Bryan Caplan  

Neuroscience: Don't Be Intimidated

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A Review to Be Envied... Against Adolescence...

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.

HT: Robin Hanson


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COMMENTS (7 to date)
John Thacker writes:

how wrong he was to hold Yates responsible for drowning her kids.

The really strange thing to me is how people believe that if people weren't responsible, then less punishment would both be appropriate and common. Why? It seems to me that if it were entirely a matter of brain chemistry and other precursors, then society would feel (and perhaps be) perfectly justified in taking action before someone actually commits a crime, based on the precursors alone.

Once you throw out the idea that people can be responsible for their actions, you end up throwing out the idea that people can only be punished for what they are responsible for.

Bruce K. Britton writes:

The seductive details effect was originally demonstrated in a paper by Britton, van Dusen, Gulgoz and Glynn in the Journal of Educational Psychology, from which Garner and Gillingham acknowledge they took off. The Britton et al paper found that the seductive details decreased understanding of a text written by Time-Life writers. The seductive details were inserted because of insistent demands by the next level of Time-Life editors for colorful 'nuggets' of information -- mostly man-bites-dog anecdotes on the topic of the text -- which because they were only tangentially related to the point of the text, served to distract the reader from the actual point of the text, thus decreasing understanding of that point.

Such insistent demands usually need not be made of journalists, because they are trained and shaped to include such 'nuggets' as a matter of course, for which one can find evidence on virtually any page of any newspaper, and television is even more suseptible -- 'if it bleeds it leads', etc.

Commentators point out that economics writing has its own seductive details dangers, but we should realize that so do all other fields, especially when journalists are let loose upon them.

Journalists do it because it sells soap.

TGGP writes:

I share Caplan's rather Szaszian tendencies, but I also found Greene & Cohen's For the law, neuroscience changes nothing and everything (which argues against non-political "libertarian free-will" and toward determinism or at least compatibilism) rather persuasive. I should note that I was already a determinist and consequentialist, so that might be confirmation bias. I should note that I did believe in the conventional view of insanity before reading Caplan's paper on Szasz, so I can change my mind sometimes. As an emotivist, I don't think there is much to the idea of "evil" and I think we should only think differently of a person that kills someone than a rock that falls on someone to the extent that it is useful to do so.

Another good paper on criminal responsibility, this time from a libertarian perspective, is Kinsella and Tinsley's Causation and Aggression, though it seems to assume free-will (or "agent-causation") and reject mechanistic explanations. I especially like the inclusion of midgets and murder-by-lightning.

As long as I'm on the subject, I still don't know what to think of David Friedman's post Justice vs Efficiency. I admit I haven't given it too much thought, but I was surprised since I hadn't come across the idea before.

Sheldon Richman writes:

Szasz in One Lesson (January 2006)

If neuroscientists discovered that mass murderers and people who claim to be Jesus had different brain chemistries from other people, most everyone would accept this as evidence that they suffered from a mental illness/brain disorder (MI/BD).

If neuroscientists discovered that homosexuals had different brain chemistries from heterosexuals, far fewer people would accept this as evidence that they suffered from a MI/BD.

If neuroscientists discovered that nuns had different brain chemistries from everyone else, very few people would accept this as evidence that they suffered from a MI/BD.

If neuroscientists discovered that married men had different brain chemistries from bachelors, no one would accept this as evidence that they suffered from a MI/BD.

Clearly, a difference in brain chemistry per se is not enough to make people believe that someone has a MI/BD. ...[P]eople, including psychiatrists, are willing to attribute behavior to mental illness/brain disorder to the extent that they disapprove of that behavior, and are unwilling to do so to the extent they approve of, or at least are willing to tolerate, that behavior.

Matt writes:

Whether or not we want to go, science will take us down the rabbit hole. This is an interesting topic in light of Brian's book. I see society become more extreme in the sense of free/not free. Either people will say these people are destined to be criminals, but we are all free and therefore we have to judge actions. Or they will go the other way, and say no one has free will, the criminal is like the rock falling in TGGP's example. When cost effective, we remove the rock. If not, the highway department puts up signs to warn people.

Karl Smith writes:

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 am not entirely sure why these to concepts are opposed. I am not a big believer in good and evil but I am even more confused about why brain scans change the judgement process.

If the brain scan of an "evil" person is different than that of a "good" person then you are simply witnessing the physical manifestation of evil.

Unless, someone is suggesting that we can alter the brain directly we are left with the indirect method of imprisonment and threat of death.

Sheldon Richman writes:

If the brain scan of an "evil" person is different than that of a "good" person then you are simply witnessing the physical manifestation of evil.

To regard a brain scan as the physical manifestation of evil is to commit a category error. There are no evil brain states. Evil is a quality of certain actions. A pathologist can't find evil during autopsies.

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