The bonds of society : an interdisciplinary study of social rationality

Cette thèse est consacrée à l'étude des principes fondamentaux de la rationalité humaine dans les interactions sociales afin de combler l'écart séparant le comportement individuel et égoïste de la coopération sociale. A cet effet, je présente d'abord une analyse logique du rôle de la connaissance dans les jeux séquentiels. Plus précisément, j'utilise la logique modale pour formaliser le raisonnement d'agents sur les stratégies et la connaissance, et examiner le théorème bien connu d'Aumann stipulant que l'induction rétrograde dans les jeux à information parfaite peut être dérivée de l'hypothèse de connaissance commune de rationalité individuelle. Ensuite, le chapitre suivant étudie la nature des relations sociales comme une explication possible du comportement coopératif humain. Après avoir fourni une définition basique des liens sociaux, je présente alors un nouveau modèle théorique basée sur l'hypothèse que de telles relations sociales influencent les préférences des individus. Afin d'étudier cette théorie, je propose l'analyse d'un nouveau type de jeu de coordination qui permet de dissocier les prédictions de théories basées sur l'intérêt personnel, les préférences sociales, et les liens sociaux. Je valide alors le modèle proposé de liens sociaux à travers une étude expérimentale qui implique des sujets humains partageant des liens réels les uns avec les autres. Enfin, je présente une généralisation de ce modèle afin de formaliser le comportement rationnel coopératif dans les interactions sociales pouvant comporter plus de deux individus. Dans ce cas, j'illustre les similarités et différences existantes avec la théorie de raisonnement en équipe de Bacharach.This thesis is devoted to study the underlying principles of human rationality in social interactions as an attempt to bridge the gap between individually egoistic behavior and social cooperation. For this purpose, I first present a logical analysis of the role of knowledge in the context of sequential games. More precisely, I use modal logic to formally model agents' reasoning about strategies and knowledge, and investigate Aumann's well known theorem stating that backward induction in perfect information games can be derived from the assumption of common knowledge of individual rationality. The next chapter focuses on studying the nature of social relationships as a possible explanation of human cooperative behavior. After providing a basic definition of social ties, I then introduce a novel theoretical model built upon the main hypothesis that such relationships directly influence the players' preferences. In order to investigate this claim, I first propose a theoretical analysis of a new kind of coordination game, which allows to disentangle predictions from theories based on self-interest, social preferences, and social ties. I then validate the proposed model of social ties through an experimental study involving subjects who share some genuine bonds with one another. Finally, I present a generalization of this model as a means to formally represent rational cooperative behavior in strategic interactions possibly involving more than two individuals. In this case, I illustrate the existing similarities and differences with Bacharach's well known theory of team reasoning

Security under Uncertainty: Adaptive Attackers Are More Challenging to Human Defenders than Random Attackers

Game Theory is a common approach used to understand attacker and defender motives, strategies, and allocation of limited security resources. For example, many defense algorithms are based on game-theoretic solutions that conclude that randomization of defense actions assures unpredictability, creating difficulties for a human attacker. However, many game-theoretic solutions often rely on idealized assumptions of decision making that underplay the role of human cognition and information uncertainty. The consequence is that we know little about how effective these algorithms are against human players. Using a simplified security game, we study the type of attack strategy and the uncertainty about an attacker's strategy in a laboratory experiment where participants play the role of defenders against a simulated attacker. Our goal is to compare a human defender's behavior in three levels of uncertainty (Information Level: Certain, Risky, Uncertain) and three types of attacker's strategy (Attacker's strategy: Minimax, Random, Adaptive) in a between-subjects experimental design. Best defense performance is achieved when defenders play against a minimax and a random attack strategy compared to an adaptive strategy. Furthermore, when payoffs are certain, defenders are as efficient against random attack strategy as they are against an adaptive strategy, but when payoffs are uncertain, defenders have most difficulties defending against an adaptive attacker compared to a random attacker. We conclude that given conditions of uncertainty in many security problems, defense algorithms would be more efficient if they are adaptive to the attacker actions, taking advantage of the attacker's human inefficiencies

Public goods and future audiences: acting as role models?

Intergenerational interactions play an important part in society with older generations often acting as role models that in uence younger ones. We investigate in a public good experiment how the behavior of more experienced and knowledgeable players (graduate students) is affected when they are informed that some of their personal and behavioral characteristics will be transmitted to future first-year undergraduates (enrolling the following year) playing the same game at the same university. In the "information" treatment, the history of behavior is transmitted with some personal characteristics (e.g. age and gender). In the \photo" treatment, a photo is also transmitted. Despite the absence of any monetary linkage between generations, our results show a significant effect of visibility by the future audience on initial contributions and dynamic behavior. Contrary to previous findings in the literature, contributions are lower in the presence of such personal identification. We explain this surprising negative effect by a "sucker aversion" bias according to which people become more sensitive to being perceived as exploited by their peers. We argue that the nature of the "audience" matters in reaching such an undesirable outcome

