Behavioral parameters
The average amount sent from the first player (Trust) is 11.1 out of 20, while the average amount sent back to the second player (Trustworthiness) is 10.0 (Figure S1A, Figure S1B). This is similar to what is generally observed in the TG literature: the first player sends about 50% of his/her endowment and the second player sends back about 95% of what was sent (see [24] for a survey). In a linear regression, males significantly trust more than females (p<0.039), while we observe no significant gender difference in trustworthiness (p>0.363) (Figure S2A and Figure S2B). Our results are distinct from [35] which reported significant gender difference in trustworthiness but not in trust. This discrepancy likely indicates slight cultural differences across populations.