Encyclopedia of Psychology and Law

Although psychopaths are not psychotic, the

neurobiological mechanisms that normally impart

emotion to cognitions, thoughts, and attitudes appear

to be dysfunctional in the psychopath. The psycholo-

gist Robert Hare suggests that whereas genetic (and

other biological) factors determine the aberrant per-

sonality structure, the environment may shape how the

disorder is expressed as behavior. Positron emission

tomography and single-photon-emission computed

tomography scans have identified a number of specific

regions in the brains of violent psychopaths that do not

function normally. In particular, the prefrontal

cortex—part of the frontal lobes of the brain largely

responsible for rational decision making and impulse

control—appears to be underaroused, rendering it

incapable of effectively managing emotional urges.

Impulsive behaviors, including crimes, are the result.

However cognitive abilities are defined, certainly

they have a major role in criminal behavior. Where

research has used IQ as a measure of intelligence, by

and large offenders have lower scores than nonoffend-

ers. Typically, individuals with low intellectual ability

have difficulty delaying gratification, curbing their

impulses, and appreciating the alternative means to

get what they want. With substantial intellectual

impairment, they tend to be less inhibited from doing

harm because they lack the appreciation for the

wrongfulness of their conduct. Although environment

can facilitate or suppress the development and expres-

sion of one’s cognitive abilities, research indicates

that these have a substantial heritable component.

The concept of emotional intelligence holds con-

siderable promise for a more comprehensive under-

standing of chronic criminality. Those with low

emotional intelligence—people who lack insight into

their own behavior and empathy toward others—are

less inhibited about violating the rights of others.

Injury to the (ventromedial) prefrontal cortex has been

linked to the onset of reckless and antisocial behavior

(including violence) without remorse, suggesting our

moral compass is rooted in specific frontal lobe func-

tions that for the chronic offender are defective.

Much neglected in the mainstream literature on

criminal behavior are the effects of traumatic events in

early childhood from a psychoanalytic perspective.

Twenty-first century technology provides for—should

we choose—a recasting of Freudian constructs as spe-

cific neurobiological factors. The id, responsible for

generating unconscious and primitive urges, may cor-

respond with the limbic system—which includes brain

structures involved in basic emotions, motivation, and

memory. The aspect of the personality Sigmund Freud

referred to as the ego mediates the self-centered

demands of the id. The ego develops in childhood and

grounds the individual in reality. It would be this ratio-

nal aspect of personality that negotiates with the emo-

tional and impulsive id. Read frontal lobes here. As for

Freud’s superego, the moral aspect of personality may

well “reside,” at least partially, in the ventromedial pre-

frontal cortex. Remorseless antisocial behavior follows

damage to this area of the brain. Reconceptualizing

Freudian constructs in this manner need not negate

their validity, for the basic tenet—relating defects

of personality to early trauma—remains intact. Rather,

a neurobiological interpretation of psychoanalytic

processes affords them something they heretofore

lacked—the ability to be empirically validated.

While we refer to disordered mental states or dis-

eased mind, frequently understated or unstated are the

neurobiological processes that underlie them. Whatever

the psychological problem, we can no longer speak of

the psychological factors associated with criminal

behavior without also discussing biological factors—

virtually in the same sentence.

Biological Factors

The numerous and varied social and psychological

factors that increase the risk of criminal behavior are

mediated by biological processes.

Proper diet is essential to optimal brain function. For

example, complex carbohydrates are broken down to

make glucose—the basic fuel for the brain. Many nutri-

ents are involved in converting that glucose into energy.

A deficiency in any one of these essential nutrients com-

promises brain function by lowering the available

energy. The frontal lobes of the brain, responsible for

rational thinking, organizing behavior, and moderating

emotional impulses, require approximately twice the

energy as the more primitive regions. If energy levels

are depleted, higher functions become impaired leaving

lower brain activity uninhibited. Effectively, our emo-

tions will have their way with us. Beyond basic energy

needs, specific nutrients are required for the synthesis of

neurotransmitters. It is, therefore, understandable how

malnutrition compromises cognitive function and, in so

doing, facilitates antisocial and aggressive behaviors.

Of the diagnosed illnesses associated with violent

behavior, substance abuse ranks highest. The disin-

hibiting effects of alcohol are evident in police

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