Journal of Child Psychology and Psychiatry 53:8 (2012), pp 826–835
doi:10.1111/j.1469-7610.2011.02492.x
Psychopathic traits moderate peer influence on
adolescent delinquency
Margaret Kerr, Maarten Van Zalk, and Håkan Stattin
Örebro University, Youth and Society (YeS), Center for Developmental Research, Örebro, Sweden
Background: Peer influence on adolescent delinquency is well established, but little is known about
moderators of peer influence. In this study, we examined adolescents’ (targets) and their peers’ psychopathic personality traits as moderators of peer influence on delinquency in peer networks. We used
three separate dimensions of the psychopathic personality: grandiose-manipulative traits, callousunemotional traits, and impulsive-irresponsible traits. Methods: We used a peer network approach
with five waves of longitudinal data from 847 adolescents in one community. Peer nominations were not
limited to the school context, thus allowing us to capture all potentially important peers. In addition,
peers reported on their own delinquency, thus allowing us to avoid problems of false consensus or
projection that arise when individuals report on their peers’ delinquency. We used simulation investigation for empirical network analyses (SIENA), which is the only program currently available that can be
used to study peer influence effects in peer networks of multiple relationships while controlling for
selection effects. Results: Targets’ and peers’ callous-unemotional and grandiose-manipulative traits
uniquely moderated peer influence on delinquency. Relative to those with low levels, targets who were
high on these traits were less influenced by peers’ delinquency, and peers who were high on these traits
were more influential on targets’ delinquency. Selection effects were found for impulsive-irresponsible
traits, but these traits did not moderate peer influence on delinquency. Conclusions: As the first study
to look at moderating effects of psychopathic traits on peer influence, this study advances knowledge
about peer influence on delinquency and about psychopathic traits in adolescents. In addition, the
study contributes to the literature by looking at unique effects of the three dimensions of psychopathy
and taking a peer network approach, in which network effects, self-selection, and other selection effects
are controlled when examining influence and moderators of influence. Keywords: Psychopathic traits,
callous-unemotional traits, delinquency, peer influence, peer network.
Introduction
Psychopathy is an adult personality disorder that
is closely linked to criminality. The psychopathic
personality includes: (a) a grandiose-manipulative
interpersonal style, (b) a callous-unemotional affective style, and (c) an impulsive-irresponsible behavioral style (Cooke & Michie, 2001). The personality
pattern and the connection to criminality have also
been identified in adolescents in both referred
(Christian, Frick, Hill, & Tyler, 1997) and nonreferred samples (Andershed, Gustafson, Kerr, &
Stattin, 2002; Andershed, Kerr, Stattin, & Levander,
2002; Frick, Cornell, Barry, Bodin, & Dane, 2003).
The identification of these traits in adolescence is
intriguing because adult psychopathy is linked to
both criminality and disturbed relationships
(Cleckley, 1976), but in adolescence criminality
commonly takes place with close peers (Warr,
2002). Peers influence adolescents’ delinquency
(Fergusson, Swain-Campbell, & Horwood, 2002;
Haynie & Osgood, 2005; Selfhout, Branje, & Meeus,
2008; Vitaro, Brendgen, & Tremblay, 2000; Vitaro,
Tremblay, Kerr, Pagani, & Bukowski, 1997), and
peers who are high on psychopathic traits might be
Conflicts of interest statement: No conflicts declared.
particularly important deviant influences because of
their high levels of delinquency and their manipulative traits (i.e. psychopathic traits might enhance
peer influence on delinquency). However, because
psychopathy is linked to disturbed relationships, the
question is whether adolescents high on psychopathic traits can secure places in tightly bonded
groups of delinquents.
To our knowledge, there are only two published
studies dealing with psychopathic traits and adolescent peer relationships, and they both suggest
that adolescents high on psychopathic traits do have
close friends (Kimonis, Frick, & Barry, 2004; Muñoz,
Kerr, & Bešić, 2008). In these studies, adolescents
high on psychopathic traits reported having close
friends, and for boys those friendships were likely to
be reciprocated (Muñoz et al., 2008). Youths high on
psychopathic traits tended to have delinquent
friends (Kimonis et al., 2004; Muñoz et al., 2008)
and reported engaging in delinquent acts with their
friends (Muñoz et al., 2008). Thus, adolescents high
on psychopathic traits do seem to establish themselves in delinquent peer groups, so they might exert
more deviant influence than other delinquent peers.
Neither of these studies examined influence, however, so the question remains whether psychopathic
traits moderate peer influence on delinquency.
