If you're opening an ice cream parlor, you might think it's better to offer sixty flavors than a measly six. But some studies have shown that consumers actually buy more when given fewer choices. To better understand this, Dartmouth College cognitive psychologist George Wolford and his students tried to sell up to twenty different kinds of black pens. Then they charted their sales success against the number of choices offered.

Scientists found that it peaked at ten, and went down on either side of ten, but they strongly felt that if you had other items, probably more complex items, they would expect it to peak at lower numbers.