Personality and antisocial behaviour: study of temperamental dimensions

Personality and Individual Differences 31 (2001) 329±348

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Personality and antisocial behaviour: study of temperamental dimensions Estrella Romero a,*, M. Angeles Luengo a, Jorge Sobral b a

Department of Clinical Psychology and Psychobiology, Faculty of Psychology, Campus Sur, 15706 Santiago de Compostela, Spain b Department of Social Psychology, University of Santiago de Compostela, Santiago de Compostela, Spain

Abstract Personality variables have been considered as major determinants of delinquent behaviour in various theoretical models and numerous empirical studies. Particular attention has been paid to ``temperament'' variables, which are considered to have a biological basis. In the present study, we examined relationships between self-reported antisocial behaviour and a number of temperament variables (extraversion, neuroticism, psychoticism, impulsivity, sensation seeking) in three subject groups: 435 school-attending male adolescents, 529 school-attending female adolescents, and 95 institutionalized delinquent male adolescents. This study design, unlike that of most previous studies of this type, allowed control for the factor of institutionalization, and included a longitudinal analysis, in that questionnaires were administered to the school-attending subjects twice with a 1-year interval. The results con®rm that several temperament variables, characterized by high sensitivity to reward and/or weak response to punishment signals, are closely associated with antisocial behaviour. Our ®ndings suggest that personality variables should be included in criminological models, and taken into account in intervention programs. # 2001 Elsevier Science Ltd. All rights reserved. Keywords: Delinquency; Adolescents; Extraversion; Neuroticism; Psychoticism; Impulsivity; Sensation seeking

1. Introduction A wide range of variables have been considered as risk factors for juvenile delinquency (see for example Rutter, Giller & Hagell, 1998). Of these, personality variables were for many years

* Corresponding author. Fax: +34-981-521581. E-mail address: [email protected] (E. Romero). 0191-8869/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved. PII: S0191-8869(00)00139-2

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attributed scant importance (Farrington, 1992; Romero, Sobral & Luengo, 1999): the powerful in¯uence of sociology on criminological theory, a certain fear of biological reductionism, and the internal crises of personality psychology itself came together to create a climate in which personality factors were dismissed as unimportant (Stitt & Giacopassi, 1992). More recently, however, there has been what might be called a `rediscovery of the person' in criminology (Andrews & Bonta, 1994). In the face of strong evidence that macrosocial variables cannot fully explain delinquency, and that there is great interindividual variability in the behaviour of subjects exposed to criminogenic conditions, increasing interest is turning to individual di€erences, even in schools of thought with a strong sociological in¯uence (Gottfredson & Hirschi, 1990). Particular attention is being paid to what have been referred to as the `temperament' variables, a group of characteristics assumed to depend on the individual's biological substrate, and showing a relatively high degree of stability over the lifespan (Bates & Wachs, 1994; Strelau, 1998). In criminal psychology, Eysenck's three fundamental dimensions (extraversion, neuroticism, psychoticism), together with impulsivity and sensation seeking, have received particular attention.1 It has been hypothesized that delinquency is related to all three Eysenck dimensions. Extraversion, associated with a low level of corticoreticular arousal, hinders conditioning and thus the acquisition of social norms. As neuroticism tends to amplify acquired behavioural tendencies, Eysenck (1964) predicts that subjects with high extraversion and neuroticism scores are those at highest risk for antisocial behaviour. In 1976, the dimension psychoticism was introduced into Eysenck's system (Eysenck & Eysenck, 1976), and since that time has likewise been considered to be a predictor of criminal behaviour, in view of the hostility and emotional insensitivity characteristic of subjects with high scores on this dimension. Impulsivity has also been the subject of increasing attention as an explicator of antisocial behaviour, despite the conceptual and methodological confusion surrounding this construct (Gerbing, Ahadi & Patton, 1987; White, Mott, Caspi, Bartusch, Needles & Stouthamer-Loeber, 1994; Romero, Luengo, Carrillo & Otero, 1994). The classical conceptions of psychopathic personality (Cleckley, 1976; Gough, 1948; Hare, 1980) include as de®ning characteristics a lack of behavioural self-control, an orientation toward immediate grati®cation, and diculty in carrying through long-term plans, all of which are implicit in the impulsivity construct. Approaches derived from Gray's model (for example, Newman, 1987) have suggested that reward sensitivity and diculty in processing punishment signals make impulsive subjects prone to antisocial behaviour. The theoretical approach adopted by Wilson and Herrnstein (1985) proposes that impulsive subjects have a short time horizon, and are thus not adequately dissuaded by the typically delayed negative consequences of delinquent acts. Finally, in more recent models (e.g. Gottfredson & Hirschi, 1990; Hirschi & Gottfredson, 1994), low self-control is considered to be a key factor underlying many types of deviant conduct, in association with situational opportunity.

1

Historically there has been considerable controversy about the concept of temperament (Strelau, 1998). Currently, however, most researches seem to agree that the de®ning characteristics of temperament include a biological origin and temporal stability. At the same time, and although there is disagreement as to exactly which dimensions of personality should be included in this domain, dimensions such as those cited are commonly considered as `temperament' in the recent literature (Angleitner & Ostendorf, 1994; Strelau; Zuckerman, 1994b).

