Evolution, as an algorithm, is very much better as an optimizer of an existing design than it is as a creator of a new design. Optimizing the size of the brain of a creature is, for evolution, an easy problem. Making a better, more efficient brain is a much harder problem, and happens slowly, comparatively speaking.
The optimization problem is essentially a kind of budgeting problem. If I have a budget of X calories per day, I can spend it on X kilos of muscle, or Y grams of brain tissue. Both will cost me the same amount of calories, and each brings its own advantages. Since evolution is good at this kind of problem, we can expect that it will correctly find the point of tradeoff—the point where the rate of gain of advantage for additional expenditure on ANY organ in the body is exactly the same.
Putting it differently, a cow design could trade larger brain for smaller muscles, or larger muscles for smaller brain. The actual cow is found at the point where those tradeoffs are pretty much balanced.
A whale has a large brain, but it’s quite small in comparison to the whale as a whole. If a whale were to double the size of its brain, it wouldn’t make a huge dent in the overall calorie budget. However, evolution’s balance of the whale body suggests that it wouldn’t be worth it. Making a whale brain that much bigger wouldn’t make the whale sufficiently better for it to cost in.
Where this argument basically leads is to turn the conventional wisdom on its head. People say that big brains are better because they are bigger. However, the argument that evolution can balance the size of body structures efficiently and quickly leads to the opposite conclusion. Modern brains are bigger because they are better. Because modern brains are better than they used to be—because evolution has managed to create better brains—it becomes more worthwhile making them bigger. Because brains are better, adding more brain gives you a bigger benefit, so the tradeoff point moves towards larger brain sizes.
Dinosaur brains were very much smaller, on the whole, than the brains of similar animals today. We can infer from this argument that this because their brains were less effective, and that in turn lowered any advantage that might have been gained from making the size of the brain larger. Consequently, dinosaurs must have been even more stupid than the small size of their brains suggests.
Although there is a nutritional argument for bigger brains in humans—the taming of fire allowed for much more efficient food usage—perhaps there is also some sense in which the human brain has recently become better, which in turn led it to become larger. Speculative, perhaps. But on the larger scale, looking at the sweeping increase in brain sizes across the whole of the geological record, the qualitative improvement in brains has to be seen in the gradual increase in size.
Although there is a nutritional argument for bigger brains in humans—the taming of fire allowed for much more efficient food usage—perhaps there is also some sense in which the human brain has recently become better, which in turn led it to become larger.
Evolution, as an algorithm, is very much better as an optimizer of an existing design than it is as a creator of a new design. Optimizing the size of the brain of a creature is, for evolution, an easy problem. Making a better, more efficient brain is a much harder problem, and happens slowly, comparatively speaking.
The optimization problem is essentially a kind of budgeting problem. If I have a budget of X calories per day, I can spend it on X kilos of muscle, or Y grams of brain tissue. Both will cost me the same amount of calories, and each brings its own advantages. Since evolution is good at this kind of problem, we can expect that it will correctly find the point of tradeoff—the point where the rate of gain of advantage for additional expenditure on ANY organ in the body is exactly the same.
Putting it differently, a cow design could trade larger brain for smaller muscles, or larger muscles for smaller brain. The actual cow is found at the point where those tradeoffs are pretty much balanced.
A whale has a large brain, but it’s quite small in comparison to the whale as a whole. If a whale were to double the size of its brain, it wouldn’t make a huge dent in the overall calorie budget. However, evolution’s balance of the whale body suggests that it wouldn’t be worth it. Making a whale brain that much bigger wouldn’t make the whale sufficiently better for it to cost in.
Where this argument basically leads is to turn the conventional wisdom on its head. People say that big brains are better because they are bigger. However, the argument that evolution can balance the size of body structures efficiently and quickly leads to the opposite conclusion. Modern brains are bigger because they are better. Because modern brains are better than they used to be—because evolution has managed to create better brains—it becomes more worthwhile making them bigger. Because brains are better, adding more brain gives you a bigger benefit, so the tradeoff point moves towards larger brain sizes.
Dinosaur brains were very much smaller, on the whole, than the brains of similar animals today. We can infer from this argument that this because their brains were less effective, and that in turn lowered any advantage that might have been gained from making the size of the brain larger. Consequently, dinosaurs must have been even more stupid than the small size of their brains suggests.
Although there is a nutritional argument for bigger brains in humans—the taming of fire allowed for much more efficient food usage—perhaps there is also some sense in which the human brain has recently become better, which in turn led it to become larger. Speculative, perhaps. But on the larger scale, looking at the sweeping increase in brain sizes across the whole of the geological record, the qualitative improvement in brains has to be seen in the gradual increase in size.
Human brains have been shrinking..