Unit 2- Biological Theories Flashcards
Explain Lombroso’s Theory of Crime
Lombroso’s Theory of Crime is a physiological theory that argues that criminals are physically different from non-criminals, in which he measured the features of thousands of prisoners and noted prominent features such as: a large jaw, exceptionally long arms, bloodshot eyes. He believed that from these features could identify a criminal, moreover that these features where Atavistic, unable to
For example, a person may have an aquline nose, suggestring theyre a murderer.
Another, having a large jaw or high cheekbones would suggest criminality also, due to it relating to atavistic features
Atavistic Features
example 1
example 2
Lombroso: Strengths
First person to study crime scientifically, prev was a moral/religious issue
Importance of examining clincal and historical records of criminals
limited account of social and environmental factors
Focus on how we might prevent further crime rather than simply punishing offenders.
Lombroso: Weaknesses
Failed to compare findings to a control group of non-crimninals. Same characteristics may be in same gen pop
“primative savages” equates non-western societies with criminals. Scientific racism
Research failed to find link between criminality and facial features
Explain Jacob’s XYY Theory
Jacob’s XYY theory is a genetic theory that suggst that criminality can be caused through chromosomal abnormality. In human genetics, chromosomes are structures that contain our genes, most people having 23 pairs. The XYY genetic condition is when a male has an extra Y chromosome,which occurs in 1 of 1000 male births. Jacob’s et al suggested that men with XYY syndrome were more aggressive than XY men.
Chromosome
Supermale
Testerosterone
Example 1- More testosterone produce, more aggressiveness = Crime
Example 2- Taller, aggressive, poor social skills, predisposed to crime
Jacob: Strengths
Jacob et al found association between XYY and offenders imprisoned for violence
Price and Whatmore found some links between XYY and property crime
Jacob: Weaknesses
Even if violent offender has XYY doesnt prove it is the cause of their violence
Tall and well built, fit sterotype of violent offenders, labelled in courts, more likely to get a prison sentance. Overstates importance of XYY in crime
Over rep in prison, low int = more likely to get caught
1 in 1000, rare, cannot explain much crime
Explain Sheldon’s Theory
Sheldon’s Somatotype theory is a physiological theory that also links criminal behaviour to a persons form. He examined 4000 pictures of men and determined there where three fundamental body types/Somatotype. There are those who are Ectomorphs who are physically thin, and are iintroverted and restrained. Endomorphs, who are physically fat, and are sociallble/relaxed. Then there are mesomorphs, who are physically muscular, and aggressive and adventurous. Sheldon argued that mesomorphs are the most likely to commit crime due to their adventorousness they’re more likely to the risktaking of crime, alongside their physicality being a potential asset in assertivness.
Somatotype - Endomorphs, Ectomorphs, Mesomorphs.
Examples- Muscular, more likely to be criminal
Sheldon: Strengths
Replicated studies. Glueck and Glueck found 60% of offenders were mesomorphs
Most serious delinquents, Sheldons sample, where most extremly mesomophic body
Sheldon: Weaknesses
Glueck and Glueck found criminality best explained through a combination of factors and not just biology
Criminals may develop a mesomorphic build as need to be physically tough to suceed. Criminality causing somotype, rather.
Social class. Offenders mainly working class males, work manual jobs, may aqquire mesomorphic build
Doesn’t account for endomorphs and ectomorphs who commit crime, or mesomophs who commit non-violent crimes
Explain Twin Studies
Twin studies is a genetic theory that believes that crime is a heritable trait and observe both Monozygotic and Dizygotic twins to support this. Monozygotic twins are known as identical twins, and share 100% of their DNA. Meanwhile Dizygotic twin are non-identical twins and only share 50% of their DNA. Comparing the concordance rate of these two twin groups give evidence to suggest how genetics can cause crime. For example, Christiansen found that there was a 52% concordance rate in MZ twins compared to 22 in DZ twins regarding both twins having a conviction.
Concordance rate
Mono/Di-Zygotic
DNA, Heritable
Example 1- If twin commits crime, more genitically predisposed to commit crime also
Twin Studies: Strengths
MZ twins genetically identical, logical to examine where offending behaviour is also identical
Christiansen- 52% vs 22% concordance rate as below
Ishikawa and Raine found higher concordance rate for MZ twins than DiZ twins (both twin being criminals) 44% vs 21.6%
Twin Studies: Weaknesses
If genes where the only cause, concordance rate should be 100% for MZ twins. But is half or less
Higher concordance may be due to sharing environment (home, school) might cause simularitiy in criminal behaviour, not genes
Parents treat MZ twins more alike than DiZ twins. Plus MZ twins usually feel closer, potential cause one twin to be influenced
Explain Adoption Studies
Adoption studies are a genetic theory that maintains the belief that crime is a heritable trait. However, it seperates genetics and environment through using adopted children and comparing their criminality to their biological parents and adoptive parents. If the child follows the criminality of the biological parents, it suggests the biological (nature) hypotheis.
Example- Dad is criminal, get adopted, commit crime also.
Adoption Studies: Strengths
Overcome problem faced in twin stdies, where MZ twins are brought in same household. Impossible to seperate
Research design is logical. Allow to see importance of nature vs nurture.
Findings give support to genetic explainations. Adoptees were more likely to have criminal records if bio parents had criminal records
Adoption Studies: Weaknesses
Gottfredson and Hirschi argue adopt studies show genes having little affect on criminality
Adopted children often places in similar environment to birth family, same class, ethnicity. Similar environments, similar behaviour
Many children not adopted immediatly after birth, remain with bio family. May be early environment may be true cause of criminality.
