The Psychology Professor’s “ Couple Simulation ” Model Helps Us Dive Into the Mysteries of Partner Selection

In your quest for true love and that elusive happily ever after, are you waiting for the “right” person to drop by, or do you go for the cutest boy or girl in the room, hoping things turn out okay? Do you leave your options open, hoping to “trade in” at the next opportunity, or are you investing in your relationship for the purpose of the cost-benefit analysis?

For something so fundamental to our existence, mate choice remains one of humanity’s most enduring mysteries. It has been the subject of intense psychological research for decades, spawning countless hypotheses about why we choose who we choose.

“Partner selection is very complicated, especially in humans,” said Dan Conroy-Beam, an assistant professor in the Department of Psychological and Brain Sciences at UC Santa Barbara, and author of an article in the journal Personality and Social Psychology Review“And there are many people who have come up with abstract ideas about how it could happen.”

One line of thinking, for example, states that we assess potential partners based on an internal threshold of preferred qualities and attributes – a “minimum bar” that they must meet in order to be considered a potential partner.

“And we learn where that minimum limit is based on how other people treat us,” he said. Another model describes the dating market somewhat like the European social dances of the 18th century.

“One side is approaching the other side and they are starting these kinds of temporary relationships,” said Conroy-Beam. “And basically you stay in a relationship until you get a better offer and everyone more or less regularly leaves their partners for better ones.”

But these partner choice models, and others like them, don’t capture much of the nuance that goes into true partner choice, Conroy-Beam noted.

“When you have a system that is particularly complicated, such as markets for human mating, sometimes verbal models are not a good way to understand what’s going on,” he said. Conflicting desires and social dynamics play a huge role in mate selection, he explained, adding layers of complexity and moving parts that cannot be captured or quantified.

So what can the humanoid hold on to multiple levels of detail and complexity? The second best: a computer simulation. In an effort to advance understanding of mate selection, Conroy-Beam has developed a new approach – called “couple simulation” – that essentially tests models of mate selection based on the characteristics and priorities of a sample of real couples.

“The real advantage we have here is that we’re moving away from just these verbal models to explicit computational models,” he said. “We’re directly simulating people’s real choices; we’re removing the boundaries to do this in our heads because we have computers that can keep track of all the very complicated interactions that are going on.”

Sim Dating

The process starts with measuring the traits and preferences of a population of a few hundred couples – real people who have made real mate choices. That data is processed into simulated copies of each person – “avatar agents” who have the same attributes and desires as their human counterparts, except they are single in the simulated world.

“We’re breaking them up and throwing all these little agents on the market,” said Conroy-Beam, who received support for his research from the National Science Foundation’s Early CAREER program. “Then we run different algorithms and see which ones work best to bring them back together with the agent representing their real partner.”

The algorithms represent different models of partner choice, which dictate the rules the agents can communicate with, based on the model’s predictions. In addition to the Aspiration Threshold Model (minimum bar) and the Gale-Shapley algorithm (optimizing stable pairs), the team also used the Kalick-Hamilton model (KHM), which assumes that people choose partners based on their attractiveness, and a new model Conroy-Beam suggested calling it the Resource Allocation Model (RAM).

“It thinks of partner choice in terms of investing limited resources,” he said. “So you only have so much time and so much money and so much energy that you can devote to potential partners. And so your question as the person looking for a partner is ‘who earns the most of these limited resources?'”

Conroy-Beam’s model, it turns out, turned out to be the most accurate, correctly matching about 45% of pairs in the simulated market in the very first series of the pair simulation. Why does the Resource Allocation Model work so well?

“There are a number of differences between RAM and the other models,” he said. “The other models treat attraction like an on / off switch, but RAM allows gradients of attraction. It also includes reciprocity: the more a potential partner chases you, the more you chase them in return,” he said. The Gale-Shapley algorithm came in second, followed by the ambitious threshold model and then the KHM (attractiveness). Random links came in last.

It’s still early for couple simulation; After all, Conroy-Beam said, 45% right is still 55% wrong. For a first pass, however, 45% accuracy is impressive, and according to the study, the people in this cohort also report having higher quality relationships (more satisfied, more committed, more love, less jealous) than the people in the inaccurate paired set.

Conroy-Beam and his team at UCSB’s Computational Mate Choice Lab will continue to refine their models, which he calls “really rough sketches,” to increase accuracy. They hope to conduct a longer-term longitudinal study soon to see if couples that are accurately predicted differ in lifespan.

“We hope to do this in different cultures and include same-sex couples in the near future,” he said. “We also have plans to try to apply this to singles in the coming years to prospectively predict their future relationships.”