The question of continuing human evolution….

It’s an interesting conundrum that I remember discussing with Nicholas Carr in the run up to his Google Making Us Stupid pieces. That is: has selection pressure (as operationally defined by sexual fitness) relaxed or at least qualitatively changed since our con-specifics were hunting and gathering? Seems to me that there are several questions embedded here:

First, modern humans emerged perhaps 50,000 years ago. Is that enough time for evolution to really make a difference? Further, the human technological advances that really start this discussion are at most only two centuries old. Is 200 years enough time?

Second, how exactly has selection pressure changed? From a selfish gene point of view, the rules haven’t changed even as we do live longer. Human traits are still selected for on the basis of the reproductive success of the trait holders. Neither the Internet nor our smart phones make any difference to that piece of the equation.

But might selection pressure change in the near future? Might we someday acquire attractive genes to acquire attractive traits? And how would those acquired genes play into reproductive success as opposed to some other kind of success (say economic)?

Finally, what about the role of epigenetics in selection? That is, might epigenetic modifications to genetic material have evolutionary consequences?

In any case, here’s a piece by Michael White on the question. Money quote:

Does this mean that we’ve transcended the messy process of evolution and made ourselves largely immune to natural selection? Not quite—just because our children aren’t eaten by predators or don’t succumb to childhood diseases does not mean that evolution has lost its power over our species. 

Those genes haven’t lost their selfish personalities….

On Crocodile Brains….

Michael Pritz of Indiana University School of Medicine gave yesterday’s regular Monday Krasnow seminar and it was fascinating. The basic questions were at the intersection of evolution and development (in biology we call this “Evo-Devo”) and basically got to the question of what are the points in the development of a brain that evolution can act upon through selection to produce new species with new brain capabilities.

Pritz’s experimental animal is the croc. Turns out crocodiles are very closely related phylogenetically to birds and….birds have remarkable cognitive capabilities with brains that have a radically different architecture from our own mammalian variety.

Evolution remains central to the scientific explorations at the Krasnow Institute for Advanced Study. Our impressive brains –the human ones in our heads–are themselves the product of evolution and hence, for all their amazing capabilities, have plenty of bugs. They weren’t engineered after all.

Jared Diamond on the cognitive need for vengeance

I’m up on Wintergreen mountain for the weekend–about the only time I can leisurely read The New Yorker–which I still believe has some of the best writing around. Jared Diamond’s latest anthropological piece about vengeance among New Guinea Highlanders makes for some powerful reading. He concludes that:

We regularly ignore the fact that the thirst for vengeance is among the strongest of human emotions. It ranks with love, anger, grief, and fear, about which we talk incessantly. Modern state societies permit and encourage us to express our love, anger, grief, and fear, but not our thirst for vengeance. We grow up being taught that such feelings are primitive, something to be ashamed of and to transcend.

My question is what is the evolutionary fitness argument for this human trait? How did the need for vengeance get selected for?

Read the entire article. It opens up some interesting questions for neuroscientists.

Jim