2011 The Authors. Journal of Child Psychology and Psychiatry 2011 Association for Child and Adolescent Mental Health.
Published by Blackwell Publishing, 9600 Garsington Road, Oxford OX4 2DQ, UK and 350 Main St, Malden, MA 02148, USA
doi:10.1111/j.1469-7610.2011.02492.x
Psychopathic traits moderate peer influence on delinquency
Moderation could occur in one of two ways. To
conceptualize them, we distinguish between targets,
or those being influenced, and peers, or those
exerting influence. In one type of moderation, targets’ psychopathic traits could make targets more or
less easily influenced by peers, and in the other,
peers’ psychopathic traits could make peers more or
less influential. The literature on both types of
moderation is limited, but targets’ susceptibility to
peer pressure (Monahan, Steinberg, & Cauffman,
2009) and closeness to parents (Vitaro, Brendgen, &
Tremblay, 2000) have been shown to moderate peer
influence on delinquency. Susceptibility to peer
pressure has also been linked to delinquency (Allen,
Porter, & McFarland, 2006) and low self-esteem
(Bámaca & Umana-Taylor, 2006; Fletcher, Darling,
Steinberg, & Dornbusch, 1995), and some have argued that popularity increases adolescents’ susceptibility to peer influence (Allen, Porter, McFarland,
Marsh, & McElhaney, 2005). In addition, in one
experimental study targets’ social anxiety increased
peer influence on antisocial attitudes (Cohen &
Prinstein, 2006). This same study showed that peers
with high social status influenced targets’ antisocial
attitudes more than those with low status. To our
knowledge, however, this is the only study in the
literature to have examined characteristics of peers
as moderators of influence. Thus, peers’ social status and targets’ susceptibility to peer influence and
social anxiety (but not self-control, see McGloin &
Shermer, 2009) seem to enhance influence effects.
We propose that the three dimensions of the psychopathic personality – both in targets and peers –
could also be important moderators of peer influence
on delinquency.
Peers’ traits
One can formulate two opposite sets of expectations
about the moderating role of peers’ psychopathic
traits. One is that for peers high on psychopathic
traits we should see little influence of peers’ delinquency on targets’ delinquency, because those high
on psychopathic traits might not commit delinquent
acts with others. The basis for this comes from
Quay’s (1993) theory, in which a psychopathy-like
group of adolescent offenders was characterized as
committing crimes alone rather than as part of a
tight-knit delinquent group, which is the more
common pattern. The brain systems and behaviors
that, according to Quay (1993), underlie this pattern are most relevant to the callous-unemotional
and impulsive-irresponsible dimensions. Thus,
peers’ callous-unemotional or impulsive-irresponsible traits might diminish peer influence on delinquency.
An opposite, but also reasonable, expectation is
that psychopathic traits would enhance peer influence on targets’ delinquency. There are at least two
reasons for this. First, others have argued (see
827
Kimonis et al., 2004) that because children high on
psychopathic traits or the callous-unemotional
dimension tend to engage in planned or premeditated antisocial behavior, these traits might increase
adolescents’ abilities to organize a group of peers to
carry out planned crimes. Second, the grandiosemanipulative dimension includes traits such as
manipulativeness and superficial charm, and
adolescents with these traits should, almost by
definition, be able to influence others. Thus, callousunemotional and grandiose-manipulative traits
might enhance peer influence.
Targets’ traits
Concerning targets’ traits, the most plausible predictions are that callous-unemotional and grandiose-manipulative traits would diminish peer
influence on targets’ delinquency. Predictions about
callous-unemotional traits rest, in part, on findings
about parenting. In several studies, poor parenting
was linked to conduct problems for youths low on
callous-unemotional traits, but not for those who
were high (Edens, Skopp, & Cahill, 2008; Oxford,
Cavell, & Hughes, 2003; Wootton, Frick, Shelton, &
Silverthorn, 1997). These studies were crosssectional, so different interpretations are possible,
but if the authors were correct in concluding that
youths high on callous-unemotional traits were
unresponsive to parental influence, then these
youths might be unreceptive to peer influence, as
well. Additional arguments can be made about
grandiose-manipulative and callous-unemotional
traits based on the literature on susceptibility to peer
influence. Being high on these traits implies high
self-esteem, which, according to previous findings
(Bámaca & Umana-Taylor, 2006; Fletcher et al.,
1995), should mean low susceptibility to peer pressure and low peer influence. Furthermore, those who
are high on callous-unemotional traits are likely to
be low on anxiety, including social anxiety, which
has been shown to diminish peer influence (Cohen &
Prinstein, 2006). Thus, targets’ callous-unemotional
or grandiose-manipulative traits might reduce peer
influence on targets’ delinquency.
In short, there are reasons to expect that peers’
psychopathic traits might either increase or reduce
their influence on targets’ delinquency, and that
targets’ psychopathic traits might reduce their tendencies to be influenced. To date, however, these
traits have not been examined as possible moderators of influence.
