Larks and Owls: Sleep, Evolution and Industrialization

1. Sleep has a long evolutionary history. And yet science does not know why we do it.

2. The concept of a single consolidated sleep period (say from 11 PM to 7 AM, vs. two separate spans) is a relatively new development derived from the industrial workday.

3. “Larks” go to bed early and wake early, whereas “owls” stay up late and get up later.

4. In the early stages of life, it turns out that toddlers tend to be larks, whereas teenagers are owls.

5. A U.S. school district in Minnesota delayed its morning schedule for teens and found average S.A.T. scores for the top 10% of the class rose by more than 200 points.

From Up All Night by Elizabeth Kolbert (New Yorker)