Notes on neuroscience

June 6, 2013

I am in no respect an expert in neuroscience, but naturally I am aware of the main technical developments of the past few decades — especially functional MRI — which now provide neuroscientists with amazing imagery related to brain activity. I am also aware of the broad effort in the field to establish correlations between brain activity and mental states.

I will not deny that I am mildly discomfited by this effort, not because there is anything suspect about such correlations but because they are so often conjoined with a strange presumption that somehow brain scans are particularly probative windows on human behaviour, whereas in fact they are usually just fancy proxies for things we already know by other means (as has been convincingly argued). One also routinely runs into a tacit neurological reductionism according to which minds are “really just” brains, and you and I are, at bottom, “really just” fleshy computers processing stimuli. In this view of things, the notion of persons as bearers of freedom, dignity, and moral responsibility tends to become, at best, occluded.

My discomfort is only mild because I am aware that, whatever the merits of any particular scientific study, the minds-are-brains view is plagued by conceptual problems and, at least within the ambit of the reigning philosophy of nature in which matter is defined to be devoid of mental properties, is doomed to failure.

But, quite apart from the question of how we should interpret findings of correlations between mental states and brain activity, there remains the question of whether we should believe that such correlations exist in the first place. It seems that we should, but with reservations, for the evidence is not as strong or as straightforward as one might think.

For instance, a few years ago an important paper identified problems with common analysis techniques in fMRI studies. The authors showed that using such techniques they could produce nice correlations using data that were pure noise. Studies which avoided such confused methods uniformly showed comparatively low correlations. The authors speculated that a significant number of the findings claimed by the field might be illusory. I do not know what revisions resulted when (or if) the data were analyzed again.

And now, in this month’s Nature Reviews, comes another paper that criticizes the results of a wide swath of neuroscience work. The authors argue that a significant fraction of neuroscience studies suffer from low statistical power, meaning that both the sample sizes and the effects being studied are generally small. The problems with low power studies are many: the probability of missing true effects is fairly high, as is the probability of falsely “discovering” something that isn’t there. Even when a finding is true, low power studies tend to exaggerate it. Here is a popular level summary of the paper and the issues at stake.

Obviously it is up to the specialists to sort these issues out, and I have no doubt that they will. But there does seem to be warrant for wariness the next time you hear a claim that the neural correlate of this-or-that aspect of your mental life has been found. Sometimes things are just not that simple.


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6 Responses to “Notes on neuroscience”

  1. Erin Burrell Says:

    I heartily agree. And am apprehensive about the apparent research priority to demonstrate all psychological phenomena on a brain scan. It is very difficult to get funding for a study on therapy, for example, unless it includes imaging. This adds considerable expense and focuses research questions in ways that do not seem practical… which is a necessity in a field where well-constructed inquiries into even basic questions are lacking.

  2. cburrell Says:

    Academic work is unfortunately vulnerable to fads — I’ve seen it in physics, and this fancy for brain images seems to be another example. Did you read the paper linked by the words “convincingly argued”? He remarks on a study in which the mere presence of a brain scan image in a phony paper caused readers to profess greater trust in its results. The imagery is amazing, but it ought not to dazzle us that much.

  3. godescalc Says:

    Sticking pretty pictures into your research results is a tried-and-tested way of getting people engaged – words and equations can go in one ear and out the other unless actually understood, but a graphic is always processed on some level by the brain and so registers more.

    The entire idea of neuroscience has been bothering me for some time – my thoughts tend to turn naturally to the massively reductionistic, so the idea that “the spirit is just fireworks in the nerve cells” seems to be both (a) obvious and (b) wrong (because qualia, philosophical arguments, religious experience, &c &c). Also, dissecting the physical component of human thought like a lab animal (a) is an obviously praiseworthy endeavour because all knowledge is good and (b) may not be good for a healthy view of human beings for trees-occluding-forest reasons you touch upon. This may be a sign I need to get into philosophy a bit more; my native distrust of neuroscience implies a “consciousness of the gaps” viewpoint which is asking to be knocked down.

  4. cburrell Says:

    I could sign my name to your comment, godescalc; you’ve put it very well. Distrust of neuroscience itself is clearly not something I want to cultivate or even tolerate in myself, yet I am well aware of the danger, too often realized, of interpreting the findings of neuroscience in a way that has an especially pernicious effect on our self-understanding. It is an area of science in which it seems the distinction between the data and the interpretation of the data is unusually difficult to draw.

    “Consciousness of the gaps” would seem to be a decent proxy for dualism; it is a view with obvious difficulties, but it’s not as though the alternatives are free of obvious difficulties! My suspicion is that our confusion is most likely tightly tied to our philosophy of nature and, in particular, our views on matter and causation. Without some fundamental revisions on those fronts, I don’t see how we can have a coherent account of the relationship between mind and brain. But it would be hard to think of many concepts more firmly entrenched. Alas!

  5. I wanted to reply to this several days ago but have been very busy. Setting aside the technical philosophical and scientific questions, I’ve long been puzzled by the obvious eagerness of some people to reduce not only mind to brain but self to nothing. John Derbyshire, who used to write for National Review, was/is really stuck on this. He delighted in asserting that the very notions of consciousness, of a self, and implicitly of rational thought, were on the verge of being completely exploded by neuroscience. It seemed important to him to believe that materialism goes all the way down. But I could never grasp how he supposed that scientific reasoning could be trusted to prove that all thought is the result of biochemical events. How could you treat both of those ideas as coexisting in the same universe? How was scientific investigation to be exempted from reduction to illusion? More importantly, why was it so very important to him to do away with the whole notion of the person?

    It’s a puzzle to me. I could grasp it as the assertion of knowledge as power, as Walker Percy treats of it in Lost in the Cosmos. But if you’ve knocked the legs out from under the concept of knowledge itself–there’s no way of attaining knowledge, and indeed no one to do the knowing–where’s the thrill?

  6. cburrell Says:

    I agree with you completely, Mac. The whole project appears to be self-defeating, in more ways than one. I don’t understand the enthusiasm at all.

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