HOLLARD Guillaume

Women are under-represented in top positions, such as Business, Politics and Science. The same under-representation occurs in chess, providing us with a unique opportunity to analyze this phenomenon. We find a macro gender gap in every country: there are fewer female than male players, especially at the top, and women have lower average rankings. One contribution of this paper is to link the macro gender gap to micro gender differences. Comparing millions of individual games, we find that women’s scores are about 2% lower than expected when playing a man rather than a woman with identical rating, age and country. Using a simple theoretical model, we explain how a small micro gap may affect women’s long-run capital formation. A small difference in outcomes generates a small difference in effort, and thus a lower future ranking. By reducing effort and increasing the probability of quitting, both effects accumulate to discourage women from competing for top positions.

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Standard economic models assume that individuals collect and process information in a way that gives them a relatively accurate perception of reality. However, this assumption is often challenged. Evidence shows that individuals often form positive biases about themselves, which can have adverse economic consequences. This thesis aims to explain the persistence of overconfidence in social interactions by showing the existence of strategic benefits of overconfidence that outweigh its social cost.Using a series of laboratory experiments, this thesis shows that (i) overconfidence occurs primarily when it provides an advantage in social interactions (Chapter 2) and (ii) identifies situations in which overconfidence is likely to harm society (Chapters 3 and 4). This thesis contributes to the literature by improving our understanding of the situational determinants of overconfidence in social interactions and lays the groundwork for improving policies to prevent or limit negative effects.

This paper uses the test/retest data from the Holt and Laury (2002) experiment to provide estimates of the measurement error in this popular risk-aversion task. Maximum likelihood estimation suggests that the variance of the measurement error is approximately equal to the variance of the number of safe choices. Simulations confirm that the coefficient on the risk measure in univariate OLS regressions is approximately half of its true value. Unlike measurement error, the discrete transformation of continuous riskaversion is not a major issue. We discuss the merits of a number of different solutions: increasing the number of observations, IV and the ORIV method developed by Gillen et al. (2019).

Standard decision theories assume that choices are based on instantaneous value readings from stable utility functions. Therefore, decision outcomes should be independent of how information is acquired. However, the information related to a choice is often encountered in a sequential manner. In this thesis, we have attempted to characterize the influence of sequential presentations on economic decision making. In our first study, we used a multiple choice task involving a sequential presentation of different options. We showed that the order of presentation could influence the direction of value comparison: subjects were more likely to choose the best option when it was presented at the beginning of a trial. We hypothesize that this is due to an active but implicit pairwise comparison process during the sequential sampling process. We validated this model formally via a Bayesian model comparison. In the second study, we compared the simultaneous presentation of information about two two-attribute options with various sequential presentations. We found that early information about a first option or attribute can modulate the weight given to later information and explain variations in response time. Overall, we have shown that the order of presentation influences choice, inviting a revision of standard decision theory.

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This thesis studies the formation of expectations and their influence on the consumption and portfolio choices of French savers. First, we study the wealth effect, i.e. the effect of changes in financial and real estate assets on household consumption. During the 2008-2009 crisis, which affected wealth and expectations, households that suffered losses on their real estate or financial wealth were more likely to reduce their consumption. Next, we address the heterogeneity of expectations about stock returns. Specifically, we show that personal experience plays a key role in the formation of expectations. Indeed, those who have experienced a gain on their financial assets in the past anticipate a higher stock return. However, the results also highlight the importance of financial knowledge in the formation of expectations. Finally, we examine the extent to which heterogeneity in expectations can explain differences in portfolio choice. In this context, we show that individuals who anticipate a higher stock market return hold a larger share of stocks in their wealth. Nevertheless, the effect of expected risk is not significant, contrary to the predictions of standard portfolio choice theory. Finally, the imprecision of responses, which we interpret as an indicator of the respondent's confidence in his or her own expectations, is negatively correlated with the share of stocks in wealth.

