assumed to possess discri-minant validity (i.e. volitional intentions and inten-tions) did not include unity (Bagozzi, 1981).

A hierarchical regression analysis was used to examine the utility of volitional intentions and forced intentions to predict effort and physical activity participation over and above the components of the theory of planned behaviour (H2) and past behaviour (H3). In the regression analyses predicting physical activity, effort was entered in the first step, intentions and perceptions of control were entered in the second step, attitudes and subjective norms were entered in the third step, past behaviour was entered in the fourth step, and volitional intentions and forced intentions were entered in the fifth step. It is important to note that effort was entered in the first step of the analysis because Ajzen’s (1985) original model of the theory of planned behaviour assumed effort, and not intentions, to constitute the most proximal determinant of behaviour. The regression analysis predicting effort specified intentions and perceptions of control in the first step, attitudes and subjective norms in the second step, past behaviour in the third step, and volitional intentions and forced intentions in the fourth step. The third hypothesis was supported if volitional intentions and forced intentions contributed to the prediction of effort over and above the theory of planned behaviour and past behaviour.

Assessment of model fit

Adequacy of confirmatory models in explaining observations was assessed through fit indices.

The most common statistic in assessing model fit is the chi-square goodness of fit test (w2), which estimates discrepancies between model-implied and observed covariance matrices. However, the chi-square test has been criticized as being insufficient to assess model fit because its power to detect miniscule differences is high as sample size increases (Cohen, 1988). We therefore used the comparative fit index and standardized root mean square residual as a means of evaluating model fit because previous research has shown that these fit indices displayed restricted random variation under various conditions of model misspecification, sample size, and estima-tion methods (Fan, Thomson, & Wang, 1999; Hu & Bentler, 1999). Furthermore, a cut-off value close to 0.95 for the confirmatory fit index and a cut-off value close to 0.08 for the standardized root mean square residual were used to evaluate the adequacy of models because the Type I and II error rates associated with these criteria are low (Hu & Bentler, 1999).

We also used Akaike’s information criterion (AIC; Akaike, 1987) as a way to compare models (e.g. Models 1, 2, and 3). The AIC indicates the extent to which a model would cross-validate in an indepen-dent sample, without requiring a second sample. When used for model comparisons, the model that obtains the lowest AIC is considered to demonstrate the best fit (Rigdon, 1989).

Results

Confirmatory factor analyses

The fit indices presented in Table I show that Model 1 exceeded recent criteria of good fit, whereas this was not necessarily the case for Models 2 and 3 (Fan

et al., 1999; Hu & Bentler, 1999). In addition, the fit indices indicated that Model 1 explained observa-tions more satisfactorily than the competing Models 2 and 3 given that the AIC of Model 1 was much lower than those of Models 2 and 3. Examination of the parameters of Model 1 showed that loadings of indicators of volitional intentions and forced inten-tions were significant and positive. The average magnitude of the standardized loadings for volitional and forced intentions was 0.72, which is well above the accepted minimum of 0.40 (Bagozzi, 1981; Ford, MacCallum, & Tait, 1986). Moreover, the confi-dence intervals of the correlations corrected for attenuation between intentions and volitional inten-tions (r¼0.64, standard error¼0.03), between intentions and forced intentions (r¼.09, standard error¼0.05), and between volitional intentions and forced intentions (r¼.03, standard error¼0.03) did not include unity. These results therefore corroborate the first hypothesis (H1), that volitional

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intentions, forced intentions, and intentions would display discriminant validity (Ford et al., 1986; Mulaik & Millsap, 2000).

Descriptive statistics

Table II presents descriptive statistics for the psychological measures and, as indicated, most of the measures attained satisfactory internal consis-tency given that the alpha coefficients exceeded 0.70. An exception was the measure of subjective norms (a¼0.64). However, the low reliability of subjective norms can be seen as a limitation of the theory of planned behaviour, since previous research applica-tions of the theory indicated low reliability for subjective norms (Courneya & McAuley, 1995). Correlations showed that behavioural intentions and perceived behavioural control were positively asso-ciated with physical activity and effort (Ajzen, 1985). Attitudes, perceptions of control, and subjective norms were also positively associated with intentions (Ajzen & Madden, 1986). Volitional intentions were positively associated with effort and physical activity, whereas forced intentions were positively associated with effort only (see Table II).

