Would you believe that golfers who believe the hole is larger actually have better results? Adding to the mound of evidence that perceptions and expectations influence performance, Guy Kawasaki cites this study and others in this post about how results match perceptions, even in golf.

So if expectations and perceptions have such significant influence, can those with a less positive outlook change the way they fundamentally think about things? Where on the nature-nurture continuum does this fall?