Results of the Indirect Reciprocity task in Experiment 1 (a1,b1) and Experiment 2 (a2,b2). (a1,a2) Reciprocity index, computed as mean influence in the Susceptible condition minus mean influence in the Insusceptible condition (in decision turns), plotted across participants. Negative values (in gold) represent participants who show anti-reciprocal behavior, while positive values (in blue) represent individuals who show indirect reciprocity and therefore increased the level of influence taken from the passive agent in the Susceptible condition. (b1,b2) Average reciprocity index in Experiment 1 and Experiment 2. Error bars represent between-subject standard error of the mean. **p < 0.01, ns: not significant. Effect of condition in Mixed-effect model.