this article is illuminating in it's citations - and it's clarity in debunking many of the points used on both sides of the debate.

this could be an empirical question, but we'll likely never have any actual useful data until we try the experiment in real time, and, even so you're looking at shifting conditions. being an empiricist also means understanding the limits of the tactic.

http://internationalviewpoint.org/spip.php?article3839