Can we increase our IQ?

Published M-Anation, Maryland Mensa newsletter, June 2018

Cover of Intelligence by Stuart Ritchie
Intelligence by Ritchie

Can we increase our IQ? We’d all like to hear the answer is yes and how to go about it.

The answer is yes, but most of it is already being done by our education system.

Stuart Ritchie’s excellent Intelligence, subtitle All That Matters.  McGraw-Hill, 2015. ISBN 9 781444 791877 presents the informative and convincing example from the 1960s.

The Norwegian government (p 92) decided to add two extra years to the mandatory curriculum for all pupils.Two additional pieces of good luck allowed researchers, who came on the scene much later, to turn this into a test of the effects of schooling on IQ.

  • First, Norway implemented the reform at different times in different sections of the country. It occurred in some areas years before it happened in others
  • Second, every male Norwegian takes an IQ test as part of their entry into compulsory army service.

In 2012 the researchers were able to compare the later IQ scores of those who had been forced to stay in school for extra years with the scores of those who hadn’t (Brinch and Galloway, 2012).

Intelligence Increase with Schooling

They worked out that the extra schooling added 3.7 IQ points per year.

This confirmed the results of many other, previous studies that hadn’t used such elegant methods.

Bell Curve

Psychometricians, those that focus on measurement of intelligence via IQ, routinely adjust the mean of test scores to maintain the IQ average of 100, yet it remains true that the ability of people to solve intelligence questions continues to grow.

Other Noteworthy Points in Intelligence

Heritability (p 67). Fifty percent heritability does not imply that 50% of an individual person’s intelligence is due to their DNA. Rather heritability describes the variation among those people about the arithmetical mean. Fifty percent heritability implies that half the variability is explained by DNA.

  • Heritability doesn’t tell us anything about the average level of intelligence. Intelligence can be 50% heritable in a group where the average IQ is 85, 100, or 115, or an other number
  • ‘Heritability’ doesn’t mean the same thing as ‘hereditary’. ‘Hereditary’ indicates the trait is passed on from parents to offspring, whereas ‘heritability’ measures of the variation of the trait that exists in the population.

Flynn Effect (p 94-99). IQs have been increasing about 3 points every decade since IQ testing began.

  • Ritchie mentions the interesting hypothesis that the cause may be cultural—we think more abstractly than our ancestors, not faster. Speculatively, we relate knowledge to how it is taught, not how it is experienced.
  • For example, a hundred years ago the answer of what do dogs and horses have in common was they are both are used to hunt (a relationship a person has seen). Now the answer is more likely they are both are mammals (a taught distinction).

But let’s not get distracted by side issues. The core finding is that two years of additional education increased the average IQ by 7.5 points.

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