In this study, we examined the psychopathic traits
of both peers and targets as moderators of peer
influence on delinquency. We used five waves of
longitudinal data representing peer ties among one
cohort in a community sample. Peer nominations
were not limited to the school context, but included
peers outside of school, because delinquent youths
(Dishion, Spracklen, Andrews, & Patterson, 1996)
2011 The Authors. Journal of Child Psychology and Psychiatry 2011 Association for Child and Adolescent Mental Health.
828
Margaret Kerr, Maarten Van Zalk, and Håkan Stattin
J Child Psychol Psychiatry 2012; 53(8): 826–35
and youths high on psychopathic traits (Muñoz
et al., 2008) tend to name out-of-school peers. Using
a network-analytic technique that controls for
structural features of the network and both target
and peer selection effects, we addressed two major
questions: (a) do targets’ psychopathic traits moderate peer influence on targets’ delinquency and
(b) do peers’ psychopathic traits moderate peer
influence on targets’ delinquency? To answer these
questions, we looked at interactions between peers’
delinquency and targets’ or peers’ psychopathic
traits in predicting changes in targets’ delinquency
over time. Because of the paucity of prior studies, we
did not formulate specific hypotheses.
Delinquency. Delinquency was measured at each
wave with 22 items similar to other commonly used,
validated, self-report measures (e.g. Haynie, 2001).
Items referred to behaviors during the past year, ranging
from acts of vandalism to shoplifting or breaking into a
building. Each item was rated on a 5-point scale ranging
from no, it has never happened (0) to more than 10 times
(4). The Cronbach’s alphas ranged from .93 to .95 across
measurements. In our analyses, changes in delinquency
were treated as ordinal categorical values (see Results
section for details). We, therefore, categorized the
delinquency scores into five groups: 0 (no delinquent
act; 35.1%–49.2% of the sample), 1 (1 delinquent act;
18.2%–28.8%), 2 (2–3 delinquent acts; 17.7%–29.54%),
3 (4–10 delinquent acts; 8.76%–14.54%), and 4 (more
than 10 delinquent acts; 4.2%–17.3%).
Method
Psychopathic traits. Adolescent psychopathic traits
were measured at each wave with the youth psychopathic traits inventory (YPI: Andershed, Kerr et al.,
2002), a self-report instrument with established reliability and construct validity (Andershed, Kerr et al.,
2002; Declercq, Markey, Vandist, & Verhaeghe, 2009;
Poythress, Dembo, Wareham, & Greenbaum, 2006;
Skeem & Cauffman, 2003). We used three YPI dimension scores, which were calculated as mean values of
the scores from the subscales making up the dimensions.
The grandiose-manipulative dimension comprised 20
items, equally divided among four subscales: Dishonest Charm, Grandiosity, Lying, and Manipulation.
Items included: ‘I have the ability to con people by
using my charm and my smile’ and ‘Sometimes I find
myself lying without any particular reason’. The Cronbach’s alphas ranged from .87 to .93 across measurements.
The callous-unemotional dimension comprised 15
items from three subscales: Unemotionality, Remorselessness, and Callousness. Items included: ‘I think that
crying is a sign of weakness, even if no one sees you’
and ‘I usually feel calm when other people are scared’.
The Cronbach’s alphas ranged from .88 to .89 across
measurements.
The impulsive-irresponsible dimension included 15
items for impulsiveness, thrill-seeking, and irresponsibility. Items included: ‘I prefer to spend my money right
away rather than save it’ and ‘I have probably skipped
school or work more than most other people’. The
Cronbach’s alphas ranged from .90 to .93 across measurements. These three dimensions were significantly
and substantially correlated with each other at Times 1
through 5 (rs from .31 to .65, ps < .01).
All within- and across-time correlations between the
three psychopathic-trait dimensions and delinquency
at all five waves are shown in a table in Appendix 1.
Most of the correlations are in the range of .30–.50,
showing considerable temporal stability of the traits
and correlations between the traits and delinquency
that are substantial, but not high enough to prevent our
using psychopathic traits as moderators.
Participants
Participants were from a community-based, cohortsequential study in a medium-sized city in Western
Europe (total population 26,000). All 4th- through
12th-grade classes in the city participated. Annual
assessments were conducted over five measurements.
To form the network used in these analyses, we began
with all 8th-graders in the dataset at Wave 1 (n = 290),
which amounted to 91% of all 317 8th-graders registered in the schools. Six failed to nominate any peers
and 7 failed to provide data on the other measures,
leaving 277 (128 girls, 149 boys; Mage = 14.28), or 87%
of the target sample. After including all additional peers
these adolescents nominated at each of five waves, the
network consisted of 847 (346 girls, 501 boys;
Mage = 14.32). Thus, the network consisted of 87% of all
8th-graders in the community at Wave 1, along with
their different-aged peers at each wave.
