Admittedly, most of the world practices exogamous marriage. But as to the other items on the list, the only people who have this particular set of family practices are the other English-speaking countries (meaning those that were settled by large numbers of English speakers, instead of ones such as India that were colonies). This makes sense, since we all inherited these features from England, even if our biological ancestors came from somewhere else.
The English allowed people to make their own marriage decisions to what was, until modern times, an unusual degree. Similarly, unlike almost all other cultures, in which designated persons are heirs by law and cannot be disinherited, the English, as far back as our records go, established no mandatory pattern of inheritance. (The Normans did impose on England the law of primogeniture, which required that the eldest son inherit all of his father’s real estate. But the English never liked it and developed ways to get around it before finally abolishing it.) So Americans resemble other English-speakers with respect to the treatment of inherited property, but are exceptional compared with the rest of the world.
The third bone-level cultural question is whether adult children form their own households rather than living with their parents. Americans, and residents of the other English speaking countries, have shown a strong preference to form their own nuclear-family homes while granting no authority over adult children to parents.
These cultural practices establish the basic structure of American exceptionalism. Immigrants who have come to America have, by and large, adopted them (until recently, anyway), largely because the law declined to enforce any others. Parents had no legal authority to interfere with the marriage decisions of adult children, for example.
The social consequences of these practices are somewhere between substantial and overwhelming. The individual in the English-speaking world has always been psychologically more independent and less willing to place himself under the control of others. He expects to be on his own, with a spouse of his own choosing, to make his own way in the world, and if possible to live in a home of his own.
These individualist nuclear families, rather than relying on extended family ties, create new networks and new sets of voluntary associations, with all their potential for exposure to new information, outlooks, and opportunities. This pattern is less extraordinary now, when most people in developed countries no longer live in farming villages and everyone is saturated in media, and active in voluntary associations, that provide such stimulation. But it’s easy to see that in earlier eras, a society with an individualist family structure would be far more dynamic than one in which adult children were controlled by parents and grandparents, and where the extended family took the place of voluntary associations.
The flip side of this freedom and autonomy is that English-speaking nuclear families do not live as part of an extended family group, which would be a source of help and protection in a hard world. English-speaking families have always been “on their own” far more than families in other cultures. As a result, American families have always coped with a stronger sense of insecurity, always knowing that they had to work hard and make a go of things. This has led to our well-known “go-getting” and “hustling” spirit. It has made the English-speaking nuclear family a powerful engine of economic development.
In sum, a person living in an individualistic society is less likely to believe he is entitled automatically to a share of anything, is less troubled by inequality, and is driven to provide for himself and his family through his own effort. By contrast, the family structures of many other cultures have over the centuries led people to feel a much stronger sense of entitlement. In parts of Western Europe, for example, it was mandatory that male children receive equal shares of the parents’ land. This led to an expectation that there would be equality of incomes. Further, the degree of parental control in many types of families leads people outside the English-speaking world to be far more willing to cede control over large areas of their lives to a lifelong, provident, controlling authority. In other words, political beliefs are a reflection of the deep structure of society, particularly family practices.