For countless generations humans lived in small groups, made up of 40 to 150 people, most of whom were closely related to each other and lived communally. As late as the year 1500, the average family group in Europe consisted of roughly twenty people whose lives were intimately connected on a daily basis. But by 1850 that number was down to ten living in close proximity, and in 1960 the number was just five. In the year 2000 the average size of a household was less than four, and a shocking 26 percent of Americans live alone.
