Each holiday season, another woman who loves the rock band No Doubt will receive a plaid skirt that only the band's singer, Gwen Stefani, could pull off. Another athletic guy will receive an oversize sports jersey – even though off the field he prefers Brooks Brothers. Why are we so terrible at predicting the tastes of the ones we love? A new study explains why familiarity with another person actually makes predicting their tastes more difficult.

Past research has argued that lack of diagnostic information causes this sort of misperception, but Davy Lerouge (Tilburg University, the Netherlands) and Luk Warlop (Katholieke University, Belgium) found that we buy unwanted gifts even when we have plenty of knowledge. In fact, we frequently have the most trouble understanding the tastes of those we know a lot about.

Not only do we feel overconfident that we'll pick something they like, but our tendency to assume that we are extremely similar to the ones we love also motivates us to ignore cues that don't support preconceived notions.

"Our results suggest that familiarity caused [people] to put an overly heavy weight on pre-stored information," write the authors. "The pre-stored information that people possess about their partner is extensive. This elaborate knowledge makes predictors overly confident, such that they do not even attend to product-specific attitude feedback."

In fact, the couples who participated in the study (all of whom had been dating for at least six months), were more likely to pay attention to feedback about their partner's preferences when they were told they were the attitudes of a complete stranger.

Davy Lerouge and Luk Warlop, "Why it is so Hard to Predict our Partner's Product Preferences: The Effect of Target Familiarity on Prediction Accuracy." Journal of Consumer Research: December 2006.