Nature Vs. Nurture: What Affects Your Behavior Profoundly?

Nature and nurture affects behavior
You like social outings and spending time with your friends. So is this because you are genetically disposed to do so, or is it because of the environment you grew up in? And what is the reason for your fear of dogs? These are some of the things that form a part of the age-old nature vs. nurture debate, and we try to understand which of two factors affects our behavior more.
It Runs in the Family!
The phrase "nature and nurture" was first coined by polymath Francis Galton, a cousin of Charles Darwin, in 1874.
Since the time man started studying their own species, one of the main topics of interest had to be understanding what makes an individual the way he is. The subject of psychology was borne from such curiosity. Since then we have looked into how the human mind and body works, with subjects like intelligence, personality, memory, sense and perception, and lifespan development, amongst others. But one of the most debated upon subjects that will forever remain is that of the study of heredity and environment, and which of the two plays a more crucial role in the development of the different traits and makeup of mankind.

Within the study of this subject is one of the most controversial topics of 'Nature vs. Nurture', and which of the two is more important while studying individual development. The term was coined by Francis Galton, who was influenced by his cousin Charles Darwin's book on evolution. Back then, they believed that our genes defined who we became (natural selection, which was proposed by Darwin) and is the only thing that influences human development. But over the years, with rigorous study, it was realized that the environment in which we were brought up and the ones in which we interact in, also plays a big hand in the development.

We explain what nature and nurture is all about, along with how it affects the different aspects of human development like personality, intelligence, and behavior.
Defining Nature and Nurture
The study of nature and nurture is in fact the study of the influence of heredity and environment on human development. So how do we define each of them individually?
Nature refers to the biological factors in a human. Essentially, it is the genetic or hereditary makeup of an individual. These are the genes that we are born with that cannot be altered with conditioning. Traits such as hair color and type, eye color, height, and physical makeup forms a part of what is called "nature". Disorders and diseases that are inherited genetically also forms a part of this view.
Nurture refers to the environmental factors and influences, along with an individual's personal experiences. This includes the childhood experiences, upbringing, relationships with friends, families, neighbors and colleagues, events, and experiences that play a role in shaping who we become.
Now that we know what each of these terms mean, let us look at the controversy that the two have given rise to in the understanding of an individual.
The Big Debate
When Galton first took inspiration from Darwin's Theory of Evolution and the idea of natural selection, he believed that intellectual ability was inherited and that natural superiority was the reason for the genius that was seen in certain people. After just observing that intelligent people tend to have families that are just as smart, he went as far as to say that to speed up the process of natural selection, people with the same intellectual ability must marry each other to produce a superior race. This kind of fallacy was the cause of many socio-political events like apartheid, the sterilization programs, and the discrimination's based on class, amongst others.

People who believed in the idea that genetics and genetics only can determine what an individual becomes, were known as Nativists, and from there grew theories like Naturalism in psychology. On the other end of the spectrum, there was a group of people who believed that environmental experiences solely determined the factors of individual development. This group was known as the Empiricists. Philosopher John Locke coined the term "Tabula Rasa" which is Latin for blank slate. According to him, at birth a human is born with a blank slate that is eventually filled with his or her own personal experiences. Theories like Behaviorism rose from this train of thought.

Over time people learned that one is not separated from the other and that it is the interaction between the two that helps define who we are as people. But with that idea came the question of "How much?". People started to debate, research upon, and come to conclusions on which of the two factors had a greater role to play in making us, well, "Us".

But before we try to come to terms with that, let us see how nature and nurture affects different segments of our development.
Effect on Different Aspects of Human Development
Nature can be thought of as the factor that defines certain physical characteristics as well as something that creates an outline for the innate abilities and potentials that we possess. Nurture on the other hand is the factor that takes these genetic predispositions and shapes it so that these abilities can be realized (meaning they can be achieved). From this we can infer that both play a role in shaping us as an individual. What we will now look at is how the two of them interact together in our developmental process.

Behavior, Personality, and Intelligence
As we know already, our genetic makeup bestows on us our physical characteristics. Along with it, certain underlying traits are also heritable. For example behavioral traits like what language we speak, how we interact with people, how we respond to certain situations, are all molded by 'nurture' - this is obvious because the environment in which we are brought up in, shapes these factors over time. But it is also noted that some of these traits are partially heritable. For example, certain disorders are genetically inherited. But their manifestation might only become more apparent if that disorder is somehow cultivated. Aggressive behavior is something that is partially received from genes. But if the person grew up in an aggressive family environment, had friends who displayed aggressive behavior, then that person will eventually grow up themselves to be very aggressive. It is noted here that even though certain behavioral traits may be partially heritable, it only manifests if that particular trait is nurtured.

