Jonathan Haidt Quotes:
Ocupation: Psychologist
Life: b. October 19, 1963
Birthday: October 19
There are a couple of watersheds in human evolution. Most people are comfortable thinking about tool use and language use as watersheds. But the ability to play non-zero-sum games was another watershed.
source: Interview with Tamler Sommers, www.believermag.com. August 2005. 
topic: Zero, Couple, Thinking, Zero Sum Game, Watersheds, Human Evolution