Prediction of physical activity participation and effort

In accordance with the assumptions underlying the theory of planned behaviour (Ajzen, 1985), the first step of the hierarchical regression analysis (see

Table III) showed that effort predicted participation in physical activities (F¼41.27, P50.05). Consis-tent with Ajzen and Madden’s (1986) predictions, the second step of the analysis showed that intentions predicted participation in physical activities (DF¼25.91, P50.01). Perceived control did not contribute to the prediction of physical activity over and above effort given that, in the second step of the regression analysis, the semi-partial correlation of perceived control with physical activity was not statistically significant (b¼0.00,P40.05). The third step in the analysis showed that attitudes and subjective norms did not improve the validity of intentions in predicting physical activity participation (DF¼0.77, P40.05). Consistent with previous research (Haggeret al., 2002), the fourth step of the analysis showed that past behaviour contributed to the prediction of physical activity (DF¼13.35,

P40.05). The fifth step of the regression analysis demonstrated that volitional intentions and forced intentions did not contribute to the prediction of physical activity (DF¼1.20, P40.05). Finally, we conducted an additional hierarchical regression analysis that predicted physical activity participation from components of the theory of planned behaviour, volitional intentions, forced intentions, and from past behaviour but not from effort. This hierarchical regression analysis revealed a significant effect of volitional intentions on physical activity (DF¼7.00,

P50.05). Forced intentions did not predict physical activity participation (DF¼0.64,P40.05).

Table I. Results of confirmatory factor analyses testing discriminant validity between volitional intentions, forced intentions, and intentions.

w2 _CFI _SRMSR _AIC

Model 1: Volitional intentions, forced intentions, and intentions 79.355 (24) 0.978 0.054 31.35 Model 2: Volitional intentions and intentions load to the same factor 421.036 (26) 0.841 0.093 369.03 Model 3: Forced intentions and intentions load to the same factor 376.103 (26) 0.856 0.114 324.10 Note: CFI¼comparative fit index; STMSR¼standardized root mean square residual; AIC¼Akaike’s information criterion.

Table II. Descriptive statistics for components of the theory of planned behaviour, volitional intentions, forced intentions, and past behaviour. mean s a 1 2 3 4 5 6 7 8 9 1. Physical activity 3.61 1.33 1.0 2. Effort 4.04 1.16 0.790 0.352* 1.0 3. Intentions 4.58 1.80 0.924 0.557* 0.398* 1.0 4. Perceived control 5.32 1.36 0.759 0.263* 0.202* 0.424* 1.0 5. Attitudes 5.54 1.20 0.785 0.355* 0.354* 0.539* 0.298* 1.0 6. Subjective norms 3.72 1.59 0.649 0.034 0.113* 0.120* 0.076 0.032 1.0 7. Volitional intentions 5.11 1.50 0.810 0.444* 0.362* 0.569* 0.270* 0.618* 0.024 1.0 8. Forced intentions 2.50 1.35 0.727 0.080 0.206* 0.141* 0.006 0.061 0.418* 0.105* 1.0 9. Past behaviour 3.63 1.69 0.531* 0.324* 0.676* 0.337* 0.384* 0.085 0.445* 0.104* 1.0 Note: Correlations with an asterisk are significant atP50.05.

