Nature vs Nurture: Genes or Environment

Nature vs nurture
(Last Updated On: March 6, 2019)

What is it that makes you who you are? Some might say that it is your genes that have the greatest influence in controlling your personality and preferences. Others might say that it is your environment and the unique experiences you have had over the course of your life that a greater role. In psychology, this argument between which side has the greatest impact on the course of development is known as the nature vs nurture debate.

What Is the Nature vs Nurture Debate?

The nature vs. nurture debate is consider one of the big philosophical and scientific questions facing psychologists. So what exactly does this debate mean? Why is it some important for understanding the human mind and behavior?  Let’s start by breaking down what each of these factors means.

  • Nature: This side of the debate argues that genes have the greatest influence over who we are, from the way we look to the way we behave. Genes determine physical traits such as height, eye color, hair color, and face shape, but they can also contribute to other attributes such as your personality traits and cognitive abilities.
  • Nurture: This side of the debate argues that environmental variables such as how we were raised, individual experience, and other social relationships play a more important role. Your upbringing, your early social interactions, school, and peers all play a role in shaping who you are and how you behave.

Let’s consider an example. If a student excels at math, is it because she inherited that ability from her parents or is it because she works hard to learn the subject? Nature would suggest that she does well because she is genetically inclined to do so, while nature argues that her talent stems from her upbringing and educational background.

History

The debate over nature and nurture predates psychology and goes back to the days of the ancient philosophers. In philosophy, this is often referred to as the nativism versus empiricism debate. What do these two terms mean and how do they relate to nature and nurture.

Nativism

The nativist approach suggests that inheritance plays the greatest role in determining characteristics. Nativism proposes that people’s characteristics, both physical and mental, are innate. These are things that are passed down genetically from our ancestors. The nativist approach essentially espouses the nature side of the argument.

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Noam Chomsky’s theory of language acquisition is one of the best-known examples of nativism in psychology.  Chomsky suggested that language develops as a result of an innate language acquisition device. He believed that people are able to learn language because they have an innate, hard-wired capacity for what he referred to as universal grammar.

Empiricism

Empiricism represents the nurture side of the debate. The empiricist approach suggests that all learning is the result of experience and environmental factors. The philosopher John Locke took and empiricist approach and proposed a concept known as tabula rasa, which means “blank slate.” This approach that the mind is essentially that – a blank slate – and that it is through learning and experience that all knowledge, skill, and behavioral patterns are acquired.

Behaviorism is one example of an empirical approach to understanding human behavior. Behaviorisms such as John B. Watson and B.F. Skinner believed that all human behavior was the result of conditioning, either classical (associative) or operant (reinforcement and punishment).

Watson was famously known for proclaiming that he could train anyone to be anything using the principles of conditioning, regardless of that individual’s genetics and background.

Approaches to Psychology

While few contemporary psychologists take an extreme, hard-lined empiricist or nativist approach, different branches of psychology do sometimes tend to emphasize one influence over the other.

Biological psychology, for example, tend to focus more on the nature side of the debate. This area of psychology focuses on how biological factors influence human behavior, so things such as the brain, neurons, and neurotransmitters are of greater interest than external factors.

Behavioral psychology tends to take the nurture side of the debate, focusing on how environmental factors and learned associations contribute to how people think and act.

Health psychology is an example of an approach that tends to lie somewhere in the middle. Health psychologists are focused on understand how both biological and environmental factors contribute and interact to affect an individual’s health.

Examples

Looking at examples can be helpful in order to understand why the nature vs nurture debate has been so important throughout psychology’s history. The topic is not just an important philosophical debate. It has been critical for understand what factors influence different aspects of human behavior and has been the source of considerable controversy at times.

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IQ

Consider the long debate over the factors that influence intelligence. Those on the nature side of the debate suggest that the greatest influence on IQ is inheritance. Some early thinkers such as Francis Galton believed that intelligence could largely be attributed to genetic factors. Such views have been used to justify discriminatory social policies and attitudes. When some studies found that black respondents had lower IQ scores, for example, some researchers interpreted such results to suggest that these individuals scored lower as a result of genetics.

Those taking the nurture side of the debate would suggest that other factors such as biased test construction and systemic discrimination impacting educational access and quality play a more important role. Inequality, discrimination, and lack of access play a role in shaping how well people perform on intelligence tests and other assessments of educational outcomes.

Gender Differences and Education

Sex differences in school performance and attainment is another area where the debate between the contributions of nature vs nurture come into play. Girls often perform better on verbal tests but less well on math. As they advance in school, girls also become less likely to enter STEM courses and STEM fields. Those taking a nature perspective might suggest that girls are inherently less capable in these subjects. Nature advocates, however, would point out that social variables including gender stereotypes and discrimination have a greater influence.

Sexual Preferences

People often use the nature or nurture debate to explain sexual preferences. Some take a nature perspective, suggesting that sexual preference are largely influenced by biological factors. Others believe that environmental influences play a greater role.

While each of the above examples focuses on two extreme positions, many researchers today believe that human behavior is influenced by both nature and nurture, and that it is often the interaction of the two variables that is even more important.

The Contributions of Nature and Nurture

Few modern psychologists would take an extreme nature or nurture position. Rather than asking which one controls specific variables, researchers are more likely to wonder about the degree to which each of these forces play a role. So what exactly are the relative contributions of nature and nurture?

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According to the research, the answer is about 50/50. Researchers collected the results of nearly every twin study conducted over the last half-century. Doing this allowed them to determine which factors played a role in determining certain characteristics.

Twin studies involve looking at twins who are either raised together or raised apart to examine similarities and differences. This allows researchers to determine the impact of genes versus environment.

Researchers analyzed more than 2,700 twin studies involving a whopping 14.5 million pairs of twins from 39 different countries and discovered that genes and environment share a roughly equal role in determining who we are. Variations in personality traits and disease were determined to be 49 percent due to genetics and 51 percent due to environment.

One important thing to note is that while the research suggests a 50/50 split, the findings did reveal that genes do play a greater role in the risk of certain diseases. Bipolar disorder, for example, was found to be approximately 70 percent heritable.

How Nature and Nurture Interact

Today, many experts suggest that we should be more concerned with how nature and nurture interact to determine how we develop. We might be genetically inclined toward a certain trait, for example, but our experiences can determine to what degree that trait is expressed.

Height is a good example of how genes and environment can interact to make you who you are. Even if you inherit genes for tallness, proper nourishment is important for reaching that height. Kids who come from tall families might not become tall if they do not receive proper nutrition during their childhood.

So while we know that both factors are about equally important, the question we are left to ponder is just how much of a role each factor plays in the development of certain characteristics. As the research suggests, some diseases are more strongly linked to genetics than to environment. As researchers continue to explore how nature and nurture interact, we will continue to gain a deeper understanding of the factors that contribute to who we are.

References:

Haworth, C. M., Davis, O. S., & Plomin, R. (2013). Twins Early Development Study (TEDS): a genetically sensitive investigation of cognitive and behavioral development from childhood to young adulthood. Twin Research and Human Genetics, 16(1), 117-125.