Pressions et expressions de normes dans les pratiques d’enseignement de l’histoire au secondaire

Les pratiques d’enseignement de l’histoire au secondaire sont reconnues comme présentant certaines caractéristiques communes : prédominance de l’enseignement magistral, centration sur les contenus historiques plutôt que sur les compétences, par exemple. Cet article s’arrête sur ce constat et cherche à lui donner sens en analysant les pratiques de cinq enseignants sur le plan didactique et sur le plan de normes organisant leur travail. La question de la norme prend ainsi plusieurs figures dans cette recherche. De fait, l’observation des pratiques permet de cerner les normes disciplinaires façonnant le travail de ces enseignants d’histoire, de même que la manière dont les prescriptions officielles sont reçues, intégrées et transformées par ceux-ci alors qu’ils cherchent à se construire un « milieu d’action » viable. Les résultats montrent que ces enseignants possèdent une culture disciplinaire propre, marquée par une centration sur l’organisation et la transmission des savoirs historiques et s’exprimant dans la construction de ce que nous nommons le « cahier d’apprentissage fait maison ».High school history teaching practices are recognized as having some common characteristics: predominance of lectures and a focus on historical contents rather than skills, for example. This article focuses on this observation and seeks to make sense of it by analyzing the specificities of the history teachers’ work. The question of the norm thus takes several figures in this research. In fact, observing practices allows disciplinary norms shaping the work of the history teacher to be considered, as well as the manner in which official prescriptions are received, integrated and transformed by history teachers, who thus create a more viable "action environment". The results show that this group of professionals has a specific disciplinary culture, which focuses on the organization and transmission of historical knowledge and the construction of what we call the "homemade learning book"

In vitro effects of nanoparticles on renal cells

<p>Abstract</p> <p>Background</p> <p>The ability of nanoparticles to cross the lung-blood barrier suggests that they may translocate to blood and to targets distant from their portal of entry. Nevertheless, nanotoxicity in organs has received little attention. The purpose of this study was to evaluate nanotoxicity in renal cells using <it>in vitro </it>models. Various carbon black (CB) (FW2–13 nm, Printex60-21 nm and LB101-95 nm) and titanium dioxide (TiO₂-15 and TiO₂-50 nm) nanoparticles were characterized on size by electron microscopy. We evaluated theirs effects on glomerular mesangial (IP15) and epithelial proximal tubular (LLC-PK₁) renal cells, using light microscopy, WST-1 assay, immunofluorescence labeling and DCFH-DA for reactive oxygen species (ROS) assay.</p> <p>Results</p> <p>Nanoparticles induced a variety of cell responses. On both IP15 and LLC-PK₁cells, the smallest FW2 NP was found to be the most cytotoxic with classic dose-behavior. For the other NPs tested, different cytotoxic profiles were found, with LLC-PK₁cells being more sensitive than IP15 cells. Exposure to FW2 NPs, evidenced in our experiments as the most cytotoxic particle type, significantly enhanced production of ROS in both IP15 and LLC-PK₁cells. Immunofluorescence microscopy using latex beads indicated that depending on their size, the cells internalized particles, which accumulated in the cell cytoplasm. Additionally using transmission electronic microscope micrographs show nanoparticles inside the cells and trapped in vesicles.</p> <p>Conclusion</p> <p>The present data constitute the first step towards determining <it>in vitro </it>dose effect of manufactured CB and TiO₂NPs in renal cells. Cytotoxicological assays using epithelial tubular and glomerular mesangial cell lines rapidly provide information and demonstrated that NP materials exhibit varying degrees of cytotoxicity. It seems clear that <it>in vitro </it>cellular systems will need to be further developed, standardized and validated (relative to <it>in vivo </it>effects) in order to provide useful screening data about the relative toxicity of nanoparticles.</p

A food web model for the Baffin Bay coastal and shelf ecosystem. Part 1 : Ecopath Technical Report

This work was undertaken as part of a multidisciplinary research project funded by the Marine Observation Prediction and Assessment Network - MEOPAR (at ULaval), Canadian Institute of Health Research – CIHR (at University of Ottawa), and Sentinel North (at ULaval), and hosted at Université Laval, in Canada. The objective of the overall project is to support the food security (i.e., the availability and access to sufficient, safe, nutritious food that meets dietary preference) of Inuit communities of the Eastern Canadian Arctic, as well as to explore ways to adapt to effects of climate change. Inuit fish and hunt local marine species, from invertebrates to fish and marine mammals, which make a large part of their diet and are central to their food security. With temperatures increasing twice as fast as the global average and sea ice becoming thinner and forming later, climate change effects on the distribution and abundance of Arctic marine species are already taking place. To better understand the effects of climate change in important subsistence species, a multi-species model (Ecopath with Ecosim) will be used to inform the development of an integrated ecosystem assessment. The model will be used as a tool to co-create scenarios of ecosystem change with the community of Qikiqtarjuaq, Nunavut, to inform adaptation strategies regarding food security (e.g., potential of new fisheries in the region). This report describes the development of an Ecopath model of the Baffin Bay coastal and shelf ecosystem. The methodology, data used to construct the model, data gaps and limitations are described

