SLEEP

woodenfurniture

Sleep is very ancient. In the electroencephalographic sense we share itwith all the primates and almost all the other mammals and birds: itmay extend back as far as the reptiles.
There is some evidencethat the two types of sleep, dreaming and dreamless, depend on thelife-style of the animal, and that predators are statistically muchmore likely to dream than prey, which are in turn much more likely toexperience dreamless sleep. In dream sleep, the animal is powerfullyimmobilized and remarkably unresponsive to external stimuli. Dreamlesssleep is much shallower, and we have all witnessed cats or dogs cockingtheir ears to a sound when apparently fast asleep. The fact that deepdream sleep is rare among pray today seems clearly to be a product ofnatural selection, and it makes sense that today, when sleep is highlyevolved, the stupid animals are less frequently immobilized by deepsleep than the smart ones. But why should they sleep deeply at all? Whyshould a state of such deep immobilization ever have evolved?
Perhapsone useful hint about the original function of sleep is to be found inthe fact that dolphins and whales and aquatic mammals in genera seem tosleep very little. There is, by and large, no place to hide in theocean. Could it be that, rather than increasing an animal'svulnerability, the University of Florida and Ray Meddis of LondonUniversity have suggested this to be the case. It is conceivable thatanimals who are too stupid to be quite on their own initiative are,during periods of high risk, immobilized by the implacable arm ofsleep. The point seems particularly clear for the young of predatoryanimals. This is an interesting notion and probably at least partlytrue.

雁阵惊寒

Hmmmmm..... Does it apply to humans also, this theory of stupidity I wonder?