Adequate Moods for Non-EU Decision Making in a Sequential Framework

In a dynamic (sequential) framework, departures from the independence axiom (IND) are reputed to induce violations of dynamic consistency (DC), which may in turn have undesirable normative consequences. This result thus questions the normative acceptability of non expected-utility (non-EU) models, which precisely relax IND. This paper pursues a twofold objective. The main one is to discuss the normative conclusion: we show that usual arguments linking violations of DC to departures from IND are actually based on specific (but usually remaining implicit) assumptions which may rightfully be released, so that it is actually possible for a non-EU maximizer to be dynamically consistent and thus avoid normative difficulties. Our second objective is to introduce a kind of 'reality principle' (through two other evaluation criteria) in order to mitigate the normative requirement when examining adequate moods for non-EU decision making.Non-expected utility, sequential choice, dynamic consistency, money pump, consequentialism.

The shape of the utility function under risk in the loss domain and the "ruinous losses" hypothesis: some experimental results

This paper reports some preliminary experimental results as regards the shape of the utility function for losses when elicited over a wide interval of consequences. Individual utility functions are elicited using the trade-off method, which, unlike standard elicitation procedures, is robust to probability weighting (and avoids most cognitive biases). Even though most utility functions exhibit the usual convex shape, nearly 25% of them appear to be inverse-S shaped, with convexity over moderate losses changing to concavity as losses grow. Though not conclusive (due mainly to the small size of our subject pool), this result brings some new support to the old idea that ruinous or unacceptable losses may induce some abrupt change in the shape of the utility function. Most importantly, it paves the way for more systematic investigation of the "ruinous losses" hypothesis.utility under risk, large losses, ruin, trade-off method, individual decision making under risk

Cooperation, the power of a single word. Some experimental evidence on wording and gender effects in a Game of Chicken

Wording has been widely shown to affect decision making. In this paper, we investigate experimentally whether and to what extent, cooperative behaviour in a Game of Chicken may be impated by a very basic change in the labelling of the strategies. Our within-subject experimental design involves two treatments. The only difference between them is that we introduce either a socially-oriented wording (‘I cooperate'/‘I do not cooperate') or colours (red/blue) to designate strategies. The level of cooperation appears to be higher in the socially-oriented context, but only when the uncertainty as regards the type of the partner is manipulated, and especially among females.Social dilemma, Game of Chicken, cooperation, wording effects, gender effects.

Metal oxides for efficient infrared to visible upconversion

Upconversion phosphor materials are attracting considerable attention for their possible applications in solar cells with improved efficiency, nanomaterials for bio-imaging, lasers and novel display technologies. Upconversion materials, usually consisting of crystals doped with lanthanide ions, can convert low-energy incident radiation into higher energy emitted radiation. Several mechanisms are involved, including multiple photon absorption and energy transfers between dopants. Up to now, reported upconversion efficiencies have been relatively low, excitation thresholds quite high, and the investigated phosphors (generally fluorides) often presented poor chemical stability (hygroscopy), limiting their industrial applicability. In this dissertation, we investigate the upconversion luminescence characteristics of rareearth-doped RE2BaZnO5 (RE = Y, Gd) phosphors, for near-infrared to visible upconversion. Being oxides, these materials have good chemical, thermal and mechanical properties. A variety of dopants, including Yb3+, Er3+, Ho3+ and Tm3+, were embedded in the host lattice, resulting in bright red, green, blue and white light emissions under 980 nm excitation and at relatively low excitation powers. Upconversion efficiencies up to ~ 5.2%, 2.6%, 1.7% and 0.3% were respectively achieved in samples doped with Yb3+, Er3+ (green and red emission), Yb3+, Ho3+ (green emission), Yb3+, Tm3+ (blue and near-infrared emission) and Yb3+, Er3+, Tm3+ (white light emission). We believe that our green, red and white emitting systems are the most efficient upconverting samples reported to date for green, red and white light emission, which makes them serious candidates for many of the applications listed above. The upconversion mechanisms were determined for the first time by means of indepth steady-state and time-resolved spectroscopic investigations, including concentration and power dependence studies associated with temperature-dependent lifetime measurements.Saint-Gobain Recherche, Franc

Comunidades y negocios sociales: hacia una propuesta sistémica

The inability of Economics to internalize environmental and social externalities makes its orientation to serve essentially to remunerate the capital through a debt-based economic growth; thus moving away from its primary goal: a correct distribution of scarce resources in order to satisfy human needs. As a consequence, unless a dramatic change in the path of development is implemented, we are leading it to an abyss. The relocation of economies and lifestyles, linked to the rise of social businesses and to the potential of cooperatives as a way of equitable distribution of wealth, inspires an opportunity to redirect human evolution to the creation of resilience generating wellbeing to tackle the increasing threats that the world is facing. There are hundreds of cases in which communities or neighborhoods are assuming an increasing role in the decisions that affect their own future. The key to an encouraging future might lie in providing these socially and environmentally desirable approaches with economical viability

