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If you find yourself unexpectedly single this week, then you are not alone. Evidence culled from Facebook status updates finds that the phrase “we broke up because …” is more popular in the two weeks before the Christmas holidays than any other time of the year. While there are many reasons relationships end, the timing of the breakup surge in the pre-Christmas season can be explained by wholly unromantic economic theories that illustrate how we behave when it is difficult to observe the intentions of others.

Imagine we have a couple that is looking forward to the Christmas season. Each person in the relationship knows how committed they are to the relationship but does not know if their lover is fully committed; only the individual has that information.

Relationships require an investment of time and energy, and so each would like to know with certainty if the relationship is going to last before investing too much. As a rule, we give our hearts only to those we feel are likely to reciprocate.

The two people in our imaginary couple might tell each other they are in love, but words are cheap. To feel truly secure in the relationship, each will look for indications of the other’s devotion. They expect their partner to send costly signals that they are committed.

The Christmas holidays are replete with opportunities to signal how committed we are to our relationships. If many couples are breaking up before Christmas, the most likely explanation is that they are either finding themselves unwilling to pay the cost of sending the appropriate signals or they are not receiving the signals they would expect from a partner who really cared about their relationship.

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Take, for example, gift giving. Christmas gives us the opportunity to buy gifts that demonstrate how invested we are in meeting our partner’s needs. A person who is fully committed to his or her relationship probably already knows what those needs are and so can find a perfect gift fairly easily. A person who is less committed to the relationship, however, will find looking for the perfect gift less of a pleasure and more of an unwelcome chore.

While it is too early to know what gifts we will receive, it is not too early for gift givers to wonder why they are spending time looking for a gift when they don’t see themselves with that person in the future. After all, why send a costly signal that you are committed to a relationship when that is not, in fact, the case? Maybe it is just easier to end the relationship now and skip the hassle of trying to impress.

Christmas is also a busy time of year for socializing with co-workers, friends and family — meaning that social conflicts are inevitable. Being in a committed relationship generally entails attending social events together, even when your friend’s party sounds like it will be more fun than spending the evening at your romantic partner’s obligatory office party. However, not going to your partner’s party sends him or her a fairly clear signal that you are not committed to the relationship.

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It isn’t hard to imagine that a number of people typing “we broke up because …” in their Facebook status will be ending it with the phrase “he/she didn’t seem to think that it was important to spend time with me” after having to spend an awkward evening alone at a Christmas party.

Finally, nothing says commitment like the phrase “Let’s spend Christmas with your family, we can always spend next Christmas with mine!” Uttering this sentence to your beloved could have two possible effects: it could fill them with joy (he/she thinks we will be together next Christmas!) or horror (he/she thinks we will be together next Christmas!?). How the beloved reacts will almost certainly determine whether or not you will survive as a couple to the next peak breakup period … Valentine’s Day.

Despite the dismal statistics on breakups at this time of the year, it is worth noting that the same conditions that are helping couples figure out that they no longer want to be together are helping other couples figure out that they do want to be together — until death do them part. According to TheKnot.com, December is the most popular month of the year to get engaged. For some, costly signaling pays off.

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