title: Benefiting friends or dominants: prosocial choices mainly depend on rank position in long-tailed macaques (Macaca fascicularis).
abstract: Long-term observational studies in a number of animal species suggest that exchange patterns of social acts depend on long-term emotional bonds. Therefore, it is expected that the frequency of prosocial behavior will depend on the strength of such a bond. In this study we tested whether variation in relationship quality among unrelated individuals, i.e., "friends" and "nonfriends," is predictive of the prosocial behavior of long-tailed macaques in two experiments. First, we related relationship quality to prosociality in a dyadic prosociality test, and second, we gave subjects the choice to give to either a friend or a nonfriend in a triadic choice test. We show that prosocial behavior of long-tailed macaques in the dyadic test is not related to relationship quality. When given the choice to give to either a friend or a nonfriend in the triadic test, there is a minor indication that long-tailed macaques show a preference to give to their friends, yet this indication is neither significant nor consistent. In contrast, subordinate long-tailed macaques make a more "competitive" choice and avoid giving to the individual closest in rank. Therefore, in the short-term situation of experimental tests, prosocial behavior of long-tailed macaques seems unaffected by the relationship quality of the dyad/triad tested, and the relative dominance position of these dyads/triads seems to have a much stronger effect on their prosocial behavior.
authors.affiliation: Behavioural Biology, Universiteit Utrecht, Padualaan 8, Room O204, P.O. Box 80086, 3508 TB, Utrecht, The Netherlands. jorgmassen@gmail.com
authors.forename: Jorg J M
authors.initials: JJ
authors.lastname: Massen
authors.forename: Inge J A F
authors.initials: IJ
authors.lastname: Luyten
authors.forename: Berry M
authors.initials: BM
authors.lastname: Spruijt
authors.forename: Elisabeth H M
authors.initials: EH
authors.lastname: Sterck
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D005260:Female; D006608:Hierarchy, Social; D008252:Macaca fascicularis / Q000502:physiology* / Q000523:psychology; D008297:Male; D009426:Netherlands; D012930:Social Dominance