Figure 1. The overview of the experiment. (A) Experimental setup. (B) Independent decision making and interactive decision making. (C) Optode locations.

Figure 2. Behavioral results. (A) Behavioral performance in experts and novices in the baseline task. (B) Interaction benefit. (C) Concession values were comparable between novices and experts in the shared responsibility condition, suggesting that dyads in this condition tended to adopt an “equality strategy”. (D) In the shared responsibility condition, novices’ interaction benefit was positively correlated with differential performance between novices and experts during the initial estimation of dot locations. *p < 0.05, **p < 0.01, ***p < 0.001. Error bars represent standard errors of the mean.

Figure 3. Interpersonal brain synchronization (IBS). (A) The one-sample t-value maps of IBS in the shared responsibility and non-shared responsibility conditions. (B) Upper: One-way ANOVA results of the IBS to identify conditional differences. At channel 5, IBS in the shared responsibility condition was larger than that in the non-shared responsibility condition. Lower: In the shared responsibility condition, IBS at channel 5 was positively correlated with interaction benefit in novices, and positively correlated with differential performance between novices and experts during the initial estimation of dot locations. *p < 0.05. Error bars denote standard errors of the mean.