Personality Traits and Health 原文.doc

Personality Traits and Health-Risk Behaviours inUniversity StudentsAbstractRelations between personality and health-risk behaviours in university undergraduates were examined using multiple measures of personality across multiple samples (N1151).Big Five personality variables, at both factor and facet levels, were used to predict three specific health-risk behaviours: (a) tobacco consumption, (b) alcohol consumption and (c)speeding in an automobile. Our findings showed that low Conscientiousness and low Agreeableness were uniformly associated with this cluster of potentially health damaging behaviours. Extraversion was additionally associated with alcohol use. Interaction effects were found between Conscientiousness and Agreeableness on smoking and (for men only) on drinking. Other personality variables not centrally related to the Big Five, such as Risk-Taking (high) and Integrity (low), were also implicated in the present health-riskbehaviours. Key words: personality traits; Big Five; Five-Factor Model; health-risk behaviours;alcohol consumption; tobacco consumption; risk-takingINTRODUCTIONThe purpose of this research was to advance our knowledge about the relations between the personality characteristics of young men and women and their tendencies to engage in behaviours that can compromise their health. The links between health and personality have, of course, been extensively studied in the past, and it is now well-established that certain personality characteristics are important predictors of health outcomes and longevity (Friedman, 2000; Friedman, Tucker, Tomlinson-Keasy, Schwartz, Wingard, &Criqui, 1993; Friedman et al., 1995; Goodwin & Friedman, 2006; Hampson, Goldberg,Vogt, & Dubanoski, 2006, 2007; Weiss & Costa, 2005). The far-reaching implications of personality on health have been demonstrated by longitudinal life-span studies suggesting that childhood personality predicts adult health outcomes, even decades later (Friedman et al., 1993, 1995; Hampson et al., 2006, 2007). The attention now is on exploring the precise psychological processes that mediate the relation of personality to health outcomes.As proposed by Adler and Matthews (1994) and Friedman (2000), personality can lead to health outcomes through its influence on processes such as psychophysiological mechanisms (e.g. general reactivity to stress), social environmental variables (e.g.availability of family and peer support) and health-related behaviours (e.g. Substance abuse). Health-risk behaviours (including substance use and abuse, lack of physical activity and exercise, unhealthy eating habits, risky sexual behaviour and dangerous driving) are by definition contributory factors for poor health and mortality. Although the complex question as to why people engage in health-promoting versus health-damaging behaviours can be addressed from a variety of perspectives (e.g. genetic predispositions, decisiontheory,health beliefs models; see Conner & Norman, 2005; Reyna & Farley, 2006),personality characteristics constitute an important class of explanatory variables.Furthermore, recent advances in models of personality organization, such as the Big Five (or the Five Factor) model, offer the advantages of (a) allowing the examination of the personality correlates of health-risk behaviours within the context of a comprehensive personality framework and (b) providing the potential for organizing and synthesizing empirical findings (Smith, 2006; Smith &Williams, 1992). The Big Five model, of course,posits that there are exactly five major dimensions of personality that account for most of the variation in human behaviour. Those factors are Neuroticism, Extraversion, Opennessto Experience, Agreeableness and Conscientiousness (see Costa & McCrae, 1992;Digman, 1990; Goldberg, 1993; John & Srivastava, 1999). The Big Five factors have been referred to in the past in developing explanatory mechanisms for health-risk behaviours (Booth-Kewley & Vickers, 1994; Hampson et al., 2006, 2007; Lemos-Giraldez & Fidalgo-Aliste, 1997).We review some of this literature in the following section in introducing our own study of the relations between personality and health-risk behaviours in university students.BIG FIVE PERSONALITY FACTORS AND HEALTH-RISK BEHAVIOURSAmong the Big Five personality factors, Conscientiousness is perhaps the single mostimportant factor that has been implicated in both health outcomes (Friedman et al., 1993;Goodwin & Friedman, 2006; Weiss & Costa, 2005) and health-risk behaviours (Booth-Kewley & Vickers, 1994; Caspi et al., 1997; Friedman et al., 1995; Hampson et al., 2006,2007; Lemos-Giraldez & Fidalgo-Aliste, 1997). Bogg and Roberts (2004) conducted a meta-analysis showing that Conscientiousness-related traits (including psychoticism,sensation-seeking and self-control) were negatively associated with a variety of health-risk activities. For example, individuals low in Conscientiousness were more likely to engage in tobacco, alcohol and drug consumption (e.g. Elkins, King, McGue, & Iacono, 2006; Flory,Lynam, Milich,Leukefeld, & Clayton, 2002; Terracciano & Costa, 2004; Trull & Sher,1994; Walton & Roberts, 2004), risky sexual activities (Schmitt, 2004) and unsafe drivingbehaviour (Arthur & Graziano, 1996; Schwebel, Severson, Ball, & Rizzo, 2006).Besides Conscientiousness, Agreeableness appears to be another Big Five personalityfactor critical to the