AC2.1 Biological theories of criminality Flashcards
What are biological theories?
Focused on the idea that physical characteristics make some people more likely to commit crimes than others. Some may be genetic or environmental.
What is the XYY theory?
Suggests that some crimes may be attributable to a chromosomal abnormality. XX is a woman, XY is a normal man but there is a chromosome abnormality that makes XYY, these men are usually nicknames ‘Super males’.
What are the characteristics of XYY men?
Can be more aggressive and inclined to violence.
What are chromosomes?
Chromosomes are the structures in cell nuclei and humans usually have 46 chromosomes (23 pairs) 44 of which determine the shape and constitution of our bodies and the other 2 determine sex.
What did Jacobs study suggest?
XYY are more likely to be criminals. 15 per 1000 in prisons, 1 per 1000 in the general population.
What did the Twin Studies support?
Supports the contention that a heritable trait may increase risk of criminal behaviour.
What are the 2 different types of twins?.
Identical twins are monozygotic as they are from one fertilised egg and share 100% of their DNA. Non identical twins are dizygotic and are from two separate eggs therefore share half of their DNA. When both twins share a trait there is said to be a concordance rate.
What did Johannes Lange ( find in his twin study?
He found that MZ twins have a much higher degree of concordance than DZ twins for criminal behaviour. He studied 13 MZ twin pairs and 17 DZ twin pairs and found that 10 of the 13 pairs of MZ twins had both been in prison where as only 2 of the 17 pairs of DZ twins had both been in prison.
What did Christiansen (1977) find in his twin study?
He studied 3,586 pairs of twins from the Danish islands and found concordance rates of 35% for MZ and 13% for DZ when it came to males, and 21% for MZ and 8% for DZ when it came to females.
What was the adoption studies?
Compared adoptive children’s likelihood to be criminal with their biological and adoptive parents to determine whether criminality is nature or nurture.
What did Hutchings and Mednick (1975) find in their adoption study?
They studied 14,000 adopted children and found that a high proportion of boys with criminal convictions had biological parents with criminal convictions which suggests a link between criminality and genetics.
What did Mednick (1994) find?
Found no relationship between the number of criminal convictions between adoptive parents and their adoptive children but did find a significant correlation in criminal convictions between biological parents and their offspring.
What were physiological theories?
Focuses on a persons physical form as an indicator of criminality.
Who is Cesare Lombroso?
An Italian psychiatrist and military doctor that developed theories about criminals. He is known as the ‘Father of modern criminology’.
What did Lombroso claim?
He claimed that criminality was heritable and those who committed crimes had atavistic features.
What does atavistic mean?
Relates to something ancient or ancestral.
What are some of the Atavistic features that Lombroso thought interlinked with criminality?
. Large or forward projection of the jaw
. High cheekbones
. Flat or upturned nose
. Low, sloping forehead
. Long arms relative to lower limbs
. Large ears
What were the findings from Lombroso’s study?
Lombroso studied the facial and cranial features of 383 dead criminals and 3839 loving ones, and concluded that 40% of criminal acts could be accounted for by atavistic features.
Other than physical traits, what, according to Lombroso, were some other aspects of born criminals?
. Insensitivity to pain
. Usage of criminal slang
. Tattoos
. Unemployment
What did Lombroso say about how criminals look?
According to Lombroso, you can tell what crime someone will commit by the way that they look. For example, murderers had bloodshot eyes and curly hair, and sex offenders had thick lips and protruding ears.
What was William Sheldon’s (1949) theory?
He agreed with Lombroso’s idea that criminality is linked with a persons physical form and put forward three body types (somatotypes).
What is a somatotype?
Body shape
What were Sheldon’s 3 body types?
Endomorphic - (fat and soft) tend to be sociable and relaxed.
Ectomorphic - (thin and fragile) are introverted and restrained.
Mesomorphic - (muscular and hard) they are more aggressive and adventurous.
What was Sheldon’s findings from the correlation study?
He found that many criminals prone to committing violent and aggressive acts were mesomorphic, and the least likely sure ectomorphic. He used a sample of college students and delinquents rated on a scale of 1-7 their resemblance to mesomorphy.
What is a PET scan?
Positron emission tomography (PET) scams are used to produce detailed three-dimensional images of inside the body.
What was the Brain Abnormality theory?
Research that shows how damage to the pre-frontal cortex of the brain may cause individuals to have altered behaviour pattern. They would become more immature and have an increased loss of self-control as well as an inability to modify behaviour.
How did Raine (1994) study brains of killers?
By using PET scans to study the living brains of impulsive killers. Damage was found in the pre-frontal cortex in the brains of criminals (the part of the brain that controls impulsive behaviour).
Phineas Gage case study:
Gage was a railroad worker that survived a large iron rod that went through his head, destroying a large part of the left frontal lobe of his brain. His personality and behaviour changed dramatically and he became extravagant, anti-social, used bad language, had bad manners and became a liar.
McIsaac case study:
A Canadian study carried out by McIsaac (2016) found that people who have suffered serious head injuries are twice as likely to end up in prison (0.5% compared to 0.2%). It also found that female prisoners were even more likely to have suffered from a traumatic brain injury and the risk of them ending up in a Canadian federal prison was 2.76 times higher than it was for women without.
What was the neurochemical theory?
The brains chemistry can be influenced by diet, for example, food additives, pollution, or hypoglycemia (low blood sugar associated with forms of diabetes). Some studies show that low levels of serotonin are linked to higher levels of aggression. Serotonin regulates signals between neurons and is said to control a persons mood.
What were Scerbo and Raine’s (1993) study and findings?
They conducted a meta-analysis on 29 studies into antisocial adults and children and found low serotonin in all of them. Control of serotonin levels by diet is possible and some foods including dark chocolate, cheese, salmon, nuts and chicken can raise the levels.
What did steroids do to Horace Williams?
Horace Williams was an American bodybuilder who beat a man to death after taking 2,000 times the recommended dosage of steroids. Over usage of steroids can cause individuals to become extremely violent(roid rage).
