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Both old wives’ tales and psychological literature posit that spouses’ faces become more similar over time. Scholars have argued that partners tend to occupy the same environments, engage in the same activities, eat the same food, and mimic each other’s emotions—and as these  factors can also influence facial appearance—their faces should converge with time. For  example, if the partners smile a lot—and make each other smile—they should co-develop  similar smile lines. 

Surprisingly, this widely accepted belief is supported by a single 1987 study of 12 couples, whose results have never been replicated. In their paper, Pin Pin Tea-makorn and Michal  Kosinski, of Stanford’s Graduate School of Business, examined this widely held belief in a large  sample of 517 couples. Using facial images taken at the beginning of the marriage and 20 to 69 years later and two independent methods of estimating facial similarity (human judgment and a  state-of-the-art facial recognition algorithm), they showed that while spouses’ faces tend to be  similar at the beginning of marriage, they do not converge over time (See Figure 1 below). 

Authors’ comments: 

Pin Pin Tea-makorn (PhD student at Stanford’s department of Electrical Engineering): “When  we started this project, I was convinced that we will easily find evidence for the convergence in  facial appearance. This is one of those theories that all undergrads learn in their Psych 101.  Also, it sounds rather intuitive: Spouses tend to spend much time together, have similar hobbies  and diet, so it is to be expected that they should grow more alike with time. Nevertheless, we  were surprised that despite using a very large sample of facial images and very sensitive  measurements of facial similarity, we could not find any evidence for convergence.” 

Dr Michal Kosinski (Associate Professor of Organizational Behaviour at Stanford’s Graduate  School of Business): “I think that scholars should spend more time validating widespread psychological theories. Many are based on scanty evidence and studies that would not be  considered appropriate today. Much of what we are teaching to students, business leaders and  policymakers is based on rather weak evidence. Now, rejecting widely accepted hypotheses is surely not as exciting or as news-worthy as coming up with new fancy theories, it is as, if not  more, important.” 


Figure 1: The average facial similarity of the spouses at marriage and 20 to 69 years later  estimated using the facial recognition algorithm. Error bars represent 95% confidence intervals.

Journal Link: Scientific Reports