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We test for a causal role of social capital, as measured by self-reported trust, in determining access to basic health facilities in Sub-Saharan Africa. To skirt the reverse-causality problems between social capital and basic health, we rely on instrumental-variable (IV) estimates. A one standard-deviation increase in trust is predicted to lead to a 0.22 standard-deviation fall in doctor absenteeism, a 0.31 standard-deviation fall in waiting time and a 0.30 standard-deviation fall in bribes. As a robustness check, we also use a different database regarding a different health issue, access to clean water. We find that a one standard-deviation rise in trust leads to a 0.33 standard-deviation rise in access to clean water. The variety of public goods considered provides insights about the possible channels through which social capital is converted into health improvements.

This dissertation investigates the supply and demand factors associated with the use of breast cancer screening. Among the supply factors, I examine how the coexistence of organized screening alongside individual screening influences the content of the screening examination as well as the regular use of screening. In addition to demand factors such as socioeconomic characteristics, particular attention is paid to the possibility of explaining regular screening uptake by risk and time preferences as well as perceptions. Based on psychological regularities identified in behavioral economics and psychology, three nudge-type interventions are tested in a randomized field experiment aimed at increasing screening rates in the national program.

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Conventional economic theory assumes that agents should be consistent across decisions. However, it is often observed that experimental subjects fail to report consistent preferences. So far, these inconsistencies are almost always examined singly. We thus wonder whether the more inconsistent individuals in one task are also more inconsistent in other tasks. We propose an experiment in which subjects are asked to report their preferences over risky bets so as to obtain, for each subject, three measures of inconsistencies: classical preference reversals, framing effects and preference instability. In line with previous experimental findings, subjects are largely inconsistent according to each of these three measures and there are considerable individual differences. The main result is that we find no correlation among these three measures of inconsistency.

A major challenge for decision theory is to account for the instability of expressed preferences across time and context. Such variability could arise from specific properties of the brain system used to assign subjective values. Growing evidence has identified the ventromedial prefrontal cortex (VMPFC) as a key node of the human brain valuation system. Here, we first replicate this observation with an fMRI study in humans showing that subjective values of painting pictures, as expressed in explicit pleasantness ratings, are specifically encoded in the VMPFC. We then establish a bridge with monkey electrophysiology, by comparing single-unit activity evoked by visual cues between the VMPFC and the orbitofrontal cortex. At the neural population level, expected reward magnitude was only encoded in the VMPFC, which also reflected subjective cue values, as expressed in Pavlovian appetitive responses. In addition, we demonstrate in both species that the additive effect of prestimulus activity on evoked activity has a significant impact on subjective values. In monkeys, the factor dominating prestimulus VMPFC activity was trial number, which likely indexed variations in internal dispositions related to fatigue or satiety. In humans, prestimulus VMPFC activity was externally manipulated through changes in the musical context, which induced a systematic bias in subjective values. Thus, the apparent stochasticity of preferences might relate to the VMPFC automatically aggregating the values of contextual features, which would bias subsequent valuation because of temporal autocorrelation in neural activity.

In this paper, we use an experimental design to compare the performance of elicitation rules for subjective beliefs. Contrary to previous works in which elicited beliefs are compared to an objective benchmark, we consider a purely subjective belief framework (confidence in one’s own performance in a cognitive task and a perceptual task). The performance of different elicitation rules is assessed according to the accuracy of stated beliefs in predicting success. We measure this accuracy using two main factors: calibration and discrimination. For each of them, we propose two statistical indexes and we compare the rules’ performances for each measurement. The matching probability method provides more accurate beliefs in terms of discrimination, while the quadratic scoring rule reduces overconfidence and the free rule, a simple rule with no incentives, which succeeds in eliciting accurate beliefs. Nevertheless, the matching probability appears to be the best mechanism for eliciting beliefs due to its performances in terms of calibration and discrimination, but also its ability to elicit consistent beliefs across measures and across tasks, as well as its empirical and theoretical properties.

