We Humans Have a Fatal Biology
Be very afraid! Our limbic system dooms us all.
Posted Jun 01, 2009
Our frontal lobes brought us from our hunter-gatherer ancestors to space travel. It all worked reasonably well, but now the older parts of our brains have caught up with us, dooming the human race.
Evolutionarily, I think we humans have come to a dead end. Our biology has become mismatched to the world that surrounds our biology. We are no longer a well-adapted organism, and therefore natural selection dooms us as a species.
Over evolutionary time, we evolved much larger frontal lobes than anyting our primate relatives had. Those frontal lobes enabled us to delay actions. During the delay, we could plan out actions of far greater complexity and sequence and effectiveness than other species, primate and otherwise, could create. In this enlarged frontal brain, we had evolved a highly specialized organ, as special, say, as the elephant's trunk or the star mole's nose or the shark's electrical sensors. The intelligence embodied in our frontal lobes became the key to our human magnificence: skyscrapers, bridges, supercomputers, space travel, Shakespeare, Picasso, Bach, in short, all our human achievements that we prize as "culture." Knowledge cumulated, and we had progress of a kind no other animal has had.
Yet we never lost what went before and still undergirds our overgrown frontal lobes: the mammalian brain, identified as such by Paul MacLean in the 1970s. No progress there. The mammalian brain remains the kind of brain that a cat or a dog, a lion or a bear, has. It's good for rapid response to emotional signals of fear or rage or lust or need. No delay--just pounce.
Using modern knowledge of the brain, we can update Plato's analogy of the charioteet trying to drive a white horse of reason coupled with a black horse of passion. Imagine a three-legged race with just one team in it, one team racing against the clock. The runner on the left is the frontal lobes' capabability for planning out the best way to shorten the time. The runner on the right is the limbic system. It responds ing emotionally to the race, grumbling, perhaps, to the runner on the left about having one leg tied to another runner's leg. This pair could do fairly well getting to the finish line.
But now imagine a three-legged race with many, many such pairs in a field so crowded that the teams keep bumping into one another. The frontal lobe runners can still plan strategy. But the limbic system runners tied to them now have many more chances to act on their anger, their greed, their sadism, their envy, and all the rest of the emotions the daily headlines tell us we humans are directing toward our fellow passengers on this planet.
In other words, our very progress has given our limbic systems more power. When economies were less global, when travel was harder, when the world's population was less, our hunter-gatherer ancestors lived in groups of two hundred or so. One group could have fights with other groups of hunter-gathers, but that was about all the trouble we could cause. (As in Kubrick's 2001.) But over historical time, our frontal lobes spread us all over the planet and vastly increased our capacities for destruction. Not only could we build magnificent bridges, skyscrapers, ocean liners, or supercomputers, but we could create governments claiming thousands of square miles, nuclear bombs, biological weapons, and
We come to the situation we face today, where the greed of a hedge fund manager on Wall Street dooms a farmer in Mali to starvation. The frontal lobe created financial instrments so ingenious only a computer (also created by frontal lobe intellection) can master them. But the limbic system harnessed that ingenuity to an unsatiable greed. And we find ourselves in the pickle we are in today with financial systems crumbling, nuclear weapons proliferating, the environment being pillaged, and religious fanatics unleashing terror on us all.
In short, I think we humans have come to an evolutionary dead end. On the positive, adaptive side, the evolution of our huge frontal intelligences made us the most successful, widespread, and populous species among the already quite successful primates. But on the negative, maladaptive side, the emotions that provide the guidance system for the deploying of intelligence doom us to using that magnifient capacity to self-destruct.
How's that for a Monday morning? Has anyone read Olaf Stapledon lately?
MacLean, Paul D. "A Triune Concept of the Brain and Behavior." The Hincks Memorial Lectures. Eds. T. Boag and D. Campbell. Toronto: University of Toronto Press, 1973. 6-66.
Stapledon, Olaf. Last and First Men: A Story of the Near and Far Future. London: Methuen, 1930.