The point about being aware of lying underneath some object was interesting. Sound might matter, like the frequency of background noise changes when you're in an enclosed space, and listening to your own shuffling noises helps you know when you've planted your feet right - or something. I have some really effective ear plugs and I notice they make it harder to move around.

Having said that, I've probably hit my head on the underside of an open cupboard door five or six times in my life, and I expect to do it again.