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Sensation seeking likewise has been considered a correlate of antisocial behaviour (Zuckerman, 1979, 1994a). It is widely considered that a desire for stimulating, intense, and novel experiences is an essential component of delinquent conduct (Farley & Farley, 1972; Haapasalo, 1990; Zuckerman, 1978). Many researchers have examined the relationship between these personality dimensions and antisocial behaviour (see for example Berman & Paisley, 1984; Daderman, 1999; Mak, 1991). Despite the vigour of these lines of research, however, most previous studies have su€ered two limitations. The ®rst frequent limitation is one of design, in that many studies have been based on comparison between institutionalized delinquents and individuals in the general population, on the implicit assumption that all non-institutionalized subjects are non-delinquent. As pointed out by other authors (Farrington, 1987; Krueger, Schmutte, Caspi, Mott, Campbell & Silva, 1994), such `known-groups' designs have a number of clear drawbacks. First, only a small proportion of subjects who commit crimes are subsequently institutionalized, so that known-groups designs cannot guarantee that the putative controls are non-delinquent subjects. In fact, the two groups probably overlap along a behavioural continuum, so that the delinquency/non-delinquency dichotomy is of little value (Eysenck & Gundjonsson, 1989). Second, institutionalization is in itself an important variable a€ecting the relationships between personality and delinquency. Certain personality traits may favour ocial processing and institutionalization (Feldman, 1977), giving rise to `di€erential apprehension': for example, impulsive and emotionally unstable individuals may be less capable of escaping detention by the police. Similarly, it should not be forgotten that internment may itself in¯uence personality variables, as suggested by various authors (Banister, Smith, Heskin & Bolton, 1973; Landau, 1976; Zamble & Porporino, 1988). As a result, it may be dicult to determine whether a given trait is associated with delinquent behaviour or simply with institutionalization. The second frequent limitation of studies of this type is that they are cross-sectional in approach. Despite the clear need for a longitudinal approach in studies of delinquent behaviour (Farrington, 1997; Heaven, 1993; Loeber, 1990), most studies have evaluated personality/delinquency relationships as existing at a given moment in time.2 However, the identi®cation of risk factors implies a need for prospective studies, allowing control of the temporal order of variables, and thus assessment of the extent to which personality variables can be considered genuine predictors of antisocial behaviour. In the present study we investigated the relationship between temperament variables and delinquency, using a design that attempted to overcome these limitations. First, delinquency was considered as a behavioural continuum rather than an all-or-nothing variable: subjects were asked to supply self-reports of antisocial behaviour, allowing direct evaluation of personality± delinquency relationships. In order to cover a wide range of levels of antisocial behaviour, we studied both school-attending adolescents and institutionalized delinquents. In addition, the inclusion of ocially recognized delinquents allowed us to perform speci®c analyses of the e€ects of the factor institutionalization. 2 Certain currents in the study of delinquent behaviour (notably that represented by Gottfredson & Hirschi, 1990) have minimized the importance of longitudinal studies; at least in criminological psychology, however, it is widely accepted that longitudinal studies are more e€ective for the identi®cation of risk factors.

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2. Method 2.1. Sample Three groups of subjects were studied. The ®rst group comprised 435 boys attending high school (78.4%) or vocational training college (21.6%) in Galicia (northwest Spain). Both public and private colleges were included in the study (81.9 and 18.1% of subjects, respectively). The subjects lived in urban (78.6%) or rural (21.4%) regions. Age was between 14 and 19 years (mean 15.45, S.D. 1.25). On the basis of Hollingshead's (1975) index, which combines information on parent's occupation and educational level, the subjects came from various socioeconomic classes, though most (66.4%) were from the lower or lower middle classes. The second group comprised 529 girls attending the same colleges as the boys (high school, 77.7%; vocational training, 22.3%; public colleges, 80.5%, private colleges, 19.5%; urban regions, 73%; rural regions, 27%). Age was again between 14 and 19 years (mean 15.49, S.D. 1.21). Socioeconomic class distribution was similar to that in the sample of boys. The third group comprised institutionalized subjects. It proved dicult to obtain a suciently large sample of institutionalized delinquent girls, so this group thus comprised 95 boys who had been institutionalized for delinquency, in juvenile rehabilitation centres and prisons in Galicia. Age ranged between 14 and 20 years (mean 17.16, S.D. 1.83). Socioeconomic class was in most cases low. 2.2. Variables and instruments Both personality variables and antisocial behaviour were evaluated using self-report instruments. Extraversion, neuroticism, and psychoticism were evaluated with the juvenile version of the Eysenck Personality Questionnaire (EPQ-J; Eysenck & Eysenck, 1975), adapted for use in Spain by TEA Ediciones (1989). As in the English language original, this questionnaire comprises 81 yes/no items, of which 24 assess extraversion, 20 neuroticism, and 17 psychoticism. The reliability and validity of this questionnaire in the Spanish population has been amply demonstrated (TEA Ediciones, 1989). In the present study, test±retest correlations between the ®rst evaluation and the second evaluation one year later were 0.51 (boys) and 0.54 (girls) for extraversion, 0.60 (boys) and 0.57 (girls) for neuroticism, and 0.50 (boys) and 0.49 (girls) for psychoticism. Impulsivity was evaluated using the I.6 scale of Eysenck, Easting and Pearson (1984), which comprises 23 yes/no items. This scale has been adapted for use in Spain by Silva, Martorell and Clemente (1987), and the adapted version shows internal consistencies of 0.80 for boys and 0.77 for girls. The relationship of this scale to other personality constructs and to external criteria support its validity for the measurement of impulsivity in the Spanish population (Luengo, Carrillo, Otero & Romero, 1994; Romero, 1996; Silva et al., 1987). In the present study, test±retest correlations between the ®rst evaluation and the second evaluation one year later were 0.61 (boys) and 0.65 (girls). Sensation seeking was measured using the Sensation Seeking Scale (Form V) developed by Zuckerman (1979). This scale, adapted for use in Spain by PeÂrez and Torrubia (1986), comprises 40 items that evaluate sensation seeking on four subscales, namely thrill-and-adventure seeking,

