International Journal of Comparative Psychology

The development of social competence depends on feedback from partners. We evaluated the social competence of 18 adult re-socialized chimpanzees with respect to (1) social group membership and (2) deprivation history combination. The groups comprised either a majority of early (EDs; mean age at onset of deprivation: 1.2 years) or late deprived chimpanzees (LDs; mean age at onset of deprivation: 3.6 years). We reapplied our model of social competence with five grades of social stimulation and found a diminished toleration of social stimulation (1) in ED-majority groups compared to the group where LDs predominate and (2) in homogeneous ED-majority dyads compared to homogeneous LD-majority dyads. LDs but not EDs representing the minority within their group were able to adjust their stimulation seeking to the majority of partners. Only the LD-dominated group and the homogeneous LD-majority dyads, respectively, showed improvements of social competence from the first to the second year following re-socialization.