Emma Pollack-Pelzner in the Yale Review of Books:
Most people think that choice is good. After all, we associate choice with autonomy, control, independence and desirable outcomes. In reality, however, this is not the case. As Schwartz emphasizes, too many choices actually lead to less happiness, a lower sense of control, and even paralysis. And this is the paradox he addresses: we think we want more choices, but when we have more options we are, in general, less satisfied.
One of many studies demonstrating this paradox involves a simple decision: buying jam. Testers set up in a supermarket offered one group of shoppers six jams to sample. They offered another group 24 varieties to taste. Despite the fact that we would predict people with a larger jam selection would be more likely to find a jam they would like, the study found that those offered only six jams were much more likely to make a jam purchase, and were more likely to be happy with that purpose.
More here.