A Framework for Explaining Aggression Involving Groups

Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
Authors Groups
2007 Blackwell
Publishing Ltd
A Framework for Explaining Aggression
Involving Groups
Brian P. Meier,1* Verlin B. Hinsz,2† and Sarah R. Heimerdinger2
Gettysburg College
North Dakota State University
Aggression involving groups (versus individuals) can be particularly severe (e.g.,
hazings). Although an impressive amount of experimental research on the
aggression of individuals exists, relatively less experimental research on aggression
involving groups exists. We use existing theories of aggression and the available
research to present a framework of aggression when groups are involved. We
propose a provisional model that suggests that the extent of aggression to be
committed depends on the composition of both source (i.e., perpetrators – group
or individual) and target (i.e., victims – group or individual) entities. Evidence
suggests that groups commit and receive more aggression than individuals. We
propose that accessible hostile thoughts and the experience of negative affect
contribute to the target effect (i.e., more aggression committed toward groups
versus individuals), whereas disinhibition processes and arousal contribute to
the source effect (i.e., more aggression committed by groups versus individuals).
Our framework can guide future theory and research on aggression involving
Substantial research literature compares group and individual behavior
in a variety of areas (e.g., norms, Sherif, 1936; conformity, Asch, 1951;
performance, Davis, 1969; see Baron & Kerr, 2004, Forsyth, 2006, Parks
& Sanna, 1999, for extensive reviews). Yet, experimental investigations of
aggression involving groups versus only individuals are rare despite the
often severe nature of this behavior. Many examples illustrate its severity.
In one instance, three adolescent boys killed a 55-year-old man confined
to a wheelchair. Before he died, the young boys tortured him for 24
hours, stabbed him 40 times, and poured salt into his wounds (Greer &
Guthey, 1993). Groups of girls can also commit aggression. In one case,
12 high school girls were charged with misdemeanor battery for throwing
buckets of paint, vinegar, and feces at several female high school juniors
in a hazing incident (‘15 teens’, 2003; ‘Police may’, 2003).
While these examples highlight examples of groups acting as the source
(perpetrator) of aggression, groups can also be the target (victim) of
© 2007 The Authors
Journal Compilation © 2007 Blackwell Publishing Ltd
2 Aggression Involving Groups
aggression. The 1984 New York City subway shootings involved a lone
man who shot a group of four young boys whom he thought were
attempting to rob him (Fletcher, 1990). Furthermore, school-shooting
incidents (e.g., Columbine, Virginia Tech) typically involve group targets.
While these selected cases highlight aggression involving groups, they do
not provide causal mechanisms or explanations for its occurrence.
Examples of aggression involving only individuals are also easy to
illustrate, but there is far less experimental research examining aggression
with groups. Indeed, a great deal is known about situational and individual
difference factors that influence aggression by individuals. For example,
situational factors such as provocation, alcohol consumption, and physical
pain (Anderson & Huesmann, 2003), and individual difference variables
such as gender (Bettencourt & Miller, 1996), hostile attributions (Crick
& Dodge, 1994), and impulsivity (Wu & Clark, 2003) increase aggression
in individuals. Unfortunately, we know comparatively less about the
factors that influence aggression involving groups (Meier & Hinsz, 2004).
Although there is existing literature (e.g., Goldstein, 2002), we are
unaware of any significant theoretical perspectives.
In this paper, we examine the experimental research on aggression
involving groups in order to provide a new theoretical perspective and
to provide a basis for future investigations. We define a ‘group’ as two or
more interacting individuals with a common identity and mutual goals.
We use experimental research that measures aggression committed by,
or against, both groups and individuals. To help propose a provisional
framework for aggression involving groups, we incorporate the general
aggression model (Anderson & Bushman, 2002), which is a model of
aggressive behavior formulated from numerous theories.
Theories of Aggression
The term aggression is used to define many behaviors, yet precise
definitions are essential for experimental research. We use the definition
of aggression proposed by Baron and Richardson (1994), which states that
aggression is any behavior intending to harm another living being that
desires to avoid such harm. Note that the intent to harm is all that is
required to meet this definition; actual harm is not needed.
