There was a programme on Radio 4's "In our time" hosted by Melvyn Bragg. The topic was "Circadian Rhythms" and it explained why some people are "earlys" and others are "lates"!It will be available as a podcast (if you live in UK).Malcolm
If you don't know which one you are - try the quiz - you might need a calculator to add up your score http://www.realsimple.com/work-life/life-strategies/time-management/early-bird-night-owlSandra
More intelligent children are more likely to grow up to be nocturnal adults who go to bed late and wake up late on both weekdays and weekend