Defining intelligence is highly problematic. Is there an ‘intelligence’ that equips us to solve all kinds of problems and answer all questions, regardless of their nature? Or are there different intelligences that help us deal with particular problems and solutions? The scientific community is divided on the issue.

One of the main tenet’s underpinning the idea of a single entity ‘intelligence’ is the concept of ‘General Intelligence’, or ‘g’. Devised by English Psychologist, Charles Spearman, in the early 20th Century ‘g’ was a statistical measure of performance across a variety of tests.

Spearman found that the same people who did well in a variety of mental tests tended to use a part in their brains that he termed ‘g’. This ‘g’ laid the foundation for the notion of a single intelligence, which enables us to undertake everyday mental tasks.

A recent study seems to endorse Spearman’s theory. Research has found that a part of the brain called the ‘lateral prefrontal cortex’ is the only area of the brain to increase in blood flow when volunteers tackle complicated puzzles.

Spearman’s concept, however, is still highly controversial with many people questioning both the statistical process and the simplistic nature of ‘g’. There is also a body of research that states that our mental ability is a function of social factors such as education and not one’s inherent biological make-up.

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