Rating rules in the helping game: An axiomatic approach

We examine a stylised helping game in which players recurrently decide whether to help others at personal cost and are assigned binary ratings of “helpfulness” based on previous choices. We propose axioms requiring that ratings are responsive to players’ decisions and change monotonically with respect to helping given or withheld. Only four rules satisfy these axioms: two standing rules and two versions of a form of binary image scoring. These results show how a single rating can encode both the “desert” perspective, linking worthiness to kindness and deservingness, and the “club” perspective, relating worthiness to a cooperative club's membership.