Tribalism and modern civilization

David Boxenhorn has an interesting post on how our modern way of life conflicts with how we evolved to live in tribal societies:

For millions of years we lived in tribal units, stretching back in time far beyond the origins of our species, and continuing almost up to the present. A mere 10,000 years ago, all our ancestors lived as hunter-gatherers. Probably, most of our ancestors were still hunter-gatherers only 5,000 years ago. But even after that date, we lived in small villages - from a social point of view not too different from a hunter-gathering tribe. Modern life, intimately bound to the social milieu of the city, became the native habitat of the majority only about a hundred years ago, and then only in the most technologically advanced countries of the world. It is a profound change for mankind that after millions of years of evolution for tribal life, we find ourselves in an habitat that doesn't support it.

It is my opinion that many of the psychopathologies of the modern world result from the breakdown of the tribal unit. We are highly adapted to tribal life, and only by understanding this fact, and what it implies, can we understand human nature. The bottom line is this: we are profoundly maladapted to our habitat. Symptoms of our maladaption include feelings of ennui, isolation and depression, so common in our society. From an evolutionary perspective, these are clearly disadvantageous. Who is more likely to survive and reproduce – a depressed, listless individual, or a happy, energetic individual? Clearly, these problems are severely selected against, and indeed in tribal societies living close to our original habitat these problems are rare.