An interesting listicle features ten topics you’d think we’d know the answer to, but don’t. Here’s one:
Often when we are about to fall asleep, we experience a kind of a falling sensation which causes us to wake up with a start. It happens to almost everybody, and the sensation is known as a hypnic jerk. It also sometimes happens when you tilt the chair you’re sitting on too far—somehow you can sense when you’re about to fall, and you wake up with a hypnic jerk. We really have no idea what causes them or whether they serve any modern purpose, but science has come up with some interesting theories.One hypothesis suggests that our bodies developed this mechanism when we used to sleep on branches or high ground, and it was meant to help us avoid a fall. But there is no evidence to support it, and humans rarely slept on trees or precarious cliffs as a matter of habit. Other theories suggest that it happens because of the slowing down of the body’s processes when you fall asleep, but again, there are no scientific studies to support that claim either.
Maybe I (O’Leary for News) am reading too much into an interesting listicle.
It’s interesting that this commentary exposes the cultural Darwinblather to critical thinking instead of just accepting it at THE explanation.
It’s indeed unlikely that we or any immediate ancestors, whatever they were like, were in the habit of sleeping on places they could fall off. Humans, unlike cats for example, don’t have any special mechanisms for reducing the harm from falling. And our body size and weight make breaking a limb a serious risk. How much more serious it must have been before modern medicine!
See also: What we know about human evolution
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Amazing: Cats are less likely to be hurt falling from a great height than a small one. Find out why: