This is a fascinating new paper by James Flynn (who’s name delivered The Flynn Effect) and Michael Shayer. The paper doesn’t present a smoking gun, but tries to see trends in countries who see a decline in average IQ and countries who don’t see the same decline. But they look deeper than averages on parts of the test, by also looking on which groups in the population are doing worse.
I can share with you the summarizing bullet points:
- Important national differences, particularly the contrast between Scandinavia and elsewhere.
- Dutch trends show that IQ gains vary by age which is indicative of the strength of various causal factors.
- Piagetian trends provide information conventional tests do not: that the largest losses may be at the top of the curve.
Or even the abstract:
The IQ gains of the 20th century have faltered. Losses in Nordic nations after 1995 average at 6.85 IQ points when projected over thirty years. On Piagetian tests, Britain shows decimation among high scorers on three tests and overall losses on one. The US sustained its historic gain (0.3 points per year) through 2014. The Netherlands shows no change in preschoolers, mild losses at high school, and possible gains by adults. Australia and France offer weak evidence of losses at school and by adults respectively. German speakers show verbal gains and spatial losses among adults. South Korea, a latecomer to industrialization, is gaining at twice the historic US rate.
When a later cohort is compared to an earlier cohort, IQ trends vary dramatically by age. Piagetian trends indicate that a decimation of top scores may be accompanied by gains in cognitive ability below the median. They also reveal the existence of factors that have an atypical impact at high levels of cognitive competence. Scandinavian data from conventional tests confirm the decimation of top scorers but not factors of atypical impact. Piagetian tests may be more sensitive to detecting this phenomenon.
But honestly, there are so many nuances in the article that both these summaries don’t do justice. I think this 2 parts of the conclusion are the most important elements of the paper.
Nations that are candidates for IQ decline give evidence that ranges from beyond dispute to fragmentary. The strongest comes from Scandinavia as a whole, Britain (Volume and Heaviness), and Germany (spatial). Nordic data cover vocabulary, similarities, analogies, shapes, metal folding, number series, geometrical figures, and letter matrices. The pivotal year for all of these nations seems to be about 1995. Data from France and Australia await further studies but cannot be dis- missed. The US is strange. All ages plow on unaffected as yet. Black gains are larger than white but white gains are still robust (Flynn, 2012a). The quick developing world (Korea) and the slow developing world will of course continue to gain for some time.
These trends come as no surprise. Flynn has argued that industrialization may eventually pay diminishing returns in developed nations. Until very recently, we have enjoyed a more favorable ratio of adults to children in the home, more and better schooling, more cognitively demanding jobs, and better health and conditions of the aged. These caused large IQ gains for several generations. However, the same factors can turn from positive to mixed or even negative. The number of children in the home has reached a minimum (and indeed there are more solo-parent homes), middle class parents have used up the tricks that make the pre-school environment cognitively enriching, we appear to have reached a limit in terms of enhanced schooling and the number we keep in school into adulthood, the economy may be producing fewer cognitively demanding jobs in favor of more service work; however, we may continue to improve the health of the aged.
Excerpt 2 (bold by me):
The Piagetian results are particularly ominous. Looming over all is their message that the pool of those who reach the top level of cognitive performance is being decimated: fewer and fewer people attain the formal level at which they can think in terms of abstractions and develop their capacity for deductive logic and systematic planning. They also reveal that something is actually targeting that level with special effect, rather than simply reducing its numbers in accord with losses over the curve as a whole. We have given our reason as to why the Piagetian tests are sensitive to this phenomenon in a way that conventional tests are not.
Massive IQ gains over time were never written in the sky as something eternal like the law of gravity. They are subject to every twist and turn of social evolution. If there is a decline, should we be too upset? During the 20th century, society escalated its skill demands and IQ rose. During the 21st century, if society reduces its skill demands, IQ will fall. Nonetheless, no one would welcome decay in the body politic, or among the elite who at present represent our best thinkers. Although it might be argued that the character of the electorate will be enhanced if it contained fewer lawyers and more plumbers and service workers.
It is always possible that our schools and universities will graduate more young people who read and become more critically astute. This in itself would put a limit on IQ losses on Vocabulary, Information, and most Verbal tests, and on accepting the stereotypes that cloud moral reasoning and political prudence.