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The Germ Theory of Democracy, Dictatorship, and All Your Most Cherished Beliefs

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Fascinating article at Pacific Standard by Ethan Watters:

One morning last fall, the evolutionary biologist Randy Thornhill was standing with me in front of the gorilla enclosure at the Albuquerque zoo. He was explaining a new theory about the origins of human culture when Mashudu, a 10-year-old western lowland gorilla, decided to help illustrate a point. In a very deliberate way, Mashudu sauntered over to the deep cement ravine at the front of his enclosure, perched his rear end over the edge, and did his morning business.

Mashudu, I suspected, had just displayed what evolutionary theorists call a “behavioral immune response”—a concept central to Thornhill’s big theory. So I asked him whether I was right about Mashudu. “Pooping downhill is pretty smart,” Thornhill said after some consideration. “He got his waste as far away from him as possible. I think that would probably count as a disease avoidance behavior.”

It might seem strange to fixate on how a gorilla goes about answering the call of nature. But according to Thornhill’s hypothesis, much of what we humans like to think of as politics, morality, and culture is motivated by the same kind of subconscious instinct that likely drove Mashudu to that ledge.

Anyone with a basic grasp of biology knows that all animals have immune systems that battle pathogens—be they viruses, bacteria, parasites, or fungi—on the cellular level. And it’s also fairly well understood that animals sometimes exhibit outward behaviors that serve to ward off disease. Just around the corner from the fastidious Mashudu, Thornhill and I watched an orangutan named Sarah grooming her six-month-old son Pixel, poring through his hair for parasites. Some species of primate, Thornhill told me, will ostracize sick members of the group to avoid the spread of disease. Cows and other ungulates are known to rotate their movements among pastures in such a way as to avoid the larvae of intestinal worms that hatch in their waste. And in ant societies, only a small number of workers are given the task of hauling away the dead, while sick ants will sometimes leave the nest to die apart from the group.

At the most quotidian level, Thornhill finds it easy to convince people that humans likewise manifest such instinctual behaviors to avoid infection and illness. Some of these habits very much parallel those seen in other creatures. I admitted to Thornhill that I had recently been displaying a bit of grooming behavior myself after the youngest primate in my care came home from preschool itching with head lice. Like Mashudu, we humans remove waste from our living quarters. We ostracize our sick, at least to the extent that we expect those with the flu to stay home from work or school. And similar to the lowly ant, we assign a small number of our fellows the solemn duty of hauling away and disposing of our dead. On examination, everyday life is full of small defensive moves against contamination, some motivated by feelings, like disgust, that arise without conscious reflection. When you open the door of a gas station bathroom only to decide you can hold it for a few more miles, or when you put as much distance as possible between yourself and a person who is coughing and sneezing in a waiting room, you are displaying a behavioral immune response.

But these individual actions are just the tip of the iceberg, according to Thornhill and a growing camp of evolutionary theorists. Our moment-to-moment psychological reactions to the threat of illness, they suggest, have a huge cumulative effect on culture. Not only that—and here’s where Thornhill’s theory really starts to fire the imagination—these deep interactions between local pathogens and human social evolution may explain many of the basic differences we observe between cultures. How does your culture behave toward strangers? What kind of government do you live under? Who are your sexual partners? What values do you share? All of these questions may mask a more fundamental one: What germs are you warding off?

The threat of disease is not uniform around the world. In general, higher, colder, and drier regions have fewer infectious diseases than warmer, wetter climates. To survive, people in this latter sort of terrain must withstand a higher degree of “pathogen stress.” Thornhill and his colleagues theorize that, over time, the pathogen stress endemic to a place tends to steer a culture in distinct ways. Research has long shown that people in tropical climates with high pathogen loads, for example, are more likely to develop a taste for spicy food, because certain compounds in these foods have antimicrobial properties. They are also prone to value physical attractiveness—a signal of health and “immunocompetence,” according to evolutionary theorists—more highly in mates than people living in cooler latitudes do. But the implications don’t stop there. According to the “pathogen stress theory of values,” the evolutionary case that Thornhill and his colleagues have put forward, our behavioral immune systems—our group responses to local disease threats—play a decisive role in shaping our various political systems, religions, and shared moral views.

If they are right, Thornhill and his colleagues may be on their way to unlocking some of the most stubborn mysteries of human behavior. Their theory may help explain why authoritarian governments tend to persist in certain latitudes while democracies rise in others; why some cultures are xenophobic and others are relatively open to strangers; why certain peoples value equality and individuality while others prize hierarchical structures and strict adherence to tradition. What’s more, their work may offer a clear insight into how societies change. According to Thornhill’s findings, striking at the root of infectious disease threats is by far the most effective form of social engineering available to any would-be reformer.

If you were looking for a paradigm-shifting theory about human behavior, . . .

Continue reading.

Written by LeisureGuy

3 March 2014 at 11:26 am

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