AGGRESSIVE BEHAVIOR
Volume 36, pages 195–204 (2010)
Social Group Norms, School Norms, and Children’s
Aggressive Intentions
Christian Nipedal1, Drew Nesdale1, and Melanie Killen2
1
2
School of Psychology, Griffith University, Queensland, Australia
Department of Human Development, University of Maryland, Maryland
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This study examined whether the effect of social group norms on 7- and 10-year-old children’s aggression can be moderated or
extinguished by contrary school norms. Children (n 5 384) participated in a simulation in which they were assigned membership in a
social group for a drawing competition against an outgroup. Participants learnt that their group had a norm of inclusion, exclusion,
or exclusion-plus-relational aggression, toward non-group members, and that the school either had a norm of inclusion, or no such
norm. Findings indicated that group norms influenced the participants’ direct and indirect aggressive intentions, but that the school
norm moderated the group norm effect, with the school’s norm effect tending to be greater for indirect vs. direct aggression, males
vs. females, and younger vs. older participants. Discussion focused on how school norms can be developed, endorsed, and presented
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so that they have their most lasting effect on children. Aggr. Behav. 36:195–204, 2010.
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Keywords: social groups; group norms; aggression; children; school norms
Research on children’s aggression and bullying,
during middle childhood and early adolescence, has
revealed that such episodes frequently involve the
presence of peers rather than simply an individual
protagonist [Atlas and Pepler, 1998; Salmivalli et al.,
1996]. Whereas much of this research has focused on
direct, overt, or physical aggression (e.g., hitting,
pushing, taking things, verbal abuse), other research
has examined aggression that is more indirect, much
of it focusing on relationships as the mechanism for
the delivery of harm [Zimmer-Gembeck et al., 2005].
This type of aversive event includes behavior, such
as exclusion, manipulation, gossip, and deception.
Although it might be assumed that the presence of
others simply reflects curiosity and/or excitement,
several researchers have proposed that young children’s participation in aggression and bullying
episodes might be influenced by their involvement
in particular social groups [e.g., DeRosier et al.,
1994]. This issue has received surprisingly little
research attention, despite the increasing recognition
that inclusion and belonging are critically important
to people, even young children [Nesdale, 2007].
Indeed, it has been argued that individuals probably
have an inborn fundamental need to belong that
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motivates them to establish friendships and to
become members of social groups [Baumeister and
Leary, 1995].
Consistent with this approach, several recent
studies have explored the impact of group norms
(i.e., the attitudes, beliefs, and behaviors considered
appropriate to be displayed by the members of a
particular group) on children’s intentions to engage
in direct and indirect forms of aggressive behavior
[e.g., Boiven et al., 1995; Henry, 2001; Henry et al.,
2000; Nesdale et al., in press; Salmivalli and Voeten,
2004; Stormshak et al., 1999; Wright et al., 1986].
This study sought to extend this research by
shedding light on the situation in which the norms
of the child’s social group conflicted with those of
the community. In particular, the research examined
whether social group norms that endorse exclusion
Correspondence to: Drew Nesdale, School of Psychology, Griffith
University, Gold Coast Campus, Parklands Drive, Southport. QLD.
4215, Australia. E-mail: d.nesdale@griffith.edu.au
Received 2 September 2009; Revised 25 January 2010; Accepted 2
February 2010
Published online 18 March 2010 in Wiley InterScience (www.
interscience.wiley.com). DOI: 10.1002/ab.20342
196 Nipedal et al.
are extinguished or, at least, moderated by community norms that oppose such behavior.
Children and Social Groups
Research has shown that, certainly by school age,
children seek to be members of social groups and
that they reveal a tendency to like and to see
themselves as similar to ingroup compared with
outgroup members [Bigler, 1995; Bigler et al., 1997;
Nesdale and Flesser, 2001; Nesdale et al., 2005a,b,c],
and that their acceptance by a social group
contributes to their sense of self-worth [Verkuyten,
2001, 2007]. In addition, children have a strong bias
toward their ingroup when they are required to
make choices, indicate preferences, or allocate
rewards between the ingroup and an outgroup,
and they display ingroup positivity vs. outgroup
negativity in their trait attributions [see, Aboud,
1988; Nesdale, 2001, for reviews].
Whereas the preceding findings indicate that peer
group membership is exceedingly important to
children, they also suggest that the peer group has
the potential to exert considerable influence on
group members. A primary mechanism through
which this is likely to be achieved is to be found in
the norms of the group—the expectations shared by
group members concerning the appropriate attitudes, beliefs, and behaviors to be displayed by
group members. Consistent with this, Nesdale et al.
