There actually is some interesting evidence with regard to this: a CEO who was
claiming disability after a head injury to dorsolateral prefrontal cortex caused by
luggage falling from a bin in an airplane. His IQ was still above normal BUT he
claimed his ability to work was affected. The clue came to a clinician evaluating him
when he mentioned offhand that he no longer enjoyed playing chess--whereupon the
clinician tested him with of test of "executive function" (planning ahead, deducing
rules, that sort of thing) called the Wisconsin Card Sort Test (any psychologist can
describe this to you if you're interested), and sure enough, this was dramatically
affected (which would of course impact on his job, and indeed, he won his case based
on this evidence). This is a second hand account (the clinician is a friend of mine
but I use the example in my teaching), but the moral is that while behavior may not be
grossly affected, if you know what subtle deficits to test for they ARE detectable.
And it's not hard to imagine this sort of "executive function" being a common
denominator between many of these complex tasks. Actually, our own interest in this
in our research group is because both activity in this brain region and this kind of
cognitive function are both abnormal in some psychiatric disorders, such as
schizophrenia. Not the whole story of course, but an intriguing piece of the puzzle.
Mark D. Morin wrote:
>> Bill Skaggs wrote:
>> > Jure <jure.sah at guest.arnes.si> wrote:
> > > > > Thursday, July 20, 2000, 22:01:22 pdt
> > > > > Scientists measuring blood flow to regions of the brain have found that
> > > > > one particular area (the frontal lateral cortex) was stimulated when
> > > > > performing complex tasks. Even tasks that required a wide range of
> > > > > cognitive functions did not stimulate numerous regions of the brain, as
> > > > > some scientists predicted. This finding gives credence to the highly
> > > > > controversial idea of a "g" factor (generalized intelligence), as
> > > > > advocated in The Bell Curve.
> > I wrote:
> > > > The next thing to do is to look for people with stroke-induced damage
> > > > to that part of the brain, and see if they're all morons. Anybody
> > > > interested in taking a bet?
> > footy <footy at dskjfhsak.net> writes:
> > > Which side do you bet on?
> > I'm betting that they're not substantially less intelligent.
> > Correlation does not imply causation: just because activity in that
> > brain region is correlated with hard thinking doesn't mean that it's
> > the locus of hard thinking. After all, a furrowed brow is also
> > correlated with hard thinking, across a wide variety of tasks, but it
> > would be absurd to say that the "g" factor is located in the muscles
> > of the face. Maybe the frontal lateral cortex is the cerebral
> > equivalent of a furrowed brow.
>> The concept of "intelligence" is pretty much of a nonsequetor in individuals with
> brain damage. Because measuring intelligence presumes an intact brain. Also
> note that the current psychometric concept of intelligence is not unitary but
> consists of any number of measures that go into the overall, composit, IQ.
>> For example, someone with frontal lobe or frontal network damage is going to have
> word finding problems. That is going to pull down their score on vocabulary. If
> it's right frontal, they are likely to have lower scores on picture arrangement
> and block design. Left or right, they are likely to have difficulties with tasks
> assessing abstract reasoning.
>> No, the purpose of IQ testing in brain damaged individuals is not to assess
> intelligence but to assist in localization of the trauma, assess current skills
> and deficits, and make appropriate recommendations given their individual
> strengths and weeknesses.
>> > My skepticism arises from a comparison of the human brain with the
> > brains of apes -- the major difference is that the human brain has
> > greatly enlarged frontal lobes. This is a much larger part of the
> > brain than the frontal lateral region that the Science paper is
> > talking about -- probably 10 to 20 times larger. I find it hard to
> > believe that everything except this small subregion is basically
> > unimportant.
> > Anyway, somebody is bound to look at this pretty soon, and it'll be
> > interesting to see how it comes out.
>> Then again, you could pretty much lob off your right frontal lobe and after maybe
> a year or two of readjustment, not many people would know that you had an injury
> (no, no cites, just a half a dozen patients I've evaluated over the past couple
> of years).
> The rainbow is more beautiful than the pot at the end of
> it, because the rainbow is now. And the pot never turns
> out to be quite what I expected.
> Hugh Prather
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