Why IQ Tests May not Measure Intelligence

The American psychologist Arthur Jensen (1973) defines intelligence as ‘abstract reasoning ability’ – the ability to discover the rules, patterns and logical principles underlying objects and events and the ability to apply these discoveries to solve problems.

Intelligence is measured by intelligence tests such as IQ (Intelligence Quotient) tests which are designed to measure abstract reasoning ability. As such they try avoid questions which ask about factual knowledge – such as ‘what is the capital of the USA?’ but instead ask questions such as – ‘what is the next number in the following sequence – 1,8,27, 64, __’

Despite their widespread use, there is a large body of evidence which suggest that IQ tests are not a valid measure of intelligence, because abstract reasoning is only one facet of the full range of mental abilities.

Culture and Intelligence

The Canadian psychologist Otto Klineberg (1971) gave an IQ test to Yakima Native American children living in Washington State, USA. The test involved timing how long it took the children to place different shaped wooden blocks in the appropriate shaped holes in a wooden frame. The children achieved only low scores, but Klineberg argued that this was because their culture, unlike Western culture, did not place a high value on speed.


This suggests that it is inappropriate to compare the intelligence of people from different cultures, as any speed-based test favours some cultures over others.

Other researchers have pointed out that cultural variations between classes within a society mean that IQ tests are biased towards the middle classes, because such tests are largely constructed by and standardised on this group. If we accept the fact that there are cultural differences between social classes, and that the working classes have lower levels of deferred gratification and higher levels of fatalism, as well as a ore negative experience of education generally, then it is likely that they will do less well in IQ tests compared to middle class children.

Further reasons why IQ tests may not measure intelligence 

Klineberg argues that at least the following factors influence how well an individual does in an IQ test:

  • The previous experience and education of the person tested
  • His degree of familiarity with the subject matter of the test
  • His motivation or desire to achieve a good score, in the appropriate time frame.
  • His rapport with the tester
  • his knowledge of the language in which the test is conducted
  • his physical health and well-being.


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