Nature, Nurture & Intelligence

One of the biggest questions people ask about intelligence is whether it is due to heredity or the environment, something which is commonly referred to as the nature vs. nurture debate.

Using these terms, nature refers to a persons potential to reach to certain level of intelligence, and nurture refers to the affect the environment has on developing or inhibiting that intelligence.

For example, two brothers are raised by the same parents, yet later in life they have two very different careers. One is a doctor, and the other is a car salesman.

Since both brothers were raised in the same family, we can say that they had pretty much the same environment. As a result, the differences in intelligence between the two must be due to genetics (nature).

However some would argue that these brothers did not have the same environment, as one child may have been given more love and attention than the other.

This may then explain why one brother grew up to become more successful than the other.

This “birth-order” argument is one proposed by psychologist Alfred Adler, who believed that the environment in which we are raised as children has a big influence on our intelligence and how we develop later in life. Therefore according to Adler, nurture is the most important factor.

Feral Children

Feral children are children who have been raised by animals or in an environment in which they receive little or no human contact.

One famous example of a feral child was a boy named Victor, who was discovered in a French forest at age seven and subsequently studied by the physician Jean-Marc-Gaspard Itard.

Despite Itard’s efforts to teach Victor, he never did achieve a normal level of intelligence, something that has occurred with all feral children that have been discovered.

What we learn from feral children is that whilst we may all have the potential to achieve a certain level of intelligence (determined by genetics / nature), it is the environment (nurture) we are exposed to which determines whether or not we realise that intelligence.

Feral children also teach us that our early years of childhood are extremely important in developing intelligence, and that if this intelligence is not given an opportunity to develop, then after a certain period in life it may never fully develop. Which is exactly what was found with Victor.

So in reality it is likely that both nature and nurture are important in developing intelligence. Nature (our genetics) may determine how intelligent we become (our potential intelligence), and nature (our environment) will either allow us to reach our potential or inhibit it.

Current research tells us that children who are brought up in a stimulus rich environment where they receive lots of love and mental stimulation, are much more likely to develop higher levels of intelligence than children who are not brought up in such an environment (we can use feral children as an extreme example of this).

Things which stimulate a child include playing with them, talking to them, exposing them to music, new toys and exposing them to printed words (without any exposure to TV as this has the opposite effect on intelligence).

Interaction

Interaction is a mathematical concept used to describe variables which affect each other in a complex way.

Interactive variables are variables which when put together result in more than the sum of their parts.

For example, 4 x 4 = 16

Additive variables are variables in which the whole is a result of the sum of its parts.

For example, 4 + 4 = 8

When we apply this type of interaction to intelligence, we can see that the relationship between nature and nurture results in something “new” that is not in the original variables (intelligence).

In other words, nature and nurture are interactive variables because they result in something which is more than the sum of its parts.

However we don’t know when this interaction occurs, or which variable is more important (if that is the case) and when it is more important for developing intelligence.

Studies on feral children (such as with Victor) suggest that this interaction occurs very early in life and at least before age seven.

So using the mathematical concept of interaction, can say that the nature vs. nurture debate is really a false argument, as both are important in developing intelligence.

We can summarise this interaction by saying :

Heredity x Environment = Intelligence

or

Nature x Nurture = Intelligence

Note : The “x” is used to symbolise interactive variables, whose relationship results in more than the sum of its parts.

Summary

• Nature refers to your potential to achieve a certain level of intelligence.

• Nurture refers to whether your potential intelligence will be developed or inhibited.

• Feral children show that nurture is important in developing intelligence at an early age.

• Mental stimulation at an early age is needed to fully develop intelligence.

• Nature and nurture are interactive variables, which results in more than the sum of their parts (intelligence).

• Intelligence is a result of nature and nurture, and both are needed for intelligence to fully develop.