[2005a,b,c] reported that children were more positive
toward outgroup members, when the group’s norms
endorsed inclusion vs. rejection, whereas Nesdale
et al. [2005a,b,c] found that a group norm of
exclusion negated individual children’s tendencies
toward empathy for the members of ethnic minority
outgroups. In addition, research has shown that,
from 5 years onward, children show less liking for
ingroup members who do not conform to group
norms [Abrams et al., 2003, 2004].
Group Norms and Aggression
Consistent with the foregoing, some research has
also examined the impact of group norms on
children’s aversive behaviors, such as aggression
and bullying. This research has revealed that classroom norms (i.e., those held by most or all members
of a class) influence children’s aggressive attitudes
and behavior [e.g., Henry, 2001; Henry et al., 2000;
Salmivalli and Voeten, 2004; Stormshak et al., 1999].
Other studies have also reported that aggressive
behavior was viewed more positively by other group
members when aggression was normative vs. nonnormative [Boiven et al., 1995; Wright et al., 1986].
Aggr. Behav.
However, few attempts have been made to
examine the impact of peer group, rather than
classroom, norms on group members’ aggressive
and bullying behavior. In one such study, Ojala and
Nesdale [2004] found that preadolescent ingroup
members considered bullying to be much more
acceptable when it was consistent with group norms,
and when it was directed at an outgroup member
who represented a threat to the ingroup. In addition,
research has shown that participants’ bullying
intentions were greater when the ingroup had
a norm of outgroup dislike vs. outgroup liking
[Nesdale et al., 2008].
Given that children form friendships with those
who are similar to them in terms of characteristics,
such as age, gender, and ethnicity, as well as in
behaviors and activities [Cairns et al., 1989; Rubin
et al., 1998], it is not surprising that other research
has reported that similarities in behaviors, such as
aggression, also occur from an early age [Cairns
et al., 1989; Kupersmidt et al., 1995]. Consistent
with this, Duffy and Nesdale [2009] found that the
naturalistic groups of children in middle childhood
that displayed most aggression, and bullying had
group norms that endorsed this behavior, whereas
groups that did not display such behavior did not
have norms that endorsed the behavior.
The preceding findings indicate that group norms
typically exert a powerful influence on the attitudes,
beliefs, and behaviors of group members, even when
they are young children in the middle childhood
years. Moreover, the findings indicate that children’s
social group norms can even enhance their
preparedness to engage in direct and/or indirect
aggression toward other children. Although
disturbing, this conclusion is perhaps unsurprising
given the critical importance that children seem to
place on being accepted by, and belonging to, a social
group [Baumeister and Leary, 1995; Nesdale, 2007].
Viewed together, such findings serve to emphasize
the difficulties faced by community and school
authorities, in attempting to moderate or extinguish
children’s aggression and bullying. In short, if
children’s social groups have norms that directly
or indirectly endorse aggressive and bullying behavior, the findings suggest that many children will
follow this prescription.
One response to the incidence of children’s aggression and bullying by school authorities has been the
specification of rules or norms concerning appropriate attitudes, beliefs, and behaviors to be displayed
by children toward each other, as well as toward the
teachers and school administrators. However, little
research has actually assessed the impact of school
Social Group Norms, School Norms 197
norms or rules that proscribe such behavior. In short,
do children attend to such proscriptions and does it
influence their subsequent behavior. Furthermore, if
an injunction by the school not to engage in a
particular behavior (e.g., aggression, bullying, intergroup prejudice) conflicts with a norm endorsed by
the child’s social group, to which does the child
respond—the group norm or the school norm?
The likely outcome is not clearcut, with at least
three alternatives being possible. First, the group
norm could take precedence over the school norm in
influencing the level of the child’s aggression.
Consistent with this is the research revealing the
strong effect exerted by social groups on the
behavior of members via their group norms. Moreover, because children are apparently very oriented
toward being accepted by, and belonging to, social
groups, it is plausible that they would be considerably influenced by their group norms, to the
detriment of the school norm.
However, a second alternative is that the school
norm could effectively extinguish the group norm and
hence reduce the aggression that would otherwise
occur. Consistent with this possibility is evidence that,
from school age onwards, children show a growing
understanding of, and tendency to engage in, selfpresentational behavior that puts them in the best
possible light, especially when they are being observed
by adults [e.g., Aloise-Young, 1993; Banerjee, 2002;
Banerjee and Yuill, 1999; Bennett and Yeeles, 1990].
