Last week's column about texting and tweeting among status-hungry primates brought in many responses from readers, including one with some interesting questions about the evolutionary roots of bullying:

"I have been thinking for a while about bullying and how common it is in kids, even otherwise typical kids, and wondering if it was a natural instinct in them, to some extent."

The reader went on to ask if bullying might serve to define the social hierarchy.

And then, suddenly, The Washington Post broke the news that presidential hopeful Mitt Romney was a high school bully, tackling a vulnerable boy and chopping his hair, as well as leading a partially blind teacher into a glass door.

Perhaps Romney has grown up since then, but his teenage behavior is what anthropologist Christopher Boehm describes as typical of an "alpha male social predator". Among other primates, indeed, such bullies prosper and rise to power, argues Boehm in his new book, "Moral Origins: the Evolution of Virtue, Altruism and Shame". Boehm thinks social predators ruled among the common ancestors we shared with chimpanzees some six million years ago.

But Boehm, who is director of the Jane Goodall Research Center, argues that our social behavior has evolved over the last six million years. By studying modern hunter-gatherer groups, he's concluded that evolution has made us kinder, more cooperative, and more egalitarian than our distant ancestors were.

According to his book, hunter-gatherer groups dole out harsh punishments to bullies. In these societies, he's observed that bullying behavior is treated as a more serious crime than lying, cheating or stealing. In Boehm's view, we've been evolving away from a social system in which bullying pays. By ostracizing or even killing the worst bullies, in other words, humans in hunter-gatherer groups have been breeding kinder, more cooperative temperaments.

It would be interesting to find out whether Boehm thinks agricultural and industrial societies have continued to suppress bullies, or whether alpha male social predators are on the rise again.