Time-stamping computer events to report .1-msec accuracy of events in the Micro Experimental Laboratory

A critical problem in most real-time programming tasks is the verification that timing of the presented displays and recorded events occur at the expected times. It is often difficult for psychologists to verify critical timing because of the lack of costly specialized tools and technicians to measure events with millisecond accuracy. Algorithms utilized in a new Time Audit mechanism, added to the Micro Experimental Laboratory, are described. This new mechanism involves the recording and time stamping of all input and output events with 0.1-msec accuracy. This allows the experimenter to determine the initiation, duration, and termination of each event and also makes it possible to relate these events to the synchronization of the screen refresh cycle. A customized user interface provides a time log and event-tracing feature that enables nonprogrammers to determine the duration of command execution to the .1-msec level, allowing rapid, precise assessment of program execution. The resulting time log provides a detailed specification of the experimental events for debugging and a permanent record of the experimental procedure.     

Child and adolescent psychopathology research: Problems and prospects for the 1990s

In November 1990 the National Institute of Mental Health (NIMH) convened a special conference of over 100 scientists and leaders to outline specific strategies and research initiatives that should be developed to implement the recently released National Plan for Research on Child and Adolescent Mental Disorders.Participants included journal editors, educators from psychology and psychiatry, representatives from private foundations, and leaders of research program areas in public funding agencies. Critical knowledge gaps were identified in five areas of child and adolescent psychopathology, including depression, attention deficit hyperactivity disorder, conduct disorder, the anxiety disorders, and the developmental disorders. For each of these areas, special emphasis was placed on developing new ideas and obtaining critical input from other areas of investigation. This report summarizes the identified research gaps and recommends research initiatives to implement the National Plan, as outlined by the conference participants.     

Space-based visual attention models and object selection: Constraints,problems, and possible solutions

Summary One of the functions of visual attention is the selection of object information. This seems to be in line with an influential group of attentional models that assume that attentional selection is space based. These models assume that the selection of an object in vision is realized by selection of the location of that object. Whether this relatively simple idea of space-based attention and the corresponding, more elaborated space-based models are sufficient to handle selected constraints and problems of object selection is the main issue of this article. The first step toward an answer is to describe the common computational structure of space-based attentional models. Two model classes will be distinguished: capacity-limited models (e.g., Treisman, 1988; LaBerge & Brown, 1989) and models that do not assume a capacity limitation (e. g., Van der Heijden, 1992). Next, three kinds of task and data on object selection are introduced that are especially challenging for space-based models. The first type of data refers to experiments that require selection between overlapping objects. The second type of data concerns the influence of early perceptual grouping - a strong object-defining factor- on late response competition, and the third type consists of a selection task in which a high-level (semantic) attribute defines an object and controls selection. In all three cases, problems of space-based models are analyzed and possible solutions are sketched. Finally, a brief evaluative summary is given.     

An asymmetry in transmodal perceptual learning

Transmodal perceptual learning was examined in a canonical same/different paradigm. Subjects naive to vibrotactile stimulation and unfamiliar with the task were asked to discriminate sequentially presented shapes moving laterally across an aperture. On all trials, the shapes were presented either visually and then vibrotactually or in the opposite modality order, and on all trials the shapes moved in opposite directions. Analyses of the data revealed that although perceptual learning was evident in both groups, the rate of the learning was more rapid in the visual-vibrotactile group. This interaction of modality order and practice was significant and was considered in terms of E.J. Gibson's theory of perceptual learning and in terms of the constructs, suggested by J.J. Gibson, of available and accessible information-in-stimulation and the education of attention.     

Smiling of preschool children in performance-oriented situations: assessment of the emotional significance in relation to other facial expressions

The goal of the reported experiment was to study how adults judge the meaning of different kinds of smiling and laughing by preschool children, and the role played by other facial movements in determining this meaning. Videotapes and photographs of spontaneous facial expressions of children in a play situation served as stimuli. The results show that different kinds of smiling were judged by the adult subjects as being significantly different from each other. In order to find subgroups within the stimuli, cluster analyses were performed, and the resulting clusters indicated different mixtures of positive and negative emotions contained within the pictures. Regression analyses showed that the adults' judgements were dependent on the number of indicators for positive and negative emotions which could be seen in the pictures. The most important indicator movement for the judged strength of the positive emotion expressed in the smile was the raising of the cheeks and, for negative emotions, the lowering of the lip corners. The significance of the components of the expressions as well as the strength of the expressed emotion were, however, dependent on the mode of presentation (video/photo).     

Opportunities For Learning: Course Sequences and Positional Advantages

Course sequences are strands of courses in particular content areas that span a student's educational career. Courses that are differentiated and sequentially organized, such as mathematics and science course sequences, create opportunities for positional advantages in a school's curricular structure. When students make a nonroutine change of schools – that is, transferring to a school outside of the regular attendance zone – they are at risk of changing their positional advantage. Using data from the National Education Longitudinal Study of 1988–94 (NELS:88–94), we examine the educational outcomes of sequences and explore curricular dislocations within the context of school choice. We find that the strongest predictors of 12th-grade mathematics and science course sequences are a student's course sequences at 10th grade. With regard to outcomes, students in higher mathematics and science sequences show greater achievement gains. Furthermore, students in higher mathematics sequences are less likely to have behavior problems and are more likely to graduate from high school and attend college. Students who make a nonroutine change of schools are more likely to be in lower course sequences than students who do not transfer. Thus, course sequences in mathematics and science are tangible experiences with real consequences for students' lives during and beyond high school and are sensitive to transitions which disrupt the continuity of students' high school careers.