Between-group hostility affects within-group interactions in tufted capuchin monkeys
Publication Type: |
Journal Article |
Year of Publication: |
2012 |
Authors: |
E. Polizzi di Sorrentino, G. Schino, L. Massaro, E. Visalberghi, F. Aureli |
Publication/Journal: |
Animal Behaviour |
Keywords: |
affiliation, aggression, between-group interaction, capuchin monkey, cebus apella |
ISBN: |
00033472 |
Abstract:
Between-group competition has long been thought to be a key factor influencing within-group social
dynamics. In humans, it has been suggested that between-group competition may favour the emergence
of within-group cooperation. However, between-group competition can also be hypothesized to induce
social tension and cause within-group social relationships to deteriorate. So far, little research has
focused on these possible effects in animal societies. In this study, we used an experimental set-up to
manipulate the opportunity for visual aggressive interactions between two adjacent groups of captive
tufted capuchin monkeys, Cebus apella, to examine the group members’ behavioural adjustment in terms
of affiliation and aggression. The ‘cooperative hypothesis’ predicted social relationships to be positively
reinforced by the visual exposure to the adjacent group to buffer between-group hostility. By contrast,
the ‘induced-tension hypothesis’ predicted social relationships to be negatively affected by the visual
exposure to the adjacent group because of the higher level of social tension induced by between-group
hostility. The experimental manipulation did not produce changes in affiliative behaviours, whereas
within-group aggression was higher and the dominance hierarchy steeper when visual aggressive
interactions between groups were allowed. Overall, interactions with a neighbouring group caused social
relationships to deteriorate and partly confirmed the induced-tension hypothesis.