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The hierarchical regression analysis that predicted effort supported a statistically significant effect from intentions to effort (F¼27.88, P50.05). Perceived control did not contribute to the prediction of effort over and above intentions given that, in the first step of the regression analysis, the semi-partial correlation of perceived control with effort was not statistically significant (b¼0.054,P40.05). The second step of the analysis indicated that attitudes improved the validity of intentions in predicting effort (DF¼4.89,

P50.05). However, the third step of the analysis showed that past behaviour did not contribute to the prediction of effort over and above the theory of planned behaviour. In accordance with the second hypothesis of the present study (H2), the fourth step of the regression analysis demonstrated that voli-tional intentions and forced intentions contributed to the prediction of effort over and above past behaviour and components of the theory of planned behaviour (DF¼8.12, P50.05). Interestingly, in accordance with hypothesis 3, in the fourth step of the analysis, the semi-partial correlations revealed that volitional intentions and forced intentions exerted a statistically significant effect on effort after controlling for past behaviour effects.

Discussion

In the present study, we examined the proposition that volitional intentions and forced intentions increased utility of intentions in indicating willingness to participate in physical activities (Meinland, 1970). Consistent with the initial hy-pothesis, our results supported discriminant validity between intentions, volitional intentions, and forced intentions, and a significant contribution of volitional intentions and forced intentions to the prediction of effort. Because measures of effort reflected will-ingness to participate in physical activity, the effects of volitional intentions and forced intentions on effort corroborate insufficiency of measures of intention in representing volitional decisions. As such, in the context of leisure time physical activity, our findings support past research and extend significantly the applications of the theory of planned behaviour model in several ways.

The relationship between volition and intentions

One clear finding that emerged from this study is that volitional intentions, forced intentions, and

Table III. Prediction of physical activity and effort.

Physical activity Effort

R2 _b _t _R2 _b _t Steps Steps 1 0.124* 1 0.161* Effort 0.352 6.424* Intentions 0.377 6.445* 2 0.261* Perceived control 0.054 0.924 Effort 0.191 3.471* 2 0.187* Intentions 0.404 6.875* Intentions 0.274 3.976*

Perceived control 0.000 0.003 Perceived control 0.028 0.471

3 0.264 Attitudes 0.175 2.558*

Effort 0.180 3.215* Subjective norms 0.094 1.762

Intentions 0.376 5.576* 3 0.193*

Perceived control 70.007 70.120 Intentions 0.226 2.486*

Attitudes 0.052 0.787 Perceived control 0.023 0.384

Subjective norms 0.046 0.894 Attitudes 0.202 2.799*

4 0.302* Subjective norms 0.095 1.740

Effort 0.176 3.197* Past behaviour 0.068 0.877

Intentions 0.180 2.099* 4 0.239*

Perceived control 0.011 0.188 Intentions 0.179 1.982*

Attitudes 0.018 0.260 Perceived control 0.036 0.608

Subjective norms 0.029 0.558 Attitudes 0.112 1.450

Past behaviour 0.265 3.656* Subjective norms 0.010 0.174

5 0.310 Past behaviour 0.054 0.715

Effort 0.174 3.072* Forced intentions 0.147 2.453*

Intentions 0.158 1.818 Volitional intentions 0.189 2.653*

Perceived control 70.004 70.068 Attitudes 70.024 70.319 Subjective norms 0.048 0.854 Past behaviour 0.274 3.780* Volitional intentions 70.072 71.242 Forced intentions 0.097 1.410

