Genes tell us who to love: a new theory about relationships
Why do we often fall in love with those who look like us?
A new look at this phenomenon offers an unexpected explanation: it may be not only about taste, but also about heredity.
According to the Association for Psychological Science, researchers from the University of Queensland have developed a model that explains the phenomenon of "assortative mating" - the tendency to choose partners who are similar to us in appearance, temperament or social traits.
We are attracted to our own kind - and for good reason
Assortative mating has been observed in humans and animals. It's often discussed in pop culture, such as in the viral game Siblings or Dating, where users guess whether two people are related or a couple.
Scientists Caitlin Harper and Brendan Zitsch explain: if, say, a person inherits a tall stature from his mother and a preference for tall partners from his father, he will grow up tall and be attracted to the same. Thus, one half of the genes is responsible for quality, the other half for attraction to it.
A pattern of behaviour from one generation to the next
To test the hypothesis, the researchers modelled the behaviour of "agents" over 100 generations. Each agent had inherited traits and preferences based on those traits. Even with 10 different preferences, there was a consistent overlap between traits and the propensity to choose carriers of those traits.
Even under natural selection (where the number of offspring affects the distribution of traits), there was still a tendency to select 'similar', albeit with less stability. This is explained by a decrease in diversity in the population.
Harper emphasises: "The strength of this finding is in its simplicity. What seemed like a mystery for decades turned out to be the result of a mechanism that biologists know well."
An interdisciplinary approach has uncovered new insights
Although the idea that preferences can be inherited had been discussed before, no one had considered it as the primary cause of assortative mating in evolutionary psychology. It was the integration of ideas from biology and psychology that allowed the authors to build a new theoretical model.
"Without the interdisciplinary view, we would not have arrived at this explanation," Harper adds. - "It lay on the surface, but only now have we been able to connect all the elements."
Applies to more than just humans
Interestingly, the model also explains animal behaviour. Unlike humans, they lack social and cultural motivations, but they also show similar mate selection - confirming the universality of the mechanism.