The classical literature in psychology describes the relationship between anxiety and performance, including mental performance, in terms of an upside-down U. At the peak of the inverted U is the optimal relationship between anxiety and performance, with a modicum of nerves propelling outstanding achievement. But too little anxiety--the first side of the U--brings about apathy or too little motivation to try hard enough to do well, while too much anxiety--the other side of the U--sabotages any attempt to do well. A