3 ms·

I read somewhere a few months ago on HN that humans didn't start sleeping 8 hour cycles till the late 17th century..... Wish I could find that article....

• al-xss 13y ago
  I think you are looking for this: http://www.bbc.co.uk/news/magazine-16964783 http://www.bbc.co.uk/news/magazine-16964783
  • kumarski 13y ago
    Thanks!