Readers respond to terrorism’s roots

Reader feedback on the July 9, 2016 issue of Science News

Rooting out terrorism

Anthropologists have moved to the front lines to determine what drives people to join terrorist organizations such as the Islamic State. New research shows that the most committed ISIS fighters revere Islamic law and identify closely with a small group of comrades, Bruce Bower reported in “Deadly devotion” (SN: 7/9/16, p. 18).

Some readers noted similarities between researcher Scott Atran’s work and philosopher Eric Hoffer’s 1951 book The True Believer. The book discusses the psychological causes of fanaticism that can be seen in political and religious movements throughout history. “It’s nice to have a scientific patina applied to Hoffer’s work, but his contributions to explaining the p-sychological bases for mass movements should always be credited,” wrote Michael Rethman.

Atran agrees with some of Hoffer’s ideas about the general conditions of fanatic devotion, including unity and self-sacrifice. But he is skeptical of other proposed conditions such as self-alienation and insecurity. “In any event, our research was driven more by trying to figure out, test and validate the cognitive and social conditions of devotion unto death regardless of personality factors,” he writes. “Hoffer provides historical comparison and depth to some of these ideas. But our task is to see what can be scientifically validated as right.”

Diet dilemma

Some microbes that live in the gut might cause obesity by converting fats in food into chemical signals that tell the brain to pack on the pounds, Tina Hesman Saey reported in “Microbial signals influence obesity” (SN: 7/9/16, p. 7).

“Then why do the olive oil fats in the Mediterranean diet not cause obesity? Why do the blubber fats in traditional Inuit diets not cause obesity? Lots more research to be done,” reader Laura Hamilton wrote online.

Saey agrees that more research is needed, but the answer may be more complex than microbes alone. Some research, for example, is already hinting that a diet’s effects may depend more on who is doing the eating than on what they are eating. Rodents on the same diet, but with different genetic makeups, may not be equally prone to g-aining weight, a recent study suggests (SN: 8/20/16, p. 13). The same could be true for people. “So while Inuit diets may not promote obesity for them, someone else may pack on pounds after munching on blubber. Olive oil may not be healthy for everyone either,” Saey says. “Researchers are just at the beginning of understanding how genetics, microbes and diet work together to influence health.”

Dog days of yore

Dogs may have been domesticated at least twice, in Europe and Asia, during the Stone Age. G­enetic analysis revealed that over time, East Asian dogs replaced dogs native to Europe, Tina Hesman Saey reported in “DNA tells of dual origins for dogs” (SN: 7/9/16, p. 15).

Some online readers wondered if disease played a role in shaping the ancient dog populations. “Given the ability of wolves, dogs and humans to travel long distances, it wouldn’t be surprising if the Asian proto-dogs carried in fleas, internal parasites or other diseases and killed off a good portion of the European proto-dogs,” Onyxhawke wrote. Online reader kudjomojo agreed, suggesting that East Asian dogs’ genomes could have offered disease resistance.

Disease spread often comes with migration to new lands. “It may also have been that the Asian dogs didn’t bring the diseases but were less susceptible to diseases that may have killed European dogs,” Saey says. Other factors could have played a part, too: Asian dogs may have had physical or behavioral traits that made them more appealing to humans and helped them become the top dogs in Europe. “It’s never a gene-to-gene or genome-to-genome fight, but rather what traits the underlying genetic makeup influences that decide which dogs will have their day,” she says.

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