Sampling Methods for Identifying Differences in Source Reliability

This study explored observer performance in using across-trial and within-trial variability information to weight sources based on reliability. Three trained observers performed a multi-element, visual signal-detection task under 3 block-type conditions: a fixed block condition and 2 random conditions. In the fixed block condition, the observers had both within- and across-trial variability information to identify differences in source reliability. The random conditions eliminated the across-trial information, leaving only within-trial variability information in 1 case and neither within- nor across-trial variability information in another case. There was a significant block-type effect. Observers could use differences in across-trial variability of individual sources to assign weights. Although there was a difference in the weights assigned to reliable and unreliable sources in the partial-random condition (in which within-trial variability information was available), only 1 participant showed a significant difference in the weight assignment relative to the full-random condition. Thus, altogether, observers were not very efficient at using within-trial variability to weight sources accordingly.     

Visual-Field Bias in the Judgment of Facial Expression of Emotion

The left and right hemispheres of the brain are differentially related to the processing of emotions. Although there is little doubt that the right hemisphere is relatively superior for processing negative emotions, controversy exists over the hemispheric role in the processing of positive emotions. Eighty right-handed normal male participants were examined for visual-field (left-right) differences in the perception of facial expressions of emotion. Facial composite (RR, LL) and hemifacial (R, L) sets depicting emotion expressions of happiness and sadness were prepared. Pairs of such photographs were presented bilaterally for 150 ms, and participants were asked to select the photographs that looked more expressive. A left visual-field superiority (a right-hemisphere function) was found for sad facial emotion. A hemispheric advantage in the perception of happy expression was not found.     

A Question of Foot Dominance

It is suggested that the popular definition of foot dominance (i.e., the limb preferred to execute a manipulative or mobilizing action while the other [nondominant] foot provides stabilizing support, e.g., kicking a ball) be reconsidered in light of understanding the functional characteristics of footedness and selected theoretical explanations. Relevance to future research designs and assessment methodology is discussed.     

Determinants of Offline Processing of Visual Information for the Control of Reaching Movements

The authors investigated the use of visual feedback as a form of knowledge of results (KR) for the control of rapid (200-250 ms) reaching movements in 40 participants. They compared endpoint accuracy and intraindividual variability of a full-vision group (FV) with those of no-vision groups provided with KR regarding (a) the endpoint in numerical form, (b) the endpoint in visual form, or (c) the endpoint and the trajectory in visual form (DEL). The FV group was more accurate and less variable than were the no-vision groups, and the analysis of limb trajectory variability indicated that their superior performance resulted primarily from better movement planning rather than from online visual processes. The FV group outperformed the DEL group even though both groups were obtaining the same amount of spatial visual information from every movement. That finding suggests that the effectiveness with which visual feedback is processed offline is not a simple function of the amount of visual information available, but depends on how that information is presented.     

Asymmetries in the Regulation of Visually Guided Aiming

An experiment was conducted to examine the contribution of sensory information to asymmetries in manual aiming. Movements were performed in four vision conditions. In the full-vision condition (FV), subjects were afforded vision of both the hand and the target throughout the course of the movement. In the ambient-illumination-off condition (AO), the room lights were extinguished at movement initiation, preventing vision of the moving limb. In the target-off (TO) condition, the target was extinguished upon initiation of the movement. In a no-vision (NV) condition, ambient illumination was removed and the target was extinguished upon initiation of the response movement. Results indicated that accuracy was superior in the full-vision and target-off conditions and when movements were made by the right hand. Movements made by the right hand were also of shorter mean duration. The magnitudes of performance asymmetries were uninfluenced by vision condition. Analyses of movement kinematics revealed that movements made in conditions in which there was vision of the limb exhibited a greater number of discrete modifications of the movement trajectory. On an individual-trial basis, no relationship existed between accuracy and the occurrence of discrete modifications. These data suggest that although vision greatly enhances accuracy, discrete modifications subserved by vision reflect the imposition of nonfunctional zero-order control processes upon continuous higher-order control regimes.     

