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When scientists are asked to give expert advice on risk-related questions, such as the authorization of medical drugs, deliberation often does not eliminate all disagreements. I propose to model these remaining discrepancies as differences in risk assessments and/or in risk acceptability thresholds. The normative question I consider, then, is how the individual expert views should best be aggregated. I discuss what \"best\" could mean, with an eye to some robustness considerations. I argue that the majority rule, which is currently often used in expert panels, has significant drawbacks.

Epistemic accounts of scientific collaboration usually assume that, one way or another, two heads really are more than twice better than one. We show that this hypothesis is unduly strong. We present a deliberately crude model with unfavorable hypotheses. We show that, even then, when the priority rule is applied, large differences in successfulness can emerge from small differences in efficiency, with sometimes increasing marginal returns. We emphasize that success is sensitive to the structure of competing communities. Our results suggest that purely epistemic explanations of the efficiency of collaborations are less plausible but have much more powerful socioepistemic versions.

A part of the scientific literature consists of intermediate results within a longer project. Scientists often publish a first result in the course of their work, while aware that they should soon achieve a more advanced result from this preliminary result. Should they follow the proverb \"a bird in the hand is worth two in the bush\", and publish any intermediate result they get? This is the normative question addressed in this paper. My aim is to clarify, to refine, and to assess informal arguments about the choice whether to publish intermediate results. To this end, I adopt a rational decision framework, supposing some utility or preferences, and I propose a formal model. The best publishing strategy turns out to depend on the research situation. In some simple circumstances, even selfish and short-minded scientists should publish their intermediate results, and should thus behave like their altruistic peers, i. e. like society would like them to behave. In other research situations, with inhomogeneous reward or difficulty profiles, the best strategy is opposite. These results suggest qualified philosophical morals.

In many countries, private health insurance companies are allowed to vary their premiums based on some information on individuals. This practice is intuitively justified by the idea that people should pay the premium corresponding to their own known risk. However, one may consider this as a form of discrimination or wrongful differential treatment. Our goal in this paper is to assess whether profiling is ethically permissible in health insurance. We go beyond the existing literature in considering a wide range of parameters, be they genetic, non-genetic, or even non-medical such as age or place of living. Analyzing several ethical concerns, and tackling the difficult question of responsibility, we argue that profiling is generally unjust in health insurance.

Human agents happen to judge that a conjunction of two terms is more probable than one of the terms, in contradiction with the rules of classical probabilities—this is the conjunction fallacy. One of the most discussed accounts of this fallacy is currently the quantum-like explanation, which relies on models exploiting the mathematics of quantum mechanics. The aim of this paper is to investigate the empirical adequacy of major quantum-like models which represent beliefs with quantum states. We first argue that they can be tested in three different ways, in a question order effect configuration which is different from the traditional conjunction fallacy experiment. We then carry out our proposed experiment, with varied methodologies from experimental economics. The experimental results we get are at odds with the predictions of the quantum-like models. This strongly suggests that this quantum-like account of the conjunction fallacy fails. Future possible research paths are discussed.

Deliberative and decisional groups play crucial roles in most aspects of social life. But it is not obvious how to organize these groups and various socio-cognitive mechanisms can spoil debates and decisions. In this paper we focus on one such important mechanism: the misrepresentation of views, i.e. when agents express views that are aligned with those already expressed, and which differ from their private opinions. We introduce a model to analyze the extent to which this behavioral pattern can warp deliberations and distort the decisions that are finally taken. We identify types of situations in which misrepresentation can have major effects and investigate how to reduce these effects by adopting appropriate deliberative procedures. We discuss the beneficial effects of (i) holding a sufficient number of rounds of expression of views; (ii) choosing an appropriate order of speech, typically a random one; (iii) rendering the deliberation dissenter-friendly; (iv) having agents express fined-grained views. These applicable procedures help improve deliberations because they dampen conformist behavior, give epistemic minorities more opportunities to be heard, and reduce the number of cases in which an inadequate consensus or majority develops.

In classical probability theory, the probability of the conjunction of two events is smaller than the probability of only one of these events. Yet, agents do not always empirically judge in this way: this is the traditional conjunction fallacy. One of the currently promising accounts of this paradox relies on so-called quantum-like models, which have been developed from mathematical tools used in quantum theory. But are these models empirically adequate? Which versions of these models can be used? In particular, can the simplest versions, the non-degenerate ones, be sufficient? We propose here an original experimental protocol to test the quantum-like models for the conjunction fallacy in the lab. The results we obtain suggest that the non-degenerate models are not empirically adequate, and that future research on quantum-like models should consider degenerate ones. Classification JEL  : C60, C91, D03.

La théorie classique des probabilités requiert que la probabilité de la conjonction de deux événements soit inférieure à la probabilité d’un des événements seul. Or les sujets ne jugent empiriquement pas toujours ainsi : c’est la traditionnelle erreur de conjonction. L’une des explications actuellement prometteuses de ce paradoxe repose sur des modèles dits quantiques, développés à partir des outils mathématiques de la mécanique quantique. Mais ces modèles sont-ils empiriquement adéquats ? Quelles versions de ces modèles peuvent être employées ? En particulier, les versions les plus simples, dites non dégénérées, peuvent-elles être suffisantes ? Nous proposons ici un protocole expérimental original pour tester en laboratoire les modèles quantiques de l’erreur de conjonction. Les résultats obtenus suggèrent que les modèles non dégénérés ne sont pas empiriquement adéquats, et que la recherche future concernant les modèles quantiques devrait s’orienter vers les modèles dégénérés. A new experimental approach to test quantum-like models for the conjunction fallacyIn classical probability theory, the probability of the conjunction of two events is smaller than the probability of only one of these events. Yet, agents do not always empirically judge in this way: this is the traditional conjunction fallacy. One of the currently promising accounts of this paradox relies on so-called quantum-like models, which have been developed from mathematical tools used in quantum theory. But are these models empirically adequate? Which versions of these models can be used? In particular, can the simplest versions, the non-degenerate ones, be sufficient? We propose here an original experimental protocol to test the quantum-like models for the conjunction fallacy in the lab. The results we obtain suggest that the non-degenerate models are not empirically adequate, and that future research on quantum-like models should consider degenerate ones.Classification JEL  : C60, C91, D03.

Human agents happen to judge that a conjunction of two terms is more probable than one of the terms, in contradiction with the rules of classical probabilities---this is the conjunction fallacy. One of the most discussed accounts of this fallacy is currently the quantum-like explanation, which relies on models exploiting the mathematics of quantum mechanics. The aim of this paper is to investigate the empirical adequacy of major quantum-like models which represent beliefs with quantum states. We first argue that they can be tested in three different ways, in a question order effect configuration which is different from the traditional conjunction fallacy experiment. We then carry out our proposed experiment, with varied methodologies from experimental economics. The experimental results we get are at odds with the predictions of the quantum-like models. This strongly suggests that this quantum-like account of the conjunction fallacy fails. Future possible research paths are discussed.