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In Denmark, the Flynn effect began declining (although didn't yet start reversing) as early as the 70s: > Teasdale and Owen (2005) examined the results of IQ t

In Denmark, the Flynn effect began declining (although didn't yet start reversing) as early as the 70s: > Teasdale and Owen (2005) examined the results of IQ tests given to Danish male conscripts. Between 1959 and 1979 the gains were 3 points per decade. Between 1979 and 1989 the increase approached 2 IQ points. Between 1989 and 1998 the gain was about 1.3 points. I don't think that trend of declining growth, shifting into the negatives recently, has much to do with something in the 90s; the decline started much earlier and has been fairly linear and consistent over time. Edit: In addition, most of these measurements have been taken from people in their mid-to-late teens — meaning that whatever caused the decline presumably started at least a decade before the decline was measured. TL;DR: I'm not convinced that social media or any reasonably-modern changes are to blame: this dates back to the Boomers or perhaps even earlier.

reissbaker 8y ago
Also, an article from Slate noting that in Norway, IQ scores began declining in 1975: > What they found is that for Norwegians born between 1962 and 1975, IQs increased within each family by 0.26 points per year: Younger brothers had slightly higher scores than their older siblings, relative to expectations. (The researchers had to control for the more general fact that older siblings tend to have higher IQs than younger ones.) From 1975 until 1991, this tendency reversed, with test scores dropping by 0.33 points per year within each family. https://slate.com/technology/2018/09/iq-scores-going-down-research-flynn-effect.html https://slate.com/technology/2018/09/iq-scores-going-down-re...
- rjf72 8y ago
  As your quote says, that study is talking about birth years, not the year they were tested. Since it's based on conscription it's around age 19-20, so the decline was measured between ~1994 and 2011. Your lead paragraph also states as much: "...At some point in the mid-1990s, IQ scores in these countries tipped into decay, losing roughly one-fifth to one-quarter of a point per year..."
rjf72 8y ago
This is misunderstanding the point. The issue is not IQ scores are not increasing less rapidly - they are now decreasing! Increases asymptotically approaching something near 0 would be completely expected. To understand why think about something like developmental malnutrition. Developmental malnutrition causes reduced IQ. As this form of malnutrition was reduced in a previously very poor area you'd see a substantial increase in average IQ. But then as future generations also have stable supplies of food, this increase would disappear as the stable food supply would no longer provide a relative increase compared to past generations. Make sense? IQs getting literally lower is something very different than IQs growing less slowly.

reissbaker 8y ago

Also, an article from Slate noting that in Norway, IQ scores began declining in 1975: > What they found is that for Norwegians born between 1962 and 1975, IQs increased within each family by 0.26 points per year: Younger brothers had slightly higher scores than their older siblings, relative to expectations. (The researchers had to control for the more general fact that older siblings tend to have higher IQs than younger ones.) From 1975 until 1991, this tendency reversed, with test scores dropping by 0.33 points per year within each family. https://slate.com/technology/2018/09/iq-scores-going-down-research-flynn-effect.html https://slate.com/technology/2018/09/iq-scores-going-down-re...

rjf72 8y ago
As your quote says, that study is talking about birth years, not the year they were tested. Since it's based on conscription it's around age 19-20, so the decline was measured between ~1994 and 2011. Your lead paragraph also states as much: "...At some point in the mid-1990s, IQ scores in these countries tipped into decay, losing roughly one-fifth to one-quarter of a point per year..."

rjf72 8y ago

This is misunderstanding the point. The issue is not IQ scores are not increasing less rapidly - they are now decreasing! Increases asymptotically approaching something near 0 would be completely expected. To understand why think about something like developmental malnutrition. Developmental malnutrition causes reduced IQ. As this form of malnutrition was reduced in a previously very poor area you'd see a substantial increase in average IQ. But then as future generations also have stable supplies of food, this increase would disappear as the stable food supply would no longer provide a relative increase compared to past generations. Make sense? IQs getting literally lower is something very different than IQs growing less slowly.