Mimetic contagion and speculative bubbles

Conclusion The present essay has focused on specularity as a type of intersubjectivitywithin self-referential systems. We have stressed the self-organizationaldimension of specular processes, which lead to the emergenceof collective objects around which the group structures itself. Rationalbubbles, sunspots, and conventions provided us with examples of thiskind of self-organization within self-referential groups. It seems thatwe have here a theoretical schema that can account for numeroussocial institutions. Such is the case with money, which the overlappinggenerations model shows to belong to the same problematic. We haveobserved that individual and collective representations play an essentialrole in the definition of specular dynamics. In fact, giving thecollectivity a means of interpreting and understanding the natural andsocial environment is a crucial function of these representations. Inspite of its great importance, this cognitive dimension of collectiverepresentations has hardly been explored in previous theorizing. Wehave given priority to a specific form of specularity, namely, mimetism,which is in our view at the very heart of financial processes. Far frombeing the aberration that traditional approaches deem it to be, imita-tion is one of the most important types of rationality in situations ofuncertain and in situations where the agents' outcomes are highlyinterdependent. Our central hypothesis amounts to considering thatthe emergence of speculative bubbles on various kinds of markets canbe explained in terms of mimetic dynamics. Should this hypothesis beconfirmed, it would be possible to account for a phenomenon that isoften observed, namely, the link between bubbles and a decrease inthe diversity of opinion on the market. In our approach, conventionsare taken to be the outcome of a mimetic process. Conventions are thesocial objects created by a unanimous mimetic polarization.     

Bivariate income distributions with lognormal conditionals

In this paper, the most general bivariate distribution with lognormal conditionals is fully characterized, using the methodology proposed by [3]. The properties of the new family are studied in detail, including marginal and conditional distributions, regression functions, dependence measures, moments and inequality measures. The new distribution is very broad, and contains as a particular case the classical bivariate lognormal distribution. Several subfamilies are studied and a generalization of the basic model is discussed. Finally, we present an empirical application. We estimate and compare the basic model proposed in the paper with a classical model, using data from the European Community Household Panel in different periods of time.     

Will They Ever Converge? Earnings of Immigrant and Canadian-born Workers over the Last Two Decades1

Using Census data covering the 1980–2000 period, this article examines what outcomes would be necessary for today's recent immigrant cohorts to achieve earnings parity with Canadian‐born workers. Our results show that today's recent immigrants would have to experience a drastic steepening of their relative age‐earnings profile in the near future for their earnings to converge with their Canadian‐born counterparts. The reason is simple: the greater relative earnings growth experienced by recent immigrant cohorts has only partially offset the drastic deterioration in their relative earnings at entry.     

Emotional displays in children's television programming

The facial expressions of emotion and the circumstances under which the expressions occurred in a sample of the most popular children's television programs were investigated in this study. Fifteen-second randomly selected intervals from episodes of five television programs were analyzed for displays of happiness, sadness, anger, fear, disgust, and surprise. In addition, the contexts in which the emotions occurred were examined. Results indicated that particular emotional expressions occurred at significantly different frequencies and that there was an association between emotional displays and emotion-contexts. The high rate of emotional displays found in television shows has implications for the development of knowledge regarding emotional display rules in viewers.We are grateful to Sharon Galligan for assistance in coding part of the data and to Carolyn Saarni and Amy Halberstadt for helpful comments on an earlier draft of this paper. This research was supported in part by a grant from the National Institute of Disabilities and Rehabilitation Research, #GOO85351. The opinions expressed herein do not necessarily reflect the position or policy of the U.S. Department of Education.     

Control charts for monitoring the median in non-negative asymmetric data

Statistical Methods & Applications - Control charts are commonly used for monitoring the mean of processes. However, there are practical applications in which asymmetric data are the standard....     

Unconstrained parametrizations for variance-covariance matrices

The estimation of variance-covariance matrices through optimization of an objective function, such as a log-likelihood function, is usually a difficult numerical problem. Since the estimates should be positive semi-definite matrices, we must use constrained optimization, or employ a parametrization that enforces this condition. We describe here five different parametrizations for variance-covariance matrices that ensure positive definiteness, thus leaving the estimation problem unconstrained. We compare the parametrizations based on their computational efficiency and statistical interpretability. The results described here are particularly useful in maximum likelihood and restricted maximum likelihood estimation in linear and non-linear mixed-effects models, but are also applicable to other areas of statistics.     

Slack-variable models versus Scheffé's mixture models

Slack-variable models are compared against Scheffé's polynomial model for mixture experiments. The notion of model equivalence and the use of various diagnostic measures provide effective tools in making such comparisons, particularly when the experimental region is highly constrained. It is demonstrated that the choice of the best fitting model, through variable selection, depends on which mixture component is selected as a slack variable, and on the size of the fitted model. In addition, the equivalence of two well-known representations of a complete mixture model is shown to be valid. Two numerical examples are presented.     

Remaining childless in affluent economies: a comparison of France, West Germany, Italy and Spain, 1994–2001 Rester sans enfant dans des sociétés d'abondances: une comparaison de la France, l'Allemagne de l'Ouest et l'Espagne, 19994–2001

This article explores why women delay childbearing and increase their likelihood to remain childless in Spain, Italy, West Germany and France. We take a macro–micro perspective and show that national institutions influence women’s life transitions, in particular partnership and motherhood. For coupled women, we find two alternative modes out of childlessness. In countries with high direct and indirect child costs, like Spain and Italy, entering a male-breadwinner couple or occupying a stable and high-income position facilitates motherhood, while in the French context motherhood is most likely in a dual-earner partnership.