An interesting article, which T99 cited over at Cassandra's place, is this one from the Wall Street Journal. Piercello will like it, with its notion that the quality of mental evolution is emergent. Joe will like it, with its positive view of the future! What I find so interesting, though, is this:
Human evolution presents a puzzle. Nothing seems to explain the sudden takeoff of the last 45,000 years—the conversion of just another rare predatory ape into a planet dominator with rapidly progressing technologies. Once "progress" started to produce new tools, different ways of life and burgeoning populations, it accelerated all over the world, culminating in agriculture, cities, literacy and all the rest. Yet all the ingredients of human success—tool making, big brains, culture, fire, even language—seem to have been in place half a million years before and nothing happened. Tools were made to the same monotonous design for hundreds of thousands of years and the ecological impact of people was minimal. Then suddenly—bang!—culture exploded, starting in Africa. Why then, why there?Yes! And yet, no.
The answer lies in a new idea, borrowed from economics, known as collective intelligence: the notion that what determines the inventiveness and rate of cultural change of a population is the amount of interaction between individuals.
I don't want to downplay the fascinating quality of the idea, which doubtless has a great deal of merit. It is surely right for a vast number of cases. What it isn't is a unified field theory. I'll give you two reasons.
First, it doesn't explain cases like the Black Death. The extraordinary progress that followed the Black Death occurred even though the number of interactions between individuals was sharply reduced -- as, indeed, was the number of individuals. These population cutbacks are not always a disaster for the rate of creativity or inventiveness: it is necessity, not trade, that has normally be called the Mother of Invention. Too, because the Black Death disrupted social structures and allowed for social mobility and better competition among workmen, it opened avenues of creativity that were not available before.
Second, the theory fails to account for the thing it set out to account for: the mystery of human evolution. Taking the theory at its best face, it offers a useful way of thinking about one factor in the rate of human creativity. It doesn't, however, explain why this "warlike ape" experienced evolution and creativity so differently from any other creature -- regardless of that other species' population size, or the length of its generations. "Trade" isn't adequate; other primates, at least, trade both goods and services (or goods for services, as for example food for sex). Why didn't they jump on the exponential ramp to Beethoven's 9th Symphony?
Indeed, the problem with this explanation is that it doesn't explain. It may help to understand why the last 45,000 years went differently than the previous millions, but it doesn't explain why it happened to be the case that trading goods and services suddenly kicked into an entirely different mode at some moment about 45,000 years ago. It also doesn't explain why it did so only for one species.
Finally, it doesn't explain the categorical difference in creativity that was already extant.
Recently at Pinnacle Point in South Africa, Curtis Marean of Arizona State University found evidence of seafood-eating people who made sophisticated "bladelet" stone tools, with small blades less than 10 millimeters wide, and who used ochre pigments to decorate themselves (implying symbolic behavior) as long as 164,000 years ago. They disappeared, but a similar complex culture re-emerged around 80,000 years ago at Blombos cave nearby. Adam Powell of University College, London, and his colleagues have recently modeled human populations and concluded that these flowerings are caused by transiently dense populations: "Variation in regional subpopulation density and/or migratory activity results in spatial structuring of cultural skill accumulation."What other species engages in "symbolic behavior"? Mankind creates art wherever it goes; if there is a single quality that defines us, it is creativity, that artistic nature. No other species does this. A crow decorates its nest with shiny things it finds, but it does not fashion shiny things in pursuit of some artistic vision. A chimp strips bark from a branch to make a better ant-catching tool, but it doesn't develop pigments meant to paint itself for rituals.
That is the real thing that needs explaining, and we are no closer with "trade" than we were before. That's not to say it's useless; I suspect this adds quite a bit to our understanding of the mechanism. What it doesn't explain is the cause. Telling me that we grew great because we learned to trade goods doesn't explain those species that trade goods without growing great; and telling me it was because we learned to trade art doesn't explain how we ever came to make, or to value, art. When we know that, we'll have learned something.
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