It has been demonstrated time after tragic time--in colonial North America, 1940's Germany, Cambodia, former Yugoslavia, Rwanda, Darfur... Large, even mainstream groups of people can be induced to slaughter other groups of people by the millions, just for political or economic convenience.
When fully automated general-purpose manufacturing is developed, one of its effects may be to reduce the economic value of the average person, while simultaneously increasing the security risk posed by individuals and small groups. History does not inspire optimism about the outcome of this shift.
Hope for human nature comes from an unexpected source: primate studies. Chimpanzees and bonobos are often cited as evidence that things could be different. They are humanity's closest genetic relatives, and are closer to each other than to us. Yet they have very different cultures: bonobos are less patriarchal and more peaceable.
Even more direct evidence that primate nature may be flexible and improvable is described in a recent article in the January/February 2006 issue of Foreign Affairs magazine. In "A Natural History of Peace," Robert M. Sapolsky describes a very unusual tribe of savanna baboons.
Savanna baboons are typically aggressive, and their social structure reflects this. A baboon researcher wrote in the 1960's that they "have acquired an aggressive temperament as a defense against predators, and aggressiveness cannot be turned on and off like a faucet. It is an integral part of the monkeys' personalities, so deeply rooted that it makes them potential aggressors in every situation."
Contrast this judgment with the behavior of an unusual troop of savanna baboons that Sapolsky studied intensively. Twenty years ago, the troop happened to lose the more aggressive half of its male members to a sudden outbreak of disease. This caused a major shift in behavior: the remaining males were less aggressive and greedy, maintained a looser hierarchy, spent more time with females, and occasionally even groomed each other.
The really interesting thing is that these changes have persisted. Male baboons migrate to new troops as adolescents, so all males in the troop today grew up in other, more typical troops. Incoming males display high aggression and low affiliation, but change over time to perpetuate the local culture rather than changing the culture back to typical savanna baboon nastiness.
Even among humans, there is some good news. Sapolsky describes some brain-imaging studies on xenophobia. Typically, when humans are shown a face of someone from a different race--even subliminally--the amygdala activates. This is important because the amygdala is heavily involved in fear and aggression. But the good news is that there are at least two situations in which the amygdala does not wake up and make us xenophobic. The first is in people who have had a lot of experience with people of different races. The second, as demonstrated by Susan Fiske of Princeton, is in people who have been predisposed to think of the people they're looking at as individuals rather than categories.
Molecular manufacturing, along with other powerful technologies, will create new incentives and possibilities for both constructive and destructive human behavior. Given the abysmally bad examples set by our own ancestors and contemporaries, it is good to know that even baboons can become less violent given the right circumstances. The next question is: How can rapidly increasing technological abundance and power be managed so as to create circumstances in which humans will naturally choose non-destructive behaviors? The answer to this is far from obvious, but at least there is hope.