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disinhibition, experience seeking, and boredom susceptibility. Unlike the original scale, which has a forced-choice format, the Spanish version has a true/false format. As recognized by Zuckerman (1994a) himself, this format has proven satisfactory and scarcely susceptible to social desirability. In Spanish samples, the Sensation Seeking Scale shows internal consistencies of 0.62±0.78 for boys, and 0.52±0.72 for girls (PeÂrez & Torrubia, 1985). In view of previous research showing that the di€erent subscales of sensation seeking are associated with delinquency to di€erent extents (Haapasalo, 1990; Simo & PeÂrez, 1991), we considered the four subscales separately. Test±retest correlations between the ®rst evaluation and the second evaluation 1 year later ranged between 0.45 for boredom susceptibility in girls and 0.63 for thrill-and-adventure seeking in boys. In this study we did not use an `omnibus' personality measurement instrument, but instead selected the personality variables to be used individually, on theoretical grounds. As a result, the di€erent variables are not expected to show orthogonality. Indeed, between-measure correlations for school-attending boys were as high as 0.35 (P< 0.001) between psychoticism and impulsivity (mean for all variable pairs 0.17), and for girls as high as 0.35 (P<0.01) between neuroticism and impulsivity (mean 0.18). For institutionalized boys, between-measure correlations were as high as 0.34 (P< 0.001) between disinhibition and experience seeking (mean 0.17). In general, the correlations observed were similar to those reported in previous studies. For example, and except among institutionalized boys, impulsivity was more closely associated with psychoticism and neuroticism than with extraversion (see for example Saklofske & Eysenck, 1983). The components of sensation seeking were more closely associated with psychoticism (particularly boredom susceptibility) and extraversion (particularly thrill-and-adventure seeking) than with neuroticism (see Eysenck & Zuckerman, 1978). Impulsivity as measured by the I.6 scale was signi®cantly correlated with all components of sensation seeking, especially experience seeking and disinhibition. Antisocial behaviour was assessed with the Antisocial Behaviour Questionnaire (ABQ) developed by our group and used in numerous previous studies (Luengo et al., 1994; Romero, Luengo & Otero, 1998; Romero, Sobral, Luengo & Marzoa, 1999). This questionnaire was developed following an extensive review of the most widely used antisocial behaviour scales, and identi®cation of the most frequent such behaviours in the Spanish context. The 82 items eventually selected were those that best discriminated between a group of delinquents detected by the legal system and a group of young people from the general population. These items related to the frequency of vandalism (e.g. ``Smash the windows of derelict houses'', ``Hit, break or scrape parked cars or motorbikes'', 13 items), theft (e.g. ``Steal objects from inside cars'', ``Remove objects or money from vending machines, juke boxes, pay phones etc.'', 18 items), aggression (``Hit someone in the course of a ®ght'', ``Molest, insult or push a stranger in the street'' 15 items), rule breaking (``Run away from home'', ``Talk someone else into doing something prohibited'', 13 items) and drug involvement (``Take amphetamines'', ``Take part in illegal acts in order to obtain drugs'', 21 items). The possible replies are ``Never (0 times)'' assigned a score of zero; ``Rarely (from 1 to 5 times)'', assigned a score of 1; ``Several times (from 6 to 10 times)'' assigned a score of 2; and ``Frequently (more than 10 times)'' assigned a score of 3. The overall antisocial behaviour score is given by the sum of the points on all 82 items. The internal consistency (Cronbach's alpha) of the scale is 0.98, and its relationships with various behavioural and psychosocial variables support its validity as a measure of antisocial behaviour (Otero, Romero & Luengo, 1994; Romero, Sobral, Luengo & Marzoa, 1999).

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2.3. Procedure The questionnaires were administered to the school-attending subjects collectively, during normal classroom hours. These subjects completed the questionnaires on two occasions (T1 and T2) about 12 months apart. In the institutionalized subjects group, the questionnaires were administered individually, and were presented orally in view of the reading de®cit displayed by many of these subjects. In all cases the questionnaires were administered by specialist personnel. All subjects took part voluntarily, and anonymity and con®dentiality were guaranteed. The subjects themselves created their own code-names, so that the di€erent questionnaires could be identi®ed to a single subject without there being any need for the subject's real name. 2.4. Statistical analyses To investigate cross-sectional relationships between personality variables and antisocial behaviour, we considered the T1 data for the school-attending subjects, and the data for the institutionalized subjects. For each subject group we performed: (1) analyses of correlation between personality variables and the antisocial behaviour score; and (2) analyses of variance in those variables, with the antisocial behaviour score as grouping factor. We also compared groups of institutionalized and non-institutionalized subjects with the same antisocial behaviour score. To investigate longitudinal relationships between personality variables and the antisocial behaviour score, we used the T1 and T2 data for the school-attending subjects. Speci®cally, we performed an analysis of regression with T2 antisocial behaviour score as dependent variable and T1 personality variables as candidate predictors. In addition, T1 antisocial behaviour was included as a predictor at the ®rst step, facilitating identi®cation of variables predicting the change in antisocial behaviour between T1 and T2 (Collins & Horn, 1991; Menard, 1991). 3. Results 3.1. Personality and antisocial behaviour: descriptive statistics Table 1 shows mean values for ABQ score and each of the personality variables (T1 data) in each subject group. Also shown for each variable are the results of F tests to compare means between school-attending boys and girls, and between school-attending and institutionalized boys, after partialling out the e€ects of age. In multivariate analysis of variance considering all personality variables, signi®cant between-gender di€erences were observed (Wilks' lambda=0.86, P< 0.001). Girls showed signi®cantly higher mean neuroticism and signi®cantly lower mean psychoticism than boys, with no signi®cant di€erence in extraversion. In addition, girls showed signi®cantly lower scores on all components of sensation seeking except experience seeking. Impulsivity did not di€er signi®cantly between boys and girls. In general, these ®ndings are in agreement with those of previous studies of Spanish subjects (Eysenck, GarcõÂa-Sevilla, PeÂrez & Ortet, 1994; PeÂrez & Torrubia, 1985; Silva et al., 1987). In addition, and in accordance with numerous previous studies (e.g. Junger-Tas, Terlow & Klein, 1994; Huizinga & Elliott, 1987), the mean antisocial behaviour score for girls was much lower than that for boys.

