Labeling something often suggests a haste
to catalogue it and be done with it. It also implies some level of
understanding of that which is labeled. But labels, especially pejorative ones,
also commonly help to insulate one from the need to enquire further. Why would
anyone who has labeled something as “trash”, for example, be bothered to read
or learn anything further about it?
Every now and then, someone who is
seemingly exasperated by the profusion of neurobiological facts describing a
localization of some function or other in the brain, labels the whole
enterprise as nothing more than the manifestation of the “new phrenology”. Nor
does such labeling come only from those outside the field; sometimes the same
dismissive label is used by neurobiologists themselves.
Essentially, (the old) phrenology supposed
that mental faculties are localized in the brain and that an especially well
developed mental faculty would result in a corresponding bump in the skull. By
measurement of the skull and its bumps one would therefore be able to infer
something about character, moral qualities and personality. Its originator was
Franz Josef Gall, who took refuge in France after his ideas had been
disapproved of in Austria and was shocked when the Institut de France, at the
instigation of Napoleon, did not promote him to membership.
There were some good reasons for dismissing
phrenology and especially the use that was later made of it to promote racists
ideas. But there is nothing wrong with its implicit assumption that the brain
is the seat of the mind.
Those who label the tendency of modern
neurobiological research to find that special cortical areas are associated
with distinct functions as nothing more than a manifestation of the “new
phrenology” do both the subject and themselves a disservice. That distinct
cortical areas are associated with distinct functions does not mean that they
can act in isolation; indeed all cortical areas have multiple inputs and
outputs, both to other cortical zones as well as to sub-cortical stations and
the healthy activity of an entire system is critical for a specialized area to
execute its functions. It is trite to suppose, as some (non-scientists) have,
that an area that is specialized for a special function, for example colour
vision, can be isolated from the rest of the cortex or the brain and still
mediate the experience of colour. No biologist has ever made such a claim and
those outside biology who make it know nothing of biology or the brain.
It is equally untrue that the whole of the
brain is involved in all its functions, as was believed in the 19th
century. No one could possibly deny that there is an area of the brain that is
specialized for vision or for some attributes of vision, such as visual motion;
nor can anyone deny that there are areas of the brain that are specialized for
audition. Nor would any reasonable person want to deny that lesions in these
different zones of the cerebral cortex have different consequences.
More recently, with the advent of brain
imaging studies, neurobiologists have shown that even the experience of
subjective mental states does not mobilize the entire brain with equal
intensity. Rather the results of such studies commonly show that a set of areas
is especially involved in some subjective state or another. But activity in the
areas comprising that set does not necessarily correlate only with one
subjective state. An area of that set may do “double” or “multiple” duty and be
active during the experience of several subjective states, even contradictory
ones. But one nevertheless commonly finds that the set of areas especially
active during some experiences is different from the set of areas active in
another, or in other, subjective experiences, even if they share common areas.
This, of course, is a far cry from those
who, usually anxious to stigmatize the findings of neurobiology, write of
neurobiologists as having discovered the “love spot” or the “beauty spot” in
the brain. Or to dismiss them as nothing more than “modern phrenologists”.
The “unity” of mind
A fertile terrain for questioning the
localizationist claim – that cortical areas with characteristic histologies and
specific sets of inputs and outputs can be associated with special functions -
lies in the so-called “unity of mind” which makes us act holistically.
But let those who ridicule the efforts of
neurobiologists consider what has been the greatest success of cortical studies
on the one hand and what has been its greatest failure on the other.
The greatest success - which almost links
the history of cortical neurobiology in one unbroken thread – is the
association of special functions with distinct cortical areas. This theme has
run through cortical studies since the day in April 1862 when Broca announced
that the third left frontal convolution is critical for the production of articulate
language.
The greatest failure has been its inability
to account for how these specialized areas “interact to provide the integration
evident in thought and behavior” as the American neuropsychologist Karl Lashley
put it in the 1930s. He also added, however, that just because the mind is a
unit, it does not follow that the brain is a unit.
Those who dismiss all these
“localizationist” studies as nothing more than a “modern phrenology” may want
to ask why neurobiology has failed so miserably just when it might have been
expected to succeed spectacularly in light of its findings.
Perhaps a good first step in this enquiry
would be to stand back – even if momentarily – and ask whether the mind is an
integrated unit after all. The answer may come as a surprise.