Wouldn't it be an awesome experiment to analyze people's behavior while playing Grand Theft Auto? Maybe correlate their choices in GTA with their real life record of malfeasance (arrests, self-reported number of fights, etc.)? Of course you'd have to somehow control for general video game skill, but that wouldn't be too hard if you allowed a training phase. If I were to conduct this experiment, here's how I would operationalize morality:
Positive points are rewarded for moral behavior, while negative points signify that you probably enjoyed the movie American Psycho a little bit too much.
1) I'd have to dock points for every time that the participant steals a car, since the person Niko's stealing from probably has something to do too. But an auto theft isn't the end of the world, since they'll definitely receive insurance money, and there would probably be a few witnesses around to corroborate the story. If the car is more expensive, the person you're stealing it from probably will have more money, so the theft is less amoral. So you get -5 points for stealing a really fast car, and -10 for stealing a less expensive one.
2) If you stop at stop sign or red light while driving, that would be +5 points per occurrence. This is the only way to receive positive points, and is probably the most unprecedented behavior on the list. I have NEVER seen anybody stop at a stop sign or red light while playing GTA. I'm not even sure that the light will ever turn green. The game might break for all I know.
3) Next up we have murder. Killing people during missions shouldn't count against you, because that's pretty much Niko's job. He's just trying to feed his family. Aside from missions, every other body bag you rack up is -20 points. If you kill them with your bare hands and they don't fight back, that's -30 for pure sadism. But if they fight back, give you lip, or chase after you when you steal their car, that's only -10 because Niko has a name to uphold. He can't let just anyone show him up.
A few other provisions for specific situations. Killing a paramedic is -40 points because it will discourage future paramedics from arriving and add to the total death count. Shooting an RPG at a ambulance counts as killing three paramedics, for -120 points. Killing an old lady is -40 points as well, because that's just messed up. And killing a fugitive who is already running from the cops (which you see from time to time) is +5 points. Think of it like a citizen's arrest, with a Micro-SMG.
I'd track the actions of your participants and sum their scores after an hour. Anything above 0, and I would slap the participant for being such a sissy. A score between 0 and -100 seems about normal. If they score between -100 and -300, they probably have some pent up anger. Maybe I'd recommend that they join an Aikido class, or do some tantric meditation. And if somebody scores below a -300, I would probably put a tab on them, and if possible, suspend their right to purchase a firearm.