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Table 1 Mean scores in each group on the di€erent personality scales and on the Antisocial Behaviour Questionnairea Mean

Extraversion Neuroticism Psychoticism Impulsivity Thrill-and-adventure seeking Experience seeking Disinhibition Boredom susceptibility Antisocial behaviour

F

Schoolattending males

Schoolattending females

Institutionalized males

School-attending males vs. school attending-females

School-attending males vs. institutionalized males

17.77 11.46 4.18 11.64 5.66 4.20 5.93 3.52 15.06

17.78 12.67 2.79 11.22 5.23 4.13 5.09 2.97 7.70

16.37 12.70 6.38 14.63 5.63 4.74 6.18 4.02 90.53

0.00 (ns)b 20.06*** 64.38*** 1.42 (ns) 6.05* 0.23 (ns) 28.54*** 22.49*** 33.15***

8.83** 5.47* 36.23*** 21.66*** 0.01 (ns) 4.23* 0.65 (ns) 4.84* 229.26***

a

Results of comparisons by analysis of variance ns. Not signi®cant (P>0.05) *P<0.05 **P<0.01 ***P<0.001 b

Personality variables likewise di€ered signi®cantly between school-attending and institutionalized boys (Wilks' lambda=0.89, P< 0.001). Note that this comparison corresponds to that performed in studies with `known groups' designs. Institutionalized boys also showed signi®cantly higher mean scores for neuroticism and psychoticism, and signi®cantly lower mean scores for extraversion. They also showed signi®cantly higher mean scores for impulsivity and on two components of sensation seeking, namely experience seeking and boredom susceptibility. 3.2. Cross-sectional analyses: personality-antisocial behaviour correlations Table 2 shows coecients of correlation (after partialling out the e€ects of age) between personality variables and antisocial behaviour in each group. Signi®cant correlations are observed in all three groups. Among school-attending boys, the strongest correlations were with psychoticism, impulsivity, disinhibition, and experience seeking. Neuroticism and the other two dimensions of sensation seeking (thrill-and-adventure seeking, and boredom susceptibility) likewise showed signi®cant positive correlations with antisocial behaviour, though with r<0.30. Among school-attending girls, the strongest correlations were with impulsivity and disinhibition. However, all variables considered showed signi®cant correlations. Girls showed signi®cantly higher correlations than boys in extraversion (P< 0.001), neuroticism (P< 0.01) and boredom susceptibility (P< 0.01). By contrast, the correlation between ABQ and psychoticism was higher among boys (P< 0.001). Among institutionalized boys, the strongest correlations (r> 0.30) were with psychoticism, impulsivity, and experience seeking. Disinhibition and boredom susceptibility likewise showed signi®cant positive correlations with antisocial behaviour, though with r values in all cases less than 0.30.

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Table 2 Correlations between personality variables and self-reported antisocial behaviour (Antisocial Behaviour Questionnaire score) in the three subject groups, after partialling out the e€ects of agea

Extraversion Neuroticism Psychoticism Impulsivity Thrill-and-adventure seeking Experience seeking Disinhibition Boredom susceptibility

School-attending males (n=435)

School-attending females (n=529)

Institutionalized males (n=95)

0.01 (0.01) 0.13** (0.15**) 0.37*** (0.47***) 0.37*** (0.42***) 0.16*** (0.18***) 0.30*** (0.38***) 0.35*** (0.42***) 0.18*** (0.22***)

0.11** (0.12**) 0.18*** (0.19***) 0.26*** (0.34***) 0.36*** (41***) 0.17*** (0.20***) 0.28*** (0.36***) 0.33*** (0.42***) 0.26*** (0.33***)

0.09 (0.11) 0.00 (0.01) 0.35*** (0.44***) 0.35*** (0.40***) 0.14 (0.16) 0.35*** (0.44***) 0.20* (0.25*) 0.19* (0.23*)

a

Values in brackets are correlations after correction for attenuation. *P<0.05 **P<0.01 ***P<0.001

In the criminological literature, research into personality±delinquency relationships has often been criticized on the grounds that personality items and antisocial behaviour items may overlap (see for example Tennenbaum, 1977). In the present study, the psychoticism scale of the EPQ contained two items that overlap in content with the aggression scale of the ABQ (``Do you think you get involved in more ®ghts than other people?'', and ''In general, do you enjoy bothering other people?''). In order to assess the extent to which the observed correlations between psychoticism and ABQ score might be attributable to this item overlap, we calculated correlations after elimination of these two items from the psychoticism scale. The correlations obtained did not di€er signi®cantly from those obtained previously: speci®cally, r values were 0.34 for school-attending boys (0.44 after correction for attenuation), 0.23 for school-attending girls (0.30 after correction for attenuation), and 0.29 for institutionalized boys (0.38 after correction for attenuation). In addition, we determined correlations between psychoticism and the individual subscales of the ABQ (vandalism, theft, aggression, rule breaking, drug involvement). We found that the correlations remained high even when there was no relationship between the psychoticism items and the items of the subscale in question: for example, the correlation between psychoticism and vandalism was 0.34 in school-attending boys (0.44 after correction for attenuation), 0.26 in school-attending girls (0.32 after correction for attenuation), and 0.36 in institutionalized boys (0.45 after correction for attenuation).

