Bryan Caplan  

My WSJ Review of Born Together - Reared Apart

PRINT
Rick Berman: Mercenary/Hero fo... Ridley, Simon, Population, and...
My review of Nancy Segal's history of the Minnesota Study of Twins Reared Apart is in Thursday's Wall St. Journal.  Highlights:

Nancy Segal's "Born Together--Reared Apart" is a thorough history of the project and of the 137 pairs of star-crossed twins who made it possible. Ms. Segal, a key member of the Minnesota team, focuses on the many scientific publications that emerged from the data. But along the way, readers meet leading twin researchers and a whole lot of twins--including the "Jim twins," the "giggle twins" (who both laughed almost nonstop) and, most incredibly, Oskar, raised as a Nazi, and his identical brother, Jack, who was raised as a Jew.

More:

Some findings go down easy: As most would expect, identical twins raised apart have virtually identical heights as adults. Some findings seem obvious after the fact: Genes, but not upbringing, have a pretty big effect on personality traits like ambition, optimism, aggression and traditionalism. Other findings perennially cause outrage: The IQs of separated identical twins are almost as similar as their heights. Critics of intelligence research often hail the importance of practice rather than inborn talent, but a three-day test of the Minnesota twins' motor skills showed that how much you benefit from practice is itself partly an inborn talent.

But:
The Minnesota study's IQ results hit a nerve years before their publication in 1990, overshadowing other controversies that might have been. Many of its findings are bipartisan shockers. Take religion, which almost everyone attributes to "socialization." Separated-twin data show that religiosity has a strong genetic component, especially in the long run: "Parents had less influence than they thought over their children's religious activities and interests as they approached adolescence and adulthood."
What about the funding?
The biggest funder was the Pioneer Fund, which was founded in 1937 by eugenicist Wycliffe Draper, though the Department of Health and Human Services was a close second. In the interest of transparency, Ms. Segal discloses the source of every dollar. She freely admits that some researchers were skittish about Pioneer, because of the foundation's perceived "racial agenda." But pragmatism prevailed: "The Pioneer Fund imposed no restriction on the investigators' procedures or publications," she writes, adding: "As Bouchard [the study's director] said in 2009, 'If not for Pioneer we would have folded long ago.'"
What about the broader social implications?
Ms. Segal has little patience for those who fear the social consequences of the Minnesota Study. The facts are on her side. Scientific support for the effect of heredity on ability, character, and success has been mounting for decades, but Western societies are more tolerant than ever, and more inclined to treat their members as individuals. Hatemongers have no need to appeal to heredity. Nazis used genetics to rationalize genocide. Communist regimes rejected genetics as "bourgeois" and murdered millions for their counterrevolutionary family backgrounds. When a powerful movement wants to commit a heinous crime, it makes up a reason.
Overall, a good book, but Segal's earlier Entwined Lives is more accessible, better-written, and deeper.



COMMENTS (3 to date)
KM writes:

"Separated-twin data show that religiosity has a strong genetic component, especially in the long run:"

This is odd. If this is true, how do you explain that in certain regions around the world (e.g. large parts of Northern Europe) has in less than 100 years gone from quite strongly religous to a situation today where the church is a very marginal phenomena and very few people attend church and/or see themselves as religous?

This would require very strong, and fast, changes in the gen set-up that seem implausible, no?

Glen Smith writes:

KM,

Some experiments in genetics indicate that something that is a social trait can become a genetic trait in as little as 3 generations (of course, these deal with selective breeding).

John Fembup writes:

"how do you explain that in certain regions around the world (e.g. large parts of Northern Europe) has in less than 100 years gone from quite strongly religous to a situation today where the church is a very marginal phenomena and very few people attend church and/or see themselves as religous? "

One obvious explanation is that a traditional "church" is not the only possible "religious" expression.

Seems to me one can be a true believer or a heretic about any number of things.

Fanaticism is not (and IMO never has been) limited to what people see in "churches". Politics for example, sports, some academic fields, many other examples.

So it's understandable that these alternative religions can take the place of traditional religions. In fact to the extent that humans may be in part "spiritual beings" I think it would be odd indeed if such alternate religions did not emerge as the influence of traditional religions declines.

Comments for this entry have been closed
Return to top