Human brain still evolving? (evolution, verse, science, Article, deformity)

[Sunstone]

The human brain is still evolving according to some recent research:

“Our studies indicate that the trend that is the defining characteristic of human evolution - the growth of brain size and complexity - is likely still going on. If our species survives for another million years or so, I would imagine that the brain by then would show significant structural differences from the human brain of today.”

http://www.rxpgnews.com/research/neu...cle_2340.shtml

[Seyorni]

What forces are in play that would lead to larger brains? Unless large-brained/intelligent individuals consistently raised more children to maturity they have no selective advantage. Currently it's not the leading lights of society that are multiplying their genetic gifts, but the poor, maladjusted and disadvantaged. There is currently an inverse relationship between intelligence and reproductive success.

[Sunstone]

I fear you are right, Seyorni! Intelligence is on the wane and we are in for a future with more and more talk radio hosts.

[Feathers in Hair]

OOooo! Take your scary portents and mobile accomidations of all qualities elsewhere! (Blatantly, shamelessly stolen from Terry Pratchett.)

[painted wolf]

There is evidence that a mutation in the brain accompanied the 'agricultural revolution'. Today we all share this mutation.
In todays world where survival is no longer due to adaptation per say.... though there is some evidence that we are moving tword a more 'domesticated' form.

I'll see if I can track sources down.

wa:do

[Seyorni]

1. Without some serious anatomical adjustments, the human pelvis will not permit any increase in infant head size. Human childbirth is already a uniquely dangerous affair.

2. Technological advances are instantly transmitted throughout society. The clever individuals who originate them reap no special advantage.

Physical disabilities are no longer impediments to reproductive success. Nearsightedness, deafness, physical weakness or deformity, congenital diseases/disabilities, feeble-mindedness, anti-social tendencies, mental illness -- none consistently impedes reproductive success, as they would in our four-legged brethren. Thus, none are weeded out of the human genome.

I have to conclude that there is no selective impetus to "improve" the human genome, or even to maintain our current station as the "paragon of animals."

[JerryL]

Agreed. I see no reason that genetically larger brain sizes would be selected for. Perhaps there is a trend of increasing brain-size, in which case I would suspect improvements in nutrition and the like to be the cause, not evolution.

[painted wolf]

larger brains are not selected for... its the wireing that is changing...

selective pressures can influence the way we think... societies that value peace and co-operation select for features that promote this... societies that value violence and agression place selective pressures on that.

There needs to be no social impetus to improve the geneome... recent mutations include increasing resistance to diseases such as heart disease and high blood pressure. They will not spread as quickly thanks to modern tecnology, but they will spread thanks to the nature of breeding.

wa:do

[Flappycat]

Have you seen what even the lowlife trash on the streets do to attract women? They sing, dance, show their mechanical skill with cars, decorate their cars aesthetically, demonstrate their skill with words through off-the-top poetry, and so on and so forth. All of these are demonstrations of different types of intelligence. In times of famine, though, there is little selective advantage in developing a brain or body that requires an excessive amount of nourishment, so desirable qualities need to be contained within a more cost-efficient, smaller, model. Also, if our intelligence and prosperity continues to increase over the next several centuries, we'll hopefully eventually rid ourselves of the prolific impoverished classes by simple virtue of them being elevated to a level of prosperity that does not encourage prolific reproduction.

Also, as (if?) we use technology to push back the tide of sexually transmitted diseases, the behavior of widely dispersing genes that give advantages in courtship will gradually come to be less problematic, therefore increasing the capacity of courtship ability to disperse. Even now, the courtship rituals have become such a deeply-ingrained behavior that women who chose not to find them appealing would be at a selective disadvantage, so it is highly unlikely that we will lose our taste for aesthetics or impressive demonstrations of skill.

Therefore, prosperity does not beget a loss of the selective advantages of aesthetics or intelligence. Does this mean anything to anyone?