In men, high levels of endogenous testosterone (T) seem to
encourage behavior intended to dominate – to enhance one's
status over – other people. Sometimes dominant behavior is
aggressive, its apparent intent being to inflict harm on another
person, but often dominance is expressed nonaggressively. Sometimes
dominant behavior takes the form of antisocial behavior, including
rebellion against authority and law breaking. Measurement of T at a
single point in time, presumably indicative of a man's basal T
level, predicts many of these dominant or antisocial behaviors. T not
only affects behavior but also responds to it. The act of competing
for dominant status affects male T levels in two ways. First, T rises
in the face of a challenge, as if it were an anticipatory response to
impending competition. Second, after the competition, T rises in
winners and declines in losers. Thus, there is a reciprocity between
T and dominance behavior, each affecting the other. We contrast a
reciprocal model, in which T level is variable, acting as
both a cause and effect of behavior, with a basal model,
in which T level is assumed to be a persistent trait that influences
behavior. An unusual data set on Air Force veterans, in which data
were collected four times over a decade, enables us to compare the
basal and reciprocal models as explanations for the relationship
between T and divorce. We discuss sociological implications of these
models.