Armand Jacobs

Publications of Armand Jacobs

• Social network modeling: a powerful tool for the study of group scale phenomena in primates.

  Authors: Armand Jacobs, Odile Petit

  American journal of primatology. 08/2011; 73(8):741-7.

  Social Network Analysis is now a valuable tool to study social complexity in many animal species, including primates. However, this framework has rarely been used to implement quantitative data onSocial Network Analysis is now a valuable tool to study social complexity in many animal species, including primates. However, this framework has rarely been used to implement quantitative data on the social structure of a group within computer models. Such approaches allow the investigation of how social organization constrains other traits and also how these traits can impact the social organization in return. In this commentary, we discuss the powerful potential of social network modeling as a way to study group scale phenomena in primates. We describe the advantages of using such a method and we focus on the specificity of this approach in primates, given the particularities of their social networks compared with those of other taxa. We also give practical considerations and a list of examples as for the choice of parameters that can be used to implement the social layer within the models.

• How can social network analysis improve the study of primate behavior?

  Authors: Cédric Sueur, Armand Jacobs, Frédéric Amblard, Odile Petit, Andrew J King

  American journal of primatology. 12/2010; 73(8):703-19.

  When living in a group, individuals have to make trade-offs, and compromise, in order to balance the advantages and disadvantages of group life. Strategies that enable individuals to achieve thisWhen living in a group, individuals have to make trade-offs, and compromise, in order to balance the advantages and disadvantages of group life. Strategies that enable individuals to achieve this typically affect inter-individual interactions resulting in nonrandom associations. Studying the patterns of this assortativity using social network analyses can allow us to explore how individual behavior influences what happens at the group, or population level. Understanding the consequences of these interactions at multiple scales may allow us to better understand the fitness implications for individuals. Social network analyses offer the tools to achieve this. This special issue aims to highlight the benefits of social network analysis for the study of primate behaviour, assessing it's suitability for analyzing individual social characteristics as well as group/population patterns. In this introduction to the special issue, we first introduce social network theory, then demonstrate with examples how social networks can influence individual and collective behaviors, and finally conclude with some outstanding questions for future primatological research.

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• Group cohesiveness during collective movements: travelling apart together.

  Authors: Armand Jacobs

  Behavioural processes. 03/2010; 84(3):678-80.

  No Abstract needed for this Special Issue.

• Social network influences decision making during collective movements in brown lemurs (Eulemur fulvus fulvus)

  Authors: Armand Jacobs, Cédric Sueur, Jean-Louis Deneubourg, Odile Petit

  International Journal of Primatology.

  Many animal species live as a group and must therefore move as such. Several authors have suggested that the mechanisms underlying collective movements in primate species appear to rely on complexMany animal species live as a group and must therefore move as such. Several authors have suggested that the mechanisms underlying collective movements in primate species appear to rely on complex cognitive skills, given their high level of cognitive abilities. However, recent studies have highlighted the fact that complex patterns do not necessarily imply complex mechanisms. We used a modeling approach to investigate the patterns of collective movement in a semi-freeranging group of brown lemurs. We recorded via digital video cameras the order and joining latencies of the 11 individuals of the group during the departure time of spontaneous group movements. We then assessed whether mimetic mechanisms or the existence of a leader were underlying conditions for the joining process by testing 5 computer models relying respectively on 5 hypotheses: the independence of individuals, an anonymous mimetism, a mimetism according to kinship, a mimetism according to affiliation, and eventually the existence of a leader. We found that departure latencies, associations, and the order of individuals at departure time could all be explained by the mimetism according to affiliation model. Thus, an individual's decision to join the collective movement or not depended on the decision taken by its preferred social partners. These results show the importance of social parameters in primate decision making and that the high cohesion displayed by the group members might not be constrained merely by ecological factors such as predation or foraging consideration