Furthermore, children have an increasing awareness
that negative attitudes and behaviors, such as
intergroup prejudice, aggression, and bullying, are
considered to be unacceptable and inappropriate by
teachers and parents [e.g., Brown and Bigler, 2004;
Greenwald and Banaji, 1995; Killen et al., 2001;
Rutland, 1999; Rutland et al., 2005; Theimer et al.,
2001]. Consistent with this, Rutland and colleagues
reported a decrease in children’s negative outgroup
attitudes when they were under adult surveillance
[Rutland, 1999; Rutland et al., 2005].
Finally, in agreement with both the preceding
possibilities, a third alternative is that the participants might be somewhat conflicted in wanting to
conform to both their group’s and the school’s
norms. That is, when the demands of their social
group and the school conflict, children might try to
conform to both the group and social norms, at least
to some extent.
Present Study
This study was designed to examine the relative
influence on young children’s aggression of the
norms of their social group vs. the norms of the
school. To address this issue, the study utilized a
simulation methodology rather than the survey
[Boulton, 1997] and observational [Atlas and Pepler,
1998] methods that have typically been utilized in
research on such topics. This simulation paradigm
has been used in a number of studies on the
development of children’s ethnic prejudice [e.g.,
Nesdale et al., 2005a,b,c], as well as on children’s
aggression [Nesdale et al., 2009] and bullying [Duffy
and Nesdale, 2010; Nesdale et al., 2008].
The essence of this paradigm is that participants
are randomly assigned membership in a peer group
and are asked to role-play participating against
another group in a purported intergroup competition. Although their peer group, and their membership in it, has only a brief existence, participants’
reactions (i.e., attitudes, beliefs, behavior intentions)
can be examined in relation to the ingroup as well as
the outgroup. In particular, these reactions can be
examined under varying conditions of ingroup
membership (e.g., group norms, group membership
position) as well as intergroup relations (e.g., outgroup threat), and other situational contexts. Moreover, the fact that the paradigm allows for the
manipulation of variables relating to the ingroup,
the outgroup, and the context, enables causal
inferences to be drawn, an advantage that is not
afforded to correlational designs. Most important,
however, the findings revealed in these minimal
group studies are remarkably similar to research
findings obtained in studies where children have
been randomly assigned to groups in a naturalistic
setting, and the effects of the group assignments
have been observed over a period of weeks [e.g.,
Bigler, 1995; Bigler et al., 1997; Sherif et al., 1961].
This similarity confirms the external validity of
findings relating to children’s ingroup membership
and its effects that are revealed using the minimal
group paradigm.
Using the group simulation paradigm, participants in this study were randomly assigned to one of
three social group norm conditions (i.e., inclusion
norm, exclusion norm, exclusion-plus-relationalaggression norm). In addition, in a fully crossed
design, each participant was randomly assigned to
one of two school norm conditions. However,
bearing in mind the ethical implications, the children
learnt either that the school had a norm of inclusion
or they received no information concerning the
school’s norm. Thus, whereas group and school
norm coincided for some children (i.e., inclusion
group norm and inclusion school norm), it conflicted for others (i.e., exclusion group and inclusion
Aggr. Behav.
198 Nipedal et al.
school norm; exclusion-plus-relational-bullying
group and inclusion school norm). Finally, to
control for order effects, the timing of delivery of
the school norm message vs. the group norm
message was manipulated, so that half the children
received the group norm information first, whereas
the remaining children received it second.
Three other features of this study are worth
noting. First, the study focused on the impact of
group and school norms on children’s aggressive
intentions, rather than their actual aggressive behavior. This emphasis reflected the fact that a central
issue addressed in the study was the potential causal
effect of group and school norms on children’s
aggression, and that it would have been extremely
difficult as well as ethically irresponsible to allow
children to engage in real acts of aggression in an
experimental study. Accordingly, the study measured the children’s intentions to engage in aggression via their responses to a series of vignettes.
Second, the study measured both the participants’
direct and indirect aggressive intentions. Direct (or
overt or physical) aggression includes acts, such as
hitting, pushing, taking things, and verbal abuse. In
contrast, indirect aggression tends to focus on relationships as the mechanism for the delivery of harm
[Zimmer-Gembeck et al., 2005] and includes aversive
acts, such as deception, exclusion, manipulation, and
gossip. The vignettes used in this study included
measures of the participants’ intentions to engage in
instances of both direct and indirect aggression.
