(linked from Signals vs. Noise). This article is a pretty interesting overview of some studies of how people behave in the face of multiple choices.
For one thing, choice can be â€œde-motivating.â€ In a study conducted several years ago, shoppers who were offered free samples of six different jams were more likely to buy one than shoppers who were offered free samples of twenty-four. This result seems irrationalâ€”surely youâ€™re more apt to find something you like from a range four times as largeâ€”but it can be replicated in a variety of contexts.