Are You Smarter Than Your Grandfather? Probably Not.

In the mid-1980s, James Flynn made a groundbreaking discovery in human intelligence. The political scientist at the University of Otago in New Zealand found that over the last century, in every nation in the developing world where intelligence-test results are on record, IQ test scores had significantly risen from one generation to the next.

“Psychologists faced a paradox: either the people of today were far brighter than their parents or, at least in some circumstances, IQ tests were not good measures of intelligence,” writes Flynn.  

Now, in a new book, Are We Getting Smarter? Rising IQ in the Twenty-First Century, Flynn unpacks his original finding, explaining the causes for this widespread increase in IQ scores, and reveals some new ones, regarding teenagers’ vocabularies and the mental decline of the extremely bright in old age. Ultimately, Flynn concludes that human beings are not smarter—just more modern.

Malcolm Gladwell explains why the “Flynn effect,” as the trend is now called, is so surprising. “If we work in the opposite direction, the typical teenager of today, with an IQ of 100, would have grandparents with average IQs of 82—seemingly below the threshold necessary to graduate from high school,” he wrote in a New Yorker article in 2007. “And, if we go back even farther, the Flynn effect puts the average IQs of the schoolchildren of 1900 at around 70, which is to suggest, bizarrely, that a century ago the United States was populated largely by people who today would be considered mentally retarded.”