understanding of the health process. Culminating evidence suggests that disagreeable and hostile individuals (i.e. low Agreeableness) are more likely to endorse negative health attitudes and engage in health-risk behaviours (Booth-Kewley &Vickers, 1994; Lemos-Giraldez & Fidalgo-Aliste, 1997) including substance use (e.g.Flory et al., 2002; Markey, Markey,& Tinsley, 2003; Terracciano & Costa, 2004;Walton &Roberts, 2004), risky sexual behaviours (Miller, Lynam, Zimmerman, Logan, Leukefeld,& Clayton, 2004; Schmitt, 2004) and traffic-related risky behaviours (Booth-Kewley &Vickers, 1994). Caspi et al. (1997), in a longitudinal study of a birth cohort, showed that adolescents who were alienated and aggressive, arguably low in Agreeableness, were more likely to be alcohol dependent and violent 3 years later, compared to controls who were more socially adapted. In that same study, aggressive adolescents were also likely to be involved in sexual and traffic risk-taking.METHODParticipants and procedureSeven independent samples, all consisting of undergraduate men and women from theUniversity of Western Ontario, were included in this present study. MeasuresBig Five personality factors and facets,Non-Big Five personality traits,Health-risk behavioursOverview of analysesGiven the multiple samples and multiple measures of personality available to us, we employed different analytic strategies to address different study goals. In evaluating relations between Big Five factors and health-risk behaviours, meta-analysis was used.We chose this method of analysing our multiple data sets because it allowed for computation of aggregated effect sizes (weighted by sample size) derived from different studies that might have used different participants and different measures. Advantages of meta-analysis in this case include (a) an objective and efficient method of deriving quantifiable summary findings from numerous idiosyncratic studies, and (b) a means of testing for potential moderators if study characteristics are heterogeneous (see Hedges & Olkin, 1985).To explore possible interaction effects we expected between the Conscientiousness and Agreeableness factors (and gender) on students health-risk behaviour, we combined Samples 1, 2 and 6 and subjected this larger sample (N407) to hierarchical regression analyses. We did this for two reasons. First, a large sample size is often needed to find elusive interaction effects. Second, participants in those three samples had all completed the NEO-PI-R, arguably the most established and validated Big Five personality instrument among the lot. (Although participants in Sample 7 had completed the NEO-PIR as well, they were not included because of the different criterion measures used.) To evaluate our hypothesized personality trait-behaviour links at the facet level, we used a replication strategy.We were able to do so because we had multiple independent samples measured on the same Big Five personality characteristics and health-risk behaviours. Although we could have combined some of the relevant data sets into one and tested our hypotheses in a single analysis, our belief is (see also Paunonen, 2003; Paunonen et al.,2003) that finding a predictor-criterion relation that replicates across multiple smaller samples has several advantages over finding that relation in one larger sample: (a) Type I errors are well controlled because an effect found in one sample is not likely to be found in a replication sample if it is spurious; (b) an effect size has to be more substantial to besignificant with the smaller samples, meaning that trivial effects are less likely to be overinterpreted;(c) regression weights for predicting the criterion of interest are more stable to the extent that they have been replicated on independent samples.RESULTSMeans and standard deviations of the three health-risk behaviours are shown in Table 1, by sample. The frequency distribution of speeding generally conformed to normality, whereas distributions of tobacco and alcohol consumption tended to be positively skewed. Across Samples 16, an average of 72.7% (range66.9%79.1%) of the participants did not smoke; 16.7% (range10.3%25.6%) smoked 15 cigarettes per day; 4.9%(range2.5%6.5%) smoked between 6 and 10 cigarettes per day; and 5.8%(range1.8%9.4%) smoked more than 10 cigarettes per day. For alcohol consumption,an average of 50.4% (range45.3%60.1%) of the participants consumed fewer than five drinks per week; 24.8% (range19.6%28.3%) consumed between 6 and 10 drinks;12.3% (range9.6%17.0%) consumed between 11 and 15 drinks; and 12.6%(range10.1%16.2%) consumed more than 16 drinks. The amount of missing datawas trivial across the three health behaviours and samples (mean6.4%).The three health-risk behaviours were meaningfully correlated. The strongestassociation (averaged across samples) was between drinking and speeding, with a meanvalue of .31 (range.27 to .36). Tobacco and alcohol consumption were moderatelycorrelated positively with a mean of .28 (range.10 to .52), whereas tobacco consumption and speeding were only weakly correlated with a mean of .13 (range?.01 to .21). Two of these health-risk behaviours were also associated with student gender: men (coded as 1) were more likely than women (coded as 2) to consume a higher number of drinks a week(mean r?.26, range?.39 to .18) and to speed in automobiles (mean r?.37,range?.47 to .28). Gender and smoking behaviour; however, were not