Couples' behavior during conflict in the lab and diurnal cortisol patterns in daily life

The current study tested whether positive and negative behaviors exhibited by couples during conflict interactions assessed in the laboratory are associated with individuals' diurnal cortisol patterns (i.e., circadian rhythms in cortisol across the course of the day) outside of the lab. Participants (N = 82) provided a total of 18 salivary cortisol samples over a 3-day period and came into the lab with their spouse to engage in two ten-minute dyadic conflict discussions. These videotaped interactions were coded to assess the intensity with which couples displayed various positive behaviors (e.g., humor, affection) and negative behaviors (e.g., defensiveness, frustration) during the conflict discussions. Multi-level modeling was used to examine the associations between couples' positive and negative behavior during conflict discussions and diurnal cortisol patterns in daily life. Results showed links between overall positive, but not negative, behaviors and diurnal cortisol patterns. Individuals who experienced more positive behaviors with their partner during the conflict discussion showed a steeper ("healthier") cortisol slope across the day in their daily lives. Exploratory analyses investigating the association between specific positive and negative behaviors and diurnal cortisol revealed that affection and scorn were associated with diurnal cortisol patterns in daily life. This research advances our understanding of the impact of social relationships on physical health from a biopsychosocial perspective and has implications for understanding how the ways in which couples resolve conflict are linked to health-related biological processes in daily life.