Based on no expertise (when was that a prerequisite for blogging or for opinionating), I had the theory that childhood events were directly associated with adult success, that play developed skills and the brain and learning was life. Those damn scientists aren't content with the obvious truth, they have to test it. As reported by New Scientist News - Play fighters do not win in later life:
"[the scientist] found that young meerkats [those cute animals who look like cats and act like prairie dogs] who played frequently were no more likely to win play fights, adult fights or become a member of the dominant pair. Furthermore, meerkats showed no sign of improvement with extra play sessions (Animal Behaviour, DOI: 10.1016/j.anbehav.2004.07.013)." So if play doesn't help in adult life, what's its purpose? The piece suggests that it may help in brain development. That would lead to the idea that meerkats with the most developed brains don't have an edge in adult life either. Ouch.