Infants' salivary oxytocin and positive affective reactions to people

Guangyu Zeng, Tiffany S. Leung, Sarah E. Maylott, Arushi Malik, Alexis A. Adornato, Mendel Lebowitz, Daniel S. Messinger, Angela Szeto, Ruth Feldman, Elizabeth A. Simpson

Research output: Contribution to journalArticlepeer-review


Oxytocin is a neuropeptide positively associated with prosociality in adults. Here, we studied whether infants' salivary oxytocin can be reliably measured, is developmentally stable, and is linked to social behavior. We longitudinally collected saliva from 62 U.S. infants (44 % female, 56 % Hispanic/Latino, 24 % Black, 18 % non-Hispanic White, 11 % multiracial) at 4, 8, and 14 months of age and offline-video-coded the valence of their facial affect in response to a video of a smiling woman. We also captured infants' affective reactions in terms of excitement/joyfulness during a live, structured interaction with a singing woman in the Early Social Communication Scales at 14 months. We detected stable individual differences in infants' oxytocin levels over time (over minutes and months) and in infants' positive affect over months and across contexts (video-based and in live interactions). We detected no statistically significant changes in oxytocin levels between 4 and 8 months but found an increase from 8 to 14 months. Infants with higher oxytocin levels showed more positive facial affect to a smiling person video at 4 months; however, this association disappeared at 8 months, and reversed at 14 months (i.e., higher oxytocin was associated with less positive facial affect). Infant salivary oxytocin may be a reliable physiological measure of individual differences related to socio-emotional development.

Original languageEnglish
Article number105579
JournalHormones and Behavior
StatePublished - Aug 2024
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2024 Elsevier Inc.


  • Hormone
  • Longitudinal
  • Physiology
  • Positive sociality
  • Social interaction


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