The example of nature vs. nurture and its effect on behavior was shown in an article in Wall Street Journal, where they showed that environmental sensitivity can be attributed to genetic factors. The scientists divided people into two groups - orchids and dandelions. The orchid were people whose behavior was more susceptible to environmental factors, while it was much less significant in the dandelions. This was because of the variation in their genes in the amount of dopamine (such as DRD4) produced in their bodies. The orchids had a lower amount of this dopamine produced, which is why they were more prone to stress and get distracted easily with the slightest stimulus. The dandelions on the other hand, had an ample amount of this hormone produced, which is why they tend to learn better from adversity and are comparatively more stable.

The ability to pick up different speech sounds, and learn a language, amongst other things is genetic and is seen in all babies, irrespective of their environmental conditions. Physical and intellectual skills like learning particular subjects, or ability to play certain sports, or being artistic may be partially heritable, but it needs to be cultivated over time for it to manifest the individual.

Based on Bowlby's Theory of Attachment, it is suggested that the bond between mother and child is innate, that is it is genetically inherited. Another propagator of the naturalist view was Chomsky, who suggested that the language is gained through the use of an inherited Language Acquisition Device (LAD).

Skinner on the other hand, believed that language was acquired by imitation and the cultivation of the same in an individual's respective environment. Certain genetic factors can also decide how an individual interacts with their environment. For example, a child who is by nature inhibited, may be shy or introverted when it comes to social interaction, while those who are predisposed to be extroverted may be sociable, friendly, and will actively seek social bonds. Conversely, when the environment is more extreme, they play a greater role in a person's development. For example even if a child is naturally intelligent, but is brought up in an environment of deprivation, he may not grow up to reach his full intellectual capacity. During prenatal development, if a child is exposed to drugs or other harmful substances through intake by the mother, then he may be susceptible to diseases, disorders, or may grow up with deformities. So what started out as an environmental factor turned into a genetic predisposition.

When it comes to personality traits, the Twin Studies is one of the major factors that can be used as reference. In this study, identical twins who were rared apart show a more similar personality that those reared together, or a random selection of people. Identical twins are more similar that fraternal twins, while natural siblings are more alike than adopted siblings. This suggests that personality is partially heritable, but eventually nurture plays a role in how these traits are shaped. Adopted Studies on the other hand showed that even when these siblings are reared in the same family environment, by adulthood, there is almost no similarity in their personality, which suggests the manifestation of nature.

In the case of intelligence, the same adoptive studies revealed certain occurrences. These show that environmental factors have a bigger hand in molding childhood IQ. But by adulthood, this correlation is almost null. They revealed that by adulthood, the difference in IQ among adoptive siblings may make them seem like strangers, despite the shared environment they grew up in. In natural siblings on the other hand, there was a correlation of about 0.6. In the twin studies, it showed that identical twin who were reared apart had a higher correlation (about 0.86) while fraternal twins raised together had just 0.6 heritability. Adoptive siblings on the other had a 0.0 heritability of IQ. This seems to suggest that nature plays a bigger role in shaping intelligence.

But we cannot rule out nurture entirely. For example, nutrition plays an important role in shaping intelligence. If a child is not put on a proper diet from the get-go, then their neural connections and pathways get disrupted, which leaves then mentally challenged. Stress and exposure to toxins can also impede intellectual growth. As mentioned earlier, a person may have innate talents, but if they were not brought up in the right surroundings, their potentials may never be realized. Conversely even someone with lower genetic inheritance of intellect may be nurtured in a rich educational environment and may be able to supersede his original potential.

After going through this you may wonder what then really affects our behavior. The fact is, that both go hand-in-hand and one cannot work without interacting with the other; and thus both play more or less an equal role in shaping how you behave. An interesting thing to note is that the nature versus nurture is a factor present in animals too. Let us see how.
Nature and Nurture in Animals
While studying the social behavior in animals, certain theories had been established. These are:
  • That social structure is shaped by environment - example, a species whose food is widely dispersed may need to live in large groups.
  • That complex societies evolve step-by-step from simple ones.
  • And the social brain hypothesis: that intelligence and brain volume increase with group size because individuals must manage more social relationships.
But recent studies seem to suggest that genetics may play a more important role than what was previously considered. Oxford biologist found out that primate species tended to have the same social structure as their close relatives, regardless of how and where they live, suggesting that the similarity in social structures of related species may be due to genes inherited from a common ancestor.

We can now see that even animals show that development relies on both nature and nurture. Despite these findings in both humans and animals, certain criticisms have been raised on moral and philosophical grounds.
Moral and Philosophical Criticisms
As mentioned earlier, certain theories that propagated both nature and nurture respectively led to socio-moral problems like racial discrimination, stereotyping, and construction of a reality based on facts that fit our train of beliefs. On the other hand, philosophers questioned the very idea of the existence of 'traits' and what it all really stood for. Also, if we are who we are because of something that is predetermined like genetics or an influence of environmental factors, then where is our own free will?
These controversies and debates regarding the influence of heredity and environment on our development started centuries ago, and with every new discovery, will come another challenge based on scientific, moral, socio-political, and philosophical grounds. So for now we will rest our case with the fact that we need both to survive and thrive and can't ignore the existence of one in favor of the other.