5 ms·

The West is still mostly in the denial phase, so nothing is really being done, yet. As such, the effect is ongoing. The Flynn Effect (and its reversal) are meas

The West is still mostly in the denial phase, so nothing is really being done, yet. As such, the effect is ongoing. The Flynn Effect (and its reversal) are measured in impact per decade. And numbers that seem small at first aren't necessarily so. For instance a 3 point decline per decade doesn't initially seem like much until you consider that IQ generally has an artificial mean of 100 with a standard deviation of 15. So 3 points per decade is 20% of a standard deviation per decade! That's enormous. In the past an IQ of 85 was considered mentally retarded. This was changed in 70s to make normal intelligence 'more inclusive.' That's another way of stating that 85 is still the best threshold for mental retardation. So a reverse Flynn Effect of 3 points/decade means you're talking about going from perfectly average to mentally retarded in 5 decades. And for many things, the effect will not be linear. If we take a test there's likely to be an exponential pattern where somebody of a certain IQ will get an answer correct e.g. 99% of the time, somebody a bit below 80%, somebody a bit below that 40%, and then somebody a bit below that will basically never get it correct beyond the point of statistical noise. Pair that with likely increased variance when looking at individual and relatively small societies, and it's fairly easy to imagine sharp swings being completely viable.

tptacek 6d ago
By the logic you've provided here, almost everybody alive during the 19th century was severely cognitively impaired.
- somenameforme 5d ago
  Not almost everybody alive, but certainly a very large percent. And you also have to keep in mind what this means in different eras. In the not so distant past the overwhelming majority of work was agrarian, any formal education was relatively rare, and issues like malnutrition were quite common. That latter aspect alone has been assessed at affecting IQ by ~15 points, enough to already send an average person into the domain of mental retardation. Go back somewhat further and drinking 'small beer', as it was called, was a frequent recommendation for young children since it was guaranteed to be relatively sterile, and had more nutrients than water. Cheers to developing brains! But if you go into the past and just look at well educated, well nourished individuals, regularly exercising their brain - then their cognitive ability was likely comparable, if not higher, than that of a typical modern era individual. But that sample made up a very small chunk of all people whereas today I'm comparing them to the norm.

tptacek 6d ago

By the logic you've provided here, almost everybody alive during the 19th century was severely cognitively impaired.

somenameforme 5d ago
Not almost everybody alive, but certainly a very large percent. And you also have to keep in mind what this means in different eras. In the not so distant past the overwhelming majority of work was agrarian, any formal education was relatively rare, and issues like malnutrition were quite common. That latter aspect alone has been assessed at affecting IQ by ~15 points, enough to already send an average person into the domain of mental retardation. Go back somewhat further and drinking 'small beer', as it was called, was a frequent recommendation for young children since it was guaranteed to be relatively sterile, and had more nutrients than water. Cheers to developing brains! But if you go into the past and just look at well educated, well nourished individuals, regularly exercising their brain - then their cognitive ability was likely comparable, if not higher, than that of a typical modern era individual. But that sample made up a very small chunk of all people whereas today I'm comparing them to the norm.