These days, psychiatrists favorite fig leaf for counter-intuitive claims is to hide behind neuroscience. "You think that serial killers are just evil people? Well, obviously you haven't seen these MRIs showing the serial killers have more/less of some brain chemical." I always counter "So what? What theory of mind predicts that serial killers' brains will be average in every way?" When I'm feeling especially flippant, I'll add, "Have you scanned nuns brains to 'disprove' the theory than nuns are just religious people?"
Now there's a neat study that confirms my point. Researchers first told respondents about a psychological puzzle known as "the curse of knowledge." It then asked respondents to choose between alternative explanations for the "curse." The novelty of the study is that some explanations contained irrelevant talk about "brain scans" and "the frontal lobe."
Punchline: irrelevant neuroscience persuades novices and neuroscience students, but not actual neuroscientists. No wonder irrelevant neuroscience shows up so often on t.v.
All this reminds me of Brian Doherty's piece on Andrea Yates in the latest Reason (not available online as far as I can tell, but here's a related blog post). Brian got a lot of hate mail for writing on this subject, mostly from semi-literates who told him that if he only understood neuroscience, he'd see how wrong he was to hold Yates responsible for drowning her kids.