Explanations of Criminal Behavior

Theories of Criminal Behavior

Who commits crime?

Brainstorm reasons for criminal behavior based on these three catagories: Social Economic Biological Other???

Theories of Criminal Behavior Biological Theories – genetic and physiological. Cause is

the individual, no real part played by social factors.

Personality Theories – certain types inclined to crime

Social Learning – learned criminal ways

Issue – Nature vs. Nurture debate

Old school theories………

Cesare Lombroso

Lombroso in 1876 argued that the criminal is a separate species, a species that is between modern and primitive humans. He argued that the physical shape of the head and face determined the "born criminal".

William Sheldon believed that body types determined criminality.

1. endomorphic (fat and soft) sociable and relaxed. 2. ectomorphic (thin and fragile) are introverted and

restrained 3. Mesomorphic = CRIMINAL (muscular and aggressive)

tend to be aggressive and adventurous. Sheldon found that many convicts were mesomorphic, and

they were least likely to be ectomorphic (Sheldon et al 1949).

MODERN THEORIES

Neurophysiological

Raine 1994 used PET scans to study the living brains of impulsive killers. Damage was found in the pre-frontal cortex, which controls impulsive behavior.

Neurophysiological

PET Scanner

Neurophysiological

PET Scan

Neurochemical

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).

The TWINKIE DEFENSE: A murderer in California claimed that the sugar in Twinkies caused him to become homicidal.

Neurochemical

STEROIDS? 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. However a direct link between steroids and violence has not been made.

http://www.youtube.com/watch?v=hN7rf4Mm1QA

Family Studies

Nature vs. Nurture

debate

Twin studies: Genetic influence on crime

IDENTICAL TWINS (same genes and gender) that have been separated at birth and brought up separately have been studied

The degree of similarity between two twins is known as the concordance rate.

This rate was compared with FRATERNAL twins who are brought up separately

Looking at a number of studies the average concordance rate is 55% for IDENTICAL twins and 17% for FRATERNAL twins (Bartol, 1999).

Psychopathy or Sociopathy? Psycho or Weirdo? PSYCHOPATHS (NATURE) Psychologists use the term psychopathy to describe a psychological disorder that is the

product of a combination of psychological, biological, genetic and, to a lesser degree environmental factors.

Studies have shown that psychopaths have inherent temperamental differences such as

impulsivity, fearlessness, and reduced physiological responsiveness resulting in a high level of risk-seeking behavior and lack of adherence to social

norms. Recent research has demonstrated that early signs predictive of psychopathy can be

present at a very young age (Viding 2005, Glenn 2007).

Sociopathy Sociopaths (Nurture) Sociologists typically prefer the term sociopath. sociopaths possess:

reasonably normal temperaments; their social pathology more a result of negative sociological factors such as parental neglect, running with the wrong crowd, poverty, and extremely low or extremely high intelligence(Lykken 1995).

Although all personality disorders are likely to be the result of some level of interaction between genetic predispositions and environmental factors, according to these definitions, psychopathy is defined primarily by hereditary and sociopathy by environmental influences.

Adoption studies

A study 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).

There was no relationship in the types of crime committed.

HOWEVER: Where there was an improvement in social conditions by adoptive parents there was a reduction in crime (going against the genetic explanation).