Before revision:  Despite the contribution, we critiqued that there are not only mathematical errors in Mark's model but also limitations in applying it to other hierarchical structures. We present a more generalized model by introducing a novel hierarchy measure to interpolate the cooperativeness of group members in any hierarchy structure of interest.
After revision:  Despite the contribution, we critiqued that there are not only mathematical errors in Mark's model that makes it less realistic than it could in explaining real-world experiences. Consequently, we present a more generalized model by introducing a novel hierarchy measure to interpolate the cooperativeness of group members in any hierarchy structure of interest.