The slippery slope that is intelligence and the IQ test to measure it

Getting good grades, generally being ‘good’ at things and being successful are by standard associated with a solid IQ, which in turn is measured by the often dreaded – and criticised – IQ test. The value of which is a topic for debate as many think that IQ testing does not measure personality, context and/or emotional intelligence and hence is flawed.

But intelligence is what precisely? Opinions differ. Economic success, for example, does not necessarily depend on being good at doing exams, an accepted indicator of IQ. A favourite person mentioned in this context is Richard Branson, an extraordinarily successful individual who left school at 16. And did not Mark Zuckerberg and Bill Gates drop out of Harvard too? Then, of course, there is the increasing importance of Emotional Intelligence, or EQ for short, as a counterargument that IQ can’t be a sole predictor of success. But the two Qs are linked, as even emotional intelligence presupposes IQ. So why the opposition to IQ tests?

What then is IQ and are IQ tests a good way to measure it?

Researchers describe IQ as a defined set of skills that include the ability to reason, learn, plan, and solve problems and they find that people who are good at one of these skills tend to be good at all of them. “Students taking IQ tests and who, for example, do well on the vocabulary test will very likely also do well on the reaction speed test and problem solving”, says Stuart Ritchie, a lecturer at the Institute of Psychology, Psychiatry and Neuroscience at King’s College London and author of the book: ‘Intelligence: All that matters’. He is a staunch defender of the IQ test, precisely because it does look at IQ alone and as such is an unbiased measuring tool that evens the playing field. Russell Warne, in his book: ‘In the Know; Debunking 35 Myths about Human Intelligence’ also counters the critics of IQ tests and is adamant that the IQ test as we know it is the most solid test of human intelligence ever invented.

Efficient brain power and IQ

The brains of people with a high IQ have neurons that conduct signals faster. They make more rapid connections, creating better neuroplasticity. It is plausible that a good or high IQ is present because of a more efficient brain. So, can an IQ test capture this brain ‘efficiency’ and does it predict exam results? IQ test performance accounts for about 65% of the variance in students’ school exam scores, with the other 35% made up by motivation and physical and mental health. Research found, for example, that GCSE scores are highly correlated to being successful at university and that most of the successful Oxbridge applicants, for example, had perfect previous GCSE scores and equally that most of the successful applicants to Ivy League colleges in the US have perfect SAT scores, further underlining the causality between IQ and test- and school exam results.

IQ as a predictor of successful outcomes

IQ (and IQ tests) are indeed very good indicators of general competence and are not only necessarily useful in school but can also predict how well people will be at their jobs, given that good problem-solving skills and rational thinking help make judgments, help navigate unexpected situations as well as deal with everyday complexities. Good reasoning and problem solving also avoid accidents as risks are more readily and quickly assessed. “Although economic success is not”, states Russel Warne, “perfectly correlated with IQ (persistence and grit certainly play a part), by most measures of success it is better being smart than not being smart.

Improving IQ

Genetics count for 50% of the difference in intelligence between people, but intelligence is by no means set in stone: our genes are not our destiny. What we ‘feed’ our brains is a big determinant of IQ too such as education, our environment, our diet and exercise as well as a good dose of luck and chance. Education plays a big role in improving IQ, with some research showing a 1-to-5-point increase for every additional year of schooling as studying math, doing comprehension, and accruing general knowledge are a good training for the kind of abstract thinking required to do well in IQ tests. In short, brighter people seem to have had more schooling and longer periods of learning.

Is intelligence a slippery slope? Not so much. Apart from a good dose of genetics it’s what we make of it. And IQ tests seem to be an appropriate way to measure it. Clever students normally should do well in IQ tests. Nothing slippery about that.

Suggested links and books:\

In the Know, Debunking 35 Myths about Human Intelligence. By Russel T. Warne. Cambridge University Press, 2020.

Intelligence: All that matters. By Stuart Ritchie. John Murray publishers. 2015.

The Brain: A User’s Guide. New Scientist. 2018.