Our framework for aggression involving groups is based on a well-tested
theory of aggression in individuals; therefore, it is necessary to first examine
the central aspects of this theory. The frustration-aggression hypothesis
(Dollard, Doob, Miller, Mowrer, & Sears, 1939) is typically considered to be the
starting point of aggression theory in social psychology. According to this
hypothesis, aggression is a consequence of the frustration of an organism
when its approach to a goal is thwarted. Research, however, revealed that
the frustration-aggression hypothesis had limitations; not all frustration led
to aggression and not all aggression resulted from frustration (Berkowitz, 1989).
© 2007 The Authors
Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
Journal Compilation © 2007 Blackwell Publishing Ltd
Aggression Involving Groups 3
Figure 1 A single episode of the General Aggression Model (Anderson & Bushman, 2002).
Reprinted with permission from the Annual Review of Psychology.
Berkowitz’s (1989, 1993) proposed a more comprehensive approach that
he labeled cognitive neoassociation theory. Berkowitz (1989) contends
that negative affect (i.e., a broad category of negative feelings or emotions)
produced by social interactions (e.g., a disagreement) or environmental
cues (e.g., high temperature) can lead to aggression. Berkowitz (1989) suggests
that negative affect can arouse aggressive thoughts and anger, and the
stronger the negative affect, the stronger the likelihood of aggression.
In Berkowitz’s (1993) theory, aggression-related thoughts and feelings,
brought on by negative affect, can automatically evoke aggressive behaviors
via associative networks in long-term memory.
Anderson and Bushman (2002; also see Anderson & Huesmann, 2003)
developed the general aggression model based on cognitive-neoassociation
theory (Berkowitz, 1989, 1993) and theories proposed by others (e.g.,
Huesmann, 1998; Zillmann, 1983). As shown in Figure 1, the general
aggression model has three basic areas: inputs, routes, and outcomes.
Inputs include situational variables (e.g., violent media exposure) and
person variables (i.e., stable characteristics of a person such as traits).
Person and situation factors can interact with one another or lead directly
to the routes that influence behavior.
The route portion of the general aggression model reflects the internal
state of the individual, defined by cognitions, affect, and arousal. Activating
or increasing the level of any one of these variables may spread or prime
the activation of the others through associative networks. The increased
activation of one of these variables can affect one’s appraisal and decisionmaking process (an outcome) leading to aggression (Anderson & Bushman,
2002). Importantly, these appraisal and decision-making process can occur
automatically without much conscious or deliberate thought.
Numerous studies support the general aggression model (e.g., Anderson,
Carnagey, & Eubanks, 2003; Anderson & Dill, 2000; Bushman, 1998;
© 2007 The Authors
Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
Journal Compilation © 2007 Blackwell Publishing Ltd
4 Aggression Involving Groups
Bartholow, Anderson, Carnagey, & Benjamin, 2005; Kirsh, Mounts, &
Olczak, 2006; Meier, Robinson, & Wilkowski, 2006; Uhlmann & Swanson,
2004). Because of the acceptance of this comprehensive model as an
explanation for aggression committed by individuals, we use it to structure
our understanding of aggression with groups. That is, the general aggression
model provides a conceptual foundation upon which we can consider
mechanisms that may be associated with aggression involving groups.
Experimental Research on Aggression Involving Groups
Much of the literature on aggression involving groups has focused on
large groups. For example, ethnic conflicts (e.g., Israelis and Palestinians)
and minority groups in the USA (Baron & Kerr, 2004; Brewer, 2003)
have been extensively examined. Baron and Kerr contend that perceived
disagreements or mistreatment relating to fairness and equity are key
mechanisms that spur this aggression. Although important in its own
right, our theoretical perspective is not concerned with this broad
intergroup aggression, but with aggression involving small, interacting
There are a limited number of experimental investigations of aggression
involving small groups. Two experimental studies ( Jaffe & Yinon, 1979;
Jaffe, Shapir, & Yinon, 1981) used the learning paradigm associated with
Milgram’s (1965) obedience to authority research to examine aggression
with a group source and individual target. In these studies, participants
acted as teachers either alone or in three-person groups with the severity
of aggression assessed from the participants’ allocated shock intensities.
