3-05 Attack And Escape Behavior (Part 1)

Front 1

Objective

Describe the effects of genetics and environment on criminal behavior.

Back 1

Genetic Factors: Monozygotic twins resemble each other more closely than dizygotic twins do with regard to violent and criminal behaviors, and adopted children resemble their biological parents more closely than their adoptive parents.

Environmental Factors: During childhood and adolescence, dizygotic twins resemble each other in terms of their delinquent behavior as much as monozygotic twins. The prenatal environment can also play a part in criminal behavior. The more a mother smokes during pregnancy, the more likely her son is to be arrested for criminal activity in adolescence and early adulthood. This effect is compounded by complications during delivery.

Environmental factors can combine with genetic factors. One study of adopted children found the highest probability of aggressive behaviors and conduct disorders among those who had biological parents with criminal records and adoptive parents with marital discord, depression, substance abuse, or legal problems. A biological predisposition alone or a troubled adopted family by itself produced only moderate effects.

Front 2

Objective

Discuss the relationship between testosterone and aggressive behavior.

Back 2

In the animal kingdom, male aggressive behavior depends heavily on testosterone, which is highest for adult males in the reproductive season. Similarly, throughout the world, men fight more often than women, get arrested for violent crimes more often, and shout insults at each other more often. Moreover, the highest incidence of violence is in men 15 to 25 years old, who have the highest testosterone levels. Also, studies have shown that high testosterone levels were more common among men imprisoned for rape or murder than among those imprisoned for non-violent crimes (burglary, drug offenses).

Testosterone does not compel violent behavior, but it alters the way people react to various stimuli. In one study, young women who received injections of testosterone showed a greater than usual increase in heart rate when they looked at photographs of angry faces. Testosterone may induce people to attend longer and respond more vigorously to situations related to aggression and conflict.

Front 3

Objective

Cite evidence that serotonin plays a part in aggressive behavior.

Back 3

Turnover is the amount of release and resynthesis of a neurotransmitter by presynaptic neurons. A brain with low serotonin turnover releases relatively small amounts of serotonin and therefore does not need to resynthesize much of it. Serotonin turnover can be low even if the brain’s total serotonin content is normal.

In humans, researchers have found low serotonin turnover in people with a history of violent behavior, including people convicted of arson and other violent crimes and people who attempt suicide by violent means. Children and adolescents with a history of aggressive behavior who have relatively low serotonin turnover are more likely to get into trouble for additional aggressive behavior during the following two years. Follow-up studies on people released from prison found that those with lower serotonin turnover had a greater probability of further convictions for violent crimes. A study of people who had survived suicide attempts found that low serotonin turnover levels predicted additional suicide attempts within the next five years. Suicide rates are highest during the times of year (late winter and early spring) when serotonin turnover is lowest. And people fed diets low in tryptophan, which is a precursor for serotonin, show an increased tendency towards aggressive behavior, as do those with low levels of tryptophan hydroxylase, the enzyme that converts tryptophan into serotonin.

Front 4

intermittent explosive disorder

Back 4

Condition marked by occasional outbursts of violent behavior with little or no provocation; linked to temporal lobe epilepsy

Front 5

turnover

Back 5

The amount of release and resynthesis of a neurotransmitter by presynaptic neurons

Front 6

5-hydroxyindoleacetic acid (5-HIAA)

Back 6

A serotonin metabolite found in the blood, CSF, or urine; high levels of 5-HIAA imply much serotonin release and turnover