To what extent does genetic inheritance influence behaviour? Use relevant research studies in your response. (To what extent means that you have to consider the merits or otherwise of an argument or concept, Opinions and conclusions should be presented clearly and supported with appropriate evidence and sound argument.)

Behavioural genetics is an understanding of how genetics and the environment work together to build up the human behavior. DNA plays a role in behavior if the genes are inherited. Studies about twins, families, and adoption show how inheritance influences behavior.

Genes and their DNA are passed to us from our parents. A human have 23 pairs of chromosomes with about 20000-25000 genes. In 1990, James D.Watson tried to identify all 25000 genes by mapping the genetic make-up of humans which were succeeded in 2003. This mapping of the genes could be an important step in explaining the human behavior. In spite of this accomplishment, however the role of specific genes in specific behavior still remains unknown.

Bouchard et. Al. (1990) carried out the Minnesota Twin Study which is a study that compared twins that was raised together (MZT) and twins that was raised apart (MZA.) This study has participants from all over the world and it is the most cross-cultural study to date. Each twin that participated in this study had to complete approximately 50 hours of testing and interviews. Bouchard Et. Al. determined a heritance estimate of 70% which means that 70% of intelligence can be linked to genetic inheritance, which means the 30% left, can be attributed to other factors such as the environment. There are some criticisms of this study even though it is one of the most impressive twin studies carried out because of the size and nature. Some of the criticism was that there were some ethical concerns about the way he reunited the twins. I don’t see how the reunion of the twins could’ve affected the results. It is not likely that the genes would change after the reunion of the twins.

A child inherits 50% genes of the mother and 50% genes of the father. Brothers and sisters share 50% of genes with one another while the grandparents share 24% of the genes with their grandchildren and cousins will have 12,5% genes in common. These levels of genetic similarities in family studies are compared with behavior. Family studies are used to compare genetic relatedness to behavior. According to family studies, we can predict how inheritability and IQ can affect each other in their relationship. The strength of family studies is that the sample that is used is more reflective to the rest of the population which means it has more ecological validity and the situation is more controlled.

An adopted child will not have any genes in common since the child is not related to the parents, but the adopted child would share 50% of genes with the biological mother. It would be reasonable to suppose that if the heritability of a behavior is high and the environment has a small part to play then the behavior of adopted children should correlate more strongly with the behavior of their biological mother, but if on the other hand the environment has a stronger influence, then the behavior would more likely be like the adoptive parents. Adoption studies are used to see the effect

of the environment on people, an example of this is when the adoption children are reunited with their biological parents to see which more they are likely more similar to. This would make the researcher see which IQ correlations are similar to the child, the adoptive parents or the biological parents. A lot of adopted children end up in homes where the parents are rich and there social status is middle or high, which may cause that all adoptive children would have similar homes and therefore there wouldn’t really be an interesting case to study, which is a limitation to the adoption study. Another limitation would be if the researcher would have to find the biological parents to see similarities which can cost a lot of money and time. A strength of this study is that this study is more likely the most direct method to study the correlation between genetic inheritance and environment and how they are more likely are effecting behavior.

Through studies and research, we can conclude that inherited genes can influence behavior but only to an extent, because the environment also plays a role in behavior.