Because of limited governmental resources, communities in Africa often rely on collective action to provide basic public goods such as schools. What drives the ability of communities to produce better schools? Two important lines of research shaped our understanding of the ability of communities to engage in collective action. The first line proposes ethnic division as a key determinant, with more ethnically heterogeneous countries having lower economic performances and levels of public goods. Thus, we expect to find better schools where ethnic fractionalization is low. The second line of research focuses on social capital as a major determinant of the ability to engage in collective action. We expect that trust among community members, a widely-used measure of social capital, is an important and positive determinant of school quality. The present work aims to disentangle the relative effects of ethnic fractionalization and social capital on school quality. We use instrumental variable estimations to address reverse causality and other endogeneity issues. We instrument both social capital and ethnic fractionalization by using historical information on the settlement patterns of ethnic groups in Sub-Saharan Africa. Our empirical strategy is implemented by combining four datasets, including Afrobarometer, covering 16 sub-Saharan countries.We find an important and positive effect of trust on the practical aspects of schooling, such as maintaining buildings or providing textbooks. A one percent increase in the level of trust increases the quality of local public goods by 0.18 to 1.05 percent, depending on the measure of school quality under consideration. In sharp contrast, ethnic fractionalization is found to have a very limited effect, if any. Our results suggest that policies designed to enhance social capital are likely to have a positive effect on schools and local public goods in general.

When it comes to interpreting others' behaviour, we almost irrepressibly engage in the attribution of mental states (beliefs, emotions…). Such "mentalizing" can become very sophisticated, eventually endowing us with highly adaptive skills such as convincing, teaching or deceiving. Here, sophistication can be captured in terms of the depth of our recursive beliefs, as in "I think that you think that I think…" In this work, we test whether such sophisticated recursive beliefs subtend learning in the context of social interaction. We asked participants to play repeated games against artificial (Bayesian) mentalizing agents, which differ in their sophistication. Critically, we made people believe either that they were playing against each other, or that they were gambling like in a casino. Although both framings are similarly deceiving, participants win against the artificial (sophisticated) mentalizing agents in the social framing of the task, and lose in the non-social framing. Moreover, we find that participants' choice sequences are best explained by sophisticated mentalizing Bayesian learning models only in the social framing. This study is the first demonstration of the added-value of mentalizing on learning in the context of repeated social interactions. Importantly, our results show that we would not be able to decipher intentional behaviour without a priori attributing mental states to others.

Theory of Mind (ToM) is the ability to attribute mental states (e.g., beliefs and desires) to other people in order to understand and predict their behaviour. If others are rewarded to compete or cooperate with you, then what they will do depends upon what they believe about you. This is the reason why social interaction induces recursive ToM, of the sort ''I think that you think that I think, etc.''. Critically, recursion is the common notion behind the definition of sophistication of human language, strategic thinking in games, and, arguably, ToM. Although sophisticated ToM is believed to have high adaptive fitness, broad experimental evidence from behavioural economics, experimental psychology and linguistics point towards limited recursivity in representing other's beliefs. In this work, we test whether such apparent limitation may not in fact be proven to be adaptive, i.e. optimal in an evolutionary sense. First, we propose a meta-Bayesian approach that can predict the behaviour of ToM sophistication phenotypes who engage in social interactions. Second, we measure their adaptive fitness using evolutionary game theory. Our main contribution is to show that one does not have to appeal to biological costs to explain our limited ToM sophistication. In fact, the evolutionary cost/benefit ratio of ToM sophistication is non trivial. This is partly because an informational cost prevents highly sophisticated ToM phenotypes to fully exploit less sophisticated ones (in a competitive context). In addition, cooperation surprisingly favours lower levels of ToM sophistication. Taken together, these quantitative corollaries of the ''social Bayesian brain'' hypothesis provide an evolutionary account for both the limitation of ToM sophistication in humans as well as the persistence of low ToM sophistication levels.

Standard economic theory postulates that individual preferences are stable. However, numerous results from psychology and experimental economics show that human behavior regularly contradicts this fundamental principle. Some factors known to influence value, such as affective context, are not taken into account in economics. Their effects are still considered contingent phenomena - anomalies at the margins of rationality, which as such do not inform theory. Now that brain imaging allows us to formulate and test new hypotheses, we question the contingent character of the influence of context on preferences, with the idea that these "biases" would result from properties inherent to the physical structure that generates behavior, namely the brain. Because they reflect the a priori conditions of any value judgment, they are not contingent but necessary, which explains their prevalence. Our first study proves this hypothesis in the case of context biases: we show that the inertia of brain activity combined with the automaticity of evaluation explains the effects of context on value in monkeys and humans. Our second study shows that trust is encoded in the same brain region as value, suggesting that the can be understood as a second-order value judgment. Finally, our third study shows a behavioral attribution bias leading to interference between value and trust, which was predicted by the combination of results from the first and second studies.

