[huepfebein]

> "Maybe there are fewer social constraints late at night because you have fewer people around who are awake," Zeitzer said. That is especially true in places like the United States and the United Kingdom, where people tend to be more isolated in the evenings. In a Mediterranean culture, where nights are more gregarious, staying up might even be good for mental health.

This is the only note on cultural norms in the entire article. Yet I wonder, how you can look at sleeping patterns and mental health without also considering the broader societal norms, especially in a (typical Western?) society where rising with the sun is seen as a virtue.