Veil of Fire

IP:
Well it's certainly better than anything you've posted in this thread, now isn't it?

SanDeigo:
I like your analogy. I'll have to think about that.

beausoleil:
(A) Thank you.
(B) While I realize that website is aimed at children, there still doesn't seem to be much substance behind it. "Many studies", while admittedly coming from a source as reliable as that one, still isn't specific enough for my tastes. What studies? Performed by whom? Under what conditions? Using what methods?

While it's evolutionarily unlikely that we'd be born with such a huge brain which we don't use, isn't it similarly unlikely that we'd be born with a huge brain which is mostly given over to redundant systems?

The Saint:
My only reali objection on this subject is the seeming teleology used by my opponents. Very few site sources, almost all seem to put their trust in appeals to ridicule and circumstantial ad homeniem (like IP). Most do as you did, tell me to go look it up for myself.

But if it were that easy, I would have resolved the conflict in my own mind and not had to bring it here at all.

Question: Which part of the brain is responsible for the placebo effect?

parkdalian

We've had a thread on this one. There is some evidence that the redundancy (i.e. brain weight) is linked to longevity and durability. It makes sense, that since we do lose neurons in early adult life, we have an abundant supply for each skilled and learned behaviors. Some neurons may be something like bench-warmers (spare players) in team sports. They may not be playing in the actual game, but they still practice with the team in case they're needed.

The implication is that humans have evolved a larger brain is for greater longevity and durability. Longevity is important for taking advantage of our increased intelligence, having more time to refine skills, perhaps leading to greater cultural complexity. Imagine if we only lived 40-50 years (like chimps). In a preliterate society, it would be more difficult to maintain a high level of culture and tool-making if there were fewer long-lived elders (passing on accumulated knowledge), and impossible with shorter overall individual lifespans, given the need for time to develop skills for group survival.

A more general thought is that the increased durability that comes with redundancy is simply a reflection of our increased dependence on our brain for survival, as well as intelligence having an increased "overhead" (I hate puns) to maintain mental acuity into old age.

I don't have links handy but I do have references:

Hofman, M. A. (1983) Energy metabolism, brain size, and longevity in mammals. Quarterly Review of Biology 58: 495-512

Di Sclafani V. Clark HW. Tolou-Shams M. Bloomer CW. Salas GA. Norman D. Fein G. PREMORBID BRAIN SIZE IS A DETERMINANT OF FUNCTIONAL RESERVE IN ABSTINENT CRACK-COCAINE AND CRACK-COCAINE-ALCOHOL-DEPENDENT ADULTS. Journal of the International Neuropsychological Society. 4(6):559-565, 1998 Nov.

Graves AB; Mortimer JA; Larson EB; Wenzlow A; Bowen JD; McCormick WC. Head circumference as a measure of cognitive reserve. Association with severity of impairment in Alzheimer's disease. British Journal of Psychiatry, 1996 Jul, 169(1):86-92.

[ July 02, 2002: Message edited by: parkdalian ]</p>

cricket

How long do you suppose those elders lived; the ones in pre-literate societies who grew to be so old?

parkdalian

For H. Sapiens, presumably about the same as modern humans, at least for a few lucky individuals.

Of course, I refer to maximum life-span and not average life expectancy which usually includes infant mortality and otherwise dying prematurely from disease or goof ups with lions.

[ July 03, 2002: Message edited by: parkdalian ]</p>

Gurdur

This is somewhat ironic, given that I initially criticised you for your bad link, and your follow-up.

Go out and buy a good book on neurophysiological anatomy (warning: they're expensive); even better, do about four or five years of neurology with the medical students at uni.

After all, I did.

Oh, and BTW, I don't use CNN as sources.

Also BTW: potential redundancy (and most of what is described as redundancy in the brain is not real redundancy, but only potential redundancy --- ask if you don't get what I mean) does not equal non-functionality at any juncture.

Not to be a smartass, but I don't really care all that much whether I'm believed or not, since
1) I'm not an Internet geek
2) I passed my exams, did a tiny bit of research on an associated area, and I'm happy enough with that
3) I have a life.

Mageth

Longevity is important for taking advantage of our increased intelligence, having more time to refine skills, perhaps leading to greater cultural complexity. Imagine if we only lived 40-50 years (like chimps). In a preliterate society, it would be more difficult to maintain a high level of culture and tool-making if there were fewer long-lived elders

Those with a "live longer" mutation would presumably live past typical reproductive age. Hence I have a problem with how a mutation with the primary benefit of longer life (past the age of reproduction) would be selected for. (Perhaps, as you implied, if a longer life, past the age of reproduction, increased the survivability of offspring???)

Am I missing something?

nyx

thefugitivesaint,

While I agree that no part of our brain is unused, there is still much to be learned in cognitive nueroscience. Would you agree?

Unfortunately I can't recall the University, but have recently heard of psychokinetic studies being performed which suggest that we may actually be able to control machines. Another study involved influencing a person's heart rate from afar.

There is so much we simply don't know.

Nyx

elwoodblues

That last part is the key, yes. If we were solitary creatures, the problem would definitely be much trickier, but we're not. We're very social animals. We care for our young, and _their_ young, even past reproductive age. We pass on the skills we've learned in our long lives, even past reproductive age. The trade-off is in the extra resources consumed by the old non-breeders, and in the extra reduncancy in the human body. The trade-off seems to be well worth it.

It definitely makes evolutionary sense. Like I said, if we weren't social critters then the problem would be valid. But we're extremely social.

Mageth

But we're extremely social.

Speak for yourself.

Thinking about it, I can see how it could work. But I think there's more to our evolving bigger brains than just the longevity factor. (And I know before you answer, no one's actually saying that longevity is the only factor).

elwoodblues

Oh, oh, another trade-off. We get bigger brains (with longer life, greater capacity to learn and conceptualize) but childbirth becomes much, much worse and we're ridiculously dependent on our parents for a much longer time. Again, the trade-off is well worth it, as evidenced by how well we're doing. Java Man could never have discovered penicillin.