Designed to promote multidisciplinary fundamental research, the Action Concertée Incitative Ville (ACIV) created by the French Ministry of Research aimed to renew the issues at stake in order to better understand contemporary urban issues, the transformations underway and to anticipate future developments. This book provides an inventory of the research supported during the four years of ACIV programming. The two volumes bring together 143 contributions from "established" teams, "young" researchers, and doctoral students, demonstrating the abundance and richness of themes, issues, methods, and fields. These contributions, which report on research financed by ACIV and the thesis grants it has supported, are organized around six themes: "Urban Forms, Cultures and Modes of", "Social and Civic Cohesion", "Changes in Scale, Recomposition of Territorial Systems and", "Urbanistic Cultures": from the sources of urban history to sustainable urban development", "Physical Environments, Urban Environments and", "Management, Management and Technical Systems". The postface opens up a critical and prospective reflection "for several" on the future of urban research.

This paper tests whether individual perceptions of markets as good or bad for a public good is correlated with the propensity to report gaps in willingness to pay and willingness to accept revealed within an incentive compatible mechanism. Identifying people based on a notion of market affinity, we find a substantial part of the gap can be explained by controlling for some variables that were not controlled for before. This result suggests the valuation gap for public goods can be reduced through well-defined variables.

Today's there is no doubt on the benefits of education. The life without it is impossible in the majority of societies. Schooling is not an option any more. it is a "Must" in many modern societies. The benefits of education are also known to the majority of people and they know that more education means better preparation for future life. Governments also have recognized that there are a lot of benefits and positive externalities in public education and almost in all countries there is a level of compulsory education which children should attend school up to a special level. As there is no doubt on the importance and benefits of education for societies we do not try to prove it here. What we would like to do is to find a costless, easy to implement, and psychologi¬cally acceptable mechanism to improve students' performance in their current situation. This mechanism should be designed carefully as children, especially girls, are so sensitive to the design (Croson and Gneezy 2009) and with a small change we would not achieve the desired goal. Of course after such a design it should be tested in real world to see whether it works or not.

This work studies the preference for power, from its definition to its encounter in the laboratory or in the field, in an experimental way. We build this thesis around three questions: what is power and the preference for power? How to identify it, distinguishing it from other types of social preferences? What are the elements, conditions of experiences or subjects' situation, that affect it? We define power as a dispositional capacity, which can be applied or not. This allows us to define then the notion of preference for power, which is nothing else than a formalized version of the will to power that we meet since antiquity. We then define four types of preference: pure or instrumental preference for potential or effective power. In the second part we build a model of power that we test in the laboratory. We identify this preference for power in its four aspects, which is the central result of this work. We then seek to understand what impacts this preference, to observe that only gender has a significant effect. Finally, we measure this preference, to find that there may be a significant correlation between pure preference for potential and actual power. The third part aims at studying these power preference behaviors among decision makers in the synthetic world of Eve Online, which we observe to be a good substitute for the laboratory. In a counterintuitive way, our observations show that the decision-makers in the virtual world do not show more preference for power than the other subjects.

This thesis focuses on a particular explanation for the glass ceiling effect faced by women in the labor market: a gender difference in preference for competition. The experimental approach adopted here allows to control for a number of factors that influence competitive behavior and that are impossible to disentangle by observing the labor market. The first chapter deals with overconfidence and proposes several incentives to reduce this cognitive bias. The second chapter studies the effect of team competition on the male-female difference in liking for competition. While women are no more attracted to team competition than to individual competition, men shun team competition while they used to massively enter individual competition. The main reason for men's disaffection with team competition is their fear of being associated with a less successful teammate. The effect of group identity on competitive behavior is discussed in the third chapter. Women's willingness to compete is not significantly affected by group membership while men become more likely to enter the tournament as a team without knowing the quality of their teammate. They therefore make decisions that benefit their group even if it means increasing the risk of being associated with an underperforming teammate.