Predicting what we will like: Asking a stranger can be as good as asking a friend

• We examine three commonsense theories for predicting future liking of an attitude object.
• These theories help people decide what information is most useful for making predictions.
• We find that people prefer (1) to have a description of an attitude object rather than a rating or advice.
• They also prefer (2) information from a friend rather than a stranger, and (3) advice rather than someone else’s rating.
• However, our results show that a description is not always best and a stranger’s opinion can be just as good as a friend’s.

When predicting how much they will like something they have not encountered before, people use three commonsense theories: It is better to have a description of the attitude object than to know how someone else felt about it (“I know better than others”), better to know how a friend felt about it than how a stranger felt (“birds of a feather”), and better to get advice from friends—how much they think we will like it—than to know how they felt about it (“my friends know me”). We present evidence that people endorse these lay theories but also that they overuse them. Sometimes people make better predictions by knowing how a stranger felt than by getting a description of the object, sometimes a stranger is as good as a friend, and sometimes advice is not any better than knowing how someone else felt.