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AGGRESSION, "EXECUTIVE FUNCTION" LINKED
A new large-scale study suggests that aggressive boys are handicapped by poor "executive
functions"-that is, they show impairment in brain functions including planning, abstract
reasoning, problem solving, attention, concentration, and controlling short-term behavior to achieve
long-term goals.
Jean R. S,guin et al. followed 177 boys from age 6 to age 12. The subjects were then divided into
three groups: "stable aggressive," "unstable aggressive" (those not as consistently aggressive as the
first group), and nonaggressive. The researchers administered tests to the boys at adolescence, and
found that "tests of executive functions had the strongest association with physical aggressive
behavior, over and above tests of verbal learning, cerebral dominance, and incidental spatial
learning." Even when social factors were controlled for, the researchers say, aggressive boys
exhibited difficulties in executive functions. Unstable aggressive boys also showed impairments.
The researchers note that deficits in executive functions have been linked to hyperactivity, which in
turn is associated with aggressive behavior. In addition, such deficits have been reported in
alcoholic men's sons, a group with an increased risk of hyperactivity and conduct disorder.
Executive functions appear to be performed by the frontal lobes of the brain, and several studies
strongly link criminal behavior to frontal lobe defects
(See Crime Times, Vol. 1, No. 1/2, Page 1 and
Crime Times, Vol. 1, No. 4, Page 6).
"Although early clear-cut frontal damage leads to comportmental difficulties in childhood and
adulthood," S,guin et al. say, "the present impairments in executive functions may be undetectable
neuroanatomically and may be solely at a neurochemical or physiological level."
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"Cognitive and neuropsychological characteristics of physically aggressive boys," Jean R. S,guin,
Robert O. Pihl, Philip W. Harden, Richard E. Tremblay, and Bernard Boulerice, Journal of
Abnormal Psychology, Vol. 104, No. 4, 1995, pp. 614-624. Address: Robert O. Pihl, Psychology
Department, McGill University, 1205 Docteur Penfield, Montreal, Quebec, Canada H3A 1B1.
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