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These results thus allow us to rule out the possibility that the observed correlation between psychoticism and ABQ is an artifact of item overlap. 3.3. Cross-sectional analyses: analyses of variance To investigate the extent to which personality variables di€ered between subjects at di€erent positions on the antisocial behaviour continuum, the three subject groups were each subdivided on the basis of antisocial behaviour scores. For male subjects (in both the school-attending and institutionalized groups), the ABQ-score cuto€s for the subgroupings were 5, 34, and 89, corresponding to the 25th, 90th and 100th percentiles for the school-attending group. As in previous studies (Carrillo, Luengo & Romero, 1994; Luengo et al., 1994), these cuto€s were used to de®ne the groups denominated ``nondelinquent'' (ND, score 45), ``moderately delinquent'' (MD, score 6±34), ``severely delinquent'' (SD, score 35±89), and ``very severely delinquent'' (SD+, score >89). For female subjects, the ABQ-score cuto€s were 1 and 17, corresponding to the 25th and 90th percentiles for this group (ND, score 41; MD, score 2±17; SD, score >17). Table 3 shows the distribution of subjects among the subgroups thus de®ned. As can be seen from the table, none of the institutionalized subjects had an ABQ score below 6 (i.e. nondelinquent). Within each group (school-attending female, school-attending male, institutionalized male), we then compared personality variables between the ABQ-score subgroups. These comparisons allowed exploration of the extent to which the di€erent variables are related to di€erent degrees of antisocial behaviour. For each group, we used multivariate analysis of variance with personality variables as response variables, ABQ-score subgroup as the grouping factor, and age as covariate (Tables 4±6). Note that analysis of variance, unlike correlation analysis, is capable of detecting non-monotonic relationships. In all three subject groups, the overall multivariate test statistic (Wilks' lambda) was signi®cant at the 1% level. Considering the F values for the individual univariate analyses, all personality variables discriminated among ABQ-score subgroups, in both the school-attending male and school-attending female groups. In the school-attending male group, pairwise comparisons indicated that mean psychoticism, impulsivity, experience seeking, and disinhibition di€ered signi®cantly between all three ABQ subgroups. Mean neuroticism, thrill-and-adventure seeking, and boredom susceptibility di€ered signi®cantly between the ND group and the other two groups (MD and SD), but not between

Table 3 Distribution of subjects in each subgroup by Antisocial Behaviour Questionnaire (ABQ) score categoriesa Subgroup

ABQ score

School-attending males

Institutionalized males

Subgroup

ABQ score

School-attending females

ND MD SD SD+

(0±5) (6±34) (35±89) (> 89)

121 262 52 ±

0 17 35 43

ND MD SD

(0±1) (2±17) (> 17)

130 352 47

a

ND, Non delinquent; MD, Moderately delinquent; SD, Severely delinquent; SD+, Very severely delinquent.

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Table 4 Comparisons of Antisocial Behaviour Questionnaire score subgroups (non delinquent [ND], moderately delinquent [MD], severely delinquent [SD]) in the school-attending males Mean

F

Signi®cant di€erences

ND

MD

SD

Extraversion

17.17

18.15

16.67

5.05*

ND-MD MD-SD

Neuroticism

10.53

11.73

12.45

4.03*

ND-MD ND-SD

Psychoticism

3.22

4.19

6.40

20.91***

ND-MD ND-SD MD-SD

Impulsivity

9.29

11.83

14.64

23.52***

ND-MD ND-SD MD-SD

Thrill-and-adventure seeking

4.99

5.67

6.02

4.91**

ND-MD ND-SD

Experience seeking

3.69

4.02

5.23

17.20***

ND-MD ND-SD MD-SD

Disinhibition

4.87

5.92

7.21

25.85***

ND-MD ND-SD MD-SD

Boredom susceptibility

2.92

3.59

4.23

10.76***

ND-MD ND-SD

Wilks' lambda= 0.73*** *P<0.05 **P<0.01 ***P<0.001

MD and SD. Extraversion showed an apparently non-monotonic trend, being signi®cantly higher in MD than in both ND and SD. In the school-attending female group, pairwise comparisons indicated that all personality variables di€ered signi®cantly between all three ABQ subgroups, except extraversion and neuroticism, which di€ered signi®cantly between ND and the other two groups but not between MD and SD. In the institutionalized male group, pairwise comparisons revealed signi®cant di€erences in psychoticism, impulsivity, experience seeking, and boredom susceptibility. Psychoticism and impulsivity were signi®cantly lower in MD than in SD and SD+. Experience seeking and boredom susceptibility were signi®cantly lower in MD and SD than in SD+. 3.4. Cross-sectional analyses: detected versus undetected delinquents The above analyses indicated that the observed relationships between personality variables and delinquency are not exclusively attributable to institutionalization, since relationships were

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Table 5 Comparisons of Antisocial Behaviour Questionnaire score subgroups (non delinquent [ND], moderately delinquent [MD], severely delinquent [SD]) in the school-attending females Mean ND

MD

SD

F

Signi®cant di€erences

Extraversion

16.44

18.06

18.75

10.32***

ND-MD ND-SD

Neuroticism

11.23

12.93

14.08

10.68***

ND-MD ND-SD

Psychoticism

2.20

2.80

4.14

11.72***

ND-MD ND-SD MD-SD

Impulsivity

8.46

11.62

15.18

42.63***

ND-MD ND-SD MD-SD

Thrill-and-adventure seeking

4.52

5.33

6.16

11.78***

ND-MD ND-SD MD-SD

Experience seeking

3.57

4.18

5.16

22.73***

ND-MD ND-SD MD-SD

Disinhibition

4.10

5.21

6.65

40.41***

ND-MD ND-SD MD-SD

Boredom susceptibility

2.56

2.97

4.02

17.87***

ND-MD ND-SD MD-SD

Wilks' lambda=0.72*** ***P<0.001

observed in the non-institutionalized groups. However, to investigate if institutionalization may a€ect these relationships, we compared the personality variables between the SD subgroups of school-attending and institutionalized boys (i.e. between ``undetected'' and ``detected'' delinquents).3 As shown in Table 7, the overall multivariate test statistic (Wilks' lambda) for this analysis was not signi®cant at the 5% level. The F values for the individual analyses were likewise not signi®cant, except for disinhibition, which was signi®cantly lower among institutionalized delinquents than among non-institutionalized delinquents. Since the two groups di€ered signi®cantly in socioeconomic class (as assessed by the index of Hollingshead, 1975), the analysis was repeated with this variable as covariate; the results were practically identical.

