The Causal Chain Problem

This paper addresses a problem that arises when it comes to inferring deterministic causal chains from pertinent empirical data. It will be shown that to every deterministic chain there exists an empirically equivalent common cause structure. Thus, our overall conviction that deterministic chains are one of the most ubiquitous (macroscopic) causal structures is underdetermined by empirical data. It will be argued that even though the chain and its associated common cause model are empirically equivalent there exists an important asymmetry between the two models with respect to model expansions. This asymmetry might constitute a basis on which to disambiguate corresponding causal inferences on non-empirical grounds.

Necessity and Language: In Defence of Conventionalism

Kalhat has forcefully criticised Wittgenstein's linguistic or conventionalist account of logical necessity, drawing partly on Waismann and Quine. I defend conventionalism against the charge that it cannot do justice to the truth of necessary propositions, renders them unacceptably arbitrary or reduces them to metalingustic statements. At the same time, I try to reconcile Wittgenstein's claim that necessary propositions are constitutive of meaning with the logical positivists’ claim that they are true by virtue of meaning. Explaining necessary propositions by reference to linguistic conventions does not reduce modal to non‐modal notions, but it avoids metaphysical accounts, which are incapable of explaining how we can have a priori knowledge of necessity.     

Identification of everyday objects on the basis of silhouette and outline versions

Line drawings of everyday objects were modified into silhouettes by filling-in the complete area enclosed by boundary contours, and outline versions were created by extracting the contours from the silhouettes. A large number of participants was asked to try to identify these silhouette and outline versions in experiment 1. Identifiability ranged from 0% to 100% correct responses with a large range in-between. Several kinds of errors and several reasons for difficulties with identification emerged in our data set. In experiment 2, we compared the original identification rates to those of inverted silhouettes (white figures on a black background), and in experiment 3 we compared the original identification rates of objects with filled-in holes or background parts to those of versions without filling-in. These stimuli and identification norms are useful for additional research on priming and context effects of object identification, neuropsychological deficits of object identification, and all kinds of studies with silhouettes where the role of top down knowledge could be of interest.     

Border Crossings by Immigrants: Legality,Illegality, and Alegality

What happens to the concept of security if legal disorder manifests itself not only as illegal behavior but also as alegal behavior—acts that challenge the very distinction between legality and illegality, as drawn by a political community? Focusing on European immigration policy, this paper examines how the distinction between illegal and alegal acts critically illuminates the relation between collective (in)security and the concept of legal (dis)order. It concludes by arguing that this distinction sheds new light on the systematic relation—and tension—between security, freedom, and justice.     

Social comparison with friends versus non‐friends

This paper investigates whether several aspects of social comparison in school classes differ as a function of the type of relation between the student and his or her target. Participants were 9612 students in the first grade of secondary education in the Netherlands (equivalent to Grade 7 in the US). Results indicated that (1) 78% of the students who had at least one friend also compared with a friend; (2) social comparison with friends was much more often reciprocal than comparison with non‐friends; (3) preferences for upward and downward comparison were less often given by students who compared with friends than students who compared with non‐friends; (4) the similarity in initial performance level between students and their comparison targets was higher when targets were friends; (5) despite these differences, which seem to imply that friends often serve as routine standards whereas non‐friends are more deliberately chosen as comparison targets, it appeared that consequences of social comparison for subsequent performance were about the same for both types of relations. Further findings of this paper suggest that previously found effects of friends' grades on subsequent performance may be explained by social comparison. Copyright © 2007 John Wiley & Sons, Ltd.     

Musiktherapie in der Psychosomatik

It is a long way to the formal recognition of a so-called non-verbal mode of therapy that was long considered only as an additional intervention in complex forms of treatment. A historical overview of the development of music therapy in German psychosomatic medicine is followed by a detailed report of the diversities of present techniques in music therapy. Outcome research shows music therapy to be a richer and more diversified method than one would suppose. On this basis specific indications for the implementation of music therapy in medical settings are identifiable.     

Transitioning between temporary and permanent employment: A two‐wave study on the entrapment,the stepping stone and the selection hypothesis

The present two‐wave study investigates how transitioning between temporary and permanent employment relates to a number of psychological consequences; namely, work engagement, affective organizational commitment, life satisfaction, and turnover intention. We hypothesize that temporary employment associates with unfavourable outcomes when it is a trap (entrapment hypothesis), while no such unfavourable outcomes are expected for those who transition to permanent employment (stepping stone hypothesis). Furthermore, we investigate the assumption that transitioning from permanent to temporary employment relates to unfavourable outcomes. Finally, we investigate dynamics related to selection into temporary or permanent employment. Hypotheses are tested on a sample of 1,475 workers. The results show that continuous temporary employment does not relate to unfavourable outcomes over time, while gaining permanent employment associates with increased work engagement. Also, permanent workers who transition to temporary employment are more engaged and committed after transitioning. No evidence for possible selection mechanisms is found.     

Factor structure of the Norwegian version of the WAIS-III in a clinical sample: the arithmetic problem

Confirmatory Factor Analyses (CFA) of the Wechsler Adult Intelligence Scale-III (WAIS-III) lend partial support to the four-factor model proposed in the test manual. However, the Arithmetic subtest has been especially difficult to allocate to one factor. Using the new Norwegian WAIS-III version, we tested factor models differing in the number of factors and in the placement of the Arithmetic subtest in a mixed clinical sample (n = 272). Only the four-factor solutions had adequate goodness-of-fit values. Allowing Arithmetic to load on both the Verbal Comprehension and Working Memory factors provided a more parsimonious solution compared to considering the subtest only as a measure of Working Memory. Effects of education were particularly high for both the Verbal Comprehension tests and Arithmetic.     

Cueing attention by relative motion in the periphery of the visual field

Sudden changes of visual stimulation attract attention. The observer's body motion generates retinal-flow field patterns containing information about his/her own speed and trajectory and relative motion of other objects. We investigated the effectiveness of relative motion as an attentional cue and compared it with conventional cueing by appearance of a frame in the far periphery of the visual field. In a group of ten subjects, contrast thresholds for the perception of static Gabor grating orientation [four alternative non-forced-choice (4ANFC)] task were determined at 20 degrees, 30 degrees, 40 degrees, and 60 degrees eccentricity. Subsequently, near-threshold discrimination performance of Gabor pattern orientation without versus with a ring-shaped cue was measured at the same positions. The same Gabor patterns were then presented embedded in a random-dot flow field, and uncued discrimination performance was compared with performance after presentation of a relative-motion cue (RMC), ie a small random-dot field with motion in the opposite direction of the flow field. Both the conventional ring cue and the RMC induced significantly increased discrimination performance at all test locations. With the parameters chosen for this study, the RMC was slightly less effective than the conventional cue, but its effects were somewhat more pronounced in the far periphery of the visual field. Thus, relative motion is a powerful cue to attract attention to peripheral visual objects and improves performance as effectively as a conventional ring cue. The findings have practical relevance for everyday life, in particular for tasks like driving and navigation.