Oxytocin → Interpersonal trust
The trust-hormone slogan is a 2005 RCT that did not survive its own authors' registered replication.
Randomized trial · High confidence · N=677
The association does not survive the backdoor. Usually SES, outdoor time, or healthy-user bias.
Mechanism
Kosfeld, Heinrichs, Zak, Fischbacher, and Fehr (2005) reported that intranasal OT raised trust-game transfers. Nave, Camerer, and McCullough (2015) documented small N and mixed follow-ups. Declerck, Boone, Pauwels, Vogt, and Fehr (2020) pre-registered a high-powered test with the original minimal-social-contact condition and found no OT effect on trusting behavior there. Exploratory post-hocs are not the registered claim.
Caveats
A contested RCT stays on the atlas. The stamp is smoke for the folk spray-equals-trust arrow, not a claim that oxytocin is biologically inert. Plasma OT, parenting, and labor are different questions.
Effect
qualitative. Kosfeld 2005 reported higher transfers. Declerck 2020 registered replication: no main effect in MSC.
Nodes
Named confounders
Cite this page
What Causes What. “Oxytocin → Interpersonal trust.” https://whatcauseswhat.org/edges/e-oxytocin-trust (atlas updated 2026-08-31).
Papers
- Oxytocin increases trust in humans
M. Kosfeld, M. Heinrichs, P. J. Zak, U. Fischbacher, E. Fehr · 2005 · Nature
- Does Oxytocin Increase Trust in Humans? A Critical Review of Research
G. Nave, C. Camerer, M. McCullough · 2015 · Perspectives on Psychological Science
- A registered replication study on oxytocin and trust
C. H. Declerck, C. Boone, L. Pauwels, B. Vogt, E. Fehr · 2020 · Nature Human Behaviour