Third, the study included 7 and 10-year-old boys
and girls because of the currently mixed pattern of
findings concerning, on the one hand, the incidence
of direct compared with indirect aggression and
bullying as children increase in age and, on the other
hand, the incidence of these forms of aggression and
bullying by boys vs. girls. Thus, some studies have
reported that more direct than indirect aggression
and bullying is displayed by children at a younger
age [e.g., Bjorkqvist et al., 1992], whereas other
studies have yielded no such difference [Crick et al.,
1997; Ostrov and Crick, 2007]. Similarly, some
studies have reported that girls display more indirect
vs. direct aggression and bullying, whereas boys do
the reverse [Crick et al., 1997; Ostrov and Crick,
2007], although other studies have not found this
effect [e.g., Atlas and Pepler, 1998; Galen and
Underwood, 1997; Little et al., 2003; Salmivalli
and Kaukiainen, 2004]. Including 7 and 10-year-old
boys and girls as participants in this study allowed
for a reexamination of these issues.
In sum, this study examined the effects of social
group and school norms, and the order of their
Aggr. Behav.
presentation, on 7- and 10-year-old male and female
children’s direct and indirect aggressive intentions.
Participants were assigned to a group that had a
norm of inclusion, exclusion, or exclusion-plusrelational aggression, and were informed that the
school had a norm of inclusion or were given no
information about a school norm. Participants
subsequently responded to a series of vignettes
designed to assess their direct and indirect aggressive
intentions toward members of an outgroup.
METHOD
Participants
The sample comprised 384 Anglo-Australian
children (173 males and 213 females), with the
younger age group (196 children; 92 males and 106
females) from grades 1–3 (M 5 7.85, SD 5 0.83) and
the older age group (188 children; 81 males and 107
females) from grades 4–6 (M 5 10.85, SD 5 1.07).
The children attended four primary schools serving
the same lower-middle class community. Children
only participated in the study with parental
approval and the child’s own assent.
Design
The experiment utilized a 2 (participant age:
7 vs. 10) 2 (participant gender) 3 (group norm:
inclusion vs. exclusion vs. exclusion1relational
aggression) 2 (school norm: inclusion vs. no
information) 2 (timing of norm presentation: group
norm first vs. group norm second) 2 (aggression
type: direct vs. indirect) mixed factorial design, with
the last factor measured within subjects. Participants
were randomly assigned to one of the between subject
conditions, with the number of males and females in
each condition approximately equal.
Materials
Group photos. A set of head-and-shoulder
color photos of Anglo-Australian children was used
to present the members of the ingroup and outgroup
to the participants. Within age, gender, and ethnicity, the photos were randomly drawn from a pool
of photos that has been developed and pretested by
the authors, as detailed in earlier reports [Nesdale
et al., 2005a,b,c]. Photos selected were matched for
expression (not smiling) and attractiveness (moderate). Each photo was 150 mm 110 mm and pasted
onto a 200 mm 200 mm white cardboard square.
A board was used to display the photos to the
children in the study. In the first photo set, there
Social Group Norms, School Norms 199
were two centered photos with one empty slot (where
the participant’s photo was to be added), whereas the
second photo set consisted of three photos.
Group norm manipulation. Group norms
were manipulated by having the children listen to a
prerecorded message spoken by a child of the same
age and gender as the child being tested. There were
three different messages recorded for each age and
gender combination, one of inclusion, one of exclusion, and one of exclusion-plus-relational aggression.
Response booklet. A response booklet was
prepared for each participant. The front page
contained brief instructions and some practice
questions. Responses to all questions were given on
5-point scales. The response options on unipolar
scales ranged from 1 (a small amount of the attribute)
to 5 (a large amount of the attribute). The response
options on bipolar scales ranged from 1 (a negative
response) to 3 (a neutral response) to 5 (a positive
response). Each point on each scale was labeled
appropriately. The response booklet contained filler
items as well as the measures of aggressive intentions.
Aggressive intentions. After the variables
were manipulated, each participant’s aggressive intentions were measured on a scale devised by the authors
[Duffy and Nesdale, 2010]. Participants responded to
five vignettes, each outlining a situation involving the
participant on the day of the drawing competition.
The purpose of the vignettes was to provide a
situation in which the participants’ direct and indirect
aggressive intentions could be measured, if they
happened to have these intentions. For example, one
vignette described the following situation:
After finishing your drawing, it’s time for lunch.
