Do Personalities Converge After Marriage?

Spouses tend to share some personality features in most studies of psychometric personality assessment.  This findings prompts the question of whether spousal personalities become more similar after marriage or are these features present at the time of marriage.  The concept of assortative mating is well known in studies of spousal selection.  Assortative mating is the concept that individuals tend to associate and select partners that share personality and other characteristics.  It is possible that similarities found in couples represents assortative mating rather than a convergence of personalities with time.

Humbad and colleagues at the Michigan State University recent examined this question.  Their study lacks a longitudinal design that would be the most powerful way to study this question.  Nevertheless, they have a large sample of couples with personality data on both spouses.  The study relied on an examination of the effect of duration of marriage on the similarities of personality between the spouses.  The hypothesis being that spouses that lived together longer should demonstrate higher correlations on personality variables than those who had only been married a brief time.

The key elements of the study included the following:

• 1298 couples with personality data on both spouse
• Personality assessed with 198-item version of the Multidimensional Personality Questionnaire
• Spouses compared for personality correlations
• Spousal personality differences compared related to length of marriage
• Statistical modeling examined the effect of years married on personality variables

The study found that spouses showed similar personality features across a variety of domains.  The highest correlations occurred in the personality variables traditionalism (.49), alienation (.31) and absorption (.18), well-being (.15) and aggression (.15).

However, longer years of marriage did not appear to contribute to similarity (or correlation of) personality variables.  The exception this finding was for aggression, where greater years of marriage predicted a greater similarity in aggression personality scores.

The authors conclude that marriage length of time do not appear to have a significant influence on personality convergence.  Assortative mating appears to be the key driver of this type of finding.  They note that assortative mating may increase the likelihood of some genetic transmission of parental traits (negative and positive) to their biological offspring.

Wedding photo courtesy of Yates photography

Humbad MN, Donnellan MB, Iacono WG, McGue M, & Burt SA (2010). Is Spousal Similarity for Personality A Matter of Convergence or Selection? Personality and individual differences, 49 (7), 827-830 PMID: 21116446