Baumgartner et al.
Baumgartner et al. (2008)
The role of oxytocin in trust in economic behavior
Aim:
To investigate the role of oxytocin after breaches of trust in a trust game.
Procedure:
- The participants played a trust game used by economists and neuroscientists to study social interaction. The “investor” (player 1) receives a sum of money and must decide whether to keep it or share it with a “trustee” (player 2). If the sum is shared the sum is tripled. Then player 2 must decide if this sum should be shared (trust) or kept (violation of trust).
- fMRI scans were carried out on 49 participants. They received either oxytocin or placebo via a nasal spray.
- Participants played against different trustees in the trust game and against a computer in a risk game. In 50% of the games their trust was broken. They received feedback on this from the experimenters during the games.
Results
- Participants in the placebo group were likely to show less trust after feedback on betrayal. They invested less. Participants in the oxytocin group continued to invest at similar rates after receiving feedback on a breach of trust.
- The fMRI scans showed decreases in responses in the amygdala and the caudate nucleus. The amygdala is involved in emotional processing and has many oxytocin receptors. The caudate nucleus is associated with learning and memory and plays a role in reward-related responses and learning to trust.
Evaluation
- Oxytocin could explain why people are able to restore trust and forgive in long-term relationships.
- Scanner research is merely mapping brain activity but nothing definite can be said about what it really means at this point in science.
- Giving oxytocin like this in an experiment may not reflect natural physiological processes. The function of oxytocin is very complex and it is too simplistic to say that it is “the trust hormone”.