Bernstein's theory of movement behavior: historical development and contemporary relevance

In present-day movement science, N. A. Bernstein's formulation of the problems of motor control is often taken as the starting point. The reliance on Bernstein has not brought agreement among his followers, however. In this article, the authors pose the following question: Does the disagreement arise from the structure of his work itself or from incomplete exploitation of his thinking? By using, inter alia, Bernstein's 24 English and German articles, the authors present an analysis of the development of Bernstein's theory of movement behavior, against the backdrop of the scientific progress in the Soviet Union in Bernstein's time and the clashes between Soviet politics and science. Bernstein addressed in his early articles the measurement and biomechanical analysis of movements. His experimental data soon indicated the need for a new understanding of the organization of movements, which he formulated in terms of coordination. Because of political problems, his work was interrupted; but after being "rehabilitated" and again allowed to work, Bernstein aimed to explain how animals find and optimize the solutions to motor problems. The structure of the theory that ensued was comprehensive exactly by virtue of his repeatedly shifting focus between the different aspects of the organization of movement: More important than the answers he gave were the questions he asked. Moreover, the way he approached those questions may help scientists solve pressing problems in present-day movement science.     

Numerical and arithmetical cognition: a longitudinal study of process and concept deficits in children with learning disability

Based on the stability and level of performance on standard achievement tests in first and second grade (mean age in first grade = 82 months), children with IQ scores in the low-average to high-average range were classified as learning disabled (LD) in mathematics (MD), reading (RD), or both (MD/RD). These children (n = 42), a group of children who showed variable achievement test performance across grades (n = 16), and a control group of academically normal peers (n = 35) were administered a series of experimental and psychometric tasks. The tasks assessed number comprehension and production skills, counting knowledge, arithmetic skills, working memory, the ease of activation of phonetic representations of words and numbers, and spatial abilities. The children with variable achievement test performance did not differ from the academically normal children in any cognitive domain, whereas the children in the LD groups showed specific patterns of cognitive deficit, above and beyond the influence of IQ. Discussion focuses on the similarities and differences across the groups of LD children.     

Culture and beliefs about time: comparisons among black Americans, black Africans, and white Americans

The authors investigated the extent to which racial factors, cultural factors, or both influence a person's beliefs about physical time, personal time, and experienced and remembered duration. A total of 750 Black American, Black African, and White American students responded to a questionnaire on these beliefs about time. Factor analysis was used to compare belief structures. Pairwise comparisons, performed separately for each statement, tested the direction and strength of the reported beliefs. The groups showed many similarities, but they also showed some differences. All 3 groups differed in beliefs about physical and personal time, but they did not differ in beliefs about duration experiences. This evidence does not support simplistic views of racial or cultural influences. Culture may differentially influence beliefs about physical time and personal time. Beliefs about duration experiences may represent an ethnic factor that transcends cultures.     

Interference from irrelevant features on visual discrimination by macaques (Macaca fuscata): a behavioral analogue of the human Stroop effect

To study the operation of selective attention in a conflict situation with automatic processes, we trained 4 Japanese macaques (Macaca fuscata) extensively on a manual go/no-go task. The monkey had to discriminate either the color, shape, motion direction, or location of a visual stimulus. In each trial, the behavioral meaning of the relevant feature (go or no-go) could either be congruent or incongruent with irrelevant features of the same stimulus. Reaction times were slowed, and error rates increased when irrelevant stimulus features were incongruent with the required response. The effects were obtained when the monkey attended to the color, shape, or motion direction, but not when it attended to the location of the stimulus. The effects were cumulative so that the interference from 1 incongruent feature was smaller than that from 2 incongruent features. We propose that the present paradigm provides a behavioral analogue of the human Stroop effect.     

Exploring the effects of icon characteristics on user performance: the role of icon concreteness, complexity, and distinctiveness

Because icons, signs, and symbols are now widely used to communicate information, it is essential for system designers to know what makes them easy to use and interpret. The authors report a series of studies that examine characteristics considered central to icon usability. After quantifying the properties of icon concreteness, complexity, and discriminability, the authors assessed each property's effects on user performance when user experience, task demands, and presentation context were systematically varied. Findings indicated that the effects of icon concreteness were primarily associated with the initial grasp of meaning, whereas complexity effects were found to persist longer and to be associated with search efficacy. The effects of icon distinctiveness were complex, but distinctiveness was enhanced by using both semantic and visual contrasts. The implications of these findings for interface design are discussed.     

The name game: using retrieval practice to improve the learning of names

In medium-sized groups such as classes, it is often desirable that the members become acquainted with one another. Toward this end, various methods of introducing group members are often used, with only anecdotal evidence for their effectiveness. The name game is a method for introducing group members that is based on the principles of retrieval practice. The authors compared 2 versions of the name game with a widely used introductory method--pairwise introductions--and found that the name game participants were much better at remembering one another's name after 30 min, 2 weeks, and 11 months. A second experiment tested the contribution of retrieval practice by comparing 2 versions of the name game with a procedure that was matched for number of repetitions and time spent on the task. Again, the name games were superior.     

Functional brain imaging as a looking-glass into the degraded brain: reviewing evidence from Alzheimer disease in relation to normal aging

Research on the real-time relationship between brain activity and mental performance is intense. However, relatively few studies have been devoted to patients with different diseases or lesions. Such studies may cast light on certain aspects of brain activity, such as plasticity. This review summarizes studies on Alzheimer's disease (AD) patients where the techniques to map brain activity in relation to mental performance have been utilized. Research findings suggest, that there is a spectrum of changes in AD patients that is distinct from that seen in healthy aging. These changes include: (i) loss of activated regions, (ii) reduced activation possibly due to brain degeneration typical of AD, (iii) the emergence of newly activated regions in order to compensate for minor brain deterioration (e.g., an enlargement of activated regions sometimes manifested as an increased bilaterality or a hemispheric shift of activation, and dedifferentiation), (iv) decreased level of activation, and (v) no change at all, which may occur in easy tasks or tasks that do not involve regions exposed to brain atrophy. In conclusion, the pattern of activation in AD depends on interactions between the clinical stage of patients, and the pattern of brain degeneration, as well as the task difficulty and specific networks necessary for solving the task.