User talk:Peoplesunionpro

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Hello, Peoplesunionpro, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are a few good links for newcomers:

I hope you enjoy editing here and being a Wikipedian! Please sign your name on talk pages using four tildes (~~~~); this will automatically produce your name and the date. If you need help, check out Wikipedia:Where to ask a question, ask me on my talk page, or place {{helpme}} on your talk page and someone will show up shortly to answer your questions. Again, welcome!  -- Longhair | Talk 02:21, 18 Jun 2005 (UTC)

[edit] Adaptations

Hi,

I noticed your message on the [race] discussion page. I have been wondering whether some of the supposed physical differences I read about 20 years ago go or thereabouts have turned out not to be real. One adaptation that sounded useful (and probably confusing to casual observers) is that the arch areas of Africans are filled in, so that their feet appears to be flat. If one is going bare foot over rough terrain, that would seem to me to be a useful adaptation. I've asked various people what the evolutionary significance of the epicanthal fold might be, and some have suggested that it may offer better protection against the fine sand that is frequently blown into China from the desert (and which forms the basis of their excellent lōss soil). Also, I seem to recall that people from that part of the world are innately better insulated, and extra layer, or extra-thick layers of subdermal fat.

People have talked about the value of black skin in protecting people against UV radiation. One thing to keep in mind is that people in Africa were probably developing their characteristic colors at a time when clothing was not used to protect the skin. People who moved to high UV areas after the development would experience less environmental pressure to evolve toward the darker colors. But there is another interesting feature of black skin vs. white skin that not many seem to have considered: Black skin absorbs infrared radiation better than does white skin, but it also radiates heat better than does white skin. Thus, for people who needed to shed heat under the cover of the jungle canopy and during the hours of darkness, black skin would have another advantage. (When we held karate classes in a near freezing dojo, I could feel my black classmates just from their ir radiation. It was like walking by a brick wall in the early evening.) The same black skin would be a disadvantage in northern regions because individuals would radiate heat wastefully, particularly during the cold nights, whereas people with white skin would not radiate so much. Without mylar blankets they would have suffered more than their white cohorts. I'd be interested in reading current research about these differences, but I think it would also be useful to point out how often supposedly Asian characteristics like shovel-shaped incisors show up in non-Asian populations, how often curly hair shows up among predominantly straight-haired people, etc. P0M 00:53, 24 October 2005 (UTC)

Interesting. Thanks for your message. :) Peoplesunionpro 04:00, 24 October 2005 (UTC)

[edit] Intelligence and brain energy (wattage) use

From a note on the same talk page:

From Gray & Thompson (2004) [1]... stuff we should integrate here --Rikurzhen 04:07, Jun 22, 2005 (UTC) Neurobiological determinants of intelligence as measured by IQ:


  1. Speed and reliability of neural transmission are related to higher intelligence (reviewed in Refs 15,20). Early neuroimaging studies using PET found that intelligence correlated negatively with cerebral glucose metabolism during mental activity54 (for a review, see Ref. 55), leading to the formulation of a 'neural efficiency' hypothesis...

"and it goes against the general biological idea that higher intelligence requires more energy use from the brain." -- What it generally indicates is that for the same mental tasks, a person with a greater g quotient will generally use less energy than a person with a lesser g quotient (adjusting for differential specific abilities that vary between people [ie. an idiot savant mathematician will use less energy than almost everyone else when doing a calculation, but that's all they'll use less energy for]). It is probable that people with lower and greater IQs would have approximately the same total energy expenditure for the most difficult tasks that they can do, but that the people with higher IQs will be able to do much more difficult tasks at that energy expenditure (and that people with the highest intelligence may have both greater energy expenditure capacity and only spend it on really difficult tasks).

"It's also confusing when debating the 'race and intelligence (genetics)' issue, because it seems odd that some population groups would average such below average IQs when there would be much to gain in metabolic efficiency in having higher IQs." -- Probably so, but there would also be much to gain in having IQs significantly greater than what even the most intelligent people have now, that doesn't mean we have them yet (luck plays a role in which new genetic alleles evolve and propogate in different groups). Sometimes other tradeoffs are made evolutionarily (such as island dwarfism - nichefying). Perhaps, in general, generally high intelligence (for the metabolic efficiency) was not needed (the total brain changes needed for it would have been counter-productive and/or unnecessary). Perhaps, in general, for certain tasks made more common in those groups, they do have more efficient brains, but such tasks are no longer as important with respect to g. I do not know.

-- 24.16.251.40 07:14, 15 June 2006 (UTC) (Formerly 24.22.227.53 8•Vomit )

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