GENOTYPE-ENVIRONMENT CORRELATION
The 20th century saw the first fierce debate on matters genes in understanding genetic informative data sets on humans’ behavior, such as understanding identical twins’ differing behaviors. As a result of this fierce debate, there was in-depth research into the causes and consequences of genetic variation in environmental exposures. This phenomenon was termed Gene-environment correlations (rGE). rGE occurs when there are genetically influenced differences as a direct consequence of exposure to risk factors in the environment. Under rGE, there are different genotypes whose differing traits are based on individuals’ ability to choose, manipulate, or inherit according to the environments. Therefore, in the presence of rGE, there is an expectation for different genotypes to systematically experience different environments as a direct consequence of the different traits. rGE, as a concept formalized the pre-existing notion that there is a link between genes and environment and that environments as well as genes, are likely to “run in families.”
Gene-Environment Correlation
rGE has a distinct influence on a person’s psychological makeup, affecting their behavioral patterns and the environmental surroundings chosen throughout their life. Gene-environment correlation is an underlying factor to behavior because it occurs upon exposure to environmental conditions that depend on one’s genotype. Gene-environment correlations between two traits, such as height and weight, means that when one changes, the other also varies and can arise from influences of both causal and non-causal mechanisms, even Genetic variants. This, in turn, influences environmental exposure indirectly through behavior. There are three types of these typical interactions, passive, evocative, and active, and each possesses negative and positive results for the correlation between genetic factors and environmental factors. Gene-environment relationships are influential influencers on child temperament, behavior, and psychiatric ailments, among other effects.
- Passive gene-environment
Passive gene-environment correlation is the association between a child’s gene inherited from the parents and the environment in which it (the child) is raised. Parents create a child-rearing home environment under their heritable characteristics. Also, biological parents pass on their genes to their offspring. When this genotype also influences the child’s behavioral or cognitive outcomes, the result can be a counterfeit relationship between environment and outcome. For example, because parents with histories of psychotic behavior (which is heritable) are at higher risk of being abusive to their children, a case can be made for saying that abusive parenting may be an indicator for the genetic risk that parents transmit to children rather than a causal risk factor for children’s behavioral problems.
- Active gene-environment
Active gene-environment correlation is when an individual possesses a heritable predisposition to selective environmental exposure. It is a genetic variation in choice behaviors. With dynamic gene-environment correlation, an individual selects environments based on genetically influenced traits. For example, a characteristically extroverted individual is likely to seek out very different social environments compared to introverts. Another example is when students with higher IQ may pursue more challenging subjects, further increasing their aptitude. In psychology, active gene-environment is the root cause of substance use and choice of friends. In ecology, this genetic variation influences choice of habitat, choice of mate, and so on, which in studies of animal behavior is also referred to as “niche-picking.”
- Evocative gene-environment
Evocative gene-environment correlation is when a person’s genetically influenced traits evoke an environmental response. For example, associations between marital conflict and depression may be a causative reflection of the tensions arising when engaging with a depressed spouse rather than a causal effect of risk for depression stemming from the marital conflict. According to the recent research, it was found that a child’s oppositional behavior toward the parent(s), which is influenced by genetic factors, elicits parent(s) use of parenting techniques such as spanking. Spanking is not genetically influenced; however, a child’s behavior may obtain more opportunities for a parent to feel the need to resort to using corporal punishment.
Conclusion
The passive gene-environment is based mainly on the family environment, which significantly influences an individual’s ability to suppress or encourage specific hereditary contributors to temperament and behavior. As for active and evocative gene-environment correlation, genetically altered traits have a differential influence on the exposure to and individual’s experiences/environments.
Reference
Plomin, R., DeFries, J. C., & Loehlin, J. C. (1977). Genotype-environment interaction and correlation in the analysis of human behavior. Psychological Bulletin, 84(2), 309.