The main aspect of human behavioral research had been to point out the influence of genetic factors as well as the environmental aspects on behavior of humans.
Various features of human beings such as cognitive ability, personality and interests are guided by various factors also. Different types of approaches have been adopted to specify the role of genes and environment on human behavior.
There are hence three levels of study;
(a)the role of genes in human behavioral make up
(b)the role of environment
(c) the additive role of genes and environment in shaping up a human behavior.
The genetic components had been divided further into two components such as the additive and non-additive components. These approaches are concerned with the linkage of genes and their dominance relationships with each other.
Whereas, the environmental components have further been simplified into shared and non-shared components. The shared components include all those sorts of environmental influences that arise in human beings due to various environmental factors (such as poverty, family income ,parental stress )that affect more than one individual at a time.
Whereas the non-shared components includes all those things that affect only one being at a time such as accidents, hypertension and differential parental treatments.
Methods used for determining the influence of these factors includes three main approaches given as the twin studies, adoption studies and gene identification methods. In the twin studies , it is concluded after examining the two types of twins such as MZT (monozygotic twins ) and DZT (dizygotic twins ) that the behavior of human being is very much influenced by genetic makeup.
The MZT’s individual will be more similar as compared to the DZT’s. Whereas the adoption techniques also concluded that various behaviors such as IQ, alcohol abuse and other social behaviors are at sometimes quite substantial.
Despite the various advanced studies we had been unable to find out the exact genes that had been influenced by environment and also the effects of these altered genes on the behavior of human beings. This failure is may be due to the heterogeneity of phenotypes produced by the same altered genes.
It is always of prime importance that the non-shared environmental influences have more prominent effects on the human behaviors as compared to the shared environmental factor.
Genotype environmental correlations have been a source of great diversity in behavior and sometimes genes are dominant and vice versa, but inadequate methods have made it impossible to issue a certain statement that either gene or environment is involved in the evolution of a desired behavior.
Hence the future approach of genotype environmental correlations would be to invent new techniques that could be fruitful for knowing the exact results. So more developments are required in field of genetic recognition as well as the environmental factors effects results to know the exact relationships.