

WE USED TO SLEEP TWICE EACH NIGHT – 6/30/15 - delanceyplace
http://delanceyplace.com/view-archives.php?p=2828

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dalke
While it's dated "6/30/15", it's an "encore selection -- from Dreamland:
Adventures in the Strange Science of Sleep", published in 2012.

The topic has hit the pages of HN before. From a bit over two years ago are
the 107 comments at
[https://news.ycombinator.com/item?id=5542453](https://news.ycombinator.com/item?id=5542453)
. One of the commenters there pointed to the 2009 paper "In short
photoperiods, human sleep is biphasic", at
[http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2869.1992....](http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2869.1992.tb00019.x/abstract)
. More background on Wehr's argument for biphasic sleep is at
[https://en.wikipedia.org/wiki/Segmented_sleep](https://en.wikipedia.org/wiki/Segmented_sleep)
and
[http://www.bbc.com/news/magazine-16964783](http://www.bbc.com/news/magazine-16964783)
.