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intentions possessed discriminant validity. Specifi-cally, parameters of the confirmatory factor Model 1 pointed out that volitional intentions, forced inten-tions, and intentions measured distinct psychological events. This is because the intentional model that assumed discriminant validity (Model 1) explained observations better than the models that assumed lack of discriminant validity (Models 2 and 3). These results for discriminant validity substantiate the proposition that intentions, volitional intentions, and forced intentions are empirically distinct: intentions measure the strength and/or direction of intentions (Ajzen, 1985; Ajzen & Fishbein, 1980; Meinland, 1970), whereas volitional intentions and forced intentions measure meta-judgemental properties of intentions (Bassili, 1996) that indicate the extent to which intentions are volitional in nature (Meinland, 1970). It is also important to emphasize that the confirmatory factor analysis supports the notion that volitional intentions, forced intentions, and intentions do not share common method factors given that Model 2 assumed zero correlations at the residual space of the factors (Bagozzi, 1981; Bentler, 1989). It is also worth noting that measures of intentions, volitional intentions, and forced intentions do not share common method variance despite the fact that the wording of the questions measuring intentions, volitional intentions, and forced intentions made reference to intentions. It therefore appears that participants identified that measures of volitional intentions and forced intentions assessed meta-judge-mental properties of intentions (i.e. how participants experience their intentions) and not intentionsper se. It is also interesting to note that the pattern of correlations between psychological variables (see Table II) indicated that intentions were positively correlated with volitional intentions and not with forced intentions. This finding is important because it suggests that, in the context of leisure time physical activity, intentions are experienced on average as volitional. This may be due to beliefs that leisure activities are enjoyable (Sansone, Sachau, & Weir, 1989; Tang & Baumeister, 1984). For many people, the narrative of leisure time represents freedom from work and duties, allowing them to be at ease, to turn to pleasure, to lay aside obligations and rules (Grayling, 2001). Alternatively, the correlation be-tween volitional intentions and intentions could reflect a relationship between strength of intentions and experiences of volition. On both theoretical (Ajzen, 1985; Ajzen & Fishbein, 1980; Meinland, 1970) and empirical (Kline, 1993) grounds, it can be suggested that strong intentions are experienced as being more volitional than weak intentions. There-fore, volitional intentions and intentions may be strongly correlated because of a positive relationship between intention strength and volition.

The prediction of effort and of physical activity participation

Another research finding from the regression analysis is the contribution that volitional intentions and forced intentions made to the prediction of effort. Specifically, the regression analysis showed that volitional intentions and forced intentions predicted effort over and above intentions (see Table III). Because our measures of effort indicated willingness to participate in physical activities, the current results support Meinland’s (1970) proposition that voli-tional intentions improve utility of intentions in representing willingness to participate in physical activities. The contribution of volitional intentions to the prediction of effort is additionally in agreement with a number of theories that have differentiated between volitional and forced decisions (Deci & Ryan, 1985; Sheldon & Elliot, 1999; Williamset al., 1996). In addition, the results of the present study can be explained with reference to tenets of self-discrimination theory (Kuhl & Kazen, 1994). According to this theory, there is a strong relation-ship between volitional decisions, forced decisions, and effort (see also Deci & Ryan, 1985; Ryanet al., 1992). However, it is important to stress that in addition to confirming tenets of psychological theories, like self-determination theory and self discrimination theory, the present study extends previous research in various ways.

The first is related to the prediction of social behaviour. The regression analysis showed that volitional intentions and forced intentions predicted effort and not physical activity behaviour. In part, this is because effort exertion is within a person’s volitional control to a greater extent than perfor-mance of behaviour (Ajzen, 1985; Bagozzi & Kimmel, 1995). Furthermore, performance of phy-sical activity is more likely to be impeded by factors that the person cannot control (e.g. transportation, resources) than behavioural attempt is (Ajzen, 1985; Hagger et al., 2002; Kuhl & Kazen, 1994). There-fore, it can be expected that volitional and forced decisions influence effort and not participation in physical activities (Chatzisarantis et al., 2002; Deci

et al., 1999; Sheldon & Elliot, 1999). Because effort is associated with participation in physical activities, the results of the present study suggest that volitional intentions contribute to the prediction of physical activity indirectly via effort.

Not only do the present findings suggest how the predictive efficacy of the theory of planned behaviour model could be improved, they also extend research in that they demonstrate the inadequacy of measures of intentions in representing volition (Meinland, 1970). In particular, researchers have not previously examined the assumption that intentions reflect

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willingness to participate in physical activities (Armitage & Conner, 2001; Hagger et al., 2002). In part, this is because researchers took for granted that intentions represent decisions that are volitional in nature (Ajzen, 1991). By comparing predictive validity of volitional intentions with intentions, the present study represents the first attempt to demon-strate empirically the insufficiency of measures of intentions in representing volition.

