Summary: Researchers examined the effects oxytocin and vasopressin had on perceptions of social dominance. Oxytocin increased perception of greater dominance. Neuroimaging revealed the findings were also reflected in changes in brain regions associated with social perception.
Source: Center for BrainHealth
Cues signaling trust and dominance are crucial for social life. Recent research from Dr. Dan Krawczyk’s lab at the Center for BrainHealth explored whether administering two chemically similar hormones known to affect social cognition – oxytocin and vasopressin – would influence the perception of trustworthiness and/or social dominance. This research extended previous studies on the effects of oxytocin, which had inconsistent findings and only explored its influence on perceptions of trustworthiness.
In the study, a group of 20 men observed images of human faces with neutral expressions and rated the levels of trustworthiness and social dominance perceived. They repeated this exercise under three conditions: with oxytocin, with vasopressin and with a saline placebo. The results are published in Psychoneuroendocrinology.
Functional Magnetic Resonance Imaging (fMRI) scans demonstrated that both hormones affected brain activity across both trustworthiness and dominance, indicating that the hormones have the potential to affect the brain even when the changes do not reach a threshold of observable behavior. Moreover, oxytocin consistently led a perception of greater dominance. This novel finding was also reflected in changes in regions of the brain related to social perception as observed in the fMRI scans.
“This research is important because it grows our understanding of the way people take in social information or social cues,” said lead author Dr. Adam Teed, whose 2015 Linda and Joel Robuck Distinguished New Scientist Friends of BrainHealth Award partially funded this research.
About this neuroscience research article
Source: Center for BrainHealth Media Contacts: Kathryn Simmons – Center for BrainHealth Image Source: The image is in the public domain.
The influence of oxytocin and vasopressin on men’s judgments of social dominance and trustworthiness: An fMRI study of neutral faces
Cues signaling trust and dominance are crucial for social life. Previous studies on the effects of oxytocin (OT) nasal sprays on trustworthiness evaluations have been inconsistent and its influence on dominance is unknown. Vasopressin (AVP) may also influence social cue perception, but even fewer investigations have evaluated this possibility. We evaluated the effects of intranasal OT and AVP compared to placebo control during three double-blinded functional magnetic resonance imaging sessions. Twenty males received a pseudo-randomized order of nasal spray conditions and rated the trustworthiness and dominance of neutral faces. OT increased facial dominance ratings compared to placebo. Neuroimaging results revealed an inverse relationship between brain activation and face ratings for OT compared to placebo in regions involved in processing emotional expressions. Specifically, the right superior temporal gyrus was attenuated as ratings increased and the left precuneus selectively diminished with increasing dominance ratings. Additionally, OT increased functional connectivity between frontoparietal regions and the right amygdala for faces rated as highly dominant, but OT increased connectivity between the fusiform gyrus, hippocampus, and bilateral ventral tegmental area (VTA) for faces perceived as highly trustworthy. Overall, OT increased the perception of dominance but did not influence trustworthiness judgments. However, we observed regional neural effects for OT that differed between judgments of trustworthiness and dominance. AVP attenuated left temporoparietal junction activity as face ratings increased, a result consistent with AVP influencing mentalization. AVP also led to increased left amygdala and right VTA connectivity with the putamen, which is consistent with cue-driven, habitual responses.