Longitudinal tracking of human plasma oxytocin suggests complex responses to moral elevation

Luke Parkitny; C Sue Carter; Melissa K Peckins; Deirdre Ann Hon; Sarina Saturn; H P Nazarloo; William Hurlbut; Brian Knutson; Steven Crane; Xiola Harris; Jarred Younger

doi:10.1016/j.cpnec.2021.100105

Longitudinal tracking of human plasma oxytocin suggests complex responses to moral elevation

Compr Psychoneuroendocrinol. 2021 Dec 22:9:100105. doi: 10.1016/j.cpnec.2021.100105. eCollection 2022 Feb.

Authors

Luke Parkitny^{1

2

3}, C Sue Carter⁴, Melissa K Peckins⁵, Deirdre Ann Hon⁶, Sarina Saturn⁷, H P Nazarloo⁴, William Hurlbut⁸, Brian Knutson⁹, Steven Crane⁸, Xiola Harris¹, Jarred Younger¹

Affiliations

¹ Department of Psychology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
² Departments of Pediatrics, Neurology and Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA.
³ Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, 77030, USA.
⁴ Kinsey Institute, Indiana University, Bloomington, IN, 47405, USA.
⁵ Department of Psychology, St. John's University, Queens, NY, 11439, USA.
⁶ School of Education, University of Portland, Portland, OR, 97203, USA.
⁷ Department of Psychological Sciences, University of Portland, Portland, OR, 97203, USA.
⁸ Department of Neurobiology, Stanford University, Stanford, CA, 94305, USA.
⁹ Department of Psychology, Stanford University, Stanford, CA, 94305, USA.

Abstract

Positive social experiences may induce oxytocin release. However, previous studies of moral elevation have generally utilized cross-sectional and simple modeling approaches to establish the relationship between oxytocin and emotional stimuli. Utilizing a cohort of 30 non-lactating women (aged 23.6 ± 5.7 years), we tested whether exposure to a video identified as capable of eliciting moral elevation could change plasma oxytocin levels. Uniquely, we utilized a high-frequency longitudinal sampling approach and multilevel growth curve modeling with landmark registration to test physiological responses. The moral elevation stimulus, versus a control video, elicited significantly greater reports of being "touched/inspired" and "happy/joyful". However, the measured plasma oxytocin response was found to be markedly heterogeneous. While the moral elevation stimulus elicited increased plasma oxytocin as expected, this increase was only modestly larger than that seen following the control video. This increase was also only present in some individuals. We found no relationship between plasma oxytocin and self-report responses to the stimulus. From these data, we argue that future studies of the relationship between oxytocin and emotion need to anticipate heterogeneous responses and thus incorporate comprehensive individual psychological data; these should include evidence-based variables known to be associated with oxytocin such as a history of trauma, and the individual's psychological and emotional state at the time of testing. Given the complexity of physiological oxytocin release, such studies also need to incorporate frequent biological sampling to properly examine the dynamics of hormonal release and response.

Keywords: Moral elevation; Oxytocin.