Association of Parkinson’s Disease and Its Subtypes with Agricultural Pesticide Exposures in Men: A Case–Control Study in France

Background: Pesticides have been associated with Parkinson’s disease (PD), but there are few data on important exposure characteristics such as dose–effect relations. It is unknown whether associations depend on clinical PD subtypes. Objectives: We examined quantitative aspects of occupational pesticide exposure associated with PD and investigated whether associations were similar across PD subtypes. Methods: As part of a French population-based case–control study including men enrolled in the health insurance plan for farmers and agricultural workers, cases with clinically confirmed PD were identified through antiparkinsonian drug claims. Two controls were matched to each case. Using a comprehensive occupational questionnaire, we computed indicators for different dimensions of exposure (duration, cumulative exposure, intensity). We used conditional logistic regression to compute odds ratios (ORs) and 95% confidence intervals (CIs) among exposed male farmers (133 cases, 298 controls). We examined the relation between pesticides and PD subtypes (tremor dominant/non-tremor dominant) using polytomous logistic regression. Results: There appeared to be a stronger association with intensity than duration of pesticide exposure based on separate models, as well as a synergistic interaction between duration and intensity (p-interaction = 0.04). High-intensity exposure to insecticides was positively associated with PD among those with low-intensity exposure to fungicides and vice versa, suggesting independent effects. Pesticide exposure in farms that specialized in vineyards was associated with PD (OR = 2.56; 95% CI: 1.31, 4.98). The association with intensity of pesticide use was stronger, although not significantly (p-heterogeneity = 0.60), for tremor-dominant (p-trend < 0.01) than for non-tremor–dominant PD (p-trend = 0.24). Conclusions: This study helps to better characterize different aspects of pesticide exposure associated with PD, and shows a significant association of pesticides with tremor-dominant PD in men, the most typical PD presentation. Citation Moisan F, Spinosi J, Delabre L, Gourlet V, Mazurie JL, Bénatru I, Goldberg M, Weisskopf MG, Imbernon E, Tzourio C, Elbaz A. 2015. Association of Parkinson’s disease and its subtypes with agricultural pesticide exposures in men: a case–control study in France. Environ Health Perspect 123:1123–1129; http://dx.doi.org/10.1289/ehp.130797

The Effects of Social Ties on Coordination: Conceptual Foundations for an Empirical Analysis

International audienceThis paper investigates the influence that social ties can have on behavior. After defining the concept of social ties that we consider, we introduce an original model of social ties. The impact of such ties on social preferences is studied in a coordination game with outside option. We provide a detailed game theoretical analysis of this game while considering various types of players, i.e., self-interest maximizing, inequity averse, and fair agents. In addition to these approaches that require strategic reasoning in order to reach some equilibrium, we also present an alternative hypothesis that relies on the concept of team reasoning. After having discussed the differences between the latter and our model of social ties, we show how an experiment can be designed so as to discriminate among the models presented in the paper

« Plus une oeuvre qu’un tribunal punisseur » : les jeunes délinquants devant la Cour de Bien-Être Social, 1950-1977

Le réseau judiciaire québécois spécialisé pour mineurs est en pleine expansion au milieu du XXe siècle. En 1950, le Québec procède à une réorganisation complète de ses tribunaux spécialisés dans le traitement de la criminalité juvénile en créant les Cours de Bien-Être Social. L’objectif principal de cette recherche est de comprendre comment, à l’intérieur d’un de ces tribunaux, entre les années 1950 et 1977, le traitement judiciaire pour jeunes délinquants a évolué. Il nous apparaît que le modèle initial d’une cour de justice coordonnée par un juge unique, souverain dans le processus décisionnel, ne pourra pas faire l’économie d’une procédure judiciaire mieux structurée et plus uniformisée d’une affaire à l’autre. Au cours des années 1960, l’approche du tribunal à l’égard des jeunes délinquants subira de profondes mutations.The Quebec juvenile’s justice is growing in the middle of thetwentieth century. In 1950, Quebec performs a complete reorganizationof its courts specialized in the treatment of juvenile crime bycreating the Cour de Bien-Être Social. The main objective of thisresearch is to understand how, inside one of these courts, between 1950and 1977, the judicial treatment for young delinquents is organized. Itseems that the initial model of a court coordinated by a single judge,sovereign in decision making, will not be able to make the economy oflegal proceedings better structured and more standardized from anaffair to the other one. In the course of 1960s, the approach of thecourt regarding the young delinquents will be subjected to deepmutations