What combination of environment and personality prompts ordinarily "good" people to do horrible, evil things? That must be just about the most vexing theological question of all, since we're still asking it after two world wars and a century marked by a whole lot of violence. In 1971, the famous Stanford prison experiment illustrated the disturbing speed with which normal people can become sadistic thugs.

I bring this up because Philip Zimbardo, the psychologist who ran the Stanford experiment, has been interviewed by Wired about what Abu Ghraib taught us about humans' capacity for evil. It's the same old story of what happens when people are given authority without accountability:

...in the Stanford prison study, I was saying [to the student guards], "You have to be powerful to prevent further rebellion." I tell them, "You're not allowed, however, to use physical force." By default, I allow them to use psychological force. In five days, five prisoners are having emotional breakdowns.

The situational forces that were going on in [Abu Ghraib] -- the dehumanization, the lack of personal accountability, the lack of surveillance, the permission to get away with anti-social actions -- it was like the Stanford prison study, but in spades.

Those sets of things are found any time you really see an evil situation occurring, whether it's Rwanda or Nazi Germany or the Khmer Rouge.

The video slideshow that accompanies the interview is worth watching, if you can stomach the extremely disturbing imagery. It's one thing to believe, as a Christian, that even the best human beings must struggle against a sin nature, and are capable of doing awful things. But it's quite another to look at photos of normal-looking, they-could-attend-my-church people laughing at the human misery they've wrought. Truly sobering.