Procedure
Data collections took place during school hours,
administered by trained research assistants. Students
were informed that their participation was voluntary
and their answers would never be shown to parents,
teachers, or anyone else. Parents were informed about
the study via letters and community-based meetings.
Before each wave, parents received new information
and a pre-paid card to return if they did not want their
adolescent to participate. Only 1% of parents did so.
The study was approved by the Ethics Review Board at
Örebro University, Sweden (approval# 020422).
Measures
Peer nominations. At each wave, adolescents were
asked to identify: (a) up to three of their most important
peers, (b) up to 10 peers with whom they spent time in
school, and (c) up to 10 peers with whom they spent
time outside of school. All of these were used in the
network analyses. We identified the nonoverlapping
peers at each wave, which averaged from 3.2 to 4.6.
From one measurement to the next, 36%–41% of all
peer ties in the network were formed, 26%–31% ended,
and 30%–33% remained stable.
Analyses
To examine selection and influence processes simultaneously, we used the simulation investigation for
2011 The Authors. Journal of Child Psychology and Psychiatry 2011 Association for Child and Adolescent Mental Health.
doi:10.1111/j.1469-7610.2011.02492.x
Psychopathic traits moderate peer influence on delinquency
empirical network analyses (SIENA) software (Snijders,
2001; Snijders, Steglich, & Schweinberger, 2007). In
the SIENA analyses, annual changes in friendship
nominations were used to estimate selection effects
across the four time intervals. Likewise, annual changes in targets’ and peers’ delinquency and psychopathic
traits were used to estimate influence and moderating
effects over each of the time intervals. From these
changes, SIENA provides overall estimates of influence
and moderation for the relevant variables (for technical
details regarding the estimation of selection and influence processes, see Snijders, Steglich, & Van de Bunt,
2010). SIENA is currently the only program available
that can assess influence processes in networks of
multiple relationships while controlling for various
selection effects. If more than 8% of information about
nominations, delinquency, or psychopathic traits was
missing, scores were imputed according to the procedure developed and validated by Huisman and Snijders
(2003).
Results
Effects controlled in the model
In the model examining our main research question
about moderating effects, a number of other effects
were controlled. They comprised selection effects
and main influence effects. The results are shown in
Table 1.
Selection effects. Selection effects examined to
what extent variables predicted that a non-peer dyad
would change to a peer dyad across time. Effects
were estimated across all five measurements, and
controlled for reciprocation or non-reciprocation of
the dyad. Selection effects included effects of the
network and the other variables.
Shown first in Table 1 are effects of the network
structure on selection (see Appendix 2 for further
descriptions of effects). The significant outdegree
parameter indicated that adolescents were selective
when forming new relationships. The reciprocated
relationship effect showed that adolescents tended to
reciprocate nominations. The triadic relationship
effect showed that adolescents tended to select the
peers of their peers over time. Thus, effects of the
network structure on selection were significant and,
therefore, needed to be controlled.
Below the network effects in Table 1 are the effects
on selection of the other variables used in the study.
For each variable, we examined three different types
of effects: selection similarity, targets select, and
peers select. Selection similarity tested to what
degree similarity between all non-peers predicted
(a) selecting a peer or (b) not selecting a peer. The
other two effects controlled for the effects of mean
levels of the variables on selection. Targets select
concerned how targets’ mean levels of the variable
predicted their selecting peers, and peers select
concerned how targets’ mean levels of the variable
predicted their being selected by peers. As shown in
829
Table 1 Unstandardized estimates and standard errors from
the simulation investigation for empirical network analyses
(SIENA) model
bk
Selection
Outdegree
Reciprocated relationship
Triadic relationship
Gender:
Selection similarity
Targets select (0 = boy, 1 = girl)
Peers select
Age:
Selection similarity
Targets select
Peers select
Delinquency:
Selection similarity
Targets select
Peers select
Grandiose-manipulative:
Selection similarity
Targets select
Peers select
Callous-unemotional:
Selection similarity
Targets select
Peers select
Impulsive-irresponsible:
Selection similarity
Targets select
Peers select
Influence
Linear shape delinquency
Quadratic shape delinquency
Targets’ characteristics:
Gender
Age
Grandiose-manipulative
Callous-unemotional
Impulsive-irresponsible
Peers’ characteristics:
Average delinquency
Grandiose-manipulative
Callous-unemotional
Impulsive-irresponsible
Interactions:
