Genes Versus Environment Genetic Transmission Methodologies Family Studies Twin Studies Adoption Studies Results References Links Home Research in behavior genetics has shown that almost all personality traits have both biological and environmental bases. One such trait is Intelligence . An alternative approach on which biology leaves its signature is Evolutionary Psychology . Genes Versus Environment Behavior genetics is a field in which variation among individuals is separated into genetic versus environmental components. The most common research methodologies are family studies, twin studies, and adoption studies.
Shared environment is the environment shared by siblings reared in the same family.
This includes such variables as socioeconomic status and parent education. Nonshared environment is the environment unique to the individual. This includes such variables as peer group. It is important to note that there is no single gene for intelligence, personality traits, behavior, or even height. Rather, such complex characteristics are polygenic, i.e., they are influenced by multiple genes.