But first, both teams need to pack up all the
pencils they’ve used. The other team leaves one
of its members to finish this job while the rest go
to get lunch. The person from the other team is
almost finished packing up when they knock the
pencil case off the table and pencils spill out
everywhere.
Each vignette was accompanied by four responses.
One of the responses was consistent with the earlier
characterization of direct aggression (e.g., namecalling, taking things from another, hitting, pushing
or teasing another); another response was consistent
with the earlier characterization of indirect aggression (e.g., ignoring, gossiping about, deceiving,
rejecting or excluding another). Thus, after the
foregoing vignette, the direct aggression response
specified Tease the person about how bad their
drawing was, whereas the indirect aggression
response was Tell your group some nasty gossip
about that person. All items were scored on a 5-point
unipolar scale ranging from 1 (Very unlikely) to 5
(Very likely). The other two responses were filler
items that were not designated as aggression actions,
instead describing mildly prosocial acts.
The participant responded to each of the five
vignettes in turn, each of which had a different set of
four responses, but each of which included a direct
aggression response, an indirect aggression response,
and two filler items, each of which related to the
content of the particular vignette. The researcher
pointed to the photo of an outgroup member in
relation to each of the vignettes, the designated
outgroup member being systematically varied in
order to control for the possible effects of particular
faces. In this study, participants’ scores on Direct and
Indirect Aggression were the sum of their responses
to the relevant measure on each of the five vignettes.
Thus, each participant received two summed scores,
one for Direct Aggression and one for Indirect
Aggression. Each score could range from 5 to 25.
The designation of the particular response items as
instances of direct vs. indirect aggression was based
on an earlier study, in which a factor analysis of the
items revealed two factors, Direct Aggression and
Indirect Aggression, accounting for 65% of the
total [Duffy and Nesdale, in press]. Each of the
subscales displayed good internal consistency, with
Cronbach’s a coefficients for the Direct Aggression
and Indirect Aggression scales being .83 and .73,
respectively. The aggressive intentions scale has been
used successfully in earlier research and has revealed
predictable findings in samples of children in middle
childhood [e.g., Duffy and Nesdale, 2010; Nesdale
et al., in press, 2008].
Procedure
All students in grades 1–6 from the participating
schools were asked by their teachers to do a drawing
of themselves on a 145 mm 210 mm piece of paper.
The children were told that during next week some
visitors would look at their drawings, if their parents
had given permission for them to participate. One to
two weeks later, each participant was called out of
his/her class and tested in a distraction-free environment. The child was asked to pretend that s/he was
going to participate in an intergroup drawing
competition that would involve children from other
schools in the area. Accordingly, they were asked to
pretend that all the children’s drawings had been
judged by an artist and that the children were being
put into groups of similar drawing ability. They
Aggr. Behav.
200 Nipedal et al.
were then asked if it was okay to have their instant
photo taken, and all participants agreed.
The children were then asked to pretend that their
drawing had been viewed by judges who had
assigned them to a team of equally well-performed
drawers. They were then shown photos of two other
children of the same age, sex, and ethnicity (photo
set 1) and were told that this was their team. They
were asked to put their photo in the empty slot
between the photos of their team members and to
have a good look at their team because they would
later be asked some questions about them. In order
to enhance ingroup identification, the participants
were then told that their team members had asked
them to pick their team’s color, which the researcher
then wrote next to their team’s photos.
The participants were then shown photos of the
same age, sex, and ethnicity children in the other team
(photo set 2), and were told of the color that they had
chosen for their team. Depending on the participant’s
randomly assigned condition, the experimenter then
subjected each participant to the appropriate manipulations of group norm and school norm. To carry
out the school norm manipulation, participants in the
school norm condition were told that your principal
and teacher wanted me to remind you that this school
wants all the children to like kids in other groups and to
be friendly toward them. Conversely, in the no school
norm condition, no mention of how the school
wanted them to behave was made.
To carry out the group norm manipulation, each
participant was told that his/her group had recorded
a ‘‘secret message’’ for him/her to hear. Thus, the
researcher told each participant before and after the
message, this is for your ears only, I am not allowed to
know what the message is, you must keep your team’s
secret message to yourself. The participant was asked
to put on head phones in order to listen to the secret
(prerecorded group norm) message, delivered by one
of your team members. In each group norm condition,
the participant first heard several same age and sex
voices welcome him/her to the team. In the inclusion
group norm condition, the participant then heard a
‘‘team member’’ explain that if the participant wanted
to be a part of the team, they must like and include all
the members of all other teams. In contrast, in the
exclusion group norm condition, the participant heard
a ‘‘team member’’ explain that if the participant
wanted to be a part of the team, they must not like or
be friendly to any members of the other teams. Finally,
in the exclusion and relational aggression group norm
condition, the participant heard a ‘‘team member’’
explain that if the participant wanted to be a part of
the team, they must not like or be friendly to any
Aggr. Behav.
members of the other teams and that they must be
prepared to say mean things about kids in the other
teams and to have them left out of games and activities.
