> Obviously we can't control this, so I see no evidence that "chronotypes" are formed by nature and not by nurture. Here’s why: The Hadza are hunter-gatherers

> Obviously we can't control this, so I see no evidence that "chronotypes" are formed by nature and not by nurture. Here’s why: The Hadza are hunter-gatherers whose lifestyle is very similar to that of early humans. The observations were found in people with lifestyles that represent that of early humans. What part of nurture would affect those people? They have no concept of a clock...