Oxytocin administration alters HPA reactivity in the context of parent-infant interaction

Weisman, O., Zagoory-Sharon, O., & Feldman, R. (2013). Oxytocin administration alters HPA reactivity in the context of parent–infant interaction. European Neuropsychopharmacology, 23(12), 1724-1731.

Hypotheses  

Oxytocin administration has an effect on the father and infant overall salivary cortisol response in the context of a social stressor and the degree of parent-infant synchronicity moderates the effect.

Design: double-blind, placebo-controlled, within subject design.

Variables Measured, Instruments Used 

1. Father’s affect: PANAS Questionnaire
2. Child stress: Face-To-Face-Still-Face (FTFSF) interactions
3. Oxytocin levels, Salivary Cortisol, Gaze Synchrony
4. Parent Stress Index Short Form

Participants

• N= 35 healthy father-infant dyads
• Participant ages: fathers were 22-38 (avg 29.7 years); infants 5 months old (range 4-8)
• Location: 2 laboratory visits 1 week apart
• Eligibility: exclusion criteria included father’s smoking, chronic mental or physical illness, and medication intake. Infants included 18 healthy females, 17 health males, 68.5% were first born.  Exclusion criteria for infants included premature birth, labor or birth related complications, multiple birth, or illness.
• SES: educated, middle class
• Additional profile:  All fathers were married to the infant’s mother.

Limitations

1. Current results offer insights into the ability to shape an infant’s endocrine stress response without direct intervention, but further studies are needed. 
2. This study does not directly manipulate oxytocin levels in infants, the effects of which are still not completely understood. 
3. As oxytocin was administered to the father, future studies are needed to understand the multi-level effects of oxytocin in both the subject (in this case the father) across subjects, and the relational effects of infants/children. 
4. This study was limited to educated, middle class males (and their infants) therefore different results may be found if replicated in diverse socioeconomic, cultural, high risk, and/or age specific groups.

Finding(s)

1. Oxytocin administration to the parent altered both the parent and infant physiological and behavioral response the social stressor. 
2. Oxytocin administration to father increased the father’s cortisol response to the social stressor (i.e., the father’s cortisol levels increased when they did not respond to the infant’s cues). 
3. Oxytocin administered to the father altered the infant’s cortisol response, suggesting biological synchronicity. 
4. This effect was moderated by the nature of the parent-infant attachment. 
5. Oxytocin administered to the father impacted the “high attachment” infants by increasing their (stress) salivary cortisol when the father was “withdrawn” through still face.         
6. Oxytocin administered to the father impacted the “low attachment” infants more by reducing their (stress) salivary cortisol when the father was “withdrawn” through still face.