Fig. 2.

Ultimatum game results. (A) Results of the model simulations for θ = 0.3. Participants are more likely to accept unfair offers as a function of their initial expectations. (B) Average acceptance rates for each offer amount for varying expectations. Importantly, the acceptance rates closely follow the pattern predicted by the Expectation model. (C) Neuroimaging results of a linear contrast of deviations from expectation, revealing linearly increasing activity in left anterior insula, anterior cingulate cortex and supplementary motor area. (D) Neuroimaging results for the linear contrast of expectation across subjects for $3 offers. Activity in the ACC/preSMA increases as a function of expectations. The color bar reflects Z-statistics. Imaging analyses are corrected for multiple comparisons using cluster correction, Z > 2.3, P < 0.05.