Common marmosets (<Emphasis Type="Italic">Callithrix jacchus</Emphasis>) do not utilize social information in three simultaneous social foraging tasks

Social foraging is suggested to increase foraging efficiency, as individuals might benefit from public information acquired by monitoring the foraging activities of other group members. We conducted a series experiments with captive common marmosets (Callithrix jacchus) to investigate to what extent marmosets utilize social information about food location when foraging simultaneously with conspecifics. Subjects were confronted with dominant and subordinate demonstrators in three experiments which differed in the amount of information about food location available to the demonstrators. In all three experiments, the focal subjects’ performance in the social condition was not enhanced in comparison to a non-social control condition. Because we could rule out kleptoparasitism and aggressive displacements as explanations, we argue that the subjects’ tendency for scramble competition by avoiding others and dispersing over the foraging area seems to inhibit or mask the acquisition of social information about the location of rewarded patches.     

A Bayesian Semiparametric Latent Variable Model for Mixed Responses

In this paper we introduce a latent variable model (LVM) for mixed ordinal and continuous responses, where covariate effects on the continuous latent variables are modelled through a flexible semiparametric Gaussian regression model. We extend existing LVMs with the usual linear covariate effects by including nonparametric components for nonlinear effects of continuous covariates and interactions with other covariates as well as spatial effects. Full Bayesian modelling is based on penalized spline and Markov random field priors and is performed by computationally efficient Markov chain Monte Carlo (MCMC) methods. We apply our approach to a German social science survey which motivated our methodological development. We thank the editor and the referees for their constructive and helpful comments, leading to substantial improvements of a first version, and Sven Steinert for computational assistance. Partial financial support from the SFB 386 “Statistical Analysis of Discrete Structures” is also acknowledged.     

Levels of Emotional Awareness Scale (LEAS)

Guided by the idea that alexithymia and other psychopathological phenomena are connected with decreased sensitivity to internal emotional states, Lane and Schwartz (1987) presented a cognitive-developmental theory describing different “Levels of Emotional Awareness”. In 1990, Lane et al. developed a performance measure to identify different states of sensivity to internal emotional states, the “Levels of Emotional Awareness Scale” (LEAS). Subjects are asked to describe anticipated own feelings and those of another person in 20 scenes in a short written answer. We present the results of a study using the German version of the LEAS, the 20-item-version of the Toronto Alexithymia-Scale (TAS 20) and the state-version of the State-Anxiety-Inventory (STAI) on 338 Students of medicine of the Cologne university. The study is discussed with regard to a similar study conducted in the USA (Lane et al. 1996). Theoretical background and psychometric charateristics of the LEAS are related to actual trends in research on alexithymia.     

Effects of cognitive heuristics and goals on negotiator performance and subsequent goal setting

The purpose of this study was to examine the effects of a situational constraint —an externally set goal — and related cognitive variables — outcome expectancies, perceived self-competency, and goal commitment — on the performance and goal setting of 79 novice negotiators. Expectancy judgments affected goal commitment but not performance or goal choice. Subjects assigned difficult goals were more profitable and set harder new goals than subjects assigned easier goals. Machiavellianism had a powerful effect on performance and exerted more causal influence on self-set goals than actual performance or prior goals. Unexpectedly, role assignment proved to be an important determinant of performance. A decision science perspective was utilized to explain the results.     

Facet theory applied to the construction and validation of the Aachen Aphasia Test

The linguistic performance of 120 aphasic patients of the four standard syndromes assessed by the Aachen Aphasia Test (AAT) is analyzed by a nonmetric (ordinal) multidimensional scaling procedure (Smallest Space Analysis, SSA1). The linguistic structure of the test items is characterized within the framework of L. Guttman's facet theory. Three systematic components (facets) are discerned: linguistic modality, unit, and regularity. Properties of the facets as well as their relations are assessed and tested empirically by analyzing the interrelations among different items or sets of items. The spatial configurations obtained by the scaling procedure fit only partially the expectations derived from the facet-theory model. The modality facet was found to have a strong overriding influence on the aphasic test performance. The facets unit and regularity were only found for the most rigorously designed subtests, Written Language and Comprehension. The results suggest the introduction of a new combined facet linguistic complexity which reflects the dependency of the facets regularity and unit.     

On progress,values, and Marx

Marx, like many of his contemporaries, uncritically assumed that humanity develops from primitive beginnings to ever more perfect stages. In his theory of human development he measured progress by two main standards: the decrease of all forms of dependence, and the increase of universality in man's relations to nature and to his fellow man. In our century, not only have new structures of power and dependence emerged, but successive movements have also been generated to restore the more ordered and limited relationships of the past. If belief in progress is nowadays no longer self-evident, such a state of affairs can help us reflect on the conditions necessary to realize the values which determined Marx's categorical imperative, or his insistence that we overthrow all relations by which man is made a debased and enslaved being. One of these conditions is the voluntary limitation of our needs: the need to use material goods without regard for others, the need to build up or maintain security even at the cost of violence, and the need to restrict the circle of those with whom we identify to our own particular culture, race, class or ways of thinking and acting.