I Love Monkey Studies

Another delightful monkey study over at NYTimes.com, about how capuchin monkeys have been found to exhibit cognitive dissonance--rationalizing neutral or poor decisions by unconsciously revising our mental preferences. They did the study with M&Ms, but they've also found the same tendencies in children (with stickers) and adults (with wedding gifts).

Once a monkey was observed to show an equal preference for three colors of M&M’s — say, red, blue and green — he was given a choice between two of them. If he chose red over blue, his preference changed and he downgraded blue. When he was subsequently given a choice between blue and green, it was no longer an even contest — he was now much more likely to reject the blue.