Jaffe and his colleagues found that when confederates failed a task, groups
delivered significantly stronger shocks compared to individuals. Jaffe et al.
(1981) had participants rate how personally responsible they were for the
shock administration. Group members rated themselves as significantly
less responsible than individuals acting alone. Although the increased
aggression by groups could be explained via this diffusion of responsibility
(e.g., Leary & Forsyth, 1987), it was not demonstrated that greater
diffusion of responsibility statistically predicted greater shock settings.
Two additional studies (Wolosin, Sherman, & Mynatt, 1975; Yinon,
Jaffe, & Feshbach, 1975) used a risky-shift paradigm to investigate aggression
involving groups. This paradigm allows groups and individuals to make
risky or cautious decisions, contrasting self-interest and altruism.
Aggression in these studies was defined as the amount of electrical shock
the source gave to a target. Yinon et al. (1975) and Wolosin et al. (1975,
Study 1) found that groups gave stronger shocks than individuals when
the target was an individual. This finding is consistent with the results of
Jaffe and Yinon (1979) and Jaffe et al. (1981). Studies 1 and 2 of Wolosin
et al. compared an individual source assigning shocks to either a group or
individual target. Neither study found a difference in the amount of shock
© 2007 The Authors
Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
Journal Compilation © 2007 Blackwell Publishing Ltd
Aggression Involving Groups 5
assigned to the target, although Study 1 found a marginal difference
indicating that groups received higher shocks than individuals. As in Jaffe
et al. (1981), Wolosin et al. asked participants to rate their perceived
responsibility for the shock administration. No differences in perceived
responsibility were found between groups and individuals.
Diener (1976) allowed individuals or groups of three to aggress against
a lone individual in a study purportedly examining physical activity.
Although participants were not told what to do, the activity could involve
aggressive actions because newspaper balls, foam swords, pellet pistols,
foam bricks, and rubber bands were in the room. In both conditions,
participants first viewed a confederate acting aggressively toward the lone
individual. Researchers found that individuals acting alone aggressed
significantly more against the lone individual than participants in groups.
Diener (1976) found results contrary to those of Jaffe and Yinon
(1979), Jaffe et al. (1981), Yinon et al. (1975), and Wolosin et al. (1975),
who all found that groups aggressed more than individuals. Furthermore,
only Wolosin et al. manipulated the target of aggression (group or
individual), which did not significantly affect the amount of aggression
committed by a lone individual. As a whole, this research sheds light on
aggression involving groups, but it leaves unanswered questions. The
research is limited in that it does not manipulate both the source and
target and does not examine causal mechanisms. Moreover, the studies
by Yinon et al. and Wolosin et al. used a risky-shift paradigm in which
participants gained a monetary reward for acting aggressively. Therefore,
self-interest possibly confounded the difference in aggression between
groups and individuals.
Manipulating the Source and Target of Aggression
To address the lack of experimental research on aggression in groups,
Meier and Hinsz (2004) conducted an experiment that manipulated both
the source and target of aggression while using a paradigm that controlled
some confounding variables. That is, aggression was measured so that
self-reward (e.g., receiving money for acting aggressive as in the risky-shift
paradigm) was not possible. The study included conditions in which the
source and target of an aggressive act was either an individual or a group,
resulting in four types of experimental interactions: intergroup (group to
group), interindividual (individual to individual), group to individual, and
individual to group.
Meier and Hinsz (2004) used a hot sauce allocation paradigm to measure
aggression (McGregor et al., 1998). In this paradigm, because very spicy
hot sauce can be painful to consume, the amount of hot sauce one
allocates for another constitutes the measure of aggression. Participants
were told that they would taste and rate hot sauce and complete personality
measures. In addition, participants were told that, because experimenters
© 2007 The Authors
Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
Journal Compilation © 2007 Blackwell Publishing Ltd
6 Aggression Involving Groups
needed to remain blind, participants would allocate portions of hot sauce
for others to consume. After participants sampled a small portion of
hot sauce, they moved into private rooms (as three-person groups or as
individuals) and were shown a bogus amount of hot sauce that another
group or individual supposedly allocated for them to consume (the
amount shown was chosen to induce mild provocation – every condition
receive the same bogus amount). Participants were then told to allocate
an amount of hot sauce for this other group or individual to consume.