Targets’ grandiose-manipulative
· Peers’ delinquency
Targets’ callous-unemotional
· Peers’ delinquency
Targets’ impulsive-irresponsible
· Peers’ delinquency
Peers’ grandiose-manipulative
· Peers’ delinquency
Peers’ callous-unemotional
· Peers’ delinquency
Peers’ impulsive-irresponsible
· Peers’ delinquency
SE
)3.59***
2.81***
.42***
.03
.04
.01
.68***
.12***
).16***
.02
.03
.02
2.27***
)0.05***
)0.02
.11
<.01
.02
1.53***
)0.21***
0.31***
.33
.01
.01
)0.01
)0.01
0.01
.04
.01
.01
0.01
)0.01
0.01
.04
.01
.01
0.14***
)0.04***
0.03**
.04
.01
.01
)0.05***
<0.01
.01
<.01
)0.03***
)0.06***
)0.01
0.01
0.03***
.01
.01
<.01
<.01
<.01
1.61***
<0.01
<0.01
<0.01
.75
<.01
<.01
<.01
)2.54***
.56
)2.21***
.52
)0.74
.50
1.24***
.04
1.27***
.36
)0.34
.97
**p < .01; ***p < .001.
Table 1, after controlling for the effects of mean levels of these variables on selection, we found selection
similarity effects for age, gender, delinquency, and
impulsive-irresponsible traits. Being similar on
these characteristics predicted a greater likelihood of
non-peers becoming peers.
2011 The Authors. Journal of Child Psychology and Psychiatry 2011 Association for Child and Adolescent Mental Health.
830
Margaret Kerr, Maarten Van Zalk, and Håkan Stattin
Main influence effects. For influence processes,
the dependent variable was changes in adolescents’
delinquency. SIENA treats changes in delinquency
as ordinal categorical values (Snijders et al., 2007)
and models changes in peers’ and targets’ delinquency as two interdependent processes, thereby
controlling each for the other. Participants are
assumed to be mutually dependent because each
participant is both a target and a peer. This mutual
dependence is mediated by effects of the network
structure (such as reciprocated relationships and
triadic relationships). This way, all selection and
influence effects are adjusted for overlap in the
network (for details, see Snijders, 2001). We also
controlled for trends in delinquency by including
the linear and quadratic tendencies of change
(Snijders et al., 2010). As shown in the table,
significant effects appeared for the linear tendency of
delinquency; targets’ gender, age, and impulsiveirresponsible traits; and peers’ average delinquency.
Moderating role of psychopathic traits
Do peers’ or targets’ psychopathic traits moderate
peer influence on delinquency? As revealed by the
significant interaction effects in the lower part of
Table 1, for targets’ and peers’ grandiose-manipulative traits and callous-unemotional traits the answer
is yes. To probe these significant interactions, we
used post-hoc multiple-groups tests (Snijders et al.,
2010) to compare effect sizes of peers’ delinquency
on adolescent delinquency within groups with different levels of psychopathic traits. To form the
groups, we divided adolescents into those who
scored low (at least one standard deviation below the
mean across measurements), medium (between one
standard deviation below and above the mean), and
high (at least one standard deviation above the mean
across measurements). Because no significant differences were found between the low and medium
groups in any of the comparisons, we collapsed
them.
Targets’ traits. The moderating effects of targets’
callous-unemotional and grandiose-manipulative
(a)
J Child Psychol Psychiatry 2012; 53(8): 826–35
traits are plotted in Figure 1. As the figure reveals,
peers’ delinquency predicted targets’ delinquency for
both high and low/medium groups, but the effects
were significantly larger (p < .01) for targets with
low/medium levels of callous-unemotional and
grandiose-manipulative traits (b^k = 2.12, SE = .65,
p < .01 and b^k = 2.31, SE = .71, p < .01 for callousunemotional and grandiose-manipulative traits,
respectively) than for those with high levels (b^k = .97,
SE = .47, p < .01 and b^k = 1.20, SE = .52, p < .01 for
callous-unemotional and grandiose-manipulative
traits, respectively). Thus, targets high on callousunemotional and grandiose-manipulative traits were
less affected by their peers’ delinquency than those
who were low on these traits.
Peers’ traits. The moderating effects of peers’ callous-unemotional and grandiose-manipulative traits
are plotted in Figure 2. Again, peers’ delinquency
predicted targets’ delinquency for both groups, but
the effects were significantly larger (p < .01) if peers
were high on callous-unemotional or grandiosemanipulative traits (b^k = 2.31, SE = .71, p < .01 and
b^k = 1.99, SE = .59, p < .01 for callous-unemotional
and grandiose-manipulative traits, respectively)
than if they were low/medium (b^k = 1.20, SE = .52,
p < .01 and b^k = 1.11, SE = .39, p < .01 for callousunemotional and grandiose-manipulative traits,
respectively). Thus, peers’ callous-unemotional and
grandiose-manipulative traits seemed to enhance
their ability to influence targets’ delinquency.
