- The intriguing question of whether couples start to look alike after years together has finally been answered
- Using modern technology and human judges, researchers concluded that it has not been scientifically proven
- However, they do suggest that people naturally gravitate towards people who look like them
It’s a question that’s been probed by psychologists and has captured public imagination for years: do the faces of couples in long-term relationships start to look alike over time?
After investigating this long-held assumption, researchers from Stanford University (SU) concluded that the hypothesis cannot be scientifically confirmed. Instead, what they suggest is that people are initially attracted to those with similar features to themselves, because of genetic similarities.
This was after they carried out an intensive study, analysing photos of hundreds of couples’ faces, as well as a facial recognition algorithm called VGGFace2.
Their findings were published in Scientific Reports.
First study to investigate the mysterious belief
A 1987 study, led by the late social psychologist Robert Zajonc and colleagues at the University of Michigan, attempted to determine whether people who live with each other for a long time developed physically similar facial features.
The study was based on an incredibly small sample of 12 married heterosexual couples whose wedding photographs, as well as photographs 25 years later, were judged for physical similarity.
The researchers believed that there was indeed an increase in similarity after the couples spent 25 years together.
To explain their findings, and how this phenomenon could be physically possible, the authors proposed that "convergence in the physical appearance of spouses” could be attributed to the fact that couples in long-term relationships become so in sync with one another, that they end up unconsciously imitating each other's expressions. This, they wrote, changes the appearance of their faces over time.
"An implication of the vascular theory of emotional efference is that habitual use of facial musculature may permanently affect the physical features of the face," they explained in their paper.
Stanford University study
“It is something people believe in, and we were curious about it,” said Pin Pin Tea-makorn, an electrical engineering PhD student at SU, who conducted the study with her colleague, computational psychologist Michal Kosinski.
“Our initial thought was if people’s faces do converge over time, we could look at what types of features they converge on.”
The research pair decided to pick up on the 1987 study and investigate the merits of supposed facial convergence – only this time, they analysed 517 public photos of married couples, and included modern technology in their investigation: a facial recognition algorithm called VGGFace2. The technology has been proven to outperform humans in judging facial similarity.
The team compared the faces of the couples shortly after they were married with images taken 20 to 69 years later.
However, their findings didn’t correspond with the initial findings of Zajonc and colleagues, as they didn't find anything to suggest that couples start looking more like each other over time.
"When we started this project, I was convinced that we would easily find evidence for the convergence in facial appearance," Tea-makorn said in a news release by SU. "This is one of those theories that all undergrads learn in their Psych 101."
"A closer look at the literature reveals that while the convergence in physical appearance hypothesis is one of the tenets of current psychological science and has been widely disseminated through textbooks, books, and landmark papers, it has virtually no empirical support," the researchers wrote.
A limitation of their study was that all of the couples were white and heterosexual, with the researchers indicating they were unable to secure a sufficient number of images of homosexual and non-white couples to allow for a meaningful analysis.
People are drawn to partners who look similar to them
Despite a lack of evidence that couples progressively resemble each other, the authors did write that their results confirm previous findings suggesting that that people do seem to pick romantic partners that look similar to them, at least compared to other faces picked randomly.
"Consistent with the previous studies, we found evidence of homogamy, or spouses' tendency to have similar faces," they said.
"Spouses' faces are similar but do not converge with time. This brings facial appearance in line with other traits – such as interests, personality, intelligence, attitudes, values, and well-being – which show initial similarity but do not converge over time."
Other studies have also found that we are subliminally attracted to features of our opposite-sex parent, as well as to features of ourselves, notes Psychology Today.
Image: Getty/Alistair Berg