PassingPsych

Genetic similarities refer to the proportion of genes or DNA that is shared between populations. Genes carry information that determines your traits, which are features or characteristics that are inherited from your parents. By examining individuals or animals that share a high proportion of DNA with us, we can understand the potential role of genes in behaviour. For instance, if we share a high proportion of genes and exhibit the same behaviour, there is a higher likelihood of this behaviour being genetic. In family studies, different degrees of genetic relations are compared with respect to behaviours. In this essay, I will provide a detailed account of the reasons and/or causes for the impact of genetic similarities on behaviour, using the supporting study of Hutchings and Mednick.

Hutchings and Mednick aimed to investigate how the level of genetic similarity affected aggressive behaviour in adopted children who had biological parents with criminal convictions, and the likelihood of future generations committing criminal acts. To investigate, they conducted a quasi-experiment involving 14,000 adopted children. They found that if both the biological and adoptive fathers had criminal records, then 36% of the sons also had a criminal record. If only the biological father had a criminal record, it dropped to 21%. If only the adoptive father had a criminal record, then only 11% of sons had a criminal record. When neither adoptive nor biological fathers had a criminal record, the rate of the sons having criminal records was 10%. This demonstrates the importance of environmental factors, combined with genetic factors, in determining whether or not one will have criminal convictions.

Hutchings and Mednick illustrate the relationship between genetic similarities of parents and children with criminal behaviour. For example, there was a higher correlation of criminal convictions from a child when their biological parent committed a crime than when an adoptive parent did. This is significant as biological parents share 50% of their genetics with their children, whereas adoptive parents share none of their genetics with their children. Therefore, it is possible to argue that criminality is genetic and thus predetermined. Consequently, family studies are useful in investigating the impact of genetic similarities on behaviour.