People with higher IQ's (intelligence quotients) tend to be more active nocturnally, going to bed later, whereas those with lower IQ's usually retire to bed sooner after nightfall. People with higher IQ's are more apt to be nocturnal night-owls. Those with lower IQ's 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 IQ's.
Why night owls are more intelligent