Additional analyses
Developmental effects. We examined possible
developmental variations in influence by calculating
interactions between a variable representing the five
waves and the interactions between psychopathic
traits and peers’ delinquency. None of these interactions was significant (allb^k < .02, SE. < .05,
p > .10). Thus, these processes did not vary significantly across the 5 years.
Gender effects. For both peers’ and targets’ traits,
we tested for gender effects by including in the model
(b)
Figure 1 (a, b) Interaction effects showing the moderating role of target’s traits: targets’ CU traits · Peers’ delinquency (a) and targets’
GM traits · peers’ delinquency (b) predicting targets’ delinquency. CU, callous-unemotional; GM, grandiose-manipulative
2011 The Authors. Journal of Child Psychology and Psychiatry 2011 Association for Child and Adolescent Mental Health.
doi:10.1111/j.1469-7610.2011.02492.x
Psychopathic traits moderate peer influence on delinquency
(a)
831
(b)
Figure 2 (a, b) Interaction effects showing the moderating role of peers’ traits: peers’ CU traits · peers’ delinquency (a) and Peers’ GM
traits · peers’ delinquency (b) predicting targets’ delinquency. CU, callous-unemotional; GM, grandiose-manipulative
the three-way interactions, Gender · Peers’ delinquency · Peers’ psychopathic traits and Gender ·
Peers’ delinquency · Targets’ psychopathic traits. All
relevant two-way interactions were included, as
well. None of the three-way effects was significant
(effect sizes < .03, SE < .10, p > .10 and effect sizes
< .06, SE < .14, p > .10 for peers’ and targets’ traits,
respectively). Thus, the moderating roles of peers’
and targets’ traits were similar for boys and for girls.
Discussion
Peer influence on delinquency is well established,
but little has been known about characteristics of
adolescents or their peers that enhance or diminish
peer influence. The current results suggest that how
much adolescents are influenced by their peers’
delinquency depends on both their peers’ and their
own psychopathic personality traits. In short, the
higher adolescents are on psychopathic traits, the
less they seem to be influenced by their peers’
delinquency, but the more they seem to influence
others.
This study makes several unique contributions to
the literature on peer influence. It is the first to
show that adolescents’ psychopathic personality
traits exacerbate deviant peer influence. Because
results appeared for targets’ traits as well as peers’,
an important practical implication is that if welladjusted and deviant youths are brought together as
part of an intervention, psychopathic traits should
be assessed and considered as a potential moderator of the intervention effect. Another of this
study’s contributions is demonstrating the unique
effects of grandiose-manipulative traits. Although
callous-unemotional traits might be most central to
identifying a psychopathy-like subgroup of conductdisordered youth (for a review, see Frick & White,
2008), grandiose-manipulative traits have been
shown to moderate the link between parenting and
conduct problems differently from callous-unemotional traits (Edens et al., 2008). The current study
is the first to show a unique role for grandiosemanipulative traits in deviant peer processes. A
third unique contribution of the current study is the
use of a network approach to look at moderation of
peer influence. The approach we used simultaneously controls for network effects, such as a
greater likelihood of forming a tie with a peer of
one’s peers; other selection effects; and nonindependence in the data caused by an individual’s
being both a target and a peer or being named as a
peer by multiple peers. Previous studies of moderation have not controlled for these effects. Thus, the
current study contributes unique, new knowledge
to this nascent area of research.
Returning to the theoretical ideas offered in the
Introduction, the results do not paint a picture of
youths high on psychopathic traits being socially
isolated, lone offenders (see Quay, 1993), and this
differs from the classic portrait of adult criminal
psychopaths (Cleckley, 1976). Rather, they seem to
be integrated into peer groups, as shown in this and
previous studies (Kimonis et al., 2004; Muñoz et al.,
2008), and influential, as shown in this study. Their
influence seems to be due to both their cool-headed
ability to plan criminal activities (i.e. callousunemotional traits) and their ability to manipulate
and dominate others (i.e. grandiose-manipulative
traits). One should bear in mind, however, that the
current study used a community sample, and some
of the most highly criminal adolescents might have
been removed from the sample by the justice system.
Just as the results paint a picture of youths high
on psychopathic traits being influential in delinquent peer groups, however, they also suggest that
these youths are relatively insensitive to the influence of others. Again, this seems to be because of
both their grandiosity and their callous-unemotionality. This finding extends those in which poor parenting was less linked to conduct problems for
youths high on callous-unemotional traits than for
those who were low (Edens et al., 2008; Oxford et al.,
2003; Wootton et al., 1997); however, the current
findings are more easily interpretable because they
are based on longitudinal data. The original suggestion in this line of research was that for those
high on callous-unemotional traits, conduct
2011 The Authors. Journal of Child Psychology and Psychiatry 2011 Association for Child and Adolescent Mental Health.
832
Margaret Kerr, Maarten Van Zalk, and Håkan Stattin
problems originate with temperamental fearlessness
and are relatively unaffected by poor parenting
(Wootton et al., 1997). That idea and the current
findings are both consistent with research showing
that psychopathic traits have a strong genetic component (e.g. Larsson, Andershed, & Lichtenstein,
2006). In short, there is mounting evidence that,
compared with other youths, those who are high on
psychopathic traits are little influenced by socialization.