To manipulate the timing of the group norm and
school norm messages, half the children heard the
group norm manipulation before the school norm
manipulation; whereas the remaining half of the
children heard the group norm manipulation after
the school norm manipulation.
After completing the experimental manipulations,
the participants were directed to their response
booklet. To ensure that each child was comfortable
with using the unipolar and bipolar scales, they first
completed some practice questions under the direction of the experimenter. The participants were then
asked to pretend that it was the day of the drawing
competition but, before presenting the questions and
statements from the response booklet, the children
were reassured that, unlike schoolwork, there are no
right or wrong answers, and that we are just
interested in what you think is the best answer for
you. The experimenter next read out the five
scenarios in turn, each of which was followed by
four questions, two of which assessed the participant’s direct and indirect aggressive intentions. As
indicated above, the participants’ responses to each
vignette were recorded on 5-point unipolar scales
ranging from 1 (Very unlikely) to 5 (Very likely).
When the sessions were completed, the participants were debriefed and given the opportunity to
ask any questions they had. In an attempt to control
for possible contamination between participants, the
participants were then asked to keep the details of
the pretend game secret from the other children so
that it would be a new game for them. All the
participants agreed to do so. They were then given
their own photos, thanked for their participation in
the pretend game, and returned to their classrooms.
RESULTS
Exploratory Analyses
Exploratory analyses were first carried out to ensure
that the data on each of the measures was suitable for
analysis on ANOVA. This analysis revealed that no
data were missing from any participant on any of the
variables and that the distributions met the requirements for analysis on ANOVA.
Main Analyses
The summed scores on the direct and indirect
aggression measures were analyzed in a 2 (participant
Social Group Norms, School Norms 201
age: 7 vs. 10 years) 2 (participant gender: females
vs. males) 3 (group norm: inclusion vs. exclusion vs.
exclusion1relational aggression) 2 (school norm:
inclusion vs. no school norm) 2 (aggression type:
direct vs. indirect) factorial ANOVA, with the last
factor measured within subjects. In the first pass, we
included timing in the analysis but, because no timing
effects were revealed, the subsequent analysis
summed over this variable.
Six significant effects were revealed in the analysis,
including a significant group norm main effect, F (2/
359) 5 11.89, P 5 .000, partial Z2 5 .06. This effect
indicated that the participants’ aggressive intentions
in the inclusion norm condition (M 5 7.44,
SD 5 2.96) were significantly lower than were the
participants’ aggressive intentions in the exclusion
norm condition (M 5 8.84, SD 5 4.08), whereas the
aggressive intentions in the latter condition did not
differ significantly from those in the exclusion-plusrelational aggression group norm condition
(M 5 9.63, SD 5 4.80).
There was also a significant aggression type main
effect, F (1/359) 5 129.92, P 5 .000, partial Z2 5 .27,
revealing that the participants displayed significantly
greater indirect (M 5 9.45, SD 5 4.22) rather than
direct aggressive intentions (M 5 7.82, SD 5 4.02).
Finally, there was a significant main effect for
participant age, F (1/359) 5 45.78, P 5 .000, partial
Z2 5 .28, with 7-year-old participants revealing
(M 5 9.89, SD 5 4.76) greater aggressive intentions
than the 10-year-old participants (M 5 7.62,
SD 5 2.99).
However, the preceding effects were qualified by
an aggression type participant age interaction,
F (1/359) 5 5.39, P 5 .02, partial Z2 5 .01, that, in
turn, was qualified by 2 4-factor interactions. First,
there was a significant participant age participant
gender school norm aggression type interaction,
F(1,359) 5 6.13, P 5 .01, partial Z2 5 .017. As
indicated in Table I, comparison of the cell means,
using Duncan’s Multiple Range Test (Po.05),
revealed that the participants’ direct and indirect
aggressive intentions tended to be generally lower
when there was a school norm endorsing inclusion
and friendliness. However, the school norm significantly reduced more of the participants’ indirect
vs. direct aggression, with its effect tending to be
greater for males vs. females, and for the younger vs.
older participants. Thus, the school norm significantly reduced the 7-year-old female (Ms 5 10.21 vs.