In addition, models of health behaviour, such as the health belief model (Janz & Becker, 1984), protection motivation theory (Rogers, 1984), and the theory of planned behaviour (Ajzen & Madden, 1986), consider various antecedents of health beha-viour to result in the formulation of a uni-dimen-sional intention. As such, the effects of forced decisions on behaviour have been ignored by these models despite evidence supporting effects of forced decisions on behaviour (Festinger & Carlsmith, 1959; Ryan et al., 1992). Hence, by measuring forced intentions, in the present study we demon-strate empirically effects from forced intentions to effort. Most importantly, we found evidence for independent effects from volitional intentions and forced intentions over and above a host of other variables such as attitudes, subjective norms, percep-tions of control, and past behaviour (H3). Therefore, the present findings rule out rival hypotheses, and document that an extended theory of planned behaviour that includes past behaviour cannot represent volitional or forced decisions satisfactorily.

Limitations and conclusions

Although the present study had a number of strengths and extended the theory of planned behaviour in a variety of ways, it was not without limitations and caveats. On the basis of the present results, causal inferences between volitional inten-tions, forced inteninten-tions, and effort cannot be drawn because volitional and forced intentions were not manipulated experimentally. In addition, we are acutely aware that our participants did not make actual decisions and our measures need further examination. Thus future research should examine whether manipulations of volitional intentions, forced intentions, and intentions exert independent effects on physical activity. Furthermore, it is important to improve the content validity of voli-tional intentions and forced intentions measures by adding new items and/or improving the comprehen-sibility of the existing ones. This is particularly germane for certain items measuring forced inten-tions. For example, the comprehensibility of the items ‘‘in order to please important others’ requests’’ and ‘‘because I would disappoint others if I do not exercise’’ might have been problematic. The reliability

analysis supports this contention given that compared with the reliability of volitional intentions, the reliability of forced intentions was low.

In conclusion, in the present study we demon-strated that measures of volitional and forced intentions improved utility of intentions in predicting willingness to participate in physical activities. In addition, the findings suggest that effort predicts physical activity participation over and above inten-tions. Of most important, we observed effects of volitional intentions and of forced intentions on effort over and above attitudes, subjective norms, perceptions of control, and past behaviour. Because effort is associated with actual participation in physical activities, the current findings suggest that volitional intentions contribute to the prediction of physical activity indirectly via effort. The implica-tions of these findings are that intenimplica-tions do not represent volitional or forced decisions accurately and that measures of volitional and forced intentions improve the predictive efficacy of intentions.

References

Ajzen, I. (1985). From intentions to actions: A theory of planned behaviour. In J. Kuhl & J. Beckmann (Eds.), Action-control: From cognition to behaviour(pp. 11 – 39). Heidelberg: Springer. Ajzen, I. (1991). The theory of planned behaviour.Organizational

Behaviour and Human Decision Processes,50, 179 – 211. Ajzen, I. (1998). Models of human social behaviour and their

application to health.Psychology and Health,13, 735 – 739. Ajzen, I. (2001). Nature and operation of attitudes.Annual Review

of Psychology,52, 27 – 58.

Ajzen, I. (2002). Residual effects of past on later behaviour: Habituation and reasoned action perspectives.Personality and Social Psychology Review,6, 107 – 122.

Ajzen, I., & Driver, B. E. (1991). Prediction of leisure participa-tion from behavioural, normative, and control beliefs: An application of the theory of planned behaviour.Leisure Sciences, 13, 185 – 204.

Ajzen, I., & Fishbein, M. (1980). Understanding attitudes and predicting social behaviour.Englewood Cliffs, NJ: Prentice-Hall. Ajzen, I., & Madden, T. J. (1986). Prediction of goal directed behaviour: Attitudes, intentions and perceived behavioural control.Journal of Experimental Social Psychology,22, 453 – 474. Akaike, H. (1987). Factor analysis and AIC.Psychometrika, 52,

317 – 332.

