Another theory deals with the social evolution of altruism versus selfishness in the context of conflicting forces. D.S. Wilson and E.O. Wilson state that selfishness beats altruism within a group but groups that are altruistic beat out groups that are selfish as there is a higher level of cooperation and coordination within an altruistic group. Whether or not a group will be altruistic and cohesive is dependent on both individual efforts as well as exterior forces. The success of a group in competition with other groups is dependent upon cooperation within.