Biological Explanations 1
Psychology: AQA A Level, topic 16.1.6
Genetic Explanation of Criminality: Adoption Studies
There are three main pieces of evidence for the genetic explanation of criminality: adoption studies (such as Mednick et al, 1984), genetic influences on aggression and extra Y chromosome studies.
Adoption studies
- Adoption studies examine concordance rates of criminal activity.
- Concordance means that if one person shows criminal behaviour, what is the likelihood that another person will.
- In the case of adoption studies, concordance is measured between the adopted child and:
- adoptive parents
- genetic/biological parents.
Concordance rates
- These studies have found that there is a higher concordance rate of criminal activity between the adopted children and their biological parents.
- This demonstrates strong evidence of the role of genetics in criminality.
- An example of an adoption study would by Mednick et al. (1984) who studied criminal behaviour in adopted children.
Method:
- 14 427 Danish adopted children were analysed according to concordance.
- The concordance rates of criminality were compared between:
- The adopted children and their adopted parents.
- The adopted children and their biological parents.
Results:
- 13.5% of adopted children had a criminal conviction with biological or adoptive parents with no criminal convictions.
- 14.7% of adopted children had a conviction with at least one adoptive parent who had a criminal conviction.
- 20% of adopted children had a conviction with at least one biological parent who had a criminal conviction.
- 24.5% of adopted children had a conviction rate with at least one biological parent and one adoptive parent with a criminal conviction.
Conclusion:
- There is a genetic link of criminality.
- However, overall, the concordance rates are low, therefore, there is likely to be other factors that lead to criminality.
Evaluation: Strengths
- Adoption studies are important in the nature vs. nurture debate as they can separate out the genetic and environmental influences. Therefore, this is a powerful study.
- The sample size was very large, increasing the validity of the results.
Evaluation: Weaknesses
- However the study only looked at criminal convictions, not at crimes committed. This is a limitation of the study.
- In other words, people could have committed crimes and not been convicted. This could cause different results.
Test yourself on Biological Explanations 1
Studies have found that there is a higher concordance rate of criminal activity between which set of relations?
What nationality were the children in the study?