Visual discrimination of spectral distributions

Human observers seem to be able to use different features that classify materials with a large degree of accuracy. In this paper, we look at human perception of statistical properties of the spectral distribution in a scene. We investigated whether human observers can discriminate just as accurately between coloured textures that have a spectral distribution due either to shading only or to both shading and specular reflectance as between uniform colours. Thresholds for the discrimination of coloured textures are about 15 times as high as thresholds for the discrimination of uniform colours, provided there is a sharp transition between the two colours. However, the coloured texture thresholds are only 1.5 times higher when we introduce a gradual transition between the two colours. There are also distinct qualitative differences in discrimination thresholds for different base colours. These differences cannot be predicted from discrimination thresholds for uniform colours. Human observers are surprisingly good at discriminating between a material edge and a shadow edge in complex scenes. Statistical differences in the orientation of the colour distributions in colour space might be used to accomplish this. In a second experiment we investigated how well observers can discriminate between two linear distributions in colour space that have the same base colour but different orientations. When we vary the line-length in R, G, B space, thresholds cannot be predicted completely by the conservation of the average distance between the two distributions. This means that observers use not only the maximum colour difference in the stimulus to do the task, but other cues are also involved.     

A solution-oriented approach to conflict resolution in a work system

The growing involvement of counsellors in organisational development is addressed by describing the application of a solution-oriented family therapy approach to conflict resolution in a work system. An account of the intervention outlines the system's storying of the problem, the development of new meanings and the identification of solutions. Key concepts in this post-modern approach are linked with the practices employed.     

The Effects of Aging and Dual Task Demands on Language Production

ABSTRACT

A digital pursuit rotor task was used to measure dual task costs of language production by young and older adults. After training on the pursuit rotor, participants were asked to track the moving target while providing a language sample. When simultaneously engaged, young adults experienced greater dual task costs to tracking, fluency, and grammatical complexity than older adults. Older adults were able to preserve their tracking performance by speaking more slowly. Individual differences in working memory, processing speed, and Stroop interference affected vulnerability to dual task costs. These results demonstrate the utility of using a digital pursuit rotor to study the effects of aging and dual task demands on language production and confirm prior findings that young and older adults use different strategies to accommodate to dual task demands.     

Psychometric Properties and Factorial Structure of the Spence Children's Anxiety Scale (SCAS) in Spanish Adolescents

The Spence Children's Anxiety Scale is an instrument widely applied in the assessment of the most common anxiety disorders in children and adolescents. This study examines its psychometric properties and the factorial structure in a large community sample of Spanish-speaking adolescents (N = 1,374) aged 13 to 17 years. The scale demonstrated strong internal consistency and good convergent and discriminant validity. Factor analysis confirmed the 6-factor original model, providing a good fit of the data for the Spanish sample. The good psychometric properties support its use by clinicians and researchers, adding evidence to the international empirical support for this measure.     

Self-Determination Skills of Adolescents Enrolled in Special Education: An Analysis of Four Cases

This study provides information about four adolescent students participating in an occupation-based self-determination program drawn from the Model of Self-Determination and the Model of Human Occupation. Students were selected from a Career Lab based on their ability to participate. The analysis of the cases demonstrate that psycho-educational strategies incorporated into a special education curriculum can instill in the students the knowledge, attitudes, and behaviors necessary for personal goal setting and attainment.     

The influence of introversion-extraversion on activity choice and satisfaction among the elderly

The present study investigated the optimum theory of aging. This theory predicts that individuals with different personality types will react differentially to the aging process. In the present study, 60 nursing-home residents were administered the Eysenck Personality Inventory and then randomly assigned to one of two experimental manipulations. Elderly subjects classified as extraverts showed a high level of satisfaction to an experimental manipulation which was of a high activity, interpersonal type; those classified as introverts evidenced more satisfaction with a low activity, non-interpersonal type manipulation. Inspection of records documenting actual participation in programs within the nursing home indicated that introverts were more often involved in low activity, non-interpersonal events whereas extraverts participated more often in high activity, interpersonal events. Implications of these results are discussed in relation to the optimum theory of aging.