Effect of social organisation on interspecific differences in overmarking behaviour of foals in African equids

Animal Cognition - Overmarking remains an unstudied topic in juvenile mammals. We have previously documented a very high rate of overmarking by foals in four captive African equid species: mountain...     

Correction to: Effects of reward magnitude and training frequency on the learning rates and memory retention of the Port Jackson shark Heterodontus portusjacksoni

Animal Cognition - In the original publication of the article, the Fig. 4 was erroneously published.     

Parental Influence on Students' Educational Choices in the United States and Germany: Different Ramifications—Same Effect?

Despite the historical trend in all Western societies to increase educational participation irrespective of students' social origin, the correlation between parents' education and socio-economic status and the educational outcomes of their offspring remains a rather universal phenomenon. Although comparative studies have consistently found this association in various nations which differ in many ways in their educational systems, little is known about the mechanism behind this effect. Drawing on the assumption that career decision points are the major gateway for social background influences, we assume that similarities, as well as differences in the structure of the correlation between parents' socioeconomic background and students' school success, can be explained. Using two longitudinal data sets from the United States (N=1425) and Germany (N=1755) covering the school careers from Grade 7 to Grade 10, the analyses supported the hypothesis that (a) achievement information is the best predictor of career relevant decisions in both nations, (b) parents' background variables are independent additional predictors of career decision but not for actual learning progress, and (c) the assumed accumulation process of social background influences is more pronounced in the German than in the U.S. school system.     

Satisfiability Testing for Boolean Formulas Using Δ-trees

The tree-based data structure of -tree for propositional formulas is introduced in an improved and optimised form. The -trees allow a compact representation for negation normal forms as well as for a number of reduction strategies in order to consider only those occurrences of literals which are relevant for the satisfiability of the input formula. These reduction strategies are divided into two subsets (meaning- and satisfiability-preserving transformations) and can be used to decrease the size of a negation normal form A at (at most) quadratic cost. The reduction strategies are aimed at decreasing the number of required branchings and, therefore, these strategies allow to limit the size of the search space for the SAT problem.     

The personal-group discrepancy: Is there a common information basis for personal and group judgment?

In contrast to motivational accounts of the personal-group discrepancy, results from this article suggest that the discrepancy is explained by aggregating different sets of comparison outcomes for either personal or group ratings. Results from a longitudinal study with East German (the minority group) and West German (the majority group) samples confirm the personal-group discrepancy and support our approach. First, social comparisons influenced evaluations of economic situation at both group and personal levels. Second, ratings of group versus personal economic situation were based on different sets of comparisons. Third, the mean structure of both sets of comparison outcomes mirrored the personal-group discrepancy. Fourth, an interaction between personal-group discrepancy and group status supported the authors' suggestions-concerning the direction of the discrepancy.     

Comparative analysis of different correction methods for measuring Rod-and-Frame Test performance

A comparative analysis was conducted of five different methods for scoring the Rod-and-Frame Test to examine the convergent validities of each of the five methods with performance on the Embedded Figures Test for a sample of 408 13- to 16-yr.-olds. The scoring methods included the absolute error, the algebraic error, the absolute value of the algebraic error, the frame effect, and an assessment of relative field dependence. Correlations obtained among the five methods and the Embedded Figures Test indicated different patterns for boys and girls. In general, the method which employed the absolute value of the algebraic error yielded the strongest convergent validity coefficients with scores on the Embedded Figures Test and Group Embedded Figures Test for boys (.62 and -.54, respectively), although, for girls, the absolute algebraic error and absolute error both yielded coefficients of .50 with Embedded Figures Test scores and -.46 with Group Embedded Figures Test scores.     

Defense and resistance in the psychoanalytic process

"Defense" and "resistance" are usually regarded as two separate and distinct concepts, the first belonging to psychic functioning in general and the second to therapy, yet this distinction is far from constant. Clinical observations indicate a frequent overlapping of these two mental functions or positions. A patient's behavior may convey the meaning of either or both concepts, and a position or response that one assumes to bespeak resistance may reveal defense instead. This state of affairs may be seen in the analysis of patients with a relatively well-integrated neurotic identity, but its main import is in the analysis of psychosomatic patients and those with severe personality disorders. Insufficient holding experiences during the infancy of these patients do not enable them to develop functional structuralization. Deficient mothering in the first stages of life also prevents the stable differentiation between defense against threats from within and resistance against influence from outside.     

Onset of obsessive-compulsive disorder: premorbid conditions and prodromal phase

This article focuses on the clinical onset of obsessive-compulsive disorder (OCD), specifically addressing the age of onset, gradual and acute onset, and whether there are some types of premorbid conditions or a prodromal phase that predispose individuals to the onset of OCD. Clinical and epidemiological studies have come to different conclusions regarding age at onset as well as regarding differences between the sexes. Data gleaned from research to date have demonstrated a relationship between OCD and obsessive-compulsive personality disorder (OCPD), although OCPD does not appear to be the more prevalent personality disorder among patients with OCD. Preliminary research has suggested that Axis I disorders may predispose individuals to OCD onset; however, the significance of this relationship remains to be clarified. Evidence of the association between OCD and subthreshold obsessive-compulsive syndrome suggests that these disorders lie on a continuum of severity, with some cases developing OCD while others do not.