Biological Theories

Created by

diya

Cards (10)

Strengths of XYY Theory 
A study was done on prison inmates and it found that a significant number of them had the extra Y chromosome
Weaknesses of XYY Theory 
Having an extra Y chromosome does not pre-determine criminality and it does not therefore mean that a person will become a criminal
Ignores the fact that many people in the general population have an extra Y chromosome but are 'non-criminal'
Strengths of Mednick-Adoption studies
It does support the fact that there is a genetic component to criminality
Overcomes the problem faced by twin studies, where biologically identical twins are brought up in the same household, which makes it impossible to separate out the influence of genes from that of the environment
Weaknesses of Mednick-Adoption studies
The study sample was small and therefore may not be fully reliable
Adopted children are often placed in environments SIMILAR to those of their birth family e.g. live locally
Strengths of Twin studies
Research support - Christiansen (1977) examined over 3500 twin pairs in Denmark and identified a higher concordance rate of criminality between identical (MZ) twins (who share 100% of genes) compared to non-identical (DZ) twins-including criminality is genetic
Weaknesses of Twin studies
However, concordance rates are never 100% indicating that criminality is not entirely genetic, but must be in part caused by upbringing
Strengths of Lombroso-Born Criminal Theory 
He's one of the first scientists to Investigate links between physiology and criminality
Weaknesses of Lombroso-Born Criminal Theory
Lombroso was criticized for being prejudiced against a person's physical traits
Many people have the characteristics that Lombroso lists (e.g. big ears, big nose etc) but are not criminals
Strengths of Sheldon-Body Types 
His study did find that the majority of criminals were mesomorphic-
Weaknesses of Sheldon-Body Types
A person's body shape may change over time. Does this mean that criminality can therefore change?