Nature VS. Nurture: The eternal debate

Nature vs. Nurture. Do you have siblings? If so, do you behave similarly to your brother? Are you shy and reserved like your sister? Nature vs nurture is a concept common throughout psychology. It proposes questions about whether these similarities exist because of genetics or if they were they fostered by the environment. The longstanding nature versus nurture debate has been the source of many theories, treatments for mental disorders, and is relevant to daily life.

Nature vs. Nurture
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What is the Nature vs Nurture Debate?

Nature vs. nurture debate describes how innate, biological predispositions of human behavior arise from either genetics (i.e. nature) or environmental influence (i.e. nurture). While nature occurs from the DNA inherited from parents and are the traits we display from birth, nurture is the shaping of personality through exposure to parenting, surrounding relationships, home life, and education.

Nature vs. nurture is referred to as a debate because scholars and the general population alike have varying opinions on which concept—nature or nurture—has the strongest effect on human behavior. These questions regarding the origin of behavior can apply to personality traits, strengths, weaknesses, whether someone will develop an illness, and even learning.

History of Nature vs Nurture

The creation of nature vs. nurture attributed to psychologist Sir Francis Galton in 1869. However, the earliest evidence of the debate stems from Hippocrates in 400 B.C. Interestingly, Hippocrates classified human behavior’s as four body fluid types that he named humor: yellow bile, blood, black bile, and phlegm. His classification reflects his belief that human behavior is biological.

The Role of Behavioral Genetics In Nature vs Nurture

John Locke is another prominent figure in the 19th-century history of nature vs. nurture. Locke believed humans are born as “blank slates.” Over time, the slate accumulates individual differences that only develop because of the environment.

This perspective eventually led to psychologist John Watson’s behaviorism. Behaviorism is the study of human behavior. From a behaviorist perspective, human behaviors are affected by genes inherited and passed down from parent to offspring. Like Locke, Watson also shared the view that the environment shapes human traits—especially events occurring during childhood.

Nature vs Nurture Theories

Two theories have originated from the nature vs nurture debate. Nativism and empiricism are theories uncommon in modern times, as the terms differentiate two extremes and most do not ascribe to one extreme or the other. However, they were once influential in the past.

Nativism

Nativism is the extreme nature position. It is the belief that behavior, personality traits, and intelligence are inherent and solely determined by heredity. These traits are instinct, preprogrammed into the brain at birth based on the genes passed down from parent to children. Nativist, which is the term for someone who possesses the nativism stance, strongly regard evolution in the nativist theory. Human characteristics gradually evolve through maturation. Similar to the bodily changes of puberty, heritable traits and the cognitive development factors not evident from birth are triggered later in life by a hard-wired biological clock.

Empiricism

Empiricism is the extreme nurture position. To empiricists, also called environmentalists, human characteristics are not inherited from an individual’s parents. Instead, the mind is a blank slate at birth that is filled by influence from the environment. Human characteristics emerge with age through learning. That is, observing others and experience of past events, parenting, and more. The environmental influence is an act of behavior, which supports the impression of behaviorism on empiricism.

How Nature and Nurture Interact

Most people in modern eras do not hold the extreme perspectives of nativism or empiricism. Contrarily, they do not view from a nature “vs” nurture schema. Rather, they consider nature “AND” nurture in which the two views interact and cannot be separated. One plays off of the other. Genetics or environment alone does not guarantee a particular trait will be expressed. For instance, someone who partakes in unhealthy lifestyle habits like consuming large amounts of junk food and rarely exercising may avoid heart disease due to their genetics counteracting his unhealthy habits. There are specific genes that require certain environmental factors to become activated.

Twin Studies of Nature vs Nurture

Twin studies are common in nature vs nurture research, as they study hereditability. In twin studies, identical twins sharing 100% of their genes or non-identical twins sharing 50% of the same genes are the subjects. Sets of twins in these studies are reared apart and together to evaluate characteristics in both like and alternate environments. The goal of twin studies is to determine if nature or nurture has more of an influence.

Nature vs. Nurture
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Results revealed ratios of nature vs nurture are trait-specific. Personality and religiosity proved to be half genetically determined, yet traits such as intelligence (I.Q. level) are 75% genetic and 25% environmentally influenced.

Nature vs Nurture’s Effect on Cognitive Development

Cognitive development is the development of thinking processes like complex reasoning, planning, memory, sustaining attention, perception, goal formation, and problem-solving. These cognitive skills develop across all ages from infancy to adulthood.