Multivariate Relationships Between Motor and Personality Measures in Culturally Deprived High School Pupils

The relationship between personality, as measured by the IPAT-HSPQ, and certain motor performance variables was studied by utilizing the multivariate technique of canonical correlation. Ss for the study were 91 culturally deprived high school students who were achieving well below their expected capacity. A significant canonical relationship was not found between the domains of personality and motor performance. Also, no significant relationships between motor sub-domains and personality were found. It was thus concluded that for the population under study, the domains of motor performance and personality were independent Some discussion of the multivariate technique of canonical correlation was offered and compared with univariate procedures.     

Dynamic and Static Balancing Ability of Preschool Children

Performance differences in dynamic and static balance ability of 150 preschool Ss aged 3,4, and 5 yr. were studied. Ss performed 4 balance-beam tasks and 2 balance-board tasks. An Age by Sex (3 × 2) factorial, design employing both univariate and multivariate ANOVA techniques were the statistics used. For both dynamic and static balance Age was highly significant, and the use of multivariate ANOVA indicated significant sex differences on the static balance tasks. The appropriateness of multivariate techniques where more than one dependent variable is measured on the same population was discussed, and the need to take into account the relationship between these variables when analyzing the data was noted.     

A Test of Order-Constrained Hypotheses for Circular Data With Applications to Human Movement Science

Researchers studying the movements of the human body often encounter data measured in angles (e.g., angular displacements of joints). The evaluation of these circular data requires special statistical methods. The authors introduce a new test for the analysis of order-constrained hypotheses for circular data. Through this test, researchers can evaluate their expectations regarding the outcome of an experiment directly by representing their ideas in the form of a hypothesis containing inequality constraints. The resulting data analysis is generally more powerful than one using standard null hypothesis testing. Two examples of circular data from human movement science are presented to illustrate the use of the test. Results from a simulation study show that the test performs well.     

Postural Mechanisms to Control Body Displacements in the Performance of Lateral Gaze Shifts

Medialateral postural control mechanisms (bodyweight distribution and center of pressure location) have been studied in static conditions. Our objective was to determine how these mechanisms are adjusted to perform voluntary movements, in our case 80° lateral gaze shifts at 0.125 Hz and 0.25 Hz. In healthy, young adults, we expected body marker (neck, lower back) and center of pressure displacements to be significantly greater in gaze shift conditions than in the stationary gaze condition. To explain these changes in center of pressure displacement, the amplitude contribution of both mechanisms was expected to increase significantly. All these results were found accordingly. Unexpectedly, the active contribution of the bodyweight distribution mechanism was negatively related to body marker displacements in the gaze shift conditions (ns in stationary condition). Moreover, changes in the contribution of the mechanisms were statistically weaker in effect size than changes in body displacement. However, the participants were not unstable because they performed the visual tasks as requested. We propose that the strength of medialateral postural control mechanisms may not only be strengthened to control challenging ML stance conditions but also slightly weakened to allow the performance of adequate body motions in ongoing tasks.     

Strategy instruction for writing composition at school and at home

Abstract

The objectives of this study are 1) to analyze the effectiveness of a writing composition intervention program aimed to increase children's writing performance and other personal variables; 2) to analyze whether implementation in the environment (school and home) or responsible figures (parents and teachers) produced different effects in program effectiveness; and 3) to check whether increasing parental involvement in doing homework was sufficient to improve children's outcomes or whether prior family training is required to enable them to be efficient. The sample consisted of 112 students (5th-6th grade) and their families. 26 of them made up the EFP group (mothers implementing a writing program), 25 of them were assigned to the PAD group (mothers increasing help with writing homework), 35 to the PRO group (teachers applying a writing program) and 26 to the OC group (ordinary curriculum). We analyze the results and present and discuss our conclusions.