Role of Genetic and Environmental Factors in Determining Human Behaviour

The environment influences an individual's behavior within a framework established by genes through their effects on morphology and physiology. The environment can impact an individual's morphological and physiological development, affecting how that person behaves because of its internal structure. Additionally, genes lay the foundation for learning, memory, and cognition—impressive processes that enable us to gather and store data about our surroundings and utilize it to guide our behavior.

Role of Genetic and Environmental Factors

One of the oldest debates in psychology is the relationship between nature and nurture. Nature includes all of the genes and inherited traits that affect who we are, from our physical qualities to our behavioral traits. All the environmental factors that shape who we are, such as our early experiences, our upbringing, our social connections, and our surroundings' culture, are referred to as nurture. The main topic of discussion is how much genetic inheritance and environmental circumstances affect human development.

Behavioral Genetics

Research claiming to find a "gene for violence" or a "gene for homosexuality" is a typical occurrence. However, how may our DNA influence the way we behave? What exactly does "a gene for X" mean? Genes and diseases have a tangled interaction, and genes and behavior have an even more convoluted link. Because: More than one genetic component often contributes to a given trait, it is frequently challenging to determine which genes and how they do so. Depending on which additional elements an individual's genotype contains, these genetic factors may interact and have various impacts. Along with genetics, other non-genetic (environmental) factors also play a role. Environmental factors interact, which plays a significant role in developing human behavior. Additionally, genetic and environmental factors also interact, known as gene-environment interaction, which is an important aspect while considering human behavior. There are two kinds of gene-environment correlations, which are explored further below.

Gene-Environment Correlation− Active

An "active gene-environment correlation," as it is known in science, is one influence that genes have on individuals. Genes impact behavior in a way that makes people seek out and create particular conditions; therefore, it is active. Then, the circumstances they choose or create for themselves impact their personality. For example, an infant might wiggle around and move more than another. Activity level has a heritability of roughly 0.4. The more energetic babies will become more interested in playing games, kicking balls, and running around as they age.

They will be first in line when they reach the age at which children begin participating in sports. The less active kids naturally become less active adults and are not as interested in activities like learning karate or playing soccer, for example. They read more, play computer games, and spend more time with friends. These young people have chosen varied activities because of differences in their beginning levels of activity, and their personalities are thus affected differently by those varied endeavors.

Gene-Environment Correlation− Reactive

Reactive or evocative gene-environment correlations are the second type of gene-environment association. It is named evocative because a person's conduct might be affected by their genes in ways that elicit particular responses from others. Let us think about the quality of irritation. How laid back versus irritated each person is varied, and these variations are inherited again.

Consider the various responses that agitated vs. calm children routinely get from adults—from their parents, teachers, and even other children. Consistently, irritable youngsters will elicit more hostile reactions from others than laid-back kids. Adults will become more irritated with them more frequently, and fewer people will want to interact with them because they are disagreeable. Compared to pleasant and laid-back kids, they regularly generate a less pleasant social atmosphere. Less encouraging comments from others will gradually change someone's personality.

Creating surroundings compatible with a child's personality by parents is another illustration of a reactive gene-environment association. If a parent notices that their child prefers music but dislikes sports, they are more likely to buy them music-related items, advocate music courses over team sports, and so on. The child's genes encouraged conduct that inspired parents to change the surroundings, which had an impact on the child's personality later on.

Research Designs

Researchers can investigate the role that genetic factors play in shaping human behavior in various ways. The first type of study is observational research, which involves evaluating and contrasting individuals from the same family, such as twins or siblings, families, and adopted kids. Because it seeks to determine how much genetic elements in a population influence variance in a characteristic, this field of study is known as quantitative genetics. Without focusing on specific genes, it analyses and compares groups of people using statistical methods.

Studying cousins with the same genes (nature) but a different environment is one technique to do this (nurture). This is made possible via adoption, a natural experiment for researchers. Since environmental parents and their adopted children do not share a common ancestor, family environment is the likely explanation for their likeness.

Empirical research has repeatedly demonstrated that adoptive children resemble their biological parents more than adoptive or environmental parents. The first rule of behavior genetics, which states that psychological qualities are often very heritable (approximately 50%), is supported by twin studies and adoption research. According to behavioral genetics, many genes—often thousands—contribute to particular behaviors.

For instance, it is estimated that about 1000 genes play a role in depression. The majority of behavioral diseases have a genetic component. Genetic factors play a role in both psychopathology and disorders, as well as in the normal variance of personality traits and cognitive ability. Even social, political, and occupational preferences seem to be influenced by genetic characteristics. Second, scientists can look for genetic variations that lead to trait variance in a person's characteristics or traits. The name of this field of study is molecular genetics. Third, researchers can examine the effects of particular genes using animals.


Both genes and environment shape us in various ways. The strong influence of DNA on people's personalities is now undeniable. Genetic factors directly influence some mental characteristics and behaviors; others are brought on inadvertently by the intricate ways our genes influence and alter our behavior and environments. Science has advanced past the age-old nature-versus-nurture debate and provided us with deep insights into the human personality by examining these impacts. The precise molecular mechanisms underlying the intricate processes by which genes affect behavior are still a mystery.

Updated on: 12-Apr-2023


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