Meier and Hinsz (2004) found that the average hot sauce allocation in
the intergroup condition was significantly greater than in the interindividual condition; the hot sauce allocation was 60% greater even though
participants knew that each member of the group would have to consume
the amount of hot sauce allocated. Although group members believed
they were less responsible for the hot sauce allocation than participants acting
on their own, a responsibility measure did not mediate the relationship
between group or individual and the allocated hot sauce amount.
Meier and Hinsz (2004) also found that groups allocated more hot
sauce than individuals regardless of the target (i.e., a source main effect),
and groups received more hot sauce than individuals regardless of the
source (i.e., a target main effect). Although the interaction between source
and target was not significant, the two main effects suggest that the extent
of aggression committed depended upon whether the source and target
was an individual or group. These results reveal that the source and target
of aggression might be important factors that can influence the magnitude
of aggression. Such factors are similar to the situational inputs (e.g., alcohol
consumption) to aggression proposed by the general aggression model.
That is, source and target composition appear to be situational variables
that can affect aggression.
The Interindividual–Intergroup Discontinuity Effect
Before proposing our provisional framework for aggression involving
groups, we examine research on competition. Even though aggression and
competition are distinct (i.e., aggression involves behavior in which harm
is intended while competition often does not), this research can point to
potential mechanisms involved in aggression with groups. After all, both
competition and aggression typically involve antagonistic social interactions
with adversarial-like entities. Wildschut, Pinter, Vevea, Insko, and Schopler
(2003) reviewed research that focused on interindividual and intergroup
interactions through the use of the prisoner’s dilemma game. As shown in
Figure 2, the parties involved can make one of two choices that give them
a monetary reward. If both parties choose the cooperative choice (choice
‘A’), then both receive a moderate reward. If both parties choose the
competitive choice (choice ‘B’), then both receive a small reward.
However, if one party chooses to cooperate (choice ‘A’) and the other
© 2007 The Authors
Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
Journal Compilation © 2007 Blackwell Publishing Ltd
Aggression Involving Groups 7
Figure 2
Typical 2 × 2 prisoner’s dilemma game matrix.
party chooses to compete (choice ‘B’), the party choosing to compete
receives a high reward and the party choosing to cooperate receives a
small reward. Over time, both parties benefit the most from choosing the
cooperative option. A consistent finding, however, is that intergroup interactions, consisting of group versus group play, are more competitive and less
cooperative than interindividual interactions, consisting of individual versus
individual play; a difference known as the interindividual–intergroup
discontinuity effect.
According to Wildschut et al. (2003), at least three mechanisms are
responsible for this effect. The first is the distrust/fear explanation, which
proposes that people distrust and fear other groups more than other
individuals, causing them to compete more with a group than with an
individual. The second is the social support or greed explanation.
Wildschut et al. contend that group members can give each other support
for committing an antisocial action (i.e., competition) whereas individuals
cannot. The third is the identifiability explanation, which is based on the
belief that one’s behavior is more easily identified by opponents in
interindividual interactions compared to opponents in intergroup interactions, which causes group members to be more likely to engage in
competitive behavior.
The interindividual–intergroup discontinuity research can inform our
examination of aggression in groups. This research (and research by Meier
& Hinsz, 2004) suggests that the source of action (group or individual)
and the target of action (group or individual) are crucial factors when
predicting the extent of both competition and aggression. Moreover, at
least two mechanisms – distrust/fear and identifiably – proposed for the
interindividual–intergroup discontinuity effect are related to the cognitive
and affective routes from the general aggression model. The distrust
© 2007 The Authors
Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
Journal Compilation © 2007 Blackwell Publishing Ltd
8 Aggression Involving Groups
associated with groups is one kind of hostile thought that might be
primed when people face group targets. Additionally, the fear associated
with a group is a type of negative affect that might be experienced when
people face group targets. The identifiability explanation for interindividual–
intergroup discontinuity rests on cognitions group members have about
their responsibility for a group’s behavior. If group members view
themselves to be less identifiable and hence less individualized, they might
be more likely to engage in antisocial behavior. In summary, accessible
hostile cognitions (distrust of groups), cognitions related to identifiability
(deindividuation), and negative affect (fear of groups) are mechanisms that
are similar in both the general aggression model and the interindividual–
intergroup discontinuity research. Such similarities can direct our thinking
about aggression in groups.
