Here’s a lovely, intriguing — and, in keeping with the holiday spirit, totally depressing — bit of holiday research: It turns out that the more familiar you are with your spouse or partner, the more likely you are to buy gifts they hate!

That’s the result of an intriguing study recently done by Davy LeRouge and Luk Warlop (PDF link), two European professors of marketing. They took a few hundred couples, showed them pictures of furniture sets, and asked them to predict which ones their partners would like. Sometimes the people simply had to guess; in other situations, the experimenters would help them out by telling them which furniture settings their partners themselves had picked. And then the researchers also asked the subjects to predict which furniture settings would please a total stranger.

The result? People were pretty good at predicting the likes and dislikes of total strangers — yet astonishly crappy at figuring out the preferences of their closest and dearest partners. And when they were given new information about which furniture their partners picked for themselves? It didn’t help. They were still better at picking gifts for total strangers than for their loved ones.

Why? Possibly, the professors theorized, because when we’re very familiar with our spouses it can be hard to separate our own preferences from theirs. We mistake things we’d like for things they’d like. Also, we tend to cherish hidebound ideas about what our partners are like, and we’re unable to step outside those assumptions — even when our partners themselves give us fresh, new information. When we face down strangers, we have none of those biases and thus are able to more clearly see them as they are.

As LeRouge and Warlop write:

Our findings reveal that being familiar with the person for whom you are predicting the product attitudes is a burden rather than an advantage, mainly because it prevents people from taking full advantage of newly provided information about that person’s product attitudes … Further evidence shows that it is the extensive amount of vivid information that the predictors hold about familiar others that prevents them from selecting more valid prediction cues.

Deck the halls. Mind you, maybe these sorts of errors are propping up the world economy. Think of it this way: What you really want is a new pair of jeans … but instead, your partner thoughfully buys you a bunch of CDs of bands that he likes and you loathe. So you go out after the holidays and buy the jeans yourself. Essentially, there have been two rounds of gift-buying: Your partner’s addled, narcissistic purchase of crap you don’t want, and your own purchase of things you’d actually like. Double the spending — double the boost to the economy! And double the landfill!