When intelligence is not (only) in our genes

When intelligence is not (only) in our genes

Scientific evidence has showed that environmental factors have an almost equal effect on intelligence than genetics, opening the nature versus nurture debate.

“Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I'll guarantee to take any one at random and train him to become any type of specialist I might select". Psychologist John Watson pronounced this bewildering statement in the early nineteenth century, seemingly ignoring the importance of our genome in determining our intellectual traits. But, are we really just coded by our genes?

In 1996, Benjamin et al. published a paper showing the importance of a certain gene, DRD4, in determining one's personality. Perhaps their findings were not elucidating under the light of explaining the biological mechanism intelligence, but scientists are nowadays working on the so-called 'quantitative trait loci', a map denoting key genetic combinations that can lead to superior intelligence.

But here psychology kicks in. Murray and Herrnstein showed in 1994 that identical twins, with very similar intelligences during childhood, experienced remarkable variations in their IQ score as adults. Their findings were trailblazing, and opened the debate of the extent to which the environment can affect one's intelligence.

A recent study analysed IQ scores in malnourished Bolivian children before and after the intake of a series of protein supplements. It was discovered that the IQ increased notably after six months, proving nutrition key in intellectual performance. Interestingly, breast-feeding has moreover been shown to increase 4.6 IQ points in contrast to those who were bottle-fed.

Another hot-topic in the field is the alleged 'Mozart Effect', which indicates that children taking IQ scores after listening to classical music can improve their results in a magnitude of almost 10 IQ points.

However, being a 'genius' is not only about intelligence. Before reaching maturity, the brain is active, plastic, and will develop certain connections when exposed to specific influences. For instance, it is well known that Albert Einstein was intrigued by physics since an early age, as he was grown in a culturally stimulating environment.

Figure 1. One of the most studied factors determining acquired intelligence is the family's socioeconomic status.

DNA has been proved to be key in intellectual development, but environmental factors seemingly can affect one's natural intelligence to a remarkable extent. Taking the dual importance of genetics and environmental factors into consideration, one may ask himself: is our educational system ideal, or are we simply feeding children crude culture?