Concern over the adverse consequences of aggression obscures the
fact that such behavior often has functional value for the user. Indeed,
there is a property unique to aggression that generally creates conditions
fostering its occurrence. Unlike other social behaviors that cannot be
effective without some reciprocity acceptable to the participants, aggres-
sion does not require willing responsiveness from others for its success.
One can injure and destroy to self-advantage regardless of whether the
victim likes it or not. By aggressive behavior, or dominance through
physical and verbal force, individuals can obtain valued resources,
change rules to fit their own wishes, gain control over and extract sub-
servience from others, eliminate conditions that adversely affect their
well-being, and remove barriers that block or delay attainment of de-
sired goals. Thus, behavior that is punishing for the victim can, at least
on a short-term basis, be rewarding for the aggressor. Although, as we
shall see later, aggression has many different causes, its utilitarian value
undoubtedly contributes heavily to the prevalence of such behavior in
the interactions of everyday life.

Over the years a number of theories have been proposed to explain
why people behave aggressively. This chapter is focused on a comparison
of the tenets of instinct and drive theories, which historically attributed
aggression to internal aggressive forces, with the explanatory system
based upon social learning theory. The basic principles of social learning
are then applied in succeeding chapters to the explanation of both in-
dividual and collective aggression. This formulation differs in several
important respects from the alternative lines of theorizing not only in
the factors considered to be the causes of aggression, but also in its im-
plications for the management and control of human aggression.

Attempts to define a concept essentially represent an invitation for a
stroll through a semantic jungle. The journey, however, is instructive
because it reveals important issues about the phenomena selected for
analysis. Aggression, like most other concepts, has been characterized in
many different ways. Variations in defining features arise mainly because
some authors describe aggression solely in terms of attributes of the be-
havior, while others include assumptions about the instigators, the emo-
tional concomitants, or the intent of potentially injurious actions.

In the theory originally advanced by Dollard, Doob, Miller, Mowrer,
and Sears ( 1939), which occupies a prominent historical position, aggres-
sion is defined as "any sequence of behavior, the goal response to which
is the injury of the person toward whom it is directed." Most subsequent

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