highly significantP < 0.0001
Stake size’s effect on cooperation rate in each role was highly significant in the first three roles (generalized linear mixed model analysis: simultaneous role, F (2, 1434) = 82.90, P < 0.0001; first player role, F (2, 1434) = 76.88, P < 0.0001; second player role in which the first player cooperated, F (2, 1434) = 32.04, P < 0.0001).