Po Bronson, co-author of "Top Dog: The Science of Winning and Losing," offers a slight addendum to Malcolm Gladwell's well-known definition of "expertise" as 10,000 hours of practice - Gladwell's assertion it leaves out the impact of a competitive drive. Bronson discusses research on a "warrior/worrier gene" that may substantially impact performance regardless of knowledge or experience. Full video available for purchase at: fora.tv/2013/02/28/Po_Bronson_Top_Dog_The_Science_of_Winning_and_Losing