Amygdala Involvement in the Ultimatum Game
Author Information
Author(s): Gospic Katarina, Mohlin Erik, Fransson Peter, Petrovic Predrag, Johannesson Magnus, Ingvar Martin
Primary Institution: Karolinska Institute, Stockholm, Sweden
Hypothesis
The amygdala drives immediate rejection in the Ultimatum Game.
Conclusion
The study shows that the amygdala is involved in the immediate rejection of unfair offers, and this response can be inhibited by the drug oxazepam without altering the perception of unfairness.
Supporting Evidence
- Benzodiazepine treatment decreased the rejection rate from 37.6% to 19.0%.
- The amygdala response to unfair proposals was diminished in the oxazepam group.
- Rejection was directly linked to an increase in amygdala activity in the control group.
- Fair proposals were never rejected in either group.
- The treatment-induced drop in rejection rate was consistent across genders.
Takeaway
When people are offered unfair deals, their brains react quickly, and a part called the amygdala helps them decide to reject those offers. A common medicine can make them less likely to say no, even if they still feel the deal is unfair.
Methodology
The study used functional MRI to observe brain activity while participants played the Ultimatum Game, comparing responses between a treatment group given oxazepam and a placebo group.
Potential Biases
Potential biases may arise from the small sample size and the specific demographic of participants.
Limitations
The study did not control for gender in the rejection rate analysis, and the sample size was relatively small.
Participant Demographics
35 right-handed volunteers, mean age 23.7 years, 13 men and 22 women.
Statistical Information
P-Value
0.0475
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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