Post by Nemesis on Sept 27, 2002 8:26:41 GMT -5
Relative to their size, humans have the biggest brains on the planet. Check out the guy sitting next to you on the bus: hunkered beneath a fringe of moussed hair and a few millimeters of skull are three crinkly pounds of brain -- the only substantive difference between you and species you regard as food or pets.
But how did this happen? What special circumstance, what unperceived evolutionary force, nudged our hulking, hairy ancestors toward intelligence, and silently trebled the size of their brains in two million years or less?
This question is seductive not only because it tells us something exquisitely interesting about ourselves, but also because the answer could give us insight into whether other intelligent beings really exist.
Many researchers have considered how the processes of natural selection might encourage higher IQ. For example, predator-prey relationships can do this. When a lioness bags an antelope, she’s more likely to snag one of the dumb ones. Result? The lioness has a meal, but the average ability of the antelopes has been raised. The next night, the dumber lions will have a harder time getting dinner, and will preferentially drop out of the leonine gene pool. In this animal arms race, the IQ of both species is ratcheted upward.
This is survival of the functionally fittest, and intelligence is certainly one component of making it in a competitive environment. But there’s another type of mechanism that might have been more important in creating our cerebral machinery. It’s called signaling for fitness, and it’s a widespread component of beastly behavior.
The way to understand signaling for fitness is to consider a canonical example: peacock tails. When choosing a mate, peahens prefer males with long, bright tails. This isn’t simply due to a quirk of their little pea brains; it’s good reproductive strategy. Those impressive tails are metabolically costly, and require both good health and success in finding food. In addition, a flashy tail can attract predators, which only the wily can avoid. So when a peahen spies a male with a well-endowed tail, she can be sure he has good genes.
If she chooses to get to know him better, their offspring will have a survival advantage.
For most species, males court and females choose. So it’s usually the males who are using these fitness signals as semaphores to indicate that they’re up to snuff. In the words of Geoffrey Miller, an evolutionary psychologist at the University of New Mexico, "evolution is driven not just by survival of the fittest, but reproduction of the sexiest."
So how does this dovetail with the evolution of intelligence?
Miller points out that musty theories claiming we developed our impressive cerebra from, for example, tool use, don’t seem to fit the facts. The stone axes chipped by our one-pound-brained ancestors were about as good as those made by their three-pound-brained successors. Instead, Miller suggests that the ramping up of IQ was the result of 100,000 generations of pre-human courtship operating on fitness signals made possible by brain power.
But how did this happen? What special circumstance, what unperceived evolutionary force, nudged our hulking, hairy ancestors toward intelligence, and silently trebled the size of their brains in two million years or less?
This question is seductive not only because it tells us something exquisitely interesting about ourselves, but also because the answer could give us insight into whether other intelligent beings really exist.
Many researchers have considered how the processes of natural selection might encourage higher IQ. For example, predator-prey relationships can do this. When a lioness bags an antelope, she’s more likely to snag one of the dumb ones. Result? The lioness has a meal, but the average ability of the antelopes has been raised. The next night, the dumber lions will have a harder time getting dinner, and will preferentially drop out of the leonine gene pool. In this animal arms race, the IQ of both species is ratcheted upward.
This is survival of the functionally fittest, and intelligence is certainly one component of making it in a competitive environment. But there’s another type of mechanism that might have been more important in creating our cerebral machinery. It’s called signaling for fitness, and it’s a widespread component of beastly behavior.
The way to understand signaling for fitness is to consider a canonical example: peacock tails. When choosing a mate, peahens prefer males with long, bright tails. This isn’t simply due to a quirk of their little pea brains; it’s good reproductive strategy. Those impressive tails are metabolically costly, and require both good health and success in finding food. In addition, a flashy tail can attract predators, which only the wily can avoid. So when a peahen spies a male with a well-endowed tail, she can be sure he has good genes.
If she chooses to get to know him better, their offspring will have a survival advantage.
For most species, males court and females choose. So it’s usually the males who are using these fitness signals as semaphores to indicate that they’re up to snuff. In the words of Geoffrey Miller, an evolutionary psychologist at the University of New Mexico, "evolution is driven not just by survival of the fittest, but reproduction of the sexiest."
So how does this dovetail with the evolution of intelligence?
Miller points out that musty theories claiming we developed our impressive cerebra from, for example, tool use, don’t seem to fit the facts. The stone axes chipped by our one-pound-brained ancestors were about as good as those made by their three-pound-brained successors. Instead, Miller suggests that the ramping up of IQ was the result of 100,000 generations of pre-human courtship operating on fitness signals made possible by brain power.
