As I explain in Chapter 3 of my latest book, The Intelligence Paradox:  Why the Intelligent Choice Isn’t Always the Smart One, perhaps no other concept in science suffers from greater misunderstanding and is plagued with more misconceptions than the concept of intelligence.

Probably the most pervasive misconception about intelligence is that IQ tests, which measure intelligence, are culturally biased against certain racial and ethnic groups or social classes.  This misconception stems from the well-established and replicated fact that different racial and ethnic groups on average score differently on standardized IQ tests.  As I explain earlier, social scientists and lay public alike assume (without any logical or empirical support) that everyone (and all racial and ethnic groups) are equally intelligent because they are equally worthy human beings.  If everybody is equally intelligent, yet some groups consistently score lower than others, then, the argument goes, it must by definition mean that the IQ tests are culturally biased against the groups who score lower.

But the claim of cultural bias rests entirely on the religious conviction and unquestioned assumption that everybody and all groups are equally intelligent, which in turn rests entirely on the religious conviction and unquestioned assumption that intelligence is the ultimate measure of human worth.  The claim is untenable once we dismiss these religious convictions and unquestioned assumptions.

Think about the sphygmomanometer, for a moment.  It is the device that doctors and nurses commonly use to measure blood pressure, with the inflatable cuff with Velcro and a mercury manometer to measure the pressure of blood flow.  It is an unbiased and accurate (albeit imperfect) device to measure blood pressure.  (It is very imperfect, as I discuss in a later post.)  Nobody would argue that it is culturally biased against any racial and ethnic group.  Yet there are well established race differences in blood pressure; blacks on average have higher blood pressure than whites.  Does that mean that the sphygmomanometer is culturally biased against (or for!) blacks?  Is blood pressure a racist concept?  Of course not.  It simply means that blacks on average have higher blood pressure than whites.  Nothing more, nothing less.

Or think of the bathroom scale.  Once again, the bathroom scale is an unbiased and accurate (albeit imperfect) device to measure someone’s weight.  Nobody would argue that it is culturally biased against certain groups.  Yet on any bathroom scale, women on average “score” lower than men, and Asians on average “score” lower than Caucasians.  Does that mean that bathroom scale is culturally biased against women or Asians?  Is weight a sexist or racist concept?  Of course not.  It simply means that women on average weigh less than men, and Asians on average weigh less than Caucasians.  Nothing more, nothing less.

Nobody argues that blood pressure is a racist concept, or that the sphygmomanometer is culturally biased, because nobody equates (low) blood pressure with human worth.  As a result, nobody gets upset about observed race difference in blood pressure.  Nobody argues that weight is a racist or sexist concept, or that the bathroom scale is culturally biased, because nobody equates weight with human worth.  As a result, nobody gets upset about observed sex or race differences in weight.  Why are race and sex differences bona fide evidence of bias only with IQ tests?

The single most accurate IQ test currently available is called the Raven’s Progressive Matrices.  Intelligence researchers universally consider it to be the single best test to measure general intelligence because scores on this test are more strongly correlated with the underlying dimension of general intelligence than any other single intelligence test.  (In technical language, Raven’s Progressive Matrices are more heavily g-loaded than any other cognitive test.)  The test comes in three different versions:  the standard version (Raven’s Standard Progressive Matrices); the advanced version for college students and other more intelligent people (Raven’s Advanced Progressive Matrices), designed to discriminate the higher end of the IQ distribution more precisely; and the multi-color version for children (Raven’s Colored Progressive Matrices).

Here is an example of a question item from Raven’s Advanced Progressive Matrices.  The test comes with only one instruction:  Choose the figure that fits the next in the progression of matrices.  Which one of the eight alternatives comes next?

All question items in all versions of Raven’s Progressive Matrices are very similar to this one.  Can anyone tell me exactly how this question, and all the other similar questions that comprise the Raven’s Progressive Matrices, can possibly be culturally biased against any group?  The question is a pure measure of reasoning ability.  The only thing it’s biased against is the inability to think logically.

By the way, if you are wondering, the correct answer to the above question is 7.  This is what intelligence looks like.

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Read more about the surprising facts about intelligence, what it is (and what it is not), how it affects you in virtually every sphere of life, and how more intelligent people are different from less intelligent people, in The Intelligence Paradox:  Why the Intelligent Choice Isn’t Always the Smart One.