11.25) and 10-year-old male participants’ indirect
aggressive intentions (Ms 5 8.14 vs. 9.40) as well as
the 7-year-old male participants direct aggressive
intentions (Ms 5 8.23 vs. 9.39).
Second, the analysis revealed a significant participant age group norm school norm aggression
type interaction effect, F(2,359) 5 4.22, P 5 .01,
partial Z2 5 .023. As indicated in Table II, comparison of the cell means using Duncan’s Multiple
Range Test (Po.05) revealed that, across group and
school norms and aggression types, the younger
children had higher aggressive intentions than the
older children. In addition, across ages and aggression types, the group norms of exclusion and
exclusion-plus-relational aggression, increased the
participants’ aggressive intentions compared with
the inclusion group norm condition. However, for
the younger children, there was a significant
difference in both their direct and indirect aggressive
intentions caused by both the exclusion group norm
conditions. In contrast, for the older children, and in
relation to both their direct and indirect aggressive
intentions, there was a significant difference between
the inclusion norm condition and the exclusionplus-relational aggression condition, with the exclusion
norm condition tending not to differ from either of
the other two conditions.
Importantly, the results also indicated that the
school norm tended to decrease the impact of the
group norm on the children’s aggressive intentions
TABLE I. Means and SDS for Participant Age Participant Gender School Norm Aggressive Type Interaction on Aggressive
Intentions
Direct aggression
School norm
7 years
Males
Females
10 years
Males
Females
Indirect aggression
No school norm
School norm
No school norm
8.23de (4.95)
8.80ef (5.08)
9.39f (4.10)
9.16f (5.21)
10.88hij (4.27)
10.21gh (5.09)
11.21ij (4.29)
11.25j (4.90)
7.02bc (2.99)
6.05a (1.61)
7.52cd (2.82)
6.41ab (2.19)
8.14de (3.53)
7.48cd (2.45)
9.40f (3.50)
7.29c (2.63)
Means sharing different subscripts are significantly different, Duncan’s Multiple Range Test, Po.05.
Aggr. Behav.
202 Nipedal et al.
TABLE II. Means and SDS for Participant Age Group Norm School Norm Aggressive Type Interaction on Aggressive
Intentions
Direct aggression
7 years
Inclusion norm
Exclusion norm
Exclusion norm
10 years
Inclusion norm
Exclusion norm
Exclusion norm
Indirect aggression
School norm
No school norm
School norm
No school norm
7.00bcd (2.85)
9.03ghi (5.17)
19.62hi (6.12)
7.24cd (2.97)
9.85hijk (4.84)
10.69jkl (5.39)
9.90ijk (4.29)
10.93l (4.38)
10.71kl (5.48)
8.51efg (4.11)
12.08m (4.30)
13.09n (4.23)
5.83a (1.52)
6.45abc (2.04)
17.16bcd (3.11)
6.16ab (1.55)
6.54abc (2.06)
7.96def (3.34)
7.06bcd (2.06)
7.64de (2.55)
8.61efgh (3.90)
7.74de (2.39)
8.00defg (3.03)
8.80fgh (3.97)
Means sharing different subscripts are significantly different, Duncan’s Multiple Range Test, Po.05.
when the two norms were in opposition, although
this effect was only significant for the younger
children. Thus, the school norm significantly reduced 7-year-old participants’ direct aggressive
intentions when the group had a norm of exclusion-plus-relational aggression (Ms 5 10.69 vs.
9.62), as well as their indirect aggressive intentions
when the group had an exclusion norm (Ms 5 12.08
vs. 10.93) or a norm of exclusion-plus-relational
aggression (Ms 5 13.09 vs. 10.71). In contrast, the
older children’s direct and indirect aggressive intentions were significantly less than those of the
younger children under each group norm condition,
and were not reduced further by the school norm.
DISCUSSION
As anticipated, the findings revealed a significant
main effect of social group norm, with children
displaying significantly greater aggressive intentions
when their social group had a norm of exclusion or
exclusion-plus-relational aggression, as opposed to a
norm of inclusion. Although this finding is consistent with other research [e.g., Boiven et al., 1995;
Henry, 2001; Henry et al., 2000; Nesdale et al., 2008,
2004; Salmivalli and Voeten, 2004; Stormshak et al.,
1999; Wright et al., 1986], it is noteworthy that the
effect occurred despite the children never having met
any other ingroup members and their membership
of their ‘‘social group’’ being excessively brief. In
addition, whereas earlier research has revealed the
influence of classroom norms on children’s aggression [Henry, 2001; Henry et al., 2000; Salmivalli and
Voeten, 2004; Stormshak et al., 1999], it is also
noteworthy that the children in this study showed a
similar degree of responsiveness to their social
group, despite its limited size. This emphasizes the
importance of group membership to young children,
Aggr. Behav.
extending to an apparently strong need to conform
to the group’s norms.
