Investigating the association between companionship and behavior concordance: a dyadic panel study

Partners in romantic relationships influence each other's behaviors through various social exchange processes. One underexplored process that is assumed to be relevant for couples' behaviors is companionship. Companionship is defined as experiencing pleasurable social interactions or engaging in shared activities for the purpose of having an enjoyable time. This study investigated how companionship is associated with physical activity and behavior concordance in physical activity (i.e., similarity in partners' physical activity) in romantic couples. A total of N = 5377 couples (M$_{age}$ = 66.80; SD$_{age}$ = 11.05) from the US‐based Health and Retirement Study completed four measurement points across 6 years. Multilevel response surface analysis was used to analyze the association between companionship and physical activity. There was a positive linear association between companionship and physical activity in mixed‐gender couples. However, this association disappeared when controlling for covariates (i.e., education, race, household wealth, body mass index, age, health status, and relationship quality). There was no evidence of an association between companionship and behavior concordance. Future research should investigate short‐term dynamics and the direction of causality for the association between companionship and behaviors of interest.