Biological theories Flashcards
Who are the physiological theorists?
Lombroso and Sheldon
What are the genetic theories?
XYY, twin studies, adoption studies
What was Lombroso’s theory?
That facial and cranial features could link to criminality. This is atavistic form.
What are examples of atavistic features?
Big ears
High cheekbones
Curly hair
Dark skin
Etc..
What are the three somatotypes?
Mesomorph
Endomorph
Ectomorph
Who is the most and least likely of the body types to become criminal?
Most likely - Mesomorph
Least likely - Ectomorph
Evaluation of Lombroso?
Could be scientifically racist
Found only 40% of over 4000 convicts studied had atavistic features
Seen as the founding father of Criminology so his theories have value in criminology
Evaluation of Sheldon?
Body shape can change over time
Not all mesomorphs commit crime/not all criminals are Mesomorphs
Could cause prejudice against mesomorphic body type.
What is the XYY theory?
Some men can have an extra XYY chromosome, which Jacobs et al has found can make men more aggressive
Example of XYY?
John Wayne Gacy, killed, tortured and sexually assaulted 33 men/boys
What are the two types of twins?
Monozygotic and Dizygotic
Christiansen (1977) found what?
Concordance rates for criminality.
MZ- 35% (males) DZ- 13% (males)
MZ- 21% (women) DZ- 8% (women)
What does Christiansen’s study suggest?
That criminality is partly genetic, but not fully genetic
What did Lange (1929) find?
MZ twins have a higher concordance rate than DZ twins for criminality.
MZ- 10/13
DZ- 2/17
Evaluation of XYY?
Jacobs et al found that XYY was overrepresented in prisons (15 in 1000 compared to 1 in 1000)
Dangerous ideology to assume someone is born evil, fuel eugenics
Sample size too small