The development of cognitive processes goes back to the interaction of nature and nurture. As nature and nurture interact, it requires a combination of genetics and the environment to influence development. Aside from the environmental factor of educational opportunity, a child’s genes have been found to control interactions. According to studies by Langlois (1995), parents respond to attractive and easygoing children in a more caring and affectionate manner than they do challenging or unattractive children, which shapes cognitive development.

Nature vs Nurture’s Influence on Mental Illness

Nature vs nurture is strongly connected to whether an individual develops a mental illness. The potential for a mental disorder is programmed by genetics. For example, having a family member with bipolar disorder increases the chances that another relative will have the diagnosis too. While the genetic predisposition to mental illness is significant, it does not dictate one will absolutely develop a condition. Genetics must interact with the environment for the condition to present itself.

Additionally, a nurturing environment can decrease the symptoms of a disorder. Families aware of an inheritable condition in their history can perform nurturing behaviors, like establishing a loving environment with optimal communication.

Substance Abuse

Substance abuse is a dependence on addictive substances (i.e. drugs, alcohol, tobacco products). Nature vs nurture is involved. Despite a genetic predisposition, the environment is critical in managing substance abuse. Sufferers or potential sufferers of substance abuse must take the necessary behaviors to ensure they have an environment without addictive substances present, as the environment promotes a genetic predisposition. A child growing up in a household is significantly less likely to become an adult who abuses substances if they are not exposed to the habits of parents and friends and if they do not have addictive substances readily accessible in their environment. “Nurture” drastically reduces the likelihood of developing the disorder or at the very least decreasing the substance abuse.

Depression

Depression is a mood disorder characterized by unexplainable sadness lasting three or more months. Irritability, apathy, fatigue, and a loss of interest in pleasurable activities are symptoms that typically accompany the diagnosis. Experts claim 40% of those with depression have a genetic phenotype for the condition. Genetics (nature) obviously play a key role in the development of depression, but that does not discount environmental influence (nurture). Unfortunate experiences, which are an environmental factor, are bound to contribute to depression symptoms.

Bipolar Disorder

Research in bipolar disorder also reflects nature vs nurture—particularly nurture. Bipolar disorder is a mood disorder causing shifts in mood ranging from manic phases to depressive phases that last weeks to months. Studies from the University of Manchester found that environmental factors such as emotional abuse were present in both children and adults with the condition. Other adversities, aside from the loss of a parent, were also proven to influence the development of bipolar disorder.

Schizophrenia

Schizophrenia is a mental disorder in which an individual distorts reality due to a breakdown between emotions, thoughts, and behavior. Nature and nurture are implicated, as discovered by researchers at John Hopkins University. By studying genetically engineered mice, researchers located schizophrenia-risk genes triggered by emotional stress after birth. Combined with stress, these gene defects lead to abnormal brain development to increase the risk of schizophrenia by 1.5 times. Their studies confirmed this consensus because individuals with only one factor, either a high risk gene or a traumatic experience during childhood, did not develop the disorder.  

Personality and Nature vs Nurture

Nature vs nurture is entwined with personality. We all have natural tendencies. People may be shy and introverted or loud, outgoing, and extraverted. But how did they possess those qualities? Sigmund Freud in 1905, along with other psychologists, emphasized a family’s role in personality development. To Freud, events in childhood and parenting were the central contributors to personality. However, researchers eventually learned that nature and nurture interact. The family does have a part in displayed personality traits, but we now recognize some personality traits are the outcome of genetics. Variances are due to differences in brain chemistry. That is not to discount the environment. There is plenty of existing evidence that environmental factors do change personality through parenting styles, socioeconomic status, relationships, and culture. For example, in American cultures, extraversion is widely accepted, yet in Asian cultures, it is not as agreeable. Development relies on what area of the world we are born in.  

References

Langlois, J. H., Ritter, J. M., Casey, R. J., & Sawin, D. B. (1995). Infant attractiveness predicts maternal behaviors and attitudes. Developmental Psychology, 31, 464–472.

Manchester University. Study finds strong link between childhood adversity and bipolar disorder diagnosis. Retrieved from https://www.news-medical.net/news/20161012/Study-finds-strong-link-between-childhood-adversity-and-bipolar-disorder-diagnosis.aspx

Pederson, T. (2018). Both Nature and Nurture Increase Risk for Schizophrenia. Retrieved from https://psychcentral.com/news/2012/03/28/both-nature-and-nurture-increase-risk-for-schizophrenia/36615.html

Shadrina, M., Bondarenko, E. A., & Slominsky, P. A. (2018). Genetics Factors in Major Depression Disease. Frontiers in psychiatry9, 334. https://doi.org/10.3389/fpsyt.2018.00334