How important are affiliation and cooperation? A reply to Sussman et al.

Abstract

Department of Ecologyand Evolution, Stony Brook University, Stony Brook,NY 11794-5245In a recent ‘‘News and Views’’ article published in theAmerican Journal of Physical Anthropology, Sussmanet al. (2005) presented a ‘‘call for a new approach to thestudy of primate sociality’’ (p. 86). In their opinion, com-petition and aggression have received too much attentionin previous and current models on the evolution of grouplife and social behavior (e.g., Trivers, 1972; Wilson, 1975;Emlen and Oring, 1977; Wrangham, 1980; van Schaik,1989; Isbell, 1991; Sterck et al., 1997), whereas the roleof cooperation and affiliation has been under-examined.In contrast to a focus on ecological risks and competitionfor limiting resources as a major cause and cost of social-ity (e.g., Alexander, 1974; Wrangham, 1980; van Schaik,1983; Terborgh and Janson, 1986; Janson, 1992), Suss-man et al. (2005) suggest that affiliation and cooperationare at the core of group living. To support their ideas,they contrast the amount of affiliation and the rates ofagonism across various diurnal primate species. Findingthat diurnal primates spent most of their social timein affiliation and not in agonism, they conclude thatsociality might be driven by mutual benefits receivedfrom ‘‘...the collective environments of living in stablegroups’’ (Sussman et al., 2005; p. 84).Although we certainly agree with the idea that affiliationand cooperation require more attention in their own right,we believe that the methods used by the authors and theirconclusions are unjustified. In the following, we will specifyour major concerns and outline some possible solutions.