When we are young, our brains grow at a prodigious rate. In a very short time, we acquire verbal language, learn how to read and write, and absorb information quickly, retaining names and reciting snippets of television commercials with 100% accuracy. Parents have forgotten how quickly they acquired knowledge and skills during their formative years, so when their offspring display these competencies at an early age, the parents assign high estimates of their children’s intelligence. Grandparents, whose fluid intelligence has been in decline for decades, rhapsodize over the learning ability of their grandchildren when they observe them navigating through the menus on a computer or cellphone. Words like, “brilliant,” or “genius,” fuelled with the pride of reflected genetic glory, move fluidly through their enthusiastic discourse about their young prodigies.
What happens when their child takes that first IQ test? The IQ test measures a child’s intelligence relative to a huge number of people in the same age group. While these tests do not purport to measure intelligence with unlimited accuracy, they are remarkably reliable in predicting a person’s cognitive abilities relative to the average. Intelligence, as measured by IQ, is distributed throughout the human population in what statisticians call a normal distribution, or bell curve, as shown in the diagram below.
Think of the area under the curve as composed of billions of dots, each dot representing the IQ of a particular person. We see that about 34% or about 1/3 of people have IQ between 100 and 115. Similarly, about 1/3 have IQ between 85 and 100. Only about 2.4% have IQ above 130. Only about 1 person in 2500 has an IQ of 150 or more, so this is an extremely rare level of intelligence. If your child takes an IQ test and scores 120, they have performed better than 90% of the people their age, though it may be significantly less than what you had anticipated. However, there is good news. You can celebrate that your child is intelligent enough to learn whatever is needed for almost any career, provided they are prepared to work hard. Many Nobel laureates had IQ’s that were not significantly greater than 120. Furthermore, IQ is only an approximate measure of intelligence, while creativity, imagination and curiosity, not measurable by IQ tests, also play a critical role in achieving success in any endeavour.
