Smaller Brains

It seems that our brains have been getting smaller for quite a long time. And they still are. There's no sign that this trend has been reversed. So, this is really quite an interesting question is Why should that be the case? And there have been lots of theories, and most of them are sort of functionalist theories that the brain is a very expensive organ. Probably it's the most expensive organ in terms of energy use. So maybe evolution has sort of selected for slightly more efficient humans with slightly less large brains. I don't really buy that one. Um, there was another theory about the amount of heat that the brain generates. I don't buy that one either. It's this sort of idea that it's a kind of radiator, and it doesn't want to get too hot. Um, what I do think has been happening, though, is in that 20,000-year period, humans have changed from being generalists, that is to say, people who could do everything that they needed to stay alive because they had to, to people like us, who are absolutely helpless without everybody else around us. So we've changed from being generalists to specialists. I mean, I can't actually do anything other than what I am doing now. And sort of making records education. I don't know how to grow anything. I don't know how to skin an animal. I don't know how to make clothes.