I learned about two new chemicals that humans and animals produce; one is called Serotonin, which produces feelings of confidence; and Octopamine, which produces a cringing personality. Winning increases the production of Serotonin while losing increases the secretion of Octopamine. In this complex equation, a winner is likely to keep on winning and a loser is likely to keep on losing. I've certainly experienced this sensation in sports where winning intensified feelings of confidence. As I considered all the areas of life where this might impact us, certainly our childhood experiences would have a dramatic affect on our feelings of confidence or cringing; security or fear, confidence in life or forecast of defeat: doom or prosperity.  Apparently the continued expression of such attributes increases or decreases production of both chemicals. It seems obvious to me that a childhood that lacked nurture would necessarily cause the child to approach life with a cringing, fearful expectation.