Babel's Dawn

I'll Be Back Jan. 14, 2008

It's holiday time and I'm taking off. Enjoy the holidays and rejoin me on Monday January 14, 2008.

A Vote for Group Selection

This classic work has had enormous impact on professional and popular thought. Could it be wrong?

The “selfish gene” theory of evolution is incomplete and cannot account for many biological facts including the presence of language among humans, say two eminent evolutionary biologists, David Sloan Wilson and Edward O. Wilson, in a paper titled, “Rethinking the Theoretical Foundation of Sociobiology,” published in the current (December) issue of The Quarterly Review of Biology (early draft of paper available here). Of course, this does not mean the idea of evolution itself is in any jeopardy. Instead, the authors hope to restore respectability to the mechanism of group selection.

The selfish gene theory holds that as genes compete to replicate themselves the most selfish ones will triumph. In a society of selfish sociopaths and generous saints the sociopaths will out-prosper the saints, if only because the saints will be generous to the sociopaths while the sociopaths will not reciprocate. Thus, generosity will always be beaten by freeloaders who take from the group without ever giving to it. After a few generations the freeload gene triumphs.

This argument has always had its difficulties in trying to explain human evolution. We are communal by nature, utterly dependent on culture and organization to survive. The idea of having to live entirely on our own individual wits, experience, and strength is too frightening to contemplate. Even Robinson Crusoe depended on a huge body of craft that has been developed by others before he tried to live alone on his predator-free island. Thus, the idea has grown that some sort of special circumstances were required to develop humans. The anti-evolutionists have found strength in the inherent contradiction between what selfish-gene theory says must be true, and what is obvious in human society.

The notion of a selfish gene has been a particular thorn for this blog because speech is a form of sharing. Speakers share what they know; listeners put their attention under the control of another. How is that possible within the context of a selfish gene? So it is with some relief that I find a biologist of E.O. Wilson’s stature saying that the selfish gene theory has created “theoretical disarray” [p. 327] and cannot be the full story.

Humanity's Pump

East Africa's Rift Valley is familiar to many travelers who find a series of lakes beneath the rift escarpment. Over the ages many such lakes have come and gone, forcing the residents of the area to make do with things as they were during their short lifetimes.

At last I’ve been shown an evolutionary reason for developing the ability to say an infinite variety of things, thanks to the current (November) special issue of the Journal of Human Evolution devoted to the African climate where the human line of descent emerged. (Table of contents here) It is a great issue, likely to have a revolutionary impact on our understanding of the conditions that gave rise to Homo. In particular, adaptation to savanna grasslands appears to have been a much later pressure than we have supposed.

In one of the early posts on this blog I discussed the possibility that humans evolved along lake shores instead of out on the open savanna (see post). Now that idea is looking even better.

Visitors to East Africa find a very mixed terrain of desert, wetland, grassland, and forest spread across mountain ranges, vast flat spaces, the complicated Rift Valley faults, and numerous volcanic peaks. Ten million years ago, however, it was a relatively flat terrain covered with rainforest. Humans evolved in this land while the terrain itself was undergoing a series of great transformations; climate-wise it was the best of times, it was the worst of times.

The Two-Stranded Timeline

Human DNA combines two contradictory tendencies: Darwinian selfishness, and Franklinesque cooperativeness. Combining the two threads took time.

The last several posts on this blog have pointed the search for speech’s evolutionary origins in a new direction. Instead of looking for the appearance of a linguistic breakthrough (such as the first word), we should be looking for a more general breakthrough to a culturally-dependent community. So I thought I would re-orient the blog by posting a revised time line noting the likely milestones the emergency of speech.