Nature vs Nurture in Behavioral Determination

“Nature versus nurture” is a term that was coined to express the debate and dual nature of human behavioral development. Nature denotes inherent characteristics to a person’s life which are innate or genetic in nature, whereas; nurture denotes shaping or rather factors that are shaped by the surroundings and personal experience (Mercadant, 2008, p. 1) The inheritance of physical characteristics from our parents is indisputable and rather outright apparent, but the inheritance of behavioral characteristics is not wholly attributable to genetics. The relative importance of genetics and environment in determining behavioral make up is not easily quantifiable, but various researches attest to the fact that human behavior is a product of nature (genetic factors) and nurture (environmental factors) (Bryner, 2006, p. 1).

Scientists studying genealogy have proven that some physical characteristics such as eye and hair color are determined by specific genes. Out of further researches some scientists have taken it a step further and stated that even abstract behaviors such as intelligence, aggression and personality are genetic and thus nature-determined. The nature theory has been supported by various research cases. For example, a research by Adrian (2008, p. 325), showed through molecular-genetic and brain imaging findings that genes alter the brain structurally and functionally in a manner that finally predisposes the affected individuals to antisocial behavior. For example, a specific polymorphism in Monoamine oxidase A has been positively associated with reductions in the brain volume of the amygdala and antisocial behavior. Similarly, a research by John, Howard and Tatiana (2010, p. 64), has shown that 50%-60% of the risk variance in developing alcoholism is genetic associated. In this study DNA variants that contribute to a higher risk as well as a group of responsible genes have been identified. Versions of the gene CYP2A6 have also shown that some people have a capacity to metabolize nicotine which is quite different from others and thus allowing them to smoke more (Mercadant, 2008, p. 1). These facts show that indeed genes are influential in behavior.

On the other hand, the influence of the environment on behavior has been proven through widespread research in psychology. Experimental studies by famous psychologists such as Pavlov and Watson have greatly contributed to the development of the classical and operant conditioning theories that popularly explain the origin of behaviors from an environmental perspective. An example through research by Mayo Clinic researchers shows that exposure to chemical agents has a greater influence in the development of Parkinson’s disease in men, while women’s susceptibility is influenced by genes. This other numerous researches bear significance to the nurture effect (Mercadant, 2008, p. 1).

However, the introduction of the environmental effect on influencing genes and genetic expression finally renders the nature effect down-played in overall effect. Some researchers have proven that epigenetic markers on genes define their level of expression, and in turn these levels of expression through the markers are subject to influence of environmental factors such as exposure to chemicals (Bryner, 2006, p. 1).  In related research Bronfenbrenner and Ceci, hold that there is a need for a stable supportive environment for a gene to attain expression and support for expression, which if absent may lead to lack of expression or suppressed expression which is weak (Lang, 1995, p. 1).  According to the two, heritability only tells about genes that the nurture brings to fruition, whilst concealing what nurture suppresses.

In conclusion, it is observed that both nurture and nature have influence on behavior, but a closer look reveals that nature has a power of expression, but which is under the control of nurture, and since nurture is self expressive as well as influential on nature. Then it can be philosophically derived that nurture determines and influences behavior by a larger margin than nature does. Therefore, a larger portion of human behavior is determined by nurture rather than nature, because nurture has a double influence-its own influence and some over nature.


Adrian, R. 2008. From Genes to Brain to Antisocial Behavior. Current Directions in Psychological Science (Wiley-Blackwell) Volume 17, Issue 5, p. 323-328.

Bryner, J. 2006. Nature vs. Nurture: Mysteries of Individuality Unraveled. Available on

John, C. C. Howard, J. E. And Tatiana, F. 2010. Genetic Research: Who Is At Risk for Alcoholism? Alcohol Research & Health, Volume 33, Issue 1/2, p. 64-75.

Lang, S. 1995. Researchers challenge nature vs. nurture argument. Human Ecology, Volume 23, Issue 3.

Mercadante, A. 2008. The Role of Nature and Nurture in Shaping Human Behavior. Available on

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