As societies became more intellectually oriented, developing increasingly more sophisticated technologies and building the abstract skills of reading and writing, our environment became more intellectually stimulating. The difference in the cave etchings of primitive populations and the art of the Renaissance suggests an enhanced sophistication in human cognitive strength. Psychologists asked, “Is this increased sophistication merely attributable to the growth in technology or is it an increase in average intelligence as measured by IQ tests?”
In 1984, New Zealand researcher, James Flynn, published a paper* in which he reported that the average IQ of Americans between 1932 and 1978 had increased by 13.8 points. This rapid increase in IQ in two generations is too fast to be attributed to genetic mutation, so Flynn and others conjectured that intelligence was increased by the demands of our technological society. It was first assumed that this difference came from an increase in what psychologists call “crystallized intelligence.” This is the part of our intelligence associated with accumulated knowledge and experience such as reading and computational skills. In his TED Talk, presented on September 26, 2013, (see: Why our IQ levels are higher than our grandparents’) Flynn hypothesized that the new technologies including radio, television, and computers are demanding more abstract thought than the environment of the early 20th century. He noted that in 1900, only 3% of jobs were cognitively demanding, including occupations such as doctor, lawyer, teacher, and accountant. He compared this to the 35% of jobs today that demand higher order thinking skills. Flynn asserted that the high-tech environment is stimulating a latent capacity for abstract thought that was not as strongly demanded in previous generations.
However, it was subsequently discovered that the actual increase in IQ scores came from higher performance on items that measure fluid intelligence, i.e., mental acuity and abstract reasoning. These are test items such as the one shown below.
Select the option, A through H, that belongs in the circle below to complete the pattern.
This increase of about 3 points per decade in average IQ became known as “The Flynn Effect.” Following the publication of the Flynn Effect, psychologists scrambled to find reasons for this increase in fluid intelligence across successive generations. However, in subsequent decades, new IQ data began to emerge. Between 1970 and 2009, Norway conscripted into the military and IQ-tested 730,000 young men (born between 1962 to 1991). An analysis conducted by the Ragnar Frisch Centre for Economic Research in Norway revealed that the average IQ reached a maximum for people born during the mid-1970s, and subsequently went into decline. This trend, called “the Negative Flynn Effect,” was confirmed in several other studies, leaving the psychologists in a quandary, attempting to explain these fluctuations in average IQ across generations.
The Negative Flynn effect challenged the explanations advanced for the Positive Flynn effect. Some psychologists attributed the reversal of the Flynn effect to the fact that those in the educated class are having fewer children than the those in the lower socioeconomic groups. Since those of high IQ are usually in the educated class, this implies that the offspring of the high IQ people are becoming a smaller percentage of the gene pool. Psychologists refer to this effect as “dysgenic,” because it acts as “negative” natural selection by a preferential selection of those of lower IQ. (see: Hong, Z. (2020). Modelling the on-going natural selection of educational attainment in contemporary societies. Journal of theoretical biology, 493, 110210.)
Gathering data across generations, is of course, a long-term endeavor, so we will have to wait some time to investigate further the trends in average IQ and account for these changes. In the absence of extensive longitudinal data and definitive research, we can only conjecture about the IQ of future generations. If indeed, IQ is mainly attributable to genetics, it seems to me that the IQ of humans may, in future, be enhanced through gene splicing, that is, incorporating into a person’s DNA those SNP’s known to contribute to intelligence. However, such a practice could open a Pandora’s box of horrors for which our species is not yet ready. As the Chinese adage advises: Be Careful what you wish for.
*Flynn, James R. (1984). The Mean IQ of Americans: Massive Gains 1932 to 1978. Psychological Bulletin 95: 29 – 51.
