Cognitive rationality and alternative belief measures

In this article, we first examine the various criticisms of the probabilistic model. Then we introduce capacities in order to show that if a probability measure corresponds to anesthetizing the belief of the agent's knowledge, it is then possible to suggest another type of rationality—namely, being able to describe a wise and a rash behavior when facing risk—and therefore another model of belief under uncertainty. While trying to specify various alternative measures, possibility, necessity, and measures resulting from a triangular norm or from a triangular conorm, we finally try to define the field of application of the probabilistic model as well as a sign of the rationality choice: constraint of mass-unity for traditional rationality, and constraint of duality for the one we present.This article is a revised version of a paper presented during the FUR V Congress, Duke University, North Carolina, USA, June 10–13, 1990. I am indebted to Bertrand Munier, Alain Chateauneuf, Olivier Favereau, Jacques-François Thisse, Bernard Walliser, and Kip Viscusi for helpful comments on earlier versions of this article.     

Self-Employment and Immigrants' Incorporation: The Case of Turks in Germany

This essay discusses the impact of self-employment on immigrants' incorporation in the host society. It focuses on empirical material coming from Turkish migrants' business activities in Germany. After introducing the main features of contemporary German-Turkish entrepreneurship, the essay presents its socio-economic and cultural consequences for the Turkish minority. Relying on the numerous debates that can be found in the literature, it argues that this impact is ambivalent. In some cases, business ownership may constitute a way of achieving upward social mobility and a path towards a harmonious and pluralistic integration. But it is also frequently a reaction to disadvantage that fosters immigrants' socio-professional vulnerability and that may then lead to ghettoization. The essay then attempts to understand the reasons behind these divergent interpretations and suggests that they lie in the intermediary nature of trade, which is an activity that may connect people from different backgrounds but only in a limited way. Ethnographic observations and the concept of ‘plural societies’ are used to address this aspect of business. The conclusion suggests that, given the globally inferior position of Turkish immigrants, business might not be enough to enable them to catch up.     

Impaired Metacognitive Capacities in Individuals with Problem Gambling

Impaired insight into behavior may be one of the clinical characteristics of pathological gambling. In the present study, we tested whether the capacity to evaluate accurately the quality of one’s own decisions during a non-gambling task was impaired in problem gamblers. Twenty-five problem gamblers and 25 matched healthy participants performed an artificial grammar-learning paradigm, in which the quality of choice remains uncertain throughout the task. After each trial of this task, participants had to indicate how confident they were in the grammaticality judgements using a scale ranging from 1 (low confidence) to 7 (high confidence). Results showed that (i), problem gamblers’ performance on the grammaticality test was lower than controls’; (ii) there was a significant correlation between grammaticality judgments and confidence for control participants, which indicates metacognitive insight and the presence of conscious knowledge; (iii) this correlation was not significant in problem gamblers, which suggests a disconnection between performance and confidence in this group. These findings suggest that problem gamblers are impaired in their metacognitive abilities on a non-gambling task, which suggests that compulsive gambling is associated with poor insight as a general factor. Clinical interventions tailored to improve metacognition in gambling could be a fruitful avenue of research in order to prevent pathological gambling.     

Un critère de choix de variables en analyse en composantes principales fondé sur des modèles graphiques gaussiens particuliers

We focus on the problem of selection of a subset of the variables so as to preserve the multivariate data structure that a principal-components analysis of the initial variables would reveal. We propose a new method based on some adapted Gaussian graphical models. This method is then compared with those developed by Bonifas et al. (1984) and Krzanowski (1987a, b). It appears that the criteria for all methods consider the same correlation submatrices and often lead to similar results. The proposed approach offers some guidance as to the number of variables to be selected. In particular, Akaike's information criterion is used.     

