Researchers at the University of Zurich tested that assumption with a hormone already known to matter in pair bonding among animals, giving it to people about to play a game involving real money and a stranger.
In the peer-reviewed study's trust game, where one player could send money to a stranger that tripled in transit, participants given oxytocin through a nasal spray sent more money than those given a placebo, and the effect was specific to trusting another person rather than a general willingness to take risks.
The result helped launch a wave of research into oxytocin's social effects, though later, larger studies found the hormone's influence on trust and generosity to be smaller and less consistent than this first study suggested, and some follow-up experiments failed to replicate the effect. Oxytocin sprays sold outside medical supervision are not an established way to recreate the result.
Read the original study
A hormone, a game, and a rise in trust.
Source
- Kosfeld, M., Heinrichs, M., Zak, P. J., Fischbacher, U., & Fehr, E. (2005). Oxytocin increases trust in humans. Nature, 435(7042), 673–6. https://doi.org/10.1038/nature03701