Deformation of the useful visual field with state of vigilance,task priority,and central task complexity

In a dual-task situation, peripheral perception can deteriorate due to different variables related to the experimental situation, such as central task complexity and the relative priority given to the two tasks. Recent studies have also shown that individual characteristics (such as the state of vigilance) can alter the useful visual field. The ability to perceive signals presented at different places in the visual field decreases in situations that lead to episodes of low vigilance. In Exp. 1, 27 subjects (18-29 years) had to perform a monotonous and prolonged dual-monitoring task involving central and peripheral vision. The test was carried out with two different sets of instructions regarding priority: the more important task was either the central task or the peripheral one. In Exp. 2, 18 subjects (18-30 years) performed the same test, but this time with two levels of complexity of the central task, either a simple monitoring activity or the same monitoring task coupled with a counting activity. Elliptical interpolation of the data enabled assessment of the deformation of the useful visual field in both experiments. The analysis of the parameters of the elliptical model indicated that the useful visual field mainly shrinks on the vertical axis, as the individual becomes drowsy. The useful visual field also shrinks on the horizontal axis when the peripheral task has priority and the monitoring activity is prolonged, or when the central task is complex.     

Lack of association of computer use and ability with spontaneous mental visualization

Relationships between frequency of computer use or ability to use the computer effectively with the tendency to construct and process visual mental images were investigated by administering a computer-use questionnaire and a visualization questionnaire to a sample of 185 Italian and Spanish undergraduates. Analysis did not support associations between either (a) frequent computer use of any kind or (b) high competence in using the computer for various purposes and spontaneous use of imagery.     

Lexical and relational influences on the processing of novel compounds

To interpret a novel compound (e.g., chocolate twig), one must access the concepts denoted by the words and select a relation that links them together. To examine the role of lexical and relation information on conceptual combination, target combinations were preceded by one of three prime combinations. In Experiment 1, the prime used a semantically similar head noun and either the same or different relation. The third prime was semantically unrelated to the target. Experiment 2 was identical, except the modifier was the semantically related constituent. Although semantic priming was observed in both experiments, relation priming was obtained only when the modifier was similar.     

Brief Strategic Family Therapy: Twenty-Five Years of Interplay Among Theory, Research and Practice in Adolescent Behavior Problems and Drug Abuse

This article describes a systematic program of research that focuses on Brief Strategic Family Therapy (BSFT) and the adaptations that were developed based on BSFT principles. The culture-specific origins of BSFT are reviewed, as well as its broader applications to the field of family therapy. Research is reviewed demonstrating that BSFT is a promising family-based approach to treating Hispanic youth behavior problems and drug abuse. Treatment innovations are described that address the combination of intergenerational and cultural differences that occur among youths and their Hispanic parents. Programmatic work is described that challenges basic principles of family therapy by expanding BSFT to a One Person modality and a strategic engagement procedure. Both of these novel approaches are intended to add tools to therapists' repertoire in working with difficult-to-engage families. A preview discussion of results is presented from a randomized clinical trial that is an application of an ecosystemic prevention version of BSFT. The implications of the work of the Center for Family Studies are discussed in the context of the broader service system. Ultimately, this article articulates a way of thinking about adolescent problem behavior, its social interactional determinants, and a range of theoretically consistent family-centered strategies that attempt to change social ecological processes that impact adolescent developmental trajectories.     

Interhemispheric inhibition, intrahemispheric activation, and lexical capacities of the right hemisphere: a tachistoscopic, divided visual-field study in normal subjects

This study proposes that the lexical-semantic capacities of the right hemisphere (RH) are underestimated in normal subjects and reexamines them in a "dynamic model" framework. As expected, overloading the left hemisphere by combining a lexical-decision task presented in divided visual field with a concurrent heavy verbal memory load, and activating the RH by combining the lexical-decision task with a concurrent visuo-imaged memory load, lead to enhanced left visual field-RH lexical performance. The RH appears to support a larger lexical-semantic network than suggested in the literature, including representations for long and nonimageable words, and the accessibility threshold for the representations stored therein is modulated by hemispheric activation-inhibition mechanisms.     

Nonhomogeneous resolution of images of natural scenes

The aim of this research is to model and simulate the loss of visual resolution as a function of retinal eccentricity in the perception of natural scenes. The model of visual resolution is based on a space-variant low-pass filter, having a variable convolution kernel according to retinal eccentricity. The parameters of the model are computed from psychophysical measures of visual acuity as a function of retinal eccentricity. The implementation of the model allowed us to generate images of scenes with nonhomogeneous space-variant resolution, simulating the filtering executed by the eye. These scenes are used to test and optimise the model by means of experiments in static vision (through tachistoscopic presentations) and in dynamic vision where the resolution of the scene is computed, in real-time, as a function of the location of gaze.