[stephen_cagle]

Putting on my armchair psychologist/anthropologist/whatever hat, I find the fact that you can sleep better with people speaking around you very interesting. I wonder if we are built to feel comfortable when we can hear people whom we trust (your background conversations in this case) speaking as we sleep? Means someone else we trust is awake and can be observant of dangers while we nod off.

[newsclues]

Sounds about right.

Also, teenagers, adults and elderly people have different sleep schedules that would allow for a tribe to have constant fire watch.

[coldtea]

Isn't that what cats who trust their human do all the time? Come to sleep on their lap for protection?

[hnick]

I have struggled with sleep at night for at least 15 years now. I get very sleepy in food courts (general hubbub in a safe feeling surrounding) and as a child who hated cricket I dozed off on the couch more than once when it was on. There's something calming about a low level of crowd noise.