This study has limitations that bear mentioning.
First, we did not examine interactions between the
psychopathic-trait dimensions, and it is possible
that one dimension might moderate the effects of
another (e.g. being high on callous-unemotional
traits might intensify the effects of grandiosity). In
addition, we did not consider the quality of relationships. Because peer influence is stronger in
high-quality than low-quality relationships (Selfhout
et al., 2008), moderation might also be stronger.
Also, by focusing on peer processes, we did not
examine those without peers. Perhaps those who
nominate peers differ from those who do not, and
Quay’s suggestions hold for those who do not. Previous studies, however, have not found those high
on psychopathic traits to be without peers (Kimonis
et al., 2004; Muñoz et al., 2008), which reduces
concern about this limitation. Still, these issues
should be addressed in future research. Finally, the
terms selection and influence are commonly used in
the peer literature and in SIENA terminology, as
they are in this study. Although these findings are
based on longitudinal data with more factors controlled than in most prior research, one should bear
in mind that the data are, nonetheless, correlational.
Despite these limitations, the study has a number
of strengths. One is the use of a network approach
and five waves of longitudinal data. For reasons
outlined above, the network approach provides a
more stringent test of selection and influence than is
possible with other methods. Using multiple waves of
longitudinal data also increases confidence in the
results, because the estimates of peer influence are
more robust than with fewer waves. Two other
strengths that go hand in hand are including peers
outside of school and using independent reports of
J Child Psychol Psychiatry 2012; 53(8): 826–35
peers’ delinquency. Most studies of peer influence on
delinquency have relied on youths’ own reports of
their peers’ delinquency, which tend to be biased
(Prinstein & Wang, 2005). Even when using independent reports and a network approach, they have
typically focused on peers in school (e.g. Baerveldt,
Völker, & Van Rossem, 2008; Haynie, 2001), but
although the majority of peers named by adolescents
will be in the school or classroom (Ennett & Bauman,
1994), the minority that are not could be the most
important deviant influences (see Kerr, Stattin, &
Kiesner, 2007). The whole-community design of this
study enabled us to include peers outside of school
and gather independent reports of their psychopathic traits and delinquency. These features,
together with the network analytic approach, give us
confidence in the results.
The influence of deviant peers on delinquency
development is well established, theoretically and
empirically. In the literature, peers’ deviance has
typically meant peers’ delinquency. The current results further specify the definition of deviance and
the conditions under which deviant influence is most
likely. Deviant peer groups, it seems, can be more or
less influential depending on the characteristics of
the peer group members. In a broader perspective,
the current results reinforce an increasingly evident
contrast between socially isolated adult psychopathic criminals (see Cleckley, 1976) and what
appear to be socially integrated, influential adolescent delinquents who are high on psychopathic
traits. Whether and how this might be important in
the development of psychopathy remains to be discovered.
Acknowledgements
The longitudinal study and Maarten Van Zalk’s work on
this manuscript were supported by grants from the
Swedish Research Council.
Correspondence to
Margaret Kerr, Örebro University, Youth and Society
(YeS), Center for Developmental Research, 701 82
Örebro, Sweden; Tel: +46 (0)19 303026; Email:
[email protected]
Key points
• Peer influence on adolescents’ delinquency is well established in the developmental psychology and criminology literatures, but little is known about moderators of influence.
• In the current study, we have shown that the grandiose-manipulative and callous-unemotional dimensions of
the psychopathic personality profile moderate peer influence. These traits enhance adolescents’ influence on
others and make them less easily influenced by others.
• These findings suggest that deviant peer groups can be more or less influential depending on the characteristics of the peer group members.
