Dual process theories: A key for understanding the diversification bias?

The diversification bias in repeated lotteries is the finding that a majority of participants fail to select the option offering the highest probability. This phenomenon is systematic and immune to classical manipulations (e.g. monetary rewards). We apply dual process theories and argue that the diversification bias is a consequence of System 1 (automatic, intuitive, associative) triggering a matching response, which fails to be corrected by System 2 (intentional, analytic, rational). Empirically, supporting the corrective functions of System 2 through appropriate contextual cues (describing the task as a statistical test rather than as a lottery) led to a decrease of diversification.

Additional Work,Family Agriculture,and the Birth of a First or a Second Child in Russia at the Beginning of the 1990s

At the beginning of the transition period, many Russian households faced substantial economic hardships and uncertainties. An economic downturn had become one of the major factors responsible for the significant and rapid decline of Russian fertility. However, many households tried to cope with this situation by engaging in multiple income generating activities and the cultivation of food on private plots of land. The question therefore arises whether these activities had a positive impact on fertility decisions. This paper explores the association between additional employment or subsistence measures (second jobs, part-time self-employment, and part-time family agriculture) and the probability to have a first or a second child in Russia during 1990 and the spring of 1993. Data from 966 respondents from the Russian component of the survey Social Stratification in Eastern Europe after 1989: General Population Survey show that activities that generate an additional income were positively associated with the birth of a second child. This is especially the case if these activities produce half of a respondent's or her household's income. The birth of a second child was also positively associated with the fact that a household consumed food that was cultivated by the household itself. However, none of these activities was significantly connected with the birth of a first child.     

Perspectivities in irreducible collineation groups of projective planes,II

Collineation groups of finite projective planes are studied which do not leave invariant any point, line or triangle and contain a non-trivial perspectivity. In many instances the collineation group G can be determined, and it can be proved that the underlying projective plane contains a desarguesian subplane, whose order is related to the order of G. This can be done, because one has rather strong results about the structure of G, in particular about the first terms of a chief series of G. Projective planes are taken here as a suitable testing ground for methods, which can be used for many classes of designs to quickly find new examples and obtain some classification.     

Wie valide sind Selbsteinschätzungen der Empathie?

Despite the relevance of the empathy-construct with regard to social behaviour, only some of the items, which are supposed to assess empathy, are theoretically useful according to Holz-Ebeling and Steinmetz (1995). This study investigates the empirical validity of the theoretically estimated useful items. As validity aspects, connections of the self-estimation with the estimation of empathy by others, with the “objective” measure of the perspective coordination, as well as connections with the self-estimated social competence, uncertainty orientation and the mental health, are investigated. Results show that different dimensions of self-estimation empathy correlate differently with other-estimation and “objective” indicators of perspective-coordination and thereby affirm the multidimensionality of the empathy-construct. As conclusion, the need to validate empathy self-reports using objective measurements is emphasised and possibilities to promote the relevant dimensions of empathy which are important to solve conflicts are developed.     

Bootstrap for generalized linear models

We consider the distribution of the (standardized) ML-estimator of the unknown parameter vector in a Generalized Linear Model with canonical link function. It will be shown that its (parametric) Bootstrap estimator is consistent under the same assumptions needed by Fahrmeir & Kaufmann (1985, 1986) to show its asymptotic normality.