It's that time of year: dirty Santa, white elephant and–my favorite–Secret Santa. They're back in full swing, and it seems like just about every social group who has heard "White Christmas," for the thousandth time is involved.

A group that you might not expect? The United States Senate.

Each year, senators have the opportunity to participate in the beloved Secret Santa tradition. This is a bipartisan activity, intended to spread Christmas cheer and promote relationships beyond party lines.

One year, a Republican West Virginia senator gifted a Democrat Michigan senator a lump of coal, emblazoned with the Michigan state seal. Gifts like these are in good fun, and break down traditional barriers that keep senators from reaching across the aisle, or even interacting with those from other states.

The thing is, just 40 percent of senators participate. Even more surprising is the fact that over half of those participating tend to be female, and the disparity grows each year consistent across both parties. This is pretty problematic considering that only 21 of all senators are female, and therefore females comprise just 21 percent of the Senate, whereas male senators comprise 79 percent.

This probably doesn't seem like that big of a deal. It's a holiday gift exchange for congressional elites. We don't take Secret Santa that seriously, why should they?

The thing is, according to the game theory of prisoner's dilemma, activities like this really do matter. According to the theory, repeated interaction leads to more favorable outcomes for all those involved. More importantly, repeated interaction leads to greater cooperation, collaboration and even toleration of one another.

With the parties stuck in such staunch opposition, it is extremely important that senators not only interact, but also interact in settings where interactions will almost always be positive.

It makes sense: if you argue with someone every time you talk to them, you'll probably just stop talking to them. But if–at least sometimes–you think they're funny, clever or even thoughtful, you'll probably keep them around. It doesn't mean you agree with them every time, but it does mean that you respect them and their ideas. It also means that you are more likely to support them, because they become a friend.

As an example, we can look at Justices Antonin Scalia and Ruth Bader Ginsburg. Though they sat at opposite ends of the political spectrum, they were extremely close friends–because they participated in one another's lives in ways that did not include discussions on the Supreme Court.

Obviously, there's no way to lobby for senators to participate in Secret Santa. That would be a bit weird. However, it would not be a waste of time. We need senators who interact, build relationships and create cohesion. This idea of Republicans or Democrats "winning," by passing policies the other side screams out against, needs to go. The first step is building relationships. You're much likely to act contrarian or ambivalent if you actually care about the ideas on the other side.