Couples who have been married for a long time often share similar personality traits. A 2019 study examined the brain composition of elderly, healthy, long-married couples to find out whether these shared personality traits occurred with brain similarity using an MRI.
The study found that couples who had been married for 30 years or more experienced change in the neural networks of their brain to the extent that their neural networks became similar to one another. According to the study, these similarities are likely the result of shared life experiences in addition to baseline personality traits.
To read the study, click here.