"All of the studies of adolescent sleep patterns in the United States are showing that the time at which teens generally fall asleep is biologically determined

"All of the studies of adolescent sleep patterns in the United States are showing that the time at which teens generally fall asleep is biologically determined -- but the time at which they wake up is socially determined" https://www.sciencedaily.com/releases/2018/12/181212140741.htm https://www.sciencedaily.com/releases/2018/12/181212140741.h...