3 The SD subgroups were used ion this analysis (as opposed to the MD subgroups) in view of the greater similarity in number of subjects (52 in the school-attending group, 35 in the institutionalised group)

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Table 6 Comparisons of Antisocial Behaviour Questionnaire score subgroups (moderately delinquent [MD], severely delinquent [SD], very severely delinquent [SD+] in the institutionalized subjects Mean

Fa

Signi®cant di€erences

MD

SD

SD+

Extraversion

16.92

16.88

16.00

0.17 (ns)

±

Neuroticism

12.15

13.70

12.39

0.58 (ns)

±

Psychoticism

4.15

5.61

6.94

6.54**

10.26

14.29

15.78

8.28**

Thrill-and-adventure seeking

4.93

5.55

5.97

1.11 (ns)

MD-SD MD-SD+ MD-SD MD-SD+ ±

Experience seeking

3.53

4.62

5.17

6.34**

Disinhibition

5.40

6.00

6.63

4.35*

Boredom susceptibility

3.00 3.00

3.85 3.85

4.17 4.17

1.97 (ns) 1.97 (ns)

Impulsivity

MD-SD+ SD-SD+ MD-SD+ SD-SD+ ± ±

Wilks' lambda=0.49** a ns, not signi®cant (P>0.05) *P<0.05 **P<0.01

Table 7 Comparisons between the severely delinquent (SD) subgroups of the school-attending male group and the institutionalized male group Fa

Mean

Extraversion Neuroticism Psychoticism Impulsivity Thrill-and-adventure seeking Experience seeking Disinhibition Boredom susceptibility

School-attending severe delinquents

Institutionalized severe delinquents

16.67 12.45 6.40 16.64 6.02 5.23 7.21 4.23

16.88 13.70 5.61 14.29 5.55 4.62 6.00 3.85

Wilks' lambda=0.77 (n.s.) a ns: Not signi®cant (P>0.05) **P<0.01

0.21 (ns) 1.65 (ns) 0.00 (ns) 0.00 (ns) 0.15 (ns) 2.67 (ns) 8.30** 0.92 (ns)

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3.5. Longitudinal analyses To identify personality variables that were e€ective predictors of increasing antisocial behaviour in the male and female school-attending groups, we performed multiple regression analyses with T2 ABQ score as response variable and personality variables and T1 ABQ score as candidate predictors (Table 8). In the male group, disinhibition, psychoticism, and experience seeking were selected as signi®cant predictors. In the female group, impulsivity and extraversion were selected. The regression coecients for personality variables were rather low, but it should be borne in mind that the time period under consideration was short, and that a conservative analysis was used (i.e. T1 ABQ score was included as a predictor, in order to partial out the strong autoregressive e€ects). 4. Discussion The results of the present study reveal signi®cant relationships between personality variables and delinquency. Such relationships were observed at all points along the antisocial behaviour continuum. Of the Eysenck dimensions, psychoticism was that which showed the strongest and most consistent relationship with antisocial behaviour. This ®nding is consistent with numerous previous studies aimed at evaluation of the Eysenck model. A number of reviews (e.g. Feldman, 1977; Furnham & Thompson, 1991; PeÂrez, 1986) have concluded that psychoticism is the Eysenck dimension most closely associated with delinquency, whereas results regarding relationships with extraversion and neuroticism have been less robust. Despite the conceptual controversies in relation to this dimension (Claridge, 1981), the behavioural style that characterizes psychoticism (interpersonal hostility, egocentrism, a€ective insensitivity) is thus clearly a useful variable for prediction of delinquency. Table 8 Multiple regression analysis to identify predictors of change in antisocial behaviour Step

Variable

Beta

R2

F for
R2

School-attending females 1 2 3 4

T1 Antisocial behaviour Disinhibition Psychoticism Experience Seeking

0.54 0.16 0.12 0.10

0.29 0.31 0.33 0.34

165.48*** 12.66*** 8.25** 5.76*

School-attending females 1 2 3

T1 Antisocial behaviour Impulsivity Extraversion

0.57 0.17 0.09

0.33 0.35 0.36

240.62*** 18.87*** 6.71*

*P<0.05 **P<0.01 ***P<0.001

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Signi®cant correlations with neuroticism were only observed in the school-attending groups, and were in any case relatively weak. As reported in previous studies, the association was strongest among girls (Silva, Martorell & Clemente, 1986). Extraversion was likewise more strongly associated with delinquency among girls than among boys; indeed, extraversion was found to be a signi®cant predictor of increasing antisocial behaviour among girls in the longitudinal analysis. These ®ndings suggest that extraversion may be more important for understanding female delinquency than male delinquency. However, the results for school-attending boys suggest that the importance of extraversion may be related to the degree of antisocial behaviour, not (or not only) to gender. Comparative analyses of schoolattending boys with di€erent levels of antisocial behaviour indicate that moderately delinquent subjects tend to have higher extraversion scores than both nondelinquent and severely delinquent subjects. A similar pattern was observed in the institutionalized boys group, with severely delinquent subjects showing lower extraversion scores than less severely delinquent subjects (though the di€erence was not statistically signi®cant). Taken together, these ®ndings suggest that mildly antisocial behaviour (as displayed by the girls or by the moderately delinquent school-attending boys) is related to high extraversion, while more severe delinquency characteristically occurs in personality types who have diculty in social situations. Other authors have likewise suggested that extraversion, though considered by Eysenck to be the key personality determinant of antisocial behaviour, may in fact be associated principally with the milder forms of such behaviour (Furnham, 1984). Our ®ndings as regards extraversion may be related to the importance of peer group culture as a cause of moderate delinquency in adolescents, as noted in previous studies (Elliott, Huizinga & Ageton, 1985). A high level of sociability may favour involvement in deviant subcultures, and thus increase the likelihood of antisocial behaviour. It would be interesting to perform research speci®cally aimed at investigating these possible mediating factors. In addition, it is worth pointing out that our results on extraversion show certain parallels with those of other studies which have examined the relationship between extraversion-related variables and delinquency. For example, the results of Mott, Caspi, Dickson, Silva and Stanton (1996) suggest that subjects showing adolescence-limited delinquency have higher social potency (assertiveness, capacity to in¯uence others, tendency to adopt leadership roles) than both ``abstainers'' (nondelinquent subjects) and subjects showing life-course-persistent delinquency. Although Mott et al point out that the two groups of delinquents are dicult to distinguish on the basis of antisocial involvement, it is possible that our moderate-delinquency group had a higher proportion of adolescence-limited delinquents, while our severe-delinquency group had a higher proportion of life-course-persistent delinquents. Impulsivity, which is conceptually related to the Eysenck supradimensions, is another personality variable that is clearly associated with antisocial behaviour. Numerous previous studies (Farrington, Loeber & Van Kammen 1990; Luengo et al., 1994; Royse & Wiehe, 1988; White et al., 1994) have shown that impulsivity (and particularly self-reported impulsivity, which evaluates the ``behavioural'' facet of this construct) is one of the most marked characteristics of antisocial individuals. These data are in accordance with numerous theoretical approaches that have considered impulsivity as a key element in the explanation of antisocial behaviour (Farrington, 1996; Gorenstein & Newman, 1980; Gottfredson & Hirschi, 1990; Mott, 1993). Sensation seeking was also a correlate of delinquent behaviour. As in other studies (Newcomb & McGee, 1991; Simo & PeÂrez, 1991), we found that disinhibition and experience seeking are the

