Neural theory for the perception of causal actions

The efficient prediction of the behavior of others requires the recognition of their actions and an understanding of their action goals. In humans, this process is fast and extremely robust, as demonstrated by classical experiments showing that human observers reliably judge causal relationships and attribute interactive social behavior to strongly simplified stimuli consisting of simple moving geometrical shapes. While psychophysical experiments have identified critical visual features that determine the perception of causality and agency from such stimuli, the underlying detailed neural mechanisms remain largely unclear, and it is an open question why humans developed this advanced visual capability at all. We created pairs of naturalistic and abstract stimuli of hand actions that were exactly matched in terms of their motion parameters. We show that varying critical stimulus parameters for both stimulus types leads to very similar modulations of the perception of causality. However, the additional form information about the hand shape and its relationship with the object supports more fine-grained distinctions for the naturalistic stimuli. Moreover, we show that a physiologically plausible model for the recognition of goal-directed hand actions reproduces the observed dependencies of causality perception on critical stimulus parameters. These results support the hypothesis that selectivity for abstract action stimuli might emerge from the same neural mechanisms that underlie the visual processing of natural goal-directed action stimuli. Furthermore, the model proposes specific detailed neural circuits underlying this visual function, which can be evaluated in future experiments.     

Schedule-induced polydipsia as a function of fixed interval length

Rats were trained to bar-press for Noyes pellets on an FI schedule which was increased serially through several values from 2 sec to as high as 300 sec. Concurrently, water was freely available. As FI length was increased, the degree of polydipsia increased linearly to a maximum value.     

Some teasers concerning conditional probabilities

A family of notorious teasers in probability is discussed. All ask for the probability that the objects of a certain pair both have some property when information exists that at least one of them does. These problems should be solved using conditional probabilities, but cause difficulties in characterizing the conditioning event appropriately. In particular, they highlight the importance of determining the way information is being obtained. A probability space for modeling verbal problems should allow for the representation of the given outcome and the statistical experiment which yielded it. The paper gives some psychological reasons for the tricky nature of these problems, and some practical tips for handling them.     

A closer look at the probabilities of the notorious three prisoners.

The "problem of three prisoners", a counterintuitive teaser, is analyzed. It is representative of a class of probability puzzles where the correct solution depends on explication of underlying assumptions. Spontaneous beliefs concerning the problem and intuitive heuristics are reviewed. The psychological background of these beliefs is explored. Several attempts to find a simple criterion to predict whether and how the probability of the target event will change as a result of obtaining evidence are examined. However, despite the psychological appeal of these attempts, none proves to be valid in general. A necessary and sufficient condition for change in the probability of the target event, following observation of new data, is proposed. That criterion is an extension of the likelihood-ratio principle (which holds in the case of only two complementary alternatives) to any number of alternatives. Some didactic implications concerning the significance of the chance set-up and reliance on analogies are discussed.     

Soziale Phobie

Social anxiety is characterised by overwhelming fears in social interactions or performance situations. Its life-time prevalence is high (about 13%) and relapses are quite common. Social anxiety disorder is a chronic disease with a high impairment for the persons afflicted. Cognitive-behavioural, psychodynamic and neurobiological models have promising implications for psychotherapy and pharmacological treatment. Neurobiological approaches have identified risk factors and possible somatic mechanisms. Cognitive-behavioural models explain the development of dysfunctional beliefs and the maintenance of social anxiety. Psychodynamic approaches refer to a disturbed self-concept and underline the importance of prior negative interpersonal relationships. Manualised treatments exist for the cognitive-behavioural approach and a manual for psychodynamic psychotherapy was recently developed. This paper presents the different approaches (neurobiological, cognitive-behavioural, psychodynamic) to social anxiety disorder and possible implications for therapy are discussed.     

Psychoanalytisch-orientierte Fokaltherapie der sozialen Phobie

Although psychodynamic therapy is one of the most frequently applied forms of psychotherapy to treat anxiety disorders in clinical practice, evidence for the efficacy of psychodynamic therapy in anxiety disorders is unsatisfactory. This is especially true with regard to randomized controlled trials of psychodynamic psychotherapy in anxiety disorders. Psychodynamically oriented treatment manuals for anxiety disorders presently exist for generalized anxiety disorder and panic disorder. For social phobia (or social anxiety disorder), however, no manual for psychodynamic treatment has yet been published. Social phobia is a very frequent mental disorder characterized by an early onset, a chronic course, severe psychosocial impairments and high socio-economic costs and at the same time in spite of these facts one of the mental disorders which are scarcely diagnosed and treated. In this article, a manual for a 30-session (5 exploratory and 25 therapy sessions) short-term psychodynamic treatment of social phobia is presented. The treatment is based on Luborsky’s supportive-expressive (SE) therapy. In the first part, the general principles of SE therapy are presented. In the second part, a manual specifically adapted to the treatment of social phobia is described. This manual includes specific additional treatment elements that have clinically proved to be useful in the therapy of social phobia. The treatment manual is presently used in a large-scale randomized controlled multi-center study comparing short-term psychodynamic psychotherapy and cognitive-behavioral therapy in the treatment of social phobia.