February 21, 2005


severed halves, intelligence, wisdom, narrative

There's nothing quite like a solid nine hours of sleep, after being up the previous day on less than four, to make you appreciate just how nice sleep is. A brain that biologically flat-out needs to effectively shut down higher facilities for a third of every day is good evidence of "intelligent design", you know. It couldn't be better designed, you faithless heathens.

But I digress.

As a last-resort type of measure to control really bad seizure-prone brains (and thus the people housing them), the corpos collusum, the major broadband connection between the two hemispheres (there are others, but they're both deeper and "simpler") is mostly severed. Because of those aforementioned parenthetical deeper connections--such as, say, motor coordination between both sides of the body--the procedure can be helpful instead of merely being an exciting modern way of crippling people. The artificial major lesion prevents the seizure activity from spreading across, making it more amenable for the more usual non-last-resort pharmaceutical controls to keep relatively manageable--think of it as a firebreak.

And for the most part, people function just fine afterwards--better, for having health-threatening seizures controlled or at least constrained. But interesting effects pop up under controlled conditions, such as isolating fields of view.

As part of how intelligently the brain is designed, the left eye talks mostly to the right side of the brain, and vice versa. When all the wiring is normal, the whole brain has pretty much full access to the full visual field. But not when the main bridge has been knocked out. In non-clinical conditions, again this isn't a major block, as eyeballs can move around (which given some of the intelligence in the body's design is actually kind of surprising). That being limited, you can isolate each brain hemisphere's access to the visual field.

Neat--and probably a little creepy, if you're emotionally vested in the superficially intuitive, but wrong, idea that a person's consciousness is somehow singular instead of an aggregate of multiple facets and functions--things arise from that. Probably the best known is things like showing an everyday object, a spoon or whatever, to the right brain, and the person knowing what it is he's seeing--but being completely unable to say what it is. This being due to, in most people, the vast bulk of language--and narrative--functions being lateralized into the left side of the noggin.

Even neater than that is this: supposedly, the right side of the noggin can be shown, say, an amusing picture that elicits a grin. Just like aforementioned spoon, the language-making side of the head isn't seeing that picture. Still not seeing it, the person can be asked why it is they grinned all of a sudden--and they'll explain why. The researcher's just funny, asking all these questions. Or they simply remembered a joke they heard earlier that day. Or, etc.

All their language-making cognition is getting is the emotional affect; it lacks the access to (rather relevant) information. What does the mind do when it has to explain something that it lacks relevant information for? It makes up a story--and more often than not, it will most certainly firmly believe it. Sometimes the story is better at convincingly matching available information than others--but that's simply a difference in narrative skill, not a difference in essence.

This isn't something that only pops up because of that unique set of constraints--it is, I'm convinced, how minds work all the time. The very complexity of the world, meeting the necessary abstraction of human senses, means minds never have access to all the information of an arbitrary event's context. Sometimes the missing information is pretty important--if the narrative of why doesn't involve it, that narrative is wrong. But good luck getting the mind to admit it.

A useful definition of intelligence is general skill at noticing and being mindful of the best amount of good available information. A useful definition of wisdom is the skill of being mindful of inherent weaknesses in the whole process.

I do believe that both of these things are skills--people vary in their innate raw capacity for both, but regardless of raw capacity, very few ever really near them. Both can be trained.

posted by Gar @ 11:24 PM
Well, the research is certainly interesting, but I have a pretty big problem with the subjects. As I see it (unless there were some very brave or well-compensated volunteers) everyone they were testing was already sufficiently different (brain-wise) from the rest of us as to require surgical correction.

That would seem (to me, anyway) to undermine the usefulness of any conclusions they draw as a result.
A related bit, from "Cognitive Neuroscience," by some blokes name of Michael Gazzaniga, Richard Ivry and George Mangun (which is just an awesome surname, sounds like a comic book character, or military-themed porn star, maybe one of the Talon News stable), pg 543:

"The interpreter..." they're referring to the cognitive system(s) that build up explanatory narratives around the umpty internal and external events a brain is constantly sparking and sizzling under as the symbiotic worms in the glial cells jazzercize it--they don't mention the jazzercise, I'm inferring that bit. "...was discovered by using a simultaneous concept test. A split-brain pateint was shown two pictures, one exclusively to the left hemisphere and one exclusively to the right, and was asked to choose from an array of pictures placed in full view in front of him the ones associated with the pictures lateralized to the left and right sides of the brain. In one example of this test, a picture of a chicken claw was flashed to the left hemishere, and a picture of a snow scene to the right hemisphere. Of the pictures placed in front of the subject, the obviously correct association is a chicken for the chicken claw and a shovel for the snow scene....subject responded by choosing the shovel with the left hand and the chicken with the right...when asked why he (his left hemisphere) replied, "oh, that's simple. The chicken claw goes with the chicken, and you need a shovel to clean out the chicken shed." Here the left side of the brain, observing the left hand's response, interprets that response into a context consistent with its sphere of knowledge--one that does not include information about the left-hemifield snow scene....however this type of test is manipulated, it always yields the same result."

Now granted, I don't think I can point to anything at all that demonstrates that only brains prone to epilepsy ever function in such a way.

Also of course, the conclusions drawn are basically only that the narrative interpreter system of the brain has always, in the few cases available to study, been lateralized in such a way. It's generally accepted in every bit of layman's and lowish (above text is more or less an undergrad-level textbook on the field) that the language-making, and thus narrating, facility is always lateralized. Split-brains are hard to come by, of course, but when strokes or brain damage fuck up the left side of the average brain, language tends to get hit hard far more often than not, as well.
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