How to decide whether to move in with your partner, if a game theorist were to say
In June 2022, Anna P. Kambhampaty wrote a New York Times article, “When the Rent Rushes Relationships.” Its cutline perfectly sums up, “Soaring rents across the county have motivated some young couples to move in together earlier than they planned.” Throughout the article, Kambhampaty covers several pieces of anecdotal evidence of people who have or have planned to move in with their partner, perhaps a bit too soon in their relationship.
First, there’s Xin-rui Lee. She was nervous about living with her partner and felt it was too early for them to take this next step of living together; however, given the monstrosity that is rental prices these days, they decided to make the leap. The section in the article on Lee starts with her concerns but ends on a note of hope. “[I]t could also be just wonderful,” Lee says. Though Lee’s financial worries seem to be somewhat soothed by this new living situation, only time will tell how her relationship unfolds with this big change.
Then, there’s Jennifer Gammarra and Michael Kaplan. They were planning on finding a new apartment together, but quickly realized just how devastating the current state of the rental market is; thus, Gammarra ended up just moving into Kaplan’s one-bedroom apartment which has a more reasonable rent ($3,000) compared to the other places they checked out ($5,000). Though this is an acceptable solution, Gammarra voices, “We wanted to move into a new place to make it our own, but I’m now moving into his apartment.” They are still technically proceeding as planned—they have moved in together—but the process and result are not what they had imagined.
Next, there’s a third anonymous couple, who realized after the initial interview that they disagreed on their motives to move in: one wanted to move in because of high rent and the other because “they believed it was the next step in their relationship.” They chose to withdraw participation in the article.
Finally, there’s Kenneth Yeung. He and his boyfriend were excited about living together after deciding they both wanted to stay in a particular neighborhood of New York City. However, Yeung and his partner broke up before moving in together. The pressure and stress of figuring out the cohabitating situation made them “re-evaluate whether this is a good thing right now.” Now, Yeung has moved into the apartment he and his partner were originally going to live in together; he is sticking to a strict budget to afford his rent.
Beyond these narratives, there is also research that touches on this phenomenon of couples moving in together. Is there a “right” time? Is there a “right” reason? Dr. Arielle Kuperberg of the University of North Carolina at Greensboro articulates how Ms. Lee’s anxieties might hold some well-warranted weight. It is harder for couples to break up after moving in together, which means that couples have to either “tolerate or work through” disagreements that might otherwise have led to breaking up. Dr. Sharon Sassler of Cornell University argues that living together leaves no room for “escape” since the other person is pretty much always there. She says, “Moving in together because of economic need, rather than relationship compatibility, is associated with lower quality in relationships.” That said, Sassler also states that moving in together could be the right decision if the relationship is strong. So, importantly, even though Kambhampaty provided examples that were not quite ideal, there are plenty of happy couples who have moved in together. It seems to be a matter of relationship well-being and the right circumstance. But what exactly does that mean?
There are the stories we learn about through New York Times articles or among our social circles; there’s the research conducted by experts like Drs. Kuperberg and Sassler. But, when we are the ones in that situation, what do we do? How do we know what to do? It isn’t an easy decision to make.
Two-person decision-making processes are game theorists’ bread and butter. The classic “game” foundational to game theory is called the Prisoner’s Dilemma. It is a situation where an individual decision-makers (or players in the game) have different incentives (or payoffs) to make a decision that could be less optimal for other individuals. In this “game,” you can determine whether there is a best response for each player. And if there is a mutual best response (a best response for both players), then that is called a Nash Equilibrium.
Another version of this game is the Coordination Game, which is what moving in with a partner should be. The players are better off if they coordinate; the two Nash Equilibrium are for both players to either not move in or for both players to move in. This makes sense, because it is fair to assume that (sans crazy rent prices and relationship pressures) partners either both move in, or they both don’t move in. Either way, it’s relatively a win-win scenario. In the table below, the payoffs for both not moving in (1, 1) are lower than the payoffs for both moving in (2, 2), because let’s assume that both moving in together is a sign of relationship progress and growth, so there’s a bit of a greater payoff (2 > 1).
Considering the couples in Kambhampaty’s article, we know that the decision-making process for whether a couple should move in together is not a perfect coordination game. While there are certainly many factors to consider, let’s focus on the two at play among those four couples—financial incentives vs. relationship well-being.
There are so many variations to game that must then be considered. What if partner 1 has a greater payoff to move in, because they do not have the financial means to afford their own place? Now, there is only one Nash Equilibrium, which would be for both partners to move in.
However, let’s say Player 2 does not want to move in; they feel pressured to make a level of commitment that they do not feel ready to make and they feel guilty if they do not move in with their partner who cannot afford rent. Their well-being declines. Now what’s the best decision?
And then let’s say you’re facing the circumstance that Yeung faces – the possibility of only one person (Partner 1) moving into the new place.
The payoffs included in the matrices provided here are mere examples, an oversimplification of the decision-making process of partners moving in together. The actual amount of the payoffs and the differences between Player 1 and Player 2’s are essentially idiosyncratic; the payoffs and incentives for moving in (or not) is different for everyone. As aforementioned, there are a slew of other factors to consider (e.g., location, current roommates, rental options, family approval, religious reasons); and it is important for the couple to take all factors and potential outcomes into consideration. Thus, it’s impossible to make one “game” that fits all.
However, if we ever find ourselves facing this decision to move in (or not) with a partner, setting up this game theory matrix could be potentially a good place to either start the decision-making process or just the conversation with our partner—what is each “player’s” payoff and why?
If you are currently facing this decision, here is a link that is helpful to set up a matrix for two players: https://mindyourdecisions.com/GameSolver.html And there are other ways to calculate a Nash Equilibrium for more than 3 players, if you need to factor other individuals into the decision (e.g., children, current roommates, parents). Here’s a helpful document that can help you set this up: https://coed.asee.org/wp-content/uploads/2020/08/8-Solving-the-Three-Person-Game-in-Game-Theory-Using-Excel.pdf
So, what would a game theorist say? A game theorist would probably tell you to draw a matrix and “game it out.” Is there a mutual best response? It might not be the answer you’re looking for or there might not be an answer at all, but it’s perhaps a helpful tool as you and your partner make this decision together.
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Link to Kambhampaty’s New York Times article: https://www.nytimes.com/2022/06/24/realestate/high-rent-couples-living-together.html?searchResultPosition=30