In 1995, Bruce Rind and Prashant Bordia did a study at a Philadelphia restaurant. They had waiters and waitresses draw smiley faces on the back of customers’ checks. The result?
Waitresses averaged 28% tips when they did not draw a smiley face and 33% when drawing smiley faces. The difference was statistical significance. Meaning it’s unlikely to be due to random chances. Waiters saw their tips decrease from 21% to 18% on average. It wasn’t statistically significant. And they never figured out exactly why it declined.