Expérimentation de laboratoire et économie :<br />Contre quelques idées reçues et faux problèmes

International audienceDespite its increasing use and legitimacy, experimental methodology in economics has been subject to some criticism, an extreme version of which concludes to its irrelevance to its object. With no claim to exhaustiveness, the paper presents and discusses some arguments that we consider to be questionable – because they are suspected to hide either a strategic temptation when facing unpleasant experimental results or a fallacious view of experimental goals and potentialities or even an inadequate approach of economic reality itself – and shows that they are at best locally or partially valid. This allows us to remind the reader of the purposes of the experimental method, of its potentialities and limits as well as of some necessary precautions to adopt.En dépit de son utilisation et de sa légitimité croissantes, l'expérimentation de laboratoire en économie fait parfois l'objet de critiques qui peuvent aller jusqu'à remettre en cause la pertinence de l'outil. Sans prétendre à l'exhaustivité, nous revenons sur ceux de ces arguments qui revêtent selon nous un caractère discutable (parce qu'ils nous semblent selon les cas témoigner soit d'une tentation stratégique face à des résultats expérimentaux considérés comme gênants, soit d'une vision erronée des finalités et potentialités de la démarche, soit encore d'une lecture partielle de la réalité économique elle-même) afin de montrer que leur validité est au mieux locale et partielle. Nous en profitons pour rappeler les finalités de la méthode expérimentale, circonscrire son domaine d'application (i.e. ses potentialités et limites) et indiquer quelques précautions d'utilisation

The shape of the utility function under risk in the loss domain and the 'ruinous losses' hypothesis: some experimental results

International audienceThis paper reports some preliminary experimental results as regards the shape of the utility function for losses when elicited over a wide interval of consequences. Individual utility functions are elicited using the trade-off method, which, unlike standard elicitation procedures, is robust to probability weighting (and avoids most cognitive biases). Even though most utility functions exhibit the usual convex shape, nearly 25% of them appear to be inverse-S shaped, with convexity over moderate losses changing to concavity as losses grow. Though not conclusive (due mainly to the small size of our subject pool), this result brings some new support to the old idea that ruinous or unacceptable losses may induce some abrupt change in the shape of the utility function. Most importantly, it paves the way for more systematic investigation of the "ruinous losses" hypothesis

Adequate Moods for Non-EU Decision Making in a Sequential Framework: A synthetic Discussion

dernière version avant publicationIn a dynamic (sequential) framework, departures from the independence axiom (IND) are reputed to induce violations of dynamic consistency (DC), which may in turn have undesirable normative consequences. This result thus questions the normative acceptability of non expected-utility (non-EU) models, which precisely relax IND. This paper pursues a twofold objective. The main one is to discuss the normative conclusion: we show that usual arguments linking violations of DC to departures from IND are actually based on specific (but usually remaining implicit) assumptions which may rightfully be released, so that it is actually possible for a non-EU maximizer to be dynamically consistent and thus avoid normative difficulties. Our second objective is to introduce a kind of 'reality principle' (through two other evaluation criteria) in order to mitigate the normative requirement when examining adequate moods for non-EU decision making

Expérimentation de laboratoire et économie : contre quelques idées reçues et faux problèmes

En dépit de son utilisation et de sa légitimité croissantes, l’expérimentation de laboratoire en économie fait parfois l’objet de critiques qui peuvent aller jusqu’à la remise en cause de la pertinence de l’outil. Sans prétendre à l’exhaustivité, nous revenons sur ceux de ces arguments qui revêtent selon nous un caractère discutable (parce qu’ils nous semblent selon les cas témoigner soit d’une tentation stratégique face à des résultats expérimentaux considérés comme gênants, soit d’une vision erronée des finalités et potentialités de la démarche, soit encore d’une lecture partielle de la réalité économique elle-même) afin de montrer que leur validité est au mieux locale et partielle. Nous en profitons pour rappeler les finalités de la méthode expérimentale, circonscrire son domaine d’application (c.-à-d. ses potentialités et limites) et indiquer quelques précautions d’utilisation.Despite its increasing use and legitimacy, experimental methodology in economics has been subject to some criticism, an extreme version of which concludes to its irrelevance to its object. With no claim to exhaustiveness, the paper presents and discusses some arguments that we consider to be questionable – because they are suspected to hide either a strategic temptation when facing unpleasant experimental results or a fallacious view of experimental goals and potentialities, or even an inadequate approach of economic reality itself – and shows that they are at best locally or partially valid. This allows us to remind the reader of the purposes of the experimental method, of its potentialities and limits as well as of some basic precautions to adopt