Recently, the economist posted an article showing a U shape curve in life satisfaction as a function of age. This reminded me of a very similar curve we generate in my statistics class using the American Time Use Survey data. Except this U-bend is for sleep as a function of age.
 U Bend, Economist 12/16/2010 |
 Amount of sleep Americans get as a function of age |
It’s hard to guess at causality, but if I had to choose I would say more sleep causes happiness, based on the school-time-shift results mentioned in Nurture Shock, where kids who got to go to school 1 hour later reported less depression. Also, the economist article mentions that happier people are less likely to get sick. It could be that sleep is contributing to both: happiness and health.