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.