Does Brain Imaging Make You Dumb?

There's no denying that the pictures used for brain imaging studies look cool. But do they actually tell us anything?
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I'm not talking about sticking your head infMRI scanner, which, so far as anybody can tell, is perfectly safe.(Unless you happen to have a pacemaker or pieces of shrapnel in yourhead, in which case you might want to give the whole procedure a miss).

No, I'm talking about what happens to peoplewhen they read about studies of brain imaging.Every 29 seconds or so, some scientist publishes a new study usingbrain imaging. And some magazine editor gets very excited. Aha, look atthe cool color pictures! Look how the brain "lights up" when people look atpictures of Hilary versus Obama. This is your brain on crack, andthis is what your brain looks like during orgasm.

There's no denying that the pictures lookcool. But do they actually tell us anything? Sometimes they do, butoften they don't.

Either way, when we look at such pictures(or even just think about them), our brains start to melt. A just-published study from Yale Universityshows that the average person's psychological IQ -- by which I mean nottheir overall intelligence, but rather their capacity to think straightabout psychology -- drops about 20 points the minute they hear thewords "frontal lobes". In the Yale study, three groups of subjects --ordinary joes, undergrads taking a neuroscience course, and experts --read brief discussions of psychological phenomena, and then had to saywhether the explanations made sense or not.

To take a typical example, subjects mightread about a phenomenon known as "the curse of knowledge" (something I discussed recently at klugetheblog.com).As the experimenters describe it, the curse of knowledge is aboutbelieving that if you know something, you expect that most other peoplewill, too:

Researcherscreated a list of facts that about 50% of people knew. Subjects in thisexperiment read the list of facts and had to say which ones they knew.They then had to judge what percentage of other people would know thosefacts. ..... If the subjects did know a fact, they [presumed] that aninaccurately large percentage of others would know it, too. Forexample, if a subject already knew that Hartford was the capital ofConnecticut, that subject might say that 80% of people would know this,even though the correct answer is 50%.

Why should that be the case? Subjects in theYale experiment had to sift through explanations like these, decidingwhich were good explanations, and which were poor explanations:

1. Theresearchers claim that this '' curse '' happens because subjects havetrouble switching their point of view to consider what someone elsemight know, mistakenly projecting their own knowledge onto others.

2. Theresearchers claim that this '' curse' happens because subjects makemore mistakes when they have to judge the knowledge of others. Peopleare much better at judging what they themselves know.

3. Brainscans indicatethat this '' curse '' happens because of thefrontallobe brain circuitry known to be involved in self-knowledge.Subjects have trouble switching their point of view to consider whatsomeoneelse might know, mistakenly projecting their own knowledge onto others.

4. Brainscans indicatethat this ''curse ''happens because of the frontal lobe brain circuitryknown to beinvolved in self-knowledge. Subjects makemore mistakes when they have to judge the knowledge of others. Peopleare much better at judging what they themselves know.

Subjects in the Yale study were pretty goodat distinguishingbetween #1 and #2. (#1 is a good explanation, since it tells us *why*the curse of knowledge might exit; #2 is empty.) But (except for theexperts) people were terribleat distinguishing #3 from #4, and in fact manythought that #4(which in reality is nomore illuminating than #2) was nearly as good as #1.

As the study's authors -- Deena Wiesbergandher colleagues -- put it ,"It is not the mere presence of verbiageabout neuroscience that encourages people to think more favorably of anexplanation. Rather, neuroscience information seems to have thespecific effect of making bad explanations look significantly moresatisfying than they would without neuroscience."

Why are we such suckers?

href="http://http://www.garymarcus.com/">Gary
Marcus is the author of the new book href="http://http://klugethebook.com/index.html">Kluge: The Haphazard Construction of the Human
Mind, an in-depth look at the fallacies of human
thought.

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