2011 The Authors. Journal of Child Psychology and Psychiatry 2011 Association for Child and Adolescent Mental Health.
doi:10.1111/j.1469-7610.2011.02492.x
Psychopathic traits moderate peer influence on delinquency
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Accepted for publication: 12 September 2011
Published online: 26 November 2011
Appendix 1 Correlations between psychopathic traits and delinquency across five waves
Grandiose-manipulative
T1
T2
Grandiose-manipulative
T1
–
T2
.57***
–
T3
.44***
.62***
T4
.46***
.57***
T5
.40***
.48***
Callous-unemotional
T1
.40***
.34***
T2
.40***
.45***
T3
.28***
.43***
T4
.30***
.41***
T5
.34***
.36***
Impulsive-irresponsible
T1
.44***
.30***
T2
.31***
.51***
T3
.31***
.40***
T4
.38***
.43***
T5
.30***
.36***
Delinquency
T1
.30***
.26***
T2
.32***
.35***
T3
.24***
.30***
T4
.24***
.34***
T5
.27***
.29***
T3
T4
–
.67***
.54***
–
.57***
.29***
.33***
.68***
.45***
.37**
Callous-unemotional
T5
T1
T2
T3
T4
T5
.26***
.31***
.44***
.70***
.43***
.20***
.29***
.47***
.39***
.76***
–
.55***
.39***
.31***
.21***
–
.49***
.40***
.23***
–
.50***
.46***
–
.47***
.26***
.35***
.56***
.50***
.38***
.28***
.36***
.39***
.62***
.44***
.18**
.32***
.35***
.30***
.65***
.33***
.24**
.20**
.23***
.22**
.21***
.37***
.26***
.18**
.16**
.22**
.33***
.48***
.30***
.37***
.23***
.34***
.32***
.56***
.34***
.16**
.27**
.36***
.25***
.62***
.20**
.30***
.32***
.34***
.37***
.24***
.32***
.35***
.42***
.37***
.11*
.21**
.21**
.24***
.42***
.14**
.19**
.20**
.33***
.30***
.06*
.18**
.19**
.18**
.13*
.15**
.27***
.28***
.26***
.34***
.21**
.31***
.31***
.39***
.36***
.06*
.15**
.16**
.20**
.37***
–
–
2011 The Authors. Journal of Child Psychology and Psychiatry 2011 Association for Child and Adolescent Mental Health.
doi:10.1111/j.1469-7610.2011.02492.x
Psychopathic traits moderate peer influence on delinquency
835
Appendix 1 Continued
Impulsive-irresponsible
T1
T2
Impulsive-irresponsible
T1
–
T2
.58***
–
T3
.43***
.60***
T4
.42***
.57***
T5
.39***
.43***
Delinquency
T1
.32***
.25***
T2
.33***
.40***
T3
.24***
.35***
T4
.27***
.37***
T5
.30***
.39***
T3
T4
–
.67***
.50***
–
.58***
.31***
.32***
.38***
.35***
.43**
.31***
.35***
.41***
.52***
.45***
Delinquency
T5
T1
T2
T3
T4
T5
.25***
.31***
.39***
.40***
.52***
–
.58***
.49***
.41***
.34***
–
.62***
.47***
.47***
–
.57***
.56***
–
.64***
–
–
*p < .05; **p < .01; ***p < .001.
Appendix 2 Terminology of current study, corresponding simulation investigation for empirical network analyses
(SIENA) terms, and conceptual meaning in this study.
Term for effect in
current study
Selection effects
Selection
Specific selection effects:
Outdegree
SIENA term
Evaluation
function
The extent to which independent variables predict a
change in friendships from being absent to being
present (i.e. formation of friends)
Outdegree
Tendency to randomly form friendships (i.e. negative
effects indicate tendency to be selective when forming
friendships)
Tendency to form reciprocated friendships
Tendency to form triadic friendships (i.e. selecting the
friends of friends)
Tendency for targets to form friendships based on
targets’ mean level on independent variable
Tendency for friends to select targets based on targets’
mean level on independent variable
Tendency for targets and friends to select each other
based on similarity between targets and friends on the
independent variable
Reciprocated relationships
Triadic relationships
Reciprocity
Transitivity
(Independent variable):
Targets select
(Independent variable):
Friends select
(independent variable):
Selection similarity
Evaluation
Ego
Evaluation
Alter
Evaluation
similarity
Influence effects
Influence
Specific influence effects:
Linear shape delinquency
Quadratic shape delinquency
Targets’ characteristics
Friends’ characteristics
Conceptual meaninga
Behavioral
function
Linear shape
Quadratic
shape
Behavioral
function
Behavioral
function
The extent to which characteristics of friends and
targets predict changes in delinquency
Tendency of the dependent variable delinquency to
change in a linear >fashion over time
Tendency of the dependent variable delinquency to
change in a quadratic fashion over time
The extent to which targets’ characteristics predict
changes in targets’ delinquency
The extent to which friends’ characteristics predict
changes in targets’ delinquency, and vice versa
a
Conceptual meaning refers to the interpretation of the selection effects only in the current study. With other
variables and/or effects included in SIENA models, the conceptual meaning may change (Snijders et al., 2010).
2011 The Authors. Journal of Child Psychology and Psychiatry 2011 Association for Child and Adolescent Mental Health.