July 4, 2008

Is the brain irrelevant to psychology?

This interesting item in the BPS Research Digest caught my eye: Is the brain irrelevant to psychology? Hmmm, at first glance I'd say no. But then I'm rather biased since I've spent the best years of my life making brain function the centre of my universe, but seriously, it still astounds me as to who can ask a question as ridiculous as this?

Lately I've had discussions on this topic on two separate occasions, both with people who seemed somehow convinced (yet producing little to no evidence to support their views) that brain function is either something that is "not quite fully understood" or that it's relevance to psychology is marginal until fully understood. Both these views were held by people with degrees in something other than psychology (anthropology and biology, actually) and it was plainly obvious that their viewpoints smacked of dualism, which, in all entirety, is almost completely irrelevant to the neuroscience field which employs a monistic viewpoint. With extremely good reason too.

However, this item was irritating for another reason: Opposing arguments are almost always brought by philosophers! Jerry Fodor, in this case. I don't know about you, but I've always been mildly irritated by how philosophers who talk about neuroscience topics almost always serve to act as a spanner in the works. If I was an optimist (which I am, but not an overly enthusiastic one) I'd appreciate their arguments as something to think about and which can provide good ideas for further research. But that's just it: We neuroscientists end up having to do all the hard slog while the philosophers sit around like armchair critics trying to poke holes in studies.

But anyway, enough of my Friday night rant, have a look at the item for yourselves and see how silly dualistic/philosophical arguments can be easily consigned to the garbage heap:

Cognitive neuroscience explores how our mental faculties emerge from, and are organised in, the slimy tissue of our brains, and it's currently a thriving field. But some critics argue it's a dead-end, that biology is irrelevant to psychological accounts of how our minds work. In the words of philosopher Jerry Fodor, "If the mind happens in space at all, it happens somewhere north of the neck. What exactly turns on knowing how far north?"

Now, writing in a special journal issue on the interface between psychology and neuroscience, language expert
Peter Hagoort has hit back, arguing that knowing something about the biology of cognition can help to shape psychological models.

Hagoort cites two key examples to support his claims. A little background is required.

When we encounter an unexpected word in a sentence ("He spread his warm bread with SOCKS."), a negative spike in electrical activity recorded from the surface of the scalp is detectable 400ms later and is thought to reflect the extra brain processing required for the surprise word.

Meanwhile, when we encounter a grammatical anomaly (e.g. "The boys kissES the girls") - there is a positive, more posterior, spike of activity, 600ms afterwards. This latter effect is observed even with nonsense sentences that violate grammatical rules, thus showing that the spike is independent from the processing of meaning.

Taken together, Hagoort says these findings have implications for psychological models of language processing because they endorse the idea that meaning and grammar are not handled by a "general-purpose language processor", as he puts it, but rather they are "
domain specific" - in other words, processed independently.

For his second example, Hagoort points to a
brain imaging study that showed the pleasantness of a smell was rated differently depending on whether it was accompanied by the label "cheese" or "body odour". Crucially, the brain imaging data showed the verbal label affected processing in the actual smell centre of the brain. "This example illustrates something that would not so easily be found out with a behavioral method: that language information acts directly in the olfactory input system," Hagoort said.

Reference: Hagoort, P. (2008). Should Psychology Ignore the Language of the Brain?. Current Directions in Psychological Science, 17(2), 96-101. DOI: 10.1111/j.1467-8721.2008.00556.x (Access is currently free).

Addendum: Yes, I have heard of Jerry Fodor and ideas on modularity and, while he is not just a philosopher, he is also a cognitive scientist and is thus in a position to know something of what he's talking about. My remarks against philosophers were directed to people such as Daniel Dennett. Shock horror! Yes, Daniel Dennett. As an undergraduate I hugely enjoyed studying the 'Consciousness' module and devoured the textbook, and found that Dennett was a prime example of one of those who act as the proverbial spanner. As Blackmore described issue after issue, Dennett seemed to pop up everywhere as a naysayer.

Ah well, perhaps I'm wrong and I was just in a bad mood when I read that book.

1 comment:

  1. Psychology is irrelevant to science.