Figure 6.

From gratitude to reciprocity. A, Average gratitude rating in the postscan gratitude recall of an individual participant predicts average monetary allocation (i.e., reciprocity) of that participant. B, Within each individual, variation in gratitude ratings predicts variation in allocation. The correlation reported here is the correlation between the postscan gratitude ratings in each of the 20 Help conditions and the average amount of allocation in the 20 Help conditions. Each dotted line indicates the regression line of a single participant, Solid line indicates the group effect. C, Individual differences in the exchange rate between gratitude and reciprocity (i.e., the slopes of the dotted lines in B). D, Neural correlates of individual differences in the exchange rate. This map is thresholded with p < 0.005 for illustrative purposes.