Hugs and Cortisol Awakening Response the Next Day: An Ecological Momentary Assessment Study.

Previous research suggests that affectionate touch such as hugs might downregulate stress systems such as the hypothalamic pituitary adrenal (HPA) axis. However, the current literature lacks in generalizability beyond the laboratory setting and outside the context of romantic relationships. The cortisol awakening response (CAR) is a measure of the HPA axis and is responsive to daily fluctuations in stress and social information. However, associations between affectionate touch and the CAR have never been assessed. This study used ecological momentary assessment (EMA) to measure daily hugging behaviors in 104 first-year college students and salivary cortisol to assess the CAR. Participants who reported more daily hugs in their social interactions had significantly smaller CARs the next morning compared to days they reported fewer hugs. This study contributes to the literature on social interactions and stress responsive systems and emphasizes the importance of assessing affectionate touch behaviors such as hugs that can be exchanged outside the context of romantic relationships.

Where is the love? A double-blind, randomized study of the effects of intranasal oxytocin on stress regulation and aggression.

Previous studies reveal that oxytocin (OT) encourages prosocial behavior in humans; however, animal studies and recent work in humans suggest that OT may also play a role in aggressive behavior and feelings. The present study investigated these competing predictions in the context of a competitive task among 85 healthy human participants (males and females). Using a randomized double-blind design, participants were assigned to an experimental (intranasal OT) or control (intranasal placebo) group. Hostility (Aggression Questionnaire) was measured at home (T1) and in the lab after intranasal administration (T2). Behavioral aggression was assessed post-intranasal administration. There was a significant difference between the OT and the placebo group on hostility scores (p = 0.03) and a significant time by group interaction for behavioral aggression (p < 0.05). Self-reported hostility was significantly higher at T2 compared to T1 (p < 0.001) among participants in the oxytocin group while no significant change was found in hostility among the placebo group. Behavioral aggression was slightly higher in the OT group (compared to the placebo group) directly after OT administration, however, the opposite relationship was found as the study period progressed. Both hostility and behavioral aggression findings were consistent across gender.