Monday, December 17, 2018

The nature-nurture war is over

Professor Robert Plomin writes in SciAm:
During the past four decades, scientists have conducted long-term studies on special relatives like twins and adoptees to test the effects of nature and nurture. This research has built a mountain of evidence showing that genetics contributes importantly to all psychological differences between us. In fact, inherited DNA differences account for about 50 percent of the differences between us, in our personality, mental health and illness, and cognitive abilities and disabilities. ...

A second crucial discovery is that the environment works completely differently from the way environmentalists thought it worked. For most of the 20th century, environmental factors were called nurture because the family was thought to be crucial in determining environmentally who we become. Genetic research has shown that this is not the case. We would essentially be the same person if we had been adopted at birth and raised in a different family. ...

The nature-nurture war is over. Nature wins, hands down.
Yes, that is generally accepted research.

The puzzling thing is that you probably assume that if DNA accounts for 50% of differences, then the environment accounts for the other 50%. The environmental causes in development would include whether you were spanked as a kid, whether you went to fancy schools, whether you played video games, etc. But the truth is that almost nothing is attributable to those measurable environmental factors.

To the extent that scientists can measure your psychological and behavior trait causes, they are maybe 50% genetic, 5% environmental, and 45% unexplained. You can think of the unexplained part as "random", but that is just another word for unexplained.

The genes in a population change slowly. A schooling policy towards a particular group is not likely to have noticeable effect. On the other hand, genetic changes can evolve over a millennium or so. So groups can have positive or negative qualities based on centuries of culture.

If you want to change a group for the better, you have to change the culture, start a eugenic plan, and wait a few centuries.

Who can do this today? No one in the West. Maybe China or Singapore or North Korea. The USA spends many billions of dollars on short-term plans that will do no good, and nothing on long-term plans that might do some good.

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