Dispersion in models of categorical perception

A signal detection theory model of auditory discrimination with a nonlinear mapping from stimulus continuum to perceptual continuum can account for the enhanced discrimination at the category boundary found in categorical perception. Properties of this transformation are specified by a unimodal “dispersion function”. Furthermore, it is shown that a system consisting of two acoustic feature detectors with an associated decision function is also a dispersive system, which models categorical perception of a stimulus continuum as well as boundary shifts under adaptation. The effect of detector adaptation on discrimination is discussed in view of three different types of decision variable and different types of detector noise.     

Professional training of child psychologists

The present authors address the need for specialized professional training for psychologists who primarily work with the problems of childhood. It is argued that the area of child psychology is an amalgam of selected components of developmental, educational, and clinical psychology, and further that it is sufficiently discrete to warrant specialized training programs for child psychologists. Questions concerning the particular content of such training, and the level at which the training should take place, are raised. Various options regarding the answers to these questions are discussed, and a specific recommendation is presented.     

The nature and treatment of social phobia in youth

A small proportion of children and adolescents experience a debilitating level of social anxiety, known as social phobia. Initially, we consider the phenomenology and aetiology of social phobia in children and adolescents. A number of age-sensitive assessment instruments or tools are briefly considered: a diagnostic interview, selj-report instruments, behavioural observations, cognitive assessment, self-monitoring and psychophysiological recording. We explore cognitive-behavioural strategies that have been found to be useful in the management of social phobia. Although there is much research support for the efficacy of cognitive-behavioural strategies for adults with social phobia, it is emphasized that controlled evaluations have yet to be undertaken with socially phobic youngsters.     

Structure and development of behavior systems

Behavior systems are particular organizations of cognitive structures that are called behavior mechanisms: perceptual, central, and motor. Thus, behavior systems are defined here in structural terms and not in terms of their functional characteristics. In young animals, behavior mechanisms often develop independently of functional experience, though specific types of experience are usually necessary for integrated systems to develop. These concepts are illustrated here by the dust-bathing, feeding, aggressive, and sexual systems of the fowl, which are considered to be typical of behavior systems in other species. Aspects of neural development are examined and found to facilitate our understanding of a wide range of developmental phenomena, such as critical periods and irreversibility. Finally, various examples of classical conditioning and instrumental learning are analyzed in terms of the type of structures involved, and they are related to general developmental processes.     

Varieties of positive and negative priming

Numerous recent investigations have focused on a particular relation between the roles a stimulus plays in successive displays: when a stimulus ignored by a subject on one occasion is to be attended on a succeeding occasion, reaction time to that stimulus is slowed relative to a control condition. But this is but one possible case ofnegative priming. There are other ways in which negative priming might occur, and there are several varieties of positive priming as well. All these possibilities were explored in the present experiment.     

Disentangling Type A behavior: The roles of ambition,insensitivity, and anxiety

This study identified stable components of Type A behavior as usually defined, and examined their relationships with more traditional psychological constructs. Overall scores on the most popular Type A measure (a version of the Jenkins Activity Survey) were moderately associated with ambition but largely unrelated to measures of adjustment. An item analysis yielded subcomponents of Drivenness and Involvement. Drivenness was unrelated to ambition, but was positively related to anxiety and negatively related to interpersonal perceptiveness. Involvement was positively related to ambition and to interpersonal competence. It is suggested that the Jenkins Activity Survey measures a heterogeneous mixture of constructive commitment and self-defeating responses that clouds its psychological interpretation.