Social dynamics and diffusion of novel behaviour patterns in wild capuchin monkeys (sapajus libidinosus) inhabiting the serra da capivara national park

Author(s)

Camila Galheigo Coelho

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Psicologia (IP/SBD)
• Defense date: 2015-07-30

Examining board members

Eduardo Benedicto Ottoni; Renata Goncalves Ferreira; Francisco Dyonisio Cardoso Mendes; Briseida Dogo de Resende; Jose de Oliveira Siqueira

• Advisor: Eduardo Benedicto Ottoni; Rachel Louise Kendal

Abstract

The existence of behavioural traditions that is, cross-generational socially mediated learning of a behaviour - in non-human animals has been the subject of intense debate in the last decade. To classify as a behavioural tradition, a behaviour must be acquired by naïve individuals through learning that must in some way be mediated or facilitated by the behaviour of a conspecific. The overarching aim of this thesis is to further our understanding of behavioural traditions in capuchin monkeys. To do so I examine the acquisition of new behaviours via socially-biased learning in two groups of wild bearded capuchin monkeys (Sapajus libidinosus) inhabiting the Serra da Capivara National Park, Piauí, Brazil. More specifically, the thesis answers three main questions: (1) what are the opportunities of social learning; (2) how can social learning be identified in wild populations and (3) how do social biases in the transmission of information affect the final behavioural repertoire of the groups. To address the first question I describe the social context in which the capuchin monkeys live as a means to characterise the opportunities monkeys have of learning from one another. My findings confirm Coussi-Korbel & Fragaszys (1995) predictions that capuchin monkeys have relationships conducive of both non-specific social learning and directed social learning. Using social network analysis I portray the groups social structures based on different measures of relationships and describe how patterns of association (social proximity, co-feeding) depict opportunities for non-specific social learning, while interactions (grooming, social play) are conducive to directed social learning. The second question is answered by implementing an open-diffusion field experiment and the application of novel data analysis methodologies (NBDA: Franz & Nunn 2009 and Option-bias: Kendal et al 2009) designed for studying social learning in wild populations. NBDA found that when the social transmission model was informed by observation networks, it presented a better fit to the diffusion data, thus providing evidence for social learning of the foraging tasks. Moreover, only observation from shorter distances produced these results, indicating that observation of the task, from close up, was needed for the behaviour to be acquired. Other social networks also provided evidence for social learning in both groups, predominantly those based on grooming relations for the lift-pull task and co-feeding relations for the tube-task. To address the third question I examine possible transmission biases, addressing, in particular, frequency-dependent and model-based transmission biases. Given the homogeneity of behavioural variants for solving foraging task, rigorous conclusions regarding frequency-dependent biases were not possible. The model-based bias revealed a selective attention towards proficient individuals, resonating with what has been described for tool-aided nut cracking in semi-free capuchin (Sapajus spp.: Ottoni et al 2005, Coelho et al, 2015) and wild capuchin monkeys (Sapajus libidinosus: Coelho et al 2008). Considering opportunities of social leaning and transmission biases together allows us to further the understanding of the dynamics involved in the establishment and maintenance of shared practices and of the spread of behavioural traditions across populations (AU)

• FAPESP's process: 11/22900-8 - Effects of the social dynamics in the diffusion of a novel tool-using behaviours in groups of capuchin monkeys (Sapajus libidinosus) inhabiting the caatinga of The Serra da Capivara National Park
• Grantee: Camila Galheigo Coelho
• Support Opportunities: Scholarships in Brazil - Doctorate