In a experiment sure to give succor to the notion that a lack of belief in free will will cause anarchy, scientists have gotten results that suggest those who don't believe in free will are more likely to cheat. Dave Munger has a good writeup here:
"Students who read the passage advocating determinism and against free will 'cheated' significantly more often than those who read the passage on consciousness that didn't mention free will. These students also were significantly more likely to believe in determinism compared to the other group, so it seems likely that this increased belief in determinism led directly to the 'cheating' behavior.
One might also be tempted to use these results to argue that belief in free will is important from a moral perspective (whether or not it actually exists). Yet many religions have very strong deterministic traditions and also strong moralistic traditions, so clearly belief in determinism isn't the only influence on moral behavior. Nonetheless, the results of this study are fascinating. I look forward to hearing what our commenters think about them.
I would be very interested to see such an experiment done with a followup test to see if the influence of the experiments sticks, or if it is something that is only a short-term effect. And of course the main lesson we should take from such results is not that we have to resurrect the notion of free will, but that we need to better explain the modulated, interconnected network of influences and desires that makes up our brains, and ultimately, our decisions.