Why do people commit Crimes? Contemporary Biological Theories of Criminology

Neurophysiological Theory  Focus on the study of brain activity and how neurological dysfunctions are connected with criminal activity  Neuroscientist James Fallon Neuroscientist James Fallon

Neurophysiological  Raine 1994 used PET (positron emission tomographyscans) to study the living brains of impulsive killers. Raine  Damage was found in the pre- frontal cortex, which controls impulsive behaviour.

Neurophysiological PET Scanner

Neurophysiological PET Scan

ADHD

A.D.H.D.  Attention deficit-hyperactivity disorder ( ADHD ) also known as hyperkinetic disorder (HKD) is a neurobehavioral disorder characterized by either significant difficulties of inattention or hyperactivity and impulsiveness or a combination of the two.neurobehavioral disorderinattentionhyperactivity impulsiveness  It is estimated that it affects 3 to 5 percent of children globally

ADHD  Another suggestion is that certain individuals, as a result of genetic predisposition or brain damage at birth, suffer from a cluster of symptoms which render them incapable of moral control  Because of cortical under arousal, they are constantly seeking stimulation.

involves the activation of the brain stem, the autonomic nervous system and the endocrine system, leading to increased heart rate and blood pressure and a condition of sensory alertness, mobility and readiness to respond.brain stemautonomic nervous systemendocrine system Cortical arousal

Neurochemical Explanations  The brain’s chemistry can be influenced by diet, for example, food additives, pollution or hypoglycaemia (low blood sugar levels associated with forms of diabetes).  i.e. Case of Dawn Stanton who attacked her husband with a knife when hypoglycaemic.  But not all diabetics without insulin act criminally.

The “Twinkie Defense”  term coined by reporters during their coverage of the trial of Dan White for the murders Harvey Milk and San Francisco mayor George Moscone.Dan WhiteHarvey MilkGeorge Moscone  White's defense was that he suffered diminished capacity as a result of his depression. Attorneys argued his change in diet from healthy food to Twinkies and other sugary food was symptomatic of his underlying depression.diminished capacity  White was convicted of voluntary manslaughter.voluntary manslaughter

Neurochemical Explanations – “Roid Rage”  Individuals who take large amounts of steroids can become extremely violent (known as "roid rage"). Steroids, usually taken to increase muscle growth, also increase testosterone levels.  Horace Williams, a body builder, beat a man to death after taking two thousand times the recommended dosage of steroids.

Twin studies  An 'MZ apart' study is when two monozygotic children have been brought up apart. If both turn out to be criminals then this would be support for a genetic explanation.  monozygotic twins identical twins developed from one fertilized ovum; they have identical genomes (genetic material).  Looking at a number of studies the average concordance rate is 55% for MZ twins and 17% for DZ twins (Bartol, 1999).

Adoption studies  A retrospective study by Mednick et al (1987) looked at court convictions in a small European country and found 14,000 adoptees amongst them.  The criminal records of their biological and adoptive parents were then investigated.  Many of the adoptees had criminal biological parents (particularly strong relationship for sons and fathers).

MAOA – “The Warrior Gene”  Monoamine oxidase A is an enzyme that breaks down important neurotransmitters in the brain,  i.e. - dopamine, norepinephrine, and serotonin.  People with the low-activity form (MAOA-L) produce less of the enzyme, while the high-activity form (MAOA-H) produces more of the enzyme.  Several studies have found a correlation between the low-activity form of MAOA and aggression in response to provocation  Born to Rage Born to Rage