IQ Test Doesn't Define Your Intelligence

During the last 50 years, there might be no scientific literatures that invites controversy as much as the book written by Charless Murray and Richard Hemstein in 1994. They write a book titled The Bell Curve: Intelligence and Class Structure in American Life, which point out that intelligence attaches to genetic properties of human, and it also determines one's social success.

Their proposed statement implies that our social roles and achievement is predetermined since the day we were born, which then leads us the a better understanding of the term 'intelligence' itself.

Studies of identical twins have shown that certain regions of the brain are highly inheritable,
affecting overall intelligence

What is Intelligence?

The controversy that emerged from Charless and Richard's is highly related with our definition of intelligence - which most of us relate this with IQ and social success. However, neuroscientists hardly accept that kind of understanding, especially when it comes to other parameters that determines one's success in society, such as motivation, persistence, and social skills - which can't be measured with IQ test. Even some of them argue that the score only indicates how well an individual accomplish an IQ test instead of indicating their intelligence level...!

So, when we talk about intelligence (in the context of its contribution towards social success) that should include various aspects, not limited to the function of education and memory that's measured by 'mere' IQ test. Personally, I believe that there's no accurate measurement for a universal intelligence rather than life itself, however, in terms of better definition of intelligence, I found that fluid intelligence, which indicates one's mental ability and efficient neural functioning, is the most appropriate one. Fluid intelligence affects many capabilities such as logical reasoning, memory, mathematical calculations and even linguistic processing.

Genetics & Other Contributing Factors

Neuroscientist found that fluid intelligence is mostly correlated with the size of our prefrontal cortex. But the size of prefrontal cortex doesn't solely related with biological properties (genetics). This phenomena has been shown in various experiment, where on of them involving twins who are separated at birth and raised separately in equivalent environments. In the end, genetics count only 72% in correlation with  intelligence.

This means that intelligence is not solely 'predetermined' as stated in Richard and Charless' work. Our brain grows, it has the ability to construct and rewire neural cells which enhance our mental function. Rather than blaming our genetics factor, we can keep on challenging our brain, learning new expertise for a better mental function.