Albarracı´n, D., Johnson, B. T., Fishbein, M., & Muellerleile, P. A. (2001). Theories of reasoned action and planned behaviour as models of condom use: A meta-analysis.Psychological Bulletin, 127, 142 – 161.

Armitage, C. J., & Conner, M. (2001). Efficacy of the theory of planned behaviour: A meta-analytic review.British Journal of Social Psychology,40, 471 – 499.

Bagozzi, R. (1981). An examination of the validity of two models of attitude.Multivariate Behavioural Research,16, 323 – 359. Bagozzi, R. P., Baumgartner, H., & Yi, Y. (1992). Appraisal

processes in the enactment of intentions to use coupons. Psychology and Marketing,9, 469 – 486.

Bagozzi, R. P., & Kimmel S. K. (1995). A comparison of leading theories for the prediction of goal directed behaviours.British Journal of Social Psychology,34, 437 – 461.

(12)

Bagozzi, R. P., & Warshaw, P. R. (1992). An examination of the etiology of the attitude – behaviour relation for goal-directed behaviours.Multivariate Behavioural Research,27, 601 – 634. Bassili, J. N. (1996). Meta-judgmental versus operative

proper-ties of psychological attributes: The case of measures of attitude strength. Journal of Personality and Social Psychology, 71, 637 – 653.

Bentler, P. M. (1989). EQS structural equations program manual. Los Angeles, CA: BMDP Statistical Software.

Chatzisarantis, N. L. D., Hagger, M. S., Biddle, S. J. H., & Karageorghis, C. (2002). The cognitive processes by which perceived locus of causality predicts participation in physical activity.Journal of Health Psychology,7, 685 – 699.

Cohen, J. (1988). Statistical power analysis for the behavioural sciences.Hillsadale, NJ: Lawrence Erlbaum.

Conner, M., & Armitage, C. J. (1998). Extending the Theory of Planned Behaviour: A review and avenues for further research. Journal of Applied Social Psychology,28, 1429 – 1464.

Courneya, K. S., & McAuley, E. (1995). Cognitive mediators of the social influence – exercise adherence relationship: A test of the theory of planned behaviour. Journal of Behavioural Medicine,18, 499 – 515.

Deci, E. L., Koestner, R., & Ryan, R. M. (1999). A meta-analytic review of experiments examining the effects of extrinsic rewards on intrinsic motivation.Psychological Bulletin,125, 627 – 668. Deci, E. L., & Ryan, R. M. (1985).Intrinsic motivation and

self-determination in human behavior.New York: Plenum Press. Fan, X., Thompson, B., & Wang, L. (1999). Effects of sample

size, estimation methods and model specification on structural equation modelling. Structural Equation Modeling: A Multi-disciplinary Journal,1, 56 – 83.

Festinger, L., & Carlsmith, M. (1959). Cognitive consequences of forced compliance.Journal of Abnormal and Social Psychology, 58, 203 – 210.

Ford, J., MacCallum, R., & Tait, M. (1986). The application of factor analysis in psychology: A critical review and analysis. Personnel Psychology,39, 291 – 314.

Godin, G., & Shephard, R. J. (1985). A simple method to assess exercise behaviour in the community. Canadian Journal of Applied Sport Science,10, 141 – 146.

Gollwiltzer, P. (1990). Action phases and mind sets. In E. T. Higgins & R. M. Sorentino (Eds.),Handbook of motivation and cognition(pp. 53 – 92). New York: Guilford Press. Grayling, A. C. (2001).The meaning of things.London: Weidenfeld

& Nicolson.

Hagger, M. S., Chatzisarantis, N. L. D., & Biddle, S. J. H. (2002). A meta-analytic review of the theories of reasoned action and planned behaviour in physical activity: Predictive validity and the contribution of additional variables. Journal of Sport and Exercise Psychology,24, 3 – 32.

Hausenblas, H. A., Carron, A. V., & Mack, D. E. (1997). Application of the Theories of Reasoned Action and Planned Behaviour to exercise behaviour: A meta analysis. Journal of Sport and Exercise Psychology,19, 36 – 41.

