Some sites claim that people with higher intelligence tend to go to bed later.
For example:
People with higher IQs are more apt to be nocturnal night-owls. Those with lower IQs tend to restrict their activities primarily to daytime. People who prefer to go to bed early, and who are early-risers, demonstrate "morningness," whereas those whose sleep patterns are shifted later demonstrate "eveningness." Researchers say eveningness tends to be a characteristic of those with higher IQs.
- Source: Dr Juliette Faraco of Stanford University, via Winnipeg Free Press.
Recently, scientists discovered a quirky side effect to having a high IQ: You tend to stay up until later hours and get up later in the morning.
- Source: Cracked
With marginal 'evidence' and no reason why this is like this (except for a nonsense reason along the lines that humans are not nocturnal; so to change that habit you must have some intelligence. To me, this sounds like a terrible explanation).
In my own circle of acquaintances, I've noticed that the more intelligent people tend sleep later than other people. The most common reason I heard is something along the lines of "I think too much at night." Of course it's well known that people with problems/depression have more trouble sleeping, because of this reason (they think about the problems too much).
Do intelligent people sleep later; and why?