University of Mannheim

About: University of Mannheim is a education organization based out in Mannheim, Germany. It is known for research contribution in the topics: Context (language use) & Politics. The organization has 4448 authors who have published 12918 publications receiving 446557 citations. The organization is also known as: Uni Mannheim & UMA.

Overconfidence of Professionals and Lay Men : Individual Differences Within and Between Tasks?

Abstract: Overconfidence can manifest itself in various forms. For example, people think that their knowledge is more precise than it really is (miscalibration) and they believe that their abilities are above average (better than average effect). The questions whether judgment biases are related or whether stable individual differences in the degree of overconfidence exist, have long been unexplored. In this paper, we present two studies that analyze whether professional traders or investment bankers who work for international banks are prone to judgment biases to the same degree as a population of lay men. We examine whether there are robust individual differences in the degree of overconfidence within various tasks. Furthermore, we analyze whether the degree of judgment biases is correlated across tasks. Based on the answers of 123 professionals, we find that expert judgment is biased. In most tasks, their degrees of overconfidence are significantly higher than the respective scores of a student control group. In line with the literature, we find stable individual differences within tasks (e.g. in the degree of miscalibration). However, we find that correlations across distinct tasks are sometimes insignificant or even negative. We conclude that some manifestations of overconfidence, that are often argued to be related, are actually unrelated.

Estimation of Hüsler–Reiss distributions and Brown–Resnick processes

Abstract: Summary Estimation of extreme value parameters from observations in the max-domain of attraction of a multivariate max-stable distribution commonly uses aggregated data such as block maxima. Multivariate peaks-over-threshold methods, in contrast, exploit additional information from the non-aggregated ‘large’ observations. We introduce an approach based on peaks over thresholds that provides several new estimators for processes η in the max-domain of attraction of the frequently used Husler–Reiss model and its spatial extension: Brown–Resnick processes. The method relies on increments η(·)−η(t0) conditional on η(t0) exceeding a high threshold, where t0 is a fixed location. When the marginals are standardized to the Gumbel distribution, these increments asymptotically form a Gaussian process resulting in computationally simple estimates of the Husler–Reiss parameter matrix and particularly enables parametric inference for Brown–Resnick processes based on (high dimensional) multivariate densities. This is a major advantage over composite likelihood methods that are commonly used in spatial extreme value statistics since they rely only on bivariate densities. A simulation study compares the performance of the new estimators with other commonly used methods. As an application, we fit a non-isotropic Brown–Resnick process to the extremes of 12-year data of daily wind speed measurements.

Inequality and happiness: When perceived social mobility and economic reality do not match

Abstract: We argue that perceived fairness of the income generation process affects the association between income inequality and subjective well-being, and that there are systematic differences in this regard between countries that are characterized by a high or, respectively, low level of actual fairness. Using a simple model of individual labor market participation under uncertainty, we predict that high levels of perceived fairness cause higher levels of individual welfare, and lower support for income redistribution. Income inequality is predicted to have a more favorable impact on subjective well-being for individuals with high fairness perceptions. This relationship is predicted to be stronger in societies that are characterized by low actual fairness. Using data on subjective well-being and a broad set of fairness measures from a pseudo micro-panel from the WVS over the 1990–2008 period, we find strong support for the negative (positive) association between fairness perceptions and the demand for more equal incomes (subjective well-being). We also find strong empirical support for the predicted differences in individual tolerance for income inequality, and the predicted influence of actual fairness.

Modelling Navigational Knowledge by Route Graphs

Abstract: Navigation has always been an interdisciplinary topic of research, because mobile agents of different types are inevitably faced with similar navigational problems. Therefore, human navigation can readily be compared to navigation in other biological organisms or in artificial mobile agents like autonomous robots. One such navigational strategy, route-based navigation, in which an agent moves from one location to another by following a particular route, is the focus of this paper. Drawing on the research from cognitive psychology and linguistics, biology, and robotics, we present a simple, abstract formalism to express the key concepts of route-based navigation in a common scientific language. Starting with the distinction of places and route segments, we develop the notion of a route graph, which can serve as the basis for complex navigational knowledge. Implications and constraints of the model are discussed along the way, together with examples of different instantiations of parts of the model in different mobile agents. By providing this common conceptual framework, we hope to advance the interdisciplinary discussion of spatial navigation.