572 Aggression, Violence, Evil, and Peace
frequently when air pollution is high (Rotton & Frey, 1985;
see also Berkowitz, 1982; Anderson & Anderson, 1998).
Second, he asserts that the emotional state consists of a
network of feelings, ideas, memories, and expressive motor
reactions that are associated with one another so that the acti-
vation of one part of the net will activate other parts. Un-
pleasant memories will promote a negative mood, and this
will increase the probability of negative thoughts and ag-
gressive behavior. An external cue that has an aggressive
meaning (e.g., a weapon) may activate aggressive thoughts
and—particularly if negative feelings are present—lead to an
increased probability of aggressive behavior. Thus, in the
classic experiment by Berkowitz and LePage (1967), angered
subjects delivered more shocks to their partner when guns
rather than badminton rackets were in the room (for further
findings see Turner, Simons, Berkowitz, & Frodi, 1977).
Even more disturbing, Berkowitz argued that cues associated
with pain, frustration, suffering, and aversive stimuli in gen-
eral may activate negative affect and increase the probability
of aggression. Thus, Berkowitz and Frodi (1979) showed that
when women university students were angered and dis-
tracted, they were more punitive when the child they were
supervising was “funny looking” and stuttered. The activa-
tion of negative affect does not necessarily lead to aggression.
Such behavior may be inhibited by either fear of punishment
or empathic concerns, and a person may learn to respond with
other behaviors. However, a person is susceptible to the influ-
ence of negative moods and external stimulation, and aggres-
sive behavior is a “natural” response to negative affect that
will tend to occur whenever self-control is reduced.
Biological Perspectives
From a biological perspective, many species of animals ex-
hibit aggressive behavior, and we may consider a good deal of
this to be instinctually based. Inasmuch as this is so, there
are constraints on the ease with which we can modify aggres-
sive behavior. The concept of instinct can be approached from
the view of contemporary behavioral evolutionary theory or
from its original conception as used by Freud.
Behavioral Evolution
Rather than view aggressive behavior as a learned response,
we may conceptualize aggression as the product of evolu-
tionary processes, that is, behavior patterns based on genetic
influences that have persisted because they have been adap-
tive, helping members of a species survive in specific envi-
ronments. Thus, we may find aggressive patterns of behavior
programmed into the nervous system because the genes that
served as the basis for these programs were selected by the
reproduction of the organisms that possessed them. In its
original conception, instinctual behavior was viewed as a sort
of drive that, like hunger, was directed toward a goal, build-
ing if it were not satisfied and becoming less and less partic-
ular about the ideal goal object until it could be satisfied by
something that would not ordinarily be chosen. However, it is
difficult to imagine the goal of an aggressive drive because
there are so many different functions for aggression. There is
the aggression involved in predation, in the defense of the
young, in the struggle between males for mates, and so on. It
may be better to consider instinctual aggression as comprised
of particular behavior patterns that can be released by partic-
ular cues in the environment. We may then consider both
internal and external factors that may influence these aggres-
sive patterns, as well as how the patterns may have adaptive
significance. For example, in most species males engage in
more intraspecies aggression than females, and this aggres-
sion is involved in the competition to fertilize females. In
some species the struggle for mates involves the establish-
ment and defense of territory and may function to spread
members of a species out over territory, thus preserving food
supplies.
When we examine the human species, we find that soci-
eties vary widely in the amount of aggression. However,
within any given society males always appear more aggres-
sive than females. Observational studies find boys more ag-
gressive than girls (E. E. Maccoby & Jacklin, 1974); teenage
males are more apt to offer more violent solutions (Archer &
McDaniel, 1995); and violent crimes are more apt to be com-
mitted by men (J. Q. Wilson & Herrnstein, 1985). However,
Straus and Gelles (1990) suggested that within-family
aggression may be as prevalent in females.
The sex differences in aggression that are found appear to
be related to testosterone, which seems to influence both the
development of the brain and some of the physiology underly-
ing current behavior (R. T. Rubin, 1987). However, the exact
relationship between testosterone and aggression is unclear,
in part because behaving aggressively appears to affect the
release of testosterone and because testosterone levels may be
related more to dominance behavior than to aggression as in-
tent to hurt. Mazur and Booth (1998) argued that testosterone
both rises in response to a challenge to dominance and in-
creases in winners and decreases in losers. Alternatively, van
Creveld (2000) argued that males gravitate toward violence
because their bodies are better adapted for aggressive combat
and because the exercise of this advantage is a way for men to
solve the existential problem posed by the fact that they cannot
bear children. They justify their existence by insisting on the
necessity of violence and their preeminence in its exercise.
In humans, as in other animals, it is easy to imagine how
aggressive behavior in a conflict between males could result