We all know that people differ mentally in a great many ways: some are reflective, others impulsive; some are sympathetic, others are sociopathic; some are creative, others seem never to have a witty or imaginative thought; some are sensible, others are flighty, fanatical, or prone to panic; and some are smart, whereas others cannot do a simple arithmetical calculation in their head or solve an elementary logical puzzle.
So how do we measure the human intellect? Among educators and psychologists, the most common procedure is to conduct a test of reasoning ability that yields a result called an intelligence quotient, or IQ.
Some people think IQ's are terrifically important and that people can be ranked from dumb to brilliant according to their IQ. Moreover, it is widely believed that one's IQ is largely genetically determined at birth.
Thus to many, IQ is a mark of inherent social rank.
A problem with this idea is that IQ's seem to vary according to experience and culture. Sub-Saharan Africans, for example, are widely said to have IQ's averaging 20 to 30 points lower than the average of about 100, which is typical of most European populations. Trouble is, when Africans migrate to Europe, their IQ's rise. Same with country folk versus city folk. The former seem to have lower IQ's until they migrate to the city, then they, or their children, match the IQ's of the city-born.
There's also the effect known as test sophistication, which means that the more IQ tests you take the better you get at them. So IQ is not quite so firmly fixed by the genes as many people seem to believe. Moreover, there are generational differences in IQ, with IQ's of most populations rising by five to as much as 30 points per generation since the beginning of the 20th Century, this phenomenon being known as the Flynn Effect.
But if people differ in intellect in ways other than reasoning capacity, what value is there in judging intellect by IQ?
For example, does IQ measure creativity, judgement, diligence, responsibility, or empathy?
Obviously not. Moreover, very little is knows about the effect of environment, diet, or culture on the many facets of human intelligence.
So why is so much attention given to the measurement of IQ?
Such a narrow view of human mentality seems not very intelligent, really.
Almost anyone with adequate schooling can learn to observe carefully, perform basic logical processes, make comparisons, draw more or less obvious logical inferences, and perform all the other operations that underlie appropriate responses to IQ test questions.
But not everyone is creative, sound in judgement, socially responsible, mentally vigorous, or possessed of the power of empathy.
And without those other qualities of mind, how useful is an abnormally high IQ?
In most circumstances, not very.
In fact, the idea of rating intellect on a single linear scale seems neither sensible nor useful, whereas it is almost certainly seriously misleading and, therefore, harmful.
CanSpeccy: Down With IQ-ism