It is quite commonly believed that in terms of their personalities, a husband and wife grow more and more alike over the course of a long married life together. However, a new study suggests that conventional wisdom is largely misinformed on this score.

Do couples gradually come to share attitudes and outlooks, and to relate to the world around them more similarly? Probably not, according to Mikhila Humbad, a doctoral candidate in clinical psychology at Michigan State University in East Lansing.

When it comes to such personality traits as human warmth, conscientiousness, optimism, ambition, a cautious approach to the world, a tendency to experience negative emotions or a take-charge manner of handling issues, Humbad’s research indicates that husbands and wives do not grow more alike over time. Instead, they possessed similar personality traits when first they met.

In fact, Humbad reports, similar personality traits help to explain why a man and woman actually select each other for marriage in the first place. Humbad led a team of researchers that has just published a report in the journal of Personality and Individual Differences attempting to explain why spouses often seem to resemble each other personality-wise.

The Draw of Shared Personality Traits

Humbad told this website that her team’s findings are consistent with what the majority of other studies in this area have found – that spouses to not gradually arrive at the point of mirroring each other’s personality, but instead were drawn to each other because of shared personality traits.

One noteworthy way wives and husbands tend to resemble each other highly is in what the research report calls “value-related domains such as religion.”

Will Internet dating sites interpret this study’s findings as a boon to their business? Humbad suspects they might, since a goal for these sites is to match people on the basis of personality similarities. And she thinks this could prove interesting. But she also had a word of caution for the online, matchmaking sites.

The fact that two people possess similar personality traits does not alone guarantee a successful match, she observed. She told me that her research does not reveal what makes some marriages successful or unsuccessful. Being “more similar to your spouse on these personality traits doesn’t guarantee you’ll be happier in the relationship,” she added.

Yet, she suspects married couples could indeed benefit from knowing what her research team learned. Developing greater awareness both of one’s own personality and that of one’s spouse could always help the relationship, she said. She thinks an improved understanding of how the other person functions always is beneficial.

Do Opposites Attract?

Should it be concluded from Humbad’s research that opposites don’t attract? After all, conventional wisdom also holds that marriages benefit greatly from the spouses’ differing likes and dislikes, hobbies and habits.

Some commentators on this research seized on the issue of opposites attracting. But it did not seem to me that the study reached that far, limiting itself instead to the various kinds of personality traits mentioned earlier. What I might infer from the study is that if opposites do attract in certain regards, they probably will not attract as strongly in the absence of other important and shared personality traits.

There is an ongoing conversation in the field of psychology about these issues. Do the personalities of a wife and husband “converge” over time or do spouses simply “select” each other as spouses because of shared personality traits. The outlines of this conversation help to explain the title of the report published by the Humbad-led team, “Is spousal similarity for personality a matter of convergence or selection?”

Existing research shows that spouses are “more similar” to each other than randomly chosen people, Humbad said. She explained: “This could reflect spouses’ influence on each other over time or this could be what attracted them to each other in the first place. Our goal in conducting this study was to help resolve this debate.”

Humbad and her team analyzed data from the Minnesota Center for Twin and Family Research profiling 1,296 couples who had been married an average of 19.8 years. The team found “that for most traits, spousal convergence does not explain spousal similarity.”

However, there is one way in which a husband and wife may tend to “converge” over time and begin to resemble each other more greatly, the researchers said. This involves the trait of aggression. The report surmised, “It is possible that individuals might reinforce each other’s aggressive tendencies due to hostile interpersonal exchanges, thereby promoting greater convergence over time.”

Humbad said: “It makes sense if you think about it. If one person is violent, the other person may respond in a similar fashion and thus become more aggressive over time.”

About the author 
David Gibson served for 37 years on the editorial staff at Catholic News Service, where he was the founding and long-time editor of Origins, CNS Documentary Service. David received a bachelor’s degree from St. John’s University in Minnesota and an M.A. in religious education from The Catholic University of America. Married for 38 years, he and his wife have three adult daughters and six grandchildren.