June 28, 2006
Cerebroscopes and Explanations
In Seed, Paul Bloom on the dubious merit of fMRI based explanations. (Via Language Log.)
A couple of years ago, a friend asked me to be a pilot subject for one of her fMRI studies. I immediately said yes, in large part because most of the psychologists I knew had their brains scanned at one time or another, and I was feeling left out. It was a tedious experience, involving the memorization of long strings of numbers—and being inside a magnet is like being buried alive, only louder. So when I emerged from the machine an hour later, I was grouchy.
But then she took me to a screen and showed me a record of my brain at work. It made up for the hour of torment. I was entranced.
Newspapers, magazines, TV and blogs very often discuss psychology these days as a series of studies that involve some measure of neural activity, usually fMRI. The most compelling studies are those which probe the brain while the subject is made to think about something controversial, such as politics, sports teams, race, sex, corporate brands or morality. It makes for great press releases. But fMRI imagery has attained an undue influence, and we shouldn't be seduced.
Posted by Robin Varghese at 01:36 PM | Permalink
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Comments
I think therefore I glow.
Very nice to read an objective description.
If you were to put your hands on the hood of your car, feel it’s warm, and conclude – ‘ hmmmmm, there’s an engine running in there somewhere ‘ you’d be at the same stage as fMRI is at at the moment.
Posted by: martin g | Jun 28, 2006 3:32:59 PM
Well, it of course all depends upon what you mean by "objective". It is pretty clear that Bloom doesn't know anything about fMRI (see if you can find what gives him away in the article!) Also, the car metaphor in the message above is more descriptive of the behavioral tests of psychology. It would be more precise to say that fMRI is like starting the car, opening the hood and observing which engine parts is involved in making the motor run; stepping og brake and observing what parts block the wheels, and so on. Naturally, this won't tell you all there is to know about the car, but if you were living in a world there the mysterious machinery of cars always had been hidden behind a locked hood, being able to open it up just a bit would be welcomed by most mechanics, I imagine.
Posted by: Martin Skov | Jun 29, 2006 4:05:50 AM
I'm not sure if what you're is actually addressing Bloom's point in the article (the big print quote in the middle of the page is hardly affected by your comments). The point is not that fMRI is useless, the point is that cog neuros are inferring too much from the pics. His supporting evidence is the experiment where cog neuros swallowed purposely constructed bad explanations when injected with irrelevent fMRI data, but rejected them when they were presented without such data.
Posted by: aegean disclosure | Jun 29, 2006 7:04:33 AM
My comment was really addressed to martin g's assertion that Bloom's criticism is an "objective" description of fMRI. Bloom clearly has no firm grap of fMRI methodology ["FMRI studies—which indirectly measure the flow of oxygenated blood in the brain(...)". Sic!], so his criticism should be treated as an outsider's take on the good and bad sides of fMRI.
If we instead look directly at the Bloom text I personally think that Bloom's main point comes at the end: mind and brain are two different things. Indeed, I will submit that he is not only irritated by the many misrepresenations of fMRI results in the press, or by cog neuro researchers infering "too much", but also - and more so - by fMRI researchers and cognitive neuroscience's very ambition of reducing mind to brain. The article is thinly disguised attempt to defend functionalism, plain and simple - i.e., the Fodorian notion that "mind" should be studied by psychologists, NOT by neuroscientists. Says Bloom: "We know far more about the mind from the study of, say, reaction times than we do from fMRI studies." Say what!
Also, shouldn't a scientist critical of the fMRI crowd "infering too much" be more prudent than this:
"In a recent study, Deena Skolnick, a graduate student at Yale, asked her subjects to judge different explanations of a psychological phenomenon. Some of these explanations were crafted to be awful. And people were good at noticing that they were awful—unless Skolnick inserted a few sentences of neuroscience. These were entirely irrelevant, basically stating that the phenomenon occurred in a certain part of the brain. But they did the trick: For both the novices and the experts (cognitive neuroscientists in the Yale psychology department), the presence of a bit of apparently-hard science turned bad explanations into satisfactory ones."
How on Earth can we tell from this description if the subjects really reacted to the results being culled from fMRI studies, or if they just reacted to being told that the explanation in questions was backed up by SOME KIND of scientific data?
Just to be clear: I am not saying that the interpretation of fMRI data is never based on problematic inferences, but to dismiss fMRI like this, as a possible tool for investigating the human mind, is just plain bogus.
Posted by: Martin Skov | Jun 29, 2006 8:44:06 AM
Re: How on Earth can we tell from this description if the subjects really reacted to the results being culled from fMRI studies, or if they just reacted to being told that the explanation in questions was backed up by SOME KIND of scientific data?
I'm tempted to joke that the subjects brains should've been fMRIed?
On another note it doesn't seem that "e is not only irritated by the many misrepresenations of fMRI results in the press, or by cog neuro researchers infering "too much", but also - and more so - by fMRI researchers and cognitive neuroscience's very ambition of reducing mind to brain." He's explicit: "But we know, scientifically, that the physical activity of the brain is the source of our mental processes. It's one of the first things the professor says in any intro psych course: The mind is what the brain does, and so every mental event, from falling in love to worrying about your taxes, is going to show up as a brain event. In fact, if anyone were to find an aspect of thought that did not correspond to a brain event, it would be the discovery of the century, as it would be the first ever proof of hardcore Cartesian dualism."
It seems rather that he's irrtated that some folk Cartesian dualism operates in people's understanding of mind, and that the effect of the use of fMRI is that they are suddenly surprised that the brain matters. "We're also natural dualists. We intuitively think of ourselves as non-physical, and so it is a shock, and endlessly interesting, to see our brains at work in the act of thinking." This is, I think, his description of people's understandings and not an endorsement of dualism.
But if you're not a dualist--and I do see how Bloom is given what he writes--showing that the brain matters in mental processes is trivial; it just shows what we assume. I do agree with you that he (or we) needs more than is offered in the Dana Skolnick study or at least in his account of it. But it's also not surprising that the bad uses of a new and promising approach can make a study seem more sound than it is.
Posted by: Robin | Jun 29, 2006 11:20:35 AM
"and I do see how Bloom is given what he writes" should read "and I don't see how Bloom is given what he writes"...
Posted by: Robin | Jun 29, 2006 1:16:18 PM
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