A Provisional Framework for Aggression Involving Groups
Prior research (e.g., Jaffe, Shapir & Yinon, 1981; Meier & Hinsz, 2004),
the general aggression model (Anderson & Bushman, 2002; Anderson &
Huesmann, 2003), and the interindividual–intergroup discontinuity
research (Wildschut et al., 2003) allow us to propose a provisional
framework for aggression involving groups. An important characteristic of
aggression appears to be the composition of the source and target. That
is, the amount of aggression an entity commits or receives depends on the
source (i.e., group or individual) and target (i.e., group or individual)
configuration. We contend that in an aggressive context, groups as a
source will commit more aggression than individuals, and groups as targets
will receive more aggression than individuals. These factors are apparent,
but the mechanisms responsible for them are not. Below, however, we
offer some theoretical speculation.
Hostile cognitions and negative affect as target mechanisms
Our previous discussion suggests that hostile cognitions and negative
affect are two potential mechanisms for the target effect. We contend that
interacting with a group increases one’s hostile cognitions and negative
affect, which would likely influence subsequent behavior. Although this
proposition has not been directly tested, there is tentative evidence.
For example, Hoyle, Pinkley, and Insko (1989) found that participants
anticipating an interaction with a group expected it to be more hostile
than an anticipated interaction with an individual. Similarly, the distrust
associated with groups found in the interindividual–intergroup discontinuity
research (Wildschut et al., 2003) suggests that an interaction with an
external group may be another type of aggressive cue much like the presence
of weapons or high temperatures. That is, when a person is about to
interact with an external group, hostile thoughts and feelings may be
© 2007 The Authors
Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
Journal Compilation © 2007 Blackwell Publishing Ltd
Aggression Involving Groups 9
activated. In support of this contention, Pinter and Insko (2003) found
that people have implicit associations between the concepts of, on the one
hand, ‘group’ and ‘abrasiveness’, and on the other hand, ‘individuals’ and
‘agreeableness’. Regardless of whether an individual or a group is the
source of aggression, because external groups would have this hostile
association, aggression could be greater for groups-as-targets than individualsas-targets.
Why might external groups be viewed as hostile? One may consider
evolutionary factors as a possible reason. Some evolutionary psychology
approaches to group interactions suggest that humans might have an
evolved reaction to perceive other groups as threatening (e.g., Brewer,
2003). Among early humans, the arrival of an unknown group likely
meant a serious threat to resources. Consequently, it is possible that a
potential interaction with an unknown group would have been perceived
as hostile. Moreover, responses to this potential threat would include
preparing to act aggressively to repel the opposing group.
Based on these considerations, we view it likely that hostile thoughts
and feelings are responsible for a target effect in which groups receive
more aggression than individuals. The studies by Hoyle et al. (1989) and
Pinter and Insko (2003) tentatively support such a contention. This
research, however, involved the assessment of attitudes, not behavior. Therefore,
a full test of this mediation hypothesis (i.e., target composition → hostile
thoughts/feelings → aggressive behavior) is required.
Disinhibition as a source mechanism
Wildschut et al. (2003) found that group members who feel less identifiable
are more likely to engage in competitive behavior. When individuals are
less identifiable, they may experience deindividuation, which is defined
as the loss of one’s individuality, self-awareness, or self-evaluation apprehension when joining a group (Diener, 1980). Some researchers suggest
that deindividuation causes individuals to commit aggression or antisocial
behavior (Le Bon, 1960; Mullen, 1986; Zimbardo, 2004), but we are
reluctant to accept this general consensus for two reasons. First, although
deindividuation is typically used as an explanation for why groups can be
more aggressive than individuals, few studies have examined deindividuation
and aggression in group and individual contexts. Second, while deindividuated
individuals might be expected to automatically commit aggression or
antisocial behavior, a meta-analysis did not find a robust link (Postmes &
Spears). Instead, Postmes and Spears (1998) conclude that deindividuation,
or the conditions expected to cause deindividuation (e.g., group size),
leads individuals to commit situation-specific behavior, which can include
antisocial or pro-social actions ( Johnson & Downing, 1979). That is,
‘deindividuating circumstances induce increased responsiveness to the
situation’ (Postmes & Spears, 1998, 252).
