The convergence hypothesis suggests that spouses and romantic partners tend to become more alike over time due to their shared environment, repeated interactions, and synchronized routines.
The convergence hypothesis became popular among social scientists and was widely used to explain the high levels of observed similarity between spouses and romantic partners in physical, physiological, demographic and psychological characteristics, such as social class, religion, be of similar height, intelligence, education.
More recent studies have called into question the hypothesis that spouses' faces become more similar over time, as suggested by Zajonc, et al[1] For example, Stanford University psychologists, Tea-makorn and Kosinski conducted a study on a sample of 517 married couples using photographs taken at the beginning of their marriages and 20 to 69 years later.
They used two independent approaches to measure the similarity of the spouses’ faces: human judges and a modern facial recognition algorithm.
Research carried out by psychologists from the Michigan State University, and the University of Minnesota M. Brent Donnellan Mikhila N. Humbad, William G. Iacono, Matthew McGue and S. Alexandra Burt[5] based on a database of 1,296 couples who have been married for an average of 19.8 years, suggested that only the degree of aggressivity actually tended to converge.They also found that couples who had been married for up to 39 years were no more alike in fundamental traits than newlyweds.