Doing business in America is often a family affair. Indeed, Forbes estimates that 90 percent of U.S. businesses are owned or controlled by a family – a truly startling statistic. But this statistic covers a wide array of set-ups. The struggles of the Cargill clan, one of the richest families in the world, are quite different from those of small-town suppliers and most family farms.

As a college student in the early 1970s, I remember being fascinated by a study carried out by social anthropologists Barry, Child and Bacon in the 1950s. They studied 46 societies to understand how modes of food production lead to different child-rearing practices and personality traits.

As a graduate student in the late 1970s, I went to my first annual convention of the American Psychological Association. Rushing about with thousands of other young professionals, most wearing khakis or some other beige clothing, I remember walking past protestors outside the convention hall holding placards with pictures of dead animals.

In Purity and Danger, a classic book on social anthropology published in 1963, Mary Douglas points out how distinctions in many societies between “clean” and “unclean” are really about what is considered out of place. And these boundaries – like borders between countries – can be quite arbitrary.