http://news.com.com/Freakonomics+wr...s/2100-1026-6177655.html?part=dht&tag=nl.e433 "He also devised two games that showed monkeys could end up feeling as if they'd won or lost, even though they'd actually broken even. Their seemingly irrational preference for the "winning" game had Chen questioning how useful the monkeys would be as a touchstone for studying human behavior. Then he found that a similar study of day traders conducted by another researcher resulted in the same psychological preference. Even when they came out even, the day traders irrationally preferred to feel they won, rather than lost money."