“Like children and adults, infants appear to rely on two key features to detect funniness. First, humour nearly always requires a social component. Using naturalistic observations, the psychologists Robert Kraut and Robert Johnston at Cornell, and later the neuroscientist Robert Provine at the University of Maryland, discovered that smiling is more strongly associated with the presence of other people, and only erratically associated with feelings of happiness. That is, smiling is more likely to be socially rather than emotionally motivated. Thus, the presence of a social partner is one key component of finding something funny. Recall that the point of laughter is to be shared.

But humour has a cognitive element too: that of incongruity. Humorous events are absurd iterations of ordinary experiences that violate our expectations.”