Aggregation of preferences: The fuzzy case

The basic purpose of this paper is to link both theorems of impossibility and existence by introducing fuzzy relations of preference and an exogeneous requirement, the planner's one, and then proving the fundamental part played by the extremist agents, leximin and leximax. In other words, to bring out the link between the planner's requirement and the difficulty of the transition from individual to collective, as well as the theoric relation between this requirement and the extremist agents, we define a fuzzy behavior of preference which allows us to build up two determinant fuzzy coalitions. These coalitions will be the base of the planner's requirement and the link between pessimistic results (Arrow's impossibility) and optimistic ones (May's theorem of majority choice).     

Improving quality of life after breast cancer: prevention of other diseases

Many women with breast cancer will be diagnosed at an early stage through screening programmes. Furthermore, most women affected by breast cancer will not die from it but from other diseases, owing to recent improvements in treatment. This article assesses whether breast cancer survivors suffer more frequently from other diseases. Specifically, it examines whether they have a higher incidence of other cancers, cardiovascular events and osteoporotic fractures. Women with breast cancer and three or more co-morbid conditions have a 20-fold higher rate of mortality from causes other than breast cancer and a 4-fold higher rate of all-cause mortality when compared with patients who have none. Breast cancer survivors are at increased risk of other cancers, such as stomach, colorectal and lung. Radiotherapy, trastuzumab and aromatase inhibitors increase the risk of cardiovascular disease. However, tamoxifen does not, although it is associated with an increased risk of venous thromboembolism. Aromatase inhibitors, but not tamoxifen, increase the risk of osteoporotoic fracture and bisphosphonate therapy should be considered.     

Is a Brownian Motion Skew?

We study the asymptotic behaviour of the maximum likelihood estimator corresponding to the observation of a trajectory of a skew Brownian motion, through a uniform time discretization. We characterize the speed of convergence and the limiting distribution when the step size goes to zero, which in this case are non‐classical, under the null hypothesis of the skew Brownian motion being an usual Brownian motion. This allows to design a test on the skewness parameter. We show that numerical simulations can be easily performed to estimate the skewness parameter and provide an application in Biology.     

RISK AVERSION AND PLANNING HORIZONS

A number of empirical studies seem to reject the additive separability of preferences that is assumed in most theoretical models of the life cycle. We show that, when additive separability is abandoned and interactions between consumptions at different dates are taken into account, an interesting relation emerges between risk aversion and length of the planning horizon. Specifically, we show that when consumptions at different dates are specific substitutes, risk aversion increases with horizon length. This may explain the surprising empirical finding that individuals seem to increase the share of wealth held in risky assets as they become older. (JEL: D11, D91, G11)     

The Management of Redundancies in Europe: The Case of the Netherlands

The paper presents the findings of comparative and interdisciplinary legal and economic study on managing labour redundancies in seven EU member countries. It is structured for comparability between the systems examined. The introductory section contains an account of the evolution of the Dutch labour market, with special reference to redundancy trends, of the features of the programmes for managing redundancies, of the roles of firms and the ‘external environment’ in handling workforce adjustments. The second section presents a map of policies that work to prevent labour redundancies (preventive measures) such as flexibility, training etc. Next, the instruments for handling temporary labour redundancies (retentive measures) are examined (e.g. short-time working, temporary layoffs etc.). The following section is devoted to instruments and programmes involved in the management of permanent labour redundancies (expulsive measures), e.g. collective dismissals, severance pay etc. The final section provides an overall assessment of the Dutch system for managing labour redundancies, and briefly discusses the national debate on the prospects for reform, in light of the principles and policies of convergence set forth by the European Union.     

Who Wins and Who Loses? Public Transfer Accounts for US Generations Born 1850 to 2090

Public transfer programs in industrial countries are thought to benefit the elderly through pension and health care programs at the expense of the young and future generations. This intergenerational picture changes, however, if public education is also considered as a transfer program. We calculate the net present value at birth of benefits received minus taxes paid for US generations born 1850 to 2090. Surprisingly, all generations 1950 to 2050 are net gainers, while many current elderly are net losers. Windfall gains from starting Social Security and Medicare partially offset windfall losses from starting public education, roughly consistent with the arguments of Becker and Murphy.