© 2007 The Authors
Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
Journal Compilation © 2007 Blackwell Publishing Ltd
Aggression Involving Groups
Postmes and Spears (1998) contend that group members will behave
according to situation-specific norms. We interpret this conceptualization
to mean that individuals in a group can be expected to be disinhibited,
committing whatever behavior is expected in the present social situation.
In prisoner’s dilemma contexts (Wildschut et al., 2003), disinhibition
prompted by group membership likely results in competitive behavior.
Similarly, it is likely that in an aggressive context, a disinhibited group
member will commit more aggression than he or she would if acting
as a lone individual. That is, direct involvement in a group in an
aggressive context might release individuals’ social constraints against
A disinhibition process gains prominence when considering that a
group source includes multiple members who might make a hostile
argument in favor of aggression. Because there are multiple members in
a group, the chance of at least one member favoring aggression increases
exponentially. Based on the binomial expansion, with a group of r
residents in which the probability of any individual making a hostile
argument is pi, the probability of the group hearing at least one argument
for hostile action becomes PG = 1 − (1 − pi)r. Moreover, because all group
members are likely to be disinhibited, an argument by one member to
respond aggressively may serve as a trigger that could further release them
from inhibition (cf. Wegner, 2002).
Group accentuation as a source mechanism
Research shows that information processing by groups tends to accentuate
beliefs that are prevalent among individuals (Hinsz, Tindale, & Nagao,
forthcoming). One example of this would be the hostile-attribution bias,
which reveals that some individuals are biased toward appraising social
interactions in a hostile manner (Crick & Dodge, 1994). If some individuals
process information in a biased fashion, leading to an attribution that a
target is hostile, then group accentuation would exaggerate this belief,
causing groups to view targets as more hostile than individuals. Such an
accentuation would be similar to the process of group polarization (Myers
& Lamm, 1978), which occurs when groups accentuate the preexisting
beliefs or attitudes of individual group members.
Arousal as a source mechanism
The general aggression model suggests that arousal is one mechanism that
can intensify aggression (Anderson & Bushman, 2002; see also Berkowitz,
1993). Aroused individuals are expected to commit more aggression than
nonaroused individuals given an aggressive context. There is a unique
form of arousal in groups associated with social facilitation (Zajonc, 1965).
Action and coaction in groups is known to increase the arousal of group
© 2007 The Authors
Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
Journal Compilation © 2007 Blackwell Publishing Ltd
Aggression Involving Groups 11
members (Aiello & Douthitt, 2001; Bond & Titus, 1983; Guerin, 1986;
Zajonc, 1980). Consequently, when groups are the source of action, one
potential result is greater arousal compared to individuals. Further research
will be necessary to determine if this arousal contributes to the degree of
aggression committed by groups, but the general aggression model
suggests that it could be a reason why groups might be more aggressive
than individuals given an aggressive situation.
Individual differences variables
The general aggression model considers individual differences (e.g., trait
aggression) to be a factor in aggression. Considering one individual
difference variable, trait aggression, Meier and Hinsz (2004) found that
it positively correlated with the amount of hot sauce allocated in the
individual source condition, but not in the group source condition (using
the average of the three group members’ scores). In addition, Meier and
Hinsz did not find significant relationships between the lowest, middle,
and highest group member’s trait aggression score with the amount of
hot sauce allocated by their group. These results reveal that the trait
aggressiveness of group members as a whole, or as individuals, did not
affect the group’s aggression. We suggest that individual differences are
predictive for aggression involving individual sources, but they might not
be predictive for aggression involving group sources. That is, strong group
situations may overwhelm the influence of individual differences in
contexts where groups act as a source (e.g., Ross & Nisbett, 1992). This
intriguing prediction reveals that it is possible that a group does not
need an aggressive member to act aggressively (for extended views, see
Berkowitz, 1999; Fiske, Harris, & Cuddy, 2004).
