Institut Jean Nicod

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A l'initiative de Philippe Schlenker, ce séminaire a pour objectif de choisir et présenter des thèmes communs à au moins à deux équipes de l'Institut Nicod, avec des intervenants internes ou externes.

Institut Jean-Nicod 29, rue d'Ulm 75005 Paris. Salle de réunion du RDC du Pavillon Jardin.



Vendredi 7 mars 2014 de 11h30 à 13h, Séance organisée conjointement par le séminaire LINGUAE et le séminaire Evolution et Cognition Sociale
Jean-Baptise André (CNRS, IBENS, UMR 8197)
"On the evolutionary origin of reciprocal cooperation"

An important mechanism by which two individuals can mutually benefit from helping each other is reciprocity (in a broad sense). However, reciprocity is the object of an evolutionary paradox: a gap between theoretical predictions and empirical observations. On one hand, evolutionary modelers have shown that it can evolve relatively easily in a wide array of circumstances. On the other hand, empirically, very few clear instances of reciprocity are found outside the human species.

In this talk, I will propose a simple explanation to resolve this paradox. Based on a multi-locus model, I will suggest that reciprocity has rarely evolved because it raises an evolutionary problem of «bootstrapping» of the same kind as communication: it entails the joint evolution of several functions in the same time. Therefore, even though reciprocity may be adaptive once it has already evolved (i.e. it can be an ESS) it cannot be shaped gradually by natural selection.

Although it raises a bootstrapping problem, however, reciprocal cooperation has been able to evolve in a few cases in non-humans, and is widespread in the human species. At the end of the talk, I will thus suggest some evolutionary pathways by which it may have emerged in spite of the boostrapping problem. I will show that understanding these pathways can be key in explaining both the distribution of reciprocity in extant species, and the evolutionary history of human cooperation.

Séances passées :

Vendredi 31 janvier 2014 de 11h30 à 13h - Séance organisée conjointement par le séminaire LINGUAE, le séminaire Jean Nicod Emerging New Ideas et le séminaire Evolution et Cognition Sociale.
Mark Sheskin (IJN),
“The Origins of Fairness: Experiments with Children and Monkeys”

Recent research has argued that surprisingly advanced fairness judgments can be found early in childhood development and even in some nonhuman primates. I present new experiments showing the opposite: situations in which monkeys do not care about fairness and young children show spiteful preferences against fairness. Which set of research should you believe? Both, of course! In a review including both sets of research, I will discuss the similarities and differences in the fairness of these populations. The interesting question becomes about which aspects of adult fairness can be found in these other populations, and how the initial state matures into the adult one.

Vendredi 17 janvier 2014 de 11h30 à 13h. Séance organisée par l'équipe LINGUAE
James L. Fuller
Columbia University, Department of Ecology, Evolution, and Environmental Biology,
City University of New York (CUNY), Department of Biology
New York Consortium in Evolutionary Primatology (NYCEP)

"The vocal signals of adult male blue monkeys (Cercopithecus mitis): an evolutionary approach to understanding communication systems."

My research focuses, generally, on the evolution of social behavior and, more specifically, on understanding the mechanisms that maintain social relationships in group living animals. My current research examines the evolution of vocal communication systems.
Across most vertebrate taxa, vocal signals play key roles in predator avoidance, reproduction, competition, and mediating social interactions. Understanding how animals use particular signals therefore provides unique insight into species’ behavior, social dynamics, and evolution.
For the past several years, I have examined vocal behavior of adult male blue monkeys (Cercopithecus mitis) in the Kakamega Forest, Kenya. Using data from natural observation, digital audio recordings, and playback experiments, I seek to characterize the entire vocal repertoire of adult males in terms of acoustic structure, signal content (i.e. consistent relationships between signal features and attributes of signalers), and signal function.
Analyses have identified six stereotyped call types used by adult males. Each call type is acoustically distinct, yet structural similarities suggest some are more closely “related” than others. Similarly, call types exhibit distinct functions (e.g. aerial predator alarm, mate attraction) and content (e.g. social status, body size), yet evidence that some calls achieve multiple functions highlight the complexity of the repertoire. I examine these findings to infer how natural selection likely favors signal usage and how repertoires might expand over evolutionary time.
The aim of my research is to provide a comprehensive assessment of the structural and functional diversity of an entire signal repertoire, as well as insight into the socio-ecological mechanisms by which signal diversity evolves and is maintained. In doing so, I hope also to demonstrate the importance of a comprehensive approach – one that evaluates form, function, and content of entire repertoires – to understanding the use and evolution of signaling systems.

Vendredi 21 février 2014 de 11h30 à 13h
Denis Bonnay, U. Paris Ouest, IRePH & DRI (IHPST@DEC)
"Groups and Clusters. A new approach to collective beliefs in unorganized groups"

Abstract :
I would like to argue in favor of a new approach to collective beliefs in unorganized groups, based on the idea of doxastic clustering.
When a group does not have dedicated mechanisms for production of collective beliefs, and when individual beliefs of members of the group are diverse, it does not make much sense to attribute to the group some average beliefs or any other kind of collective beliefs produced by aggregating individual beliefs. Rather, beliefs are meaningfully attributed to coherent subgroups of individuals who share similar opinions.
In this case, attribution of collective beliefs involves both clustering, that is partitioning the group into coherent doxastic units, and aggregation, that is aggregating individual opinions within coherent clusters. Adapting standard judgment aggregation theory, I propose a formal framework for doxastic clustering and provide an axiomatic characterization of majoritarian intra-cluster aggregation.