Memory and sociality: how individual recognition affects group formation

Author(s)

Vitor Passos Rios

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2016-07-29

Examining board members

Roberto Andre Kraenkel; Marcus Aloizio Martinez de Aguiar; Elaine Cristina Cambui Barbosa; Hilton Ferreira Japyassú; Paulo Inácio de Knegt López de Prado

• Advisor: Roberto Andre Kraenkel

Abstract

In this thesis, we investigate the effects of individual recognition on group formation. In chapter 2 we review the current knowledge on the evolutionary basis of social behavior, and in chapter 3 we focus on a specific mechanism, individual recognition. We review the basis of individual recognition to devise a minimal model of how individual recognition works, aiming to investigate its consequences on the social structure of animals. Chapter 4 is structured as an introduction to computational modelling. Using agent-based modelling, in chapter 5 we build a population of individuals which can recognize one another and can remember past interactions. We show that presence of memory and individual recognition can dramatically affect the number and size of groups in the absence of memory, individuals form small, unstructured groups. In the presence of memory, individuals form clusters about an order of magnitude greater in size, and consequently less groups are formed. We also show that the group\'s internal structure changes: with memory, group modularity is higher, that is, subgroups are formed within the cluster, in which frequency of interactions is greater than outside the subgroup. Our results also show that density affects group formation: when density is low, even with individual recognition, encounter probabilities are so low that recognition\'s effects are not visible, and the opposite holds for too high densities (AU)

• FAPESP's process: 12/13779-3 - Effects of spatial distribution and memory of interactions on the formation of animal groups
• Grantee: Vitor Passos Rios
• Support Opportunities: Scholarships in Brazil - Doctorate