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dimensions of sensation seeking most closely related to delinquency. This is in accordance with the views of Zuckerman himself, who considered thrill-and-adventure seeking to be the most conventional mode of sensation seeking, but disinhibition and experience seeking to be the most sociopathic modes (Zuckerman, 1978). Our results reveal that signi®cant relationships between personality variables and delinquency were maintained after accounting for the e€ects of ocial processing and institutionalization. These results are of relevance to two criticisms that have been raised against studies with knowngroups designs (Feldman, 1977; Krueger et al., 1994). First, it has been suggested that observed relationships between personality and detected delinquency may in fact simply re¯ect relationships between personality and likelihood of apprehension and/or subsequent internment. Secondly, it has been suggested that internment may itself in¯uence personality. In the present study, however, signi®cant relationships between personality and delinquency were observed not only among institutionalized subjects but also among non-institutionalized subjects; furthermore, the personality variables most closely related to degree of antisocial behaviour in the non-institutionalized group were likewise related to degree of antisocial behaviour in the institutionalized group. Indeed, our results indicate that the personality variables considered in the present study (except disinhibition) do not di€er signi®cantly between institutionalized and non-institutionalized delinquents. Our ®ndings that mean disinhibition score was higher among school-attending delinquent boys than among institutionalized delinquent boys may be explicable in terms of power-control theory (Hagan, Gillis & Simpson, 1985, 1990). These authors suggest that middleclass adolescents are protected from incarceration by their parents' social status, and thus they can a€ord to behave in a disinhibited and risk-taking manner. Recently, evidence consistent with this idea has been reported (Wright, Caspi, Mott, Miech & Silva, 1999). Alternatively, the lower mean disinhibition scores of institutionalized delinquents may simply re¯ect the restrictive character of their current environment; as pointed out by Zuckerman (1994a), the items of the disinhibition scale refer to real experiences, unlike the items of the thrill-and-adventure seeking scale, which are expressed as behavioural intentions (``I would like to. . .''): thus disinhibition responses may be more strongly in¯uenced by environmental conditions. In any case, our results suggest that personality is in general not a key factor for explaining why some severely delinquent individuals are in institutions and others not. In fact, other variables probably have more important e€ects on apprehension and incarceration rates. For example, it has been suggested that risk of apprehension may be higher for less intelligent subjects, though one study that tested this hypothesis in fact found that intelligence was related to antisocial behaviour but not to apprehension risk (Mott & Silva, 1988). It has also been suggested that socioeconomic factors may make some individuals more prone to ocial processing (Box, 1981; Chambliss, 1969). Numerous studies have demonstrated that social class shows a strong correlation with ocially recognized delinquency (Piliavin, 1969; Reiss & Rhodes, 1961) but weak or non-existent correlations with self-reported delinquency (Gold & Reimer, 1975; Jensen & Thompson, 1990; Junger-Tas et al., 1994; Romero, 1996). The results of the present study likewise indicate that institutionalized delinquents typically come from lower socioeconomic strata than undetected delinquents. Taken together, these results suggest that social class may be a key determinant of the risks of apprehension and incarceration. Our results also suggest that personality variables may be useful predictors of change over time in delinquent behaviour, despite the fact that the time interval considered was relatively short.