Summary and Implications
Our provisional framework leads us to contend that source and target
composition is a central aspect when considering aggressive behavior.
Specifically, we suggest that when a context favors aggression, group
sources of action will commit more aggression than individuals, and
group targets of action will receive more aggression than individuals.
The target effect can occur because the anticipation of interaction with
external groups produces hostility (Hoyle et al., 1989). That is, we predict
that interacting with an external group (versus an individual) will increase
the level of hostile thoughts and negative affect, which will mediate the
relationship between target condition (group or individual) and the extent
of aggression received. As already mentioned, however, an empirical test
of this mediation hypothesis is necessary.
Considering the source effect, we hypothesize that groups commit
more aggression than individuals because of disinhibition processes and
© 2007 The Authors
Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
Journal Compilation © 2007 Blackwell Publishing Ltd
Aggression Involving Groups
arousal. We believe that conventional constraints against aggression are
disinhibited by membership in an interacting group (Postmes & Spears,
1998). Furthermore, because arousal increases aggression (Anderson &
Bushman, 2002), and intragroup interaction increases arousal (Zajonc,
1980), when a situation favors aggression, groups are likely to be more
aggressive than individuals because of arousal. Like our other predictions,
however, this hypothesis requires empirical examination.
Our framework reveals that not all factors associated with aggression by
individuals will have similar affects on aggression by groups. That is, if a
group situation is powerful, individual differences might not influence
aggression by groups (e.g., Ross & Nisbett, 1992). One testable inference
from this speculation is that groups of females may act just as aggressively
as groups of males, in contrast to the finding that males are typically more
physically aggressive than females (Bettencourt & Miller, 1996).
Our framework provides a basis for developing numerous hypotheses
about aggression involving groups as well as a better understanding of the
potential mechanisms. Many incidents of aggression are committed by, or
directed toward, groups. Although one can just as easily illustrate examples
of aggression involving individuals, there is little experimental research
devoted to aggression involving groups. Aggression is a complex behavior
that can be difficult to experimentally examine. If research continues to
focus only on aggression committed by individuals, however, we will lack
a comprehensive understanding of this detrimental behavior.
Preparation of this manuscript was supported by grants from the Air Force
Office of Scientific Research to the second author.
Short Biographies
Brian P. Meier received his undergraduate and PhD (in Social Psychology)
degrees from North Dakota State University. He has been a faculty member
at Gettysburg College since 2005, where he teaches courses in social
psychology and statistics. Professor Meier’s primary research interest lies in
emotion and social cognition. His recent publications cover a wide range
of topics in these areas, including embodied cognition and emotion,
personality and aggression, and implicit processes in social cognition.
Verlin B. Hinsz received his undergraduate degree in Psychology
and Sociology from North Dakota State University and his PhD in
Social–Organizational Psychology from the University of Illinois at
Urbana-Champaign. Since earning his doctorate, he has been on the
faculty of North Dakota State University, where he is now Professor of
Psychology. Like his doctoral degree, Professor Hinsz’s research lies at the
intersection of social and organizational psychology. Some of Professor
© 2007 The Authors
Social and Personality Psychology Compass 1 (2007): 10.1111/j.1751-9004.2007.00015.x
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Aggression Involving Groups 13
Hinsz’s recent publications have dealt with information processing in
groups, motivating food safety, group and individual judgment and
decision-making, and approach and avoidance motivation in groups.
Sarah R. Heimerdinger received her undergraduate degree in Psychology
and her master’s degree in Clinical Psychology from North Dakota State
University. She is in the doctoral program in Counseling Psychology at
Iowa State University. Her research interests lie at the intersection of
clinical and social psychology. Specifically, she is interested in social
mechanism leading to interpersonal violence and the prevention thereof.
* Correspondence addresses: Department of Psychology, Gettysburg College, Gettysburg, PA
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University, Fargo, ND 58105, USA. Email: [email protected]
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