Central to this study was the question of whether
school norms that oppose the norms endorsed by
children’s social groups can extinguish or, at least,
moderate, the effects of the social group’s norms on
children’s aggression. Consistent with this, the
findings revealed that, regardless of their age, the
participants’ direct and indirect aggressive intentions were lower in the school norm vs. no school
norm condition in both the exclusion and exclusionplus-relational aggression group norm conditions.
However, the reduction was only significant among
the younger and not the older children. Moreover,
although there was a significant reduction in their
indirect aggressive intentions regardless of their
exclusion norm condition, the reduction in relation
to their direct aggressive intentions was significant in
the exclusion-plus-relational aggression group norm
condition, but not in the exclusion group norm
condition.
One reason why the school norm effect might not
have been stronger is that the group vs. school
norms might have had had differential salience as a
result of the difference in their methods of delivery.
Thus, as with so much that is imparted at school, the
school norm was yet another prescription delivered
by an adult. In contrast, the group’s norm was
delivered via a ‘‘secret message’’ from the group
members, perhaps giving it something of a mysterious and conspiratorial, hence, exciting impression.
However, although this might have been the case, it
nevertheless seems likely that the two modes of
delivery actually map onto reality. Teachers and
other adults do deliver homilies and injunctions
about behaviors that they wish children to display as
well as those they do not wish to see displayed. In
contrast, the norms that are held by groups belong
to the group members and hence are not widely
Social Group Norms, School Norms 203
broadcast (i.e., they may be secret). Perhaps, one
implication of the foregoing discussion is that
teachers and school administrators should give
special consideration to methods that can be
employed to keep school norms and rules fresh
and vibrant to young children.
In addition to the preceding effects, the analysis
also revealed a set of significant effects on participants’ aggressive intentions involving participant
age. In general, these effects revealed that the older
children were generally less disposed toward displaying either direct or indirect aggressive intentions
than were the younger children.
These findings are contrary to the approach that
argues that aggression is predominantly physical
among younger children who have not acquired
sufficient verbal skills and social intelligence to be
able to use the more sophisticated, manipulative
aggressive strategies that are required in indirect
aggression and are displayed more by older children
[Bjorkqvist et al., 1992; Kaukiainen et al., 1996]. In
addition, the findings are contrary to the approach
that proposes that girls display more indirect vs.
direct aggression, whereas boys do the reverse,
especially as they increase in age [Crick et al.,
1997; Ostrov and Crick, 2007; Rigby, 2005]. Instead,
the present findings are consistent with other studies
that have not found the aggression type gender
effect [e.g., Atlas and Pepler, 1998; Galen and
Underwood, 1997; Little et al., 2003; Nesdale
et al., 2008, 2009; Salmivalli and Kaukiainen,
2004], including a meta-analysis of 148 studies
which concluded that ‘‘the support for negligible
gender differences in indirect aggression seems
conclusive’’ [Card et al., 2008; p 1203].
Rather, the present findings are more consistent
with the view that the participants might have been
self-regulating their aggressive intentions. This
explanation fits with other evidence mentioned
earlier that with increasing age children have an
increasing awareness that negative attitudes and
behaviors are considered unacceptable by adults and
that children show a growing tendency to engage in
self-presentational behavior that puts them in the
best possible light when they are being observed by
adults [e.g., Aloise-Young, 1993; Banerjee, 2002;
Banerjee and Yuill, 1999; Bennett and Yeeles, 1990;
Brown and Bigler, 2004; Greenwald and Banaji,
1995; Killen et al., 2001; Theimer et al., 2001;
Rutland, 1999; Rutland et al., 2005].
In sum, these findings indicate that school norms
can moderate, if not extinguish, contrary social
group norms, at least in younger vs. older children.
However, given that the latter participants may have
been managing their impressions, and that the
school norm generally tended to lower the participants’ aggressive intentions, there are good grounds
for pursuing the utilization of school norms as yet
another strategy for moderating children’s aggression. Research now needs to explore ways in which
school norms can be developed, endorsed, and
presented, so that they have their most lasting effect
on children.
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