11-01-2016, 12:08 PM
(11-01-2016, 10:58 AM)X_4AD_84 Wrote:(11-01-2016, 09:50 AM)Warren Dew Wrote: The Flynn effect appears to have reversed starting with birth cohorts around 1980 or a little before. I know of papers showing reversal in at least Denmark, Germany, Finland, and the UK, and no papers showing it continuing. The fact that it can reverse convinces me that it's real. I suspect the timing matching that of the end of the 20th century height increases is not coincidental, either.
In my opinion, the Flynn effect reversal is most likely due to changes in nutrition - first improved nutrition, but since 1980, poorer nutrition. More junk food may be a reason for the recent decline, as pbrower2a suggests, and perhaps government recommendations that emphasize carbohydrates over the fats needed for brain development also contributed.
None of the above. It's due to "browning."
People from Asia, Latin America, the Middle East - are short. The tall Northern European genes are being bred out.
That could be part of it, although that can't explain why Japanese got 7 or 8 inches taller over the 20th century. They're only a couple inches shorter than Americans now.