Hu, L., & Bentler, P. M. (1999). Cutoff criteria for fit indexes in covariance structure analysis: Conventional criteria versus new alternatives. Structural Equation Modeling: A Multidisciplinary Journal,6, 1 – 55.

Jacobs, D. R., Ainsworth, B. E., Hartman, T. J., & Leon, A. S. (1993). A simultaneous evaluation of ten commonly used physical activity questionnaires. Medicine and Science in Sports and Exercise,25, 81 – 91.

Janz, N., & Becker, M. H. (1984). The health belief model: A decade later.Health Education Quarterly,11, 1 – 47.

Kim, M. S., & Hunter, J. E. (1993). Relationships among attitudes, behavioural intentions, and behaviour: A meta-analysis of past research, part 2.Communication Research, 20, 331 – 364.

Kline, P. (1993). The handbook of psychological testing. London: Routledge.

Kuhl, J., & Kazen, M. (1994). Self discrimination and memory: State orientation and false self-ascription of assigned activities. Journal of Personality and Social Psychology,66, 1103 – 1115. Liska, A. E. (1984). A critical examination of the causal structure

of the Fishbein/Ajzen attitude – behaviour model. Social Psychology Quarterly,47, 61 – 74.

Meinland, J. W. (1970). The nature of intentions. London: Methuen.

Mulaik, A., & Millsap, R. E. (2000). Doing the four-step right.Structural Equation Modeling: A Multidisciplinary Journal, 7, 36 – 73.

Rigdon, E. E. (1999). Using the Friedman method of ranks for model comparison in structural equation modelling.Structural Equation Modeling: A Multidisciplinary Journal,3, 219 – 232. Rogers, R. W. (1984). Cognitive and physiological processes in

fear appeals and attitude change: A revised theory of protection motivation. In J. T. Cacioppo & R. E. Petty (Eds.), Social psychophysiology(pp. 153 – 176). New York: Guilford. Ryan, R., Koestner, R., & Deci, E. (1992). Ego-involved

persistence: When free-choice behaviour is not intrinsically motivated.Motivation and Emotion,15, 185 – 205.

Sansone, C., Sachau, D. A., & Weir, C. (1989). Effects of instruction on intrinsic interest.Journal of Personality and Social Psychology,57, 819 – 829.

Sheeran, P., & Orbell, S. (1998). Do intentions predict condom use? Meta-analysis and examination of six moderator variables. British Journal of Social Psychology,37, 231 – 250.

Sheeran, P., & Orbell, S. (1999). Augmenting the Theory of Planned Behaviour: Roles for anticipated regret and descriptive norms.Journal of Applied Social Psychology,29, 2107 – 2142. Sheeran, P., & Taylor, S. (1999). Predicting intentions to use

condoms: A meta-analysis and comparison of the theories of reasoned action and planned behaviour. Journal of Applied Social Psychology,29, 1624 – 1675.

Sheldon, K. M., & Elliot, A. (1999). Goal striving, need satisfaction and longitudinal well-being: The self-concordance model.Journal of Personality and Social Psychology,3, 482 – 497. Sheppard, B. H., Hartwick, J., & Warshaw, P. R. (1988). The theory of reasoned action: A meta-analysis of past research with recommendation and future research. Journal of Consumer Research,15, 325 – 343.

Tang, T. L., & Baumeister, R. A. (1984). Effects of personal values, perceived surveillance, and task labels on task preference: The ideology of turning play into work.Journal of Applied Psychology,69, 99 – 105.

van Ryn, M., Lytle, L. A., & Kirscht, J. P. (1996). A test of the Theory of Planned Behaviour for two health-related practices. Journal of Applied Social Psychology,26, 871 – 883.

Williams, G., Freedman, Z., Ryan, R. M., & Deci, E. L. (1996). Motivational predictors of weight loss and maintenance.Journal of Personality and Social Psychology,70, 115 – 126.