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Three variables (disinhibition, psychoticism, and experience seeking) were signi®cant predictors of the change in antisocial behaviour occurring in non-institutionalized male subjects between the ®rst evaluation and the second evaluation about one year later. For non-institutionalized female subjects, the signi®cant predictors were impulsivity and extraversion. These results con®rm the importance of variables that were likewise found to be associated with antisocial behaviour in the cross-sectional analyses with T1 data. All of these dimensions that are consistently associated with antisocial behaviour have been considered in the psychobiology of personality as ``approach'' traits (Revelle, 1995; Zuckerman, 1994a). Psychoticism, impulsivity, sensation seeking, and extraversion form a group of dimensions de®ned by a strong sensitivity to rewarding experiences and/or weak inhibition in response to punishment signals. Underlying these dimensions there are biological di€erences that likewise show some correlation with antisocial behaviour: for example, signi®cant correlations have been found with platelet monoamine oxidase levels, with the activity of the serotonergic system, and with psychophysiological phenomena such as augmenting (Raine, 1993). Thus, in both psychobiological and psychometric terms, research is consolidating the relationship between delinquency and a ``disinhibited'' personal style with a strong sensitivity to reward and weak behavioural ``brakes'', interfering with the acquisition of norms and constituting a risk factor for antisocial behaviour. Findings of this type demonstrate the importance of incorporating personality variables into criminological theories, which have traditionally been strongly in¯uenced by sociological viewpoints and have paid little attention to individual di€erences. Even in so-called ``integrative'' models (e.g. Elliott et al., 1985), the personality factors have been ignored. It is clearly very important to overcome this short-sighted and discipline-bound approach, and to construct models that mesh biological and personality factors with psychosocial and sociocultural factors. To provide an appropriate knowledge base for the development of theoretical frameworks of this type, it is likewise clearly important for the study of personality-delinquency relationships to continue. For example, there is a need for long-term longitudinal studies (of which there are already good examples in the psychology of antisocial behaviour: Caspi, Henry, McGee, Mott & Silva, 1995; Farrington, 1995), with the aim of assessing the importance of the di€erent personality variables at di€erent stages in delinquent careers. Furthermore, studies of this type should take into account the heterogeneity of antisocial individuals: in this connection, a particularly promising approach would appear to be that of distinguishing between adolescence-limited and life-course-persistent antisocial behaviour (Mott, 1993). Indeed, some studies have suggested that personality pro®les may di€er between these two types of individual (Mott et al., 1996), and it seems likely that this line of research could help to clarify some of the apparent inconsistencies observed in this ®eld. At the same time, there is a need to analyse the probably complex relationships between personality and other risk factors: although many constructs associated with maladapted behaviour are currently known, the study of factors that mediate and moderate these relationships is still poorly understood (Raine, Brennan, Farrington & Mednick, 1997; Romero, Sobral, Luengo & Marzoa 1999). The relationship between personality and delinquency is not of theoretical interest alone, but has a number of practical implications. Currently, there can be no doubt that to speak of personality variables in criminology is not to speak of Lombrosian ``stigmas'' that lead irremediably to crime or that inevitably require a nihilistic approach. Taking personality into account implies

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accepting the existence of cognitive, a€ective, and behavioural tendencies that may favour delinquency; improving understanding of these tendencies will facilitate prevention and treatment. The implementation of educational programs based on the delinquent subject's sensitivity to reward, channelling of sensation seeking, or training in self-control are just some of the strategies suggested by this approach. Intervention to deal with a problem of such complex origins as delinquency requires attention to all the sources of information available: personality factors and interindividual di€erences in response styles should not be forgotten. Acknowledgements The authors thank Terrie Mott for her insightful comments on an earlier version of this article. References Andrews, D. A., & Bonta, J. (1994). The psychology of criminal conduct. Cincinnati, OH: Anderson Publishing. Angleitner, A., & Ostendorf, F. (1994). Temperament and the Big Five factors of personality. In C. F. Halverson, G. A. Kohnstamm, & R. P. Martin, The developing structure of temperament and personality from infancy to adulthood (pp. 69±95). Hillsdale, NJ: Erlbaum. Banister, P. A., Smith, F. V., Heskin, K. J., & Bolton, N. (1973). Psychological correlates of long-term imprisonment: I: Cognitive variables, II: Personality variables. British Journal of Criminology, 13, 312±330. Bates, J. E., & Wachs, T. D. (1994). Temperament. Individual di€erences at the interface of biology and behavior. Washington: American Psychological Association. Berman, T., & Paisley, T. (1984). Personality in assaultive and non-assaultive juvenile male o€enders. Psychological Reports, 54, 527±530. Box, S. (1981). Deviance, reality and society. London: Holt, Rhinehart & Winston. Carrillo, M. T., Luengo, M. A., & Romero, E. (1994). Conducta antisocial juvenil y perspectiva de tiempo futuro: un anaÂlisis de la in¯uencia de la institucionalizacioÂn [Juvenile antisocial behaviour and future time perspective: analysis of the in¯uence of institutionalization]. Anuario de PsicologõÂa, 62, 67±80. Caspi, A., Henry, B., McGee, R., Mott, T. E., & Silva, P. (1995). Temperamental origins of child and adolescent behavior problems: from age 3 to 15. Child Development, 66, 55±88. Chambliss, W. (1969). Crime and the legal process. New York: McGraw-Hill. Claridge, G. (1981). Psychoticism. In R. Lynn, Dimensions of personality: Papers in honour of H.J. Eysenck (pp. 79± 109). Oxford: Pergamon Press. Cleckley, H. (1976). The mask of sanity (5th ed.). ST Louis, MO: Mosby. Collins, L. M., & Horn, T. D. (1991). Best methods for the analysis of change. Washington: APA. Daderman, A. M. (1999). Di€erences between severely conduct-disordered juvenile males and normal juvenile males: the study of personality traits. Personality and Individual Di€erences, 26, 827±845. Elliott, D. S., Huizinga, D., & Ageton, S. S. (1985). Explaining delinquency and drug use. Beverly Hills, CA: Sage. Eysenck, H. J. (1964). Crime and personality. London: Routledge & Kegan Paul. Eysenck, H. J., & Eysenck, S. B. G. (1975). Manual of the Eysenck Personality Questionnaire. London: Hodder & Stoughton. Eysenck, H. J., & Eysenck, S. B. G. (1976). Psychoticism as a dimension of personality. London: Hodder & Stoughton. Eysenck, S. B. G., & Zuckerman, M. (1978). The relationship between sensation-seeking and Eysenck's dimensions of personality. British Journal of Criminology, 69, 483±487. Eysenck, H. J., & Gudjonsson, G. H. (1989). The causes and cures of criminality. New York: Plenum. Eysenck, S. B. G., Easting, G., & Pearson, P. R. (1984). Age norms for impulsiveness, venturesomeness and empathy in children. Personality and Individual Di€erences, 5, 315±321.

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