The human brain, however, always seeks simple answers. Enter the third candidate. Huber told some people there was also a choice of a four-star restaurant that was farther away than the five-star option. People now gravitated toward the five-star choice, since it was better and closer than the third candidate. (The three-star restaurant was closer, but not as good as the new candidate.)

Another group was given a different third candidate, a two-star restaurant halfway between the first two. Many people now chose the three-star restaurant, because it beat the new option on convenience and quality. (The five-star restaurant outdid this third candidate on only one measure, quality.)

What the decoy effect basically shows is that when people cannot decide between two front-runners, they use the third candidate as a sort of measuring stick. If one front-runner looks much better than the third candidate, people gravitate toward that front-runner. Third candidates, in other words, can make a complicated decision feel simple.