This interaction effect was more obvious in group extraction ( figure 2 a ; electronic supplementary material, table S1, p = 0.012) and marginally significant in individual extraction ( figure 2 b ; electronic supplementary material, table S2, p = 0.059).
Although the results did not reach statistical significance, the effects were in the expected direction: the negative effect on cooperation of combining people-chatting sounds and future stakes was stronger for individualists than prosocials, and this was true even though having a future stake had a stronger positive effect for individualists than prosocials without people-chatting sounds (electronic supplementary material, figure S1).