A stochastic model for test-retest correlations

A simple stochastic model is formulated in order to determine the optimal time between the first test and the second test when the test-retest method of assessing reliability is used. A forgetting process and a change in true score process are postulated. The optimal time between tests is derived by maximizing the probability that the respondent has not remembered the response on the first test and has not had a change in true score. The resulting test-retest correlation is then found to be a linear function of the true reliability of the test, where the slope of this function is the key probability of not remembering and having no change in true score. Some numerical examples and suggestions for using the results in empirical studies are given. Specific recommendations are presented for improved design and analysis of intentions data.This research was made possible by a grant from the Center for Food Policy Research, Graduate School of Business, Columbia University, New York, New York, 10027.     

The family and the child with epilepsy

Reports documenting psychosocial epiphenomena of chronic illness in individuals with that illness have been common in recent years. Few studies, however, have been concerned with how illness might affect the family. Those that have appeared in the literature often lack critical controls (i.e., control groups) and often fail to investigate possible links between illness-specific variables (i.e. chronicity, inhibition of mobility) and psychosocial outcomes on the family. The present study of 45 families focused on how children with epilepsy affect their families' functioning relative to families with a child with diabetes and families with no chronically ill members. The results suggest several areas of child and family adjustment (i.e. child self-concept, family communication, family cohesion) in which the families of epileptic children have great difficulty. Implications of these results are discussed with regard to differential influences of various chronic illnesses on families and family-based preventive and remedial treatment programs.     

Evaluation of a coaching strategy to reduce swimming stroke errors with beginning age-group swimmers

A coaching strategy to decrease errors in swimming strokes with swimmers who had not improved under "standard" coaching procedures was investigated using a multiple baseline design across subjects and swimming strokes. The procedure resulted in a large decrease in errors on swimming strokes during sessions in a training pool. Stimulus generalization of improved performance to normal practice conditions in the regular pool was observed with all but one swimmer. This improvement was maintained during two maintenance phases lasting approximately 2 weeks, as well as under standard coaching conditions during at least a 2-week follow-up. For two swimmers, error rates on one of the strokes showed a gradual increase between the third and fifth week of follow-up, but brief remedial prompting sessions immediately corrected their performance. Some beneficial response generalization to other components of the stroke being trained was observed, but no improvements were found on untrained strokes. The error correction package did not disrupt practice, require excessive amounts of the coach's time, or necessitate the use of cumbersome apparatus. In addition, the coach and the swimmers considered the procedures to be effective, and expressed their willingness to participate in them again in the future.     

A CULTURAL DIFFERENCE IN VISUAL MEMORY: ON LE VOIT,ON NE LE VOIT PLUS

Further to the debate between Kearins (1978) and Drinkwater (1978), visual memory skills of Aboriginal and white Australian children were examined using Drinkwater's version of Kim's game with desert Aboriginal and rural white children. Older children remembered more than younger ones, and Aboriginal children recalled more natural objects than white children. There was no difference between the groups in recall of manufactured objects, nor between recall of manufactured and natural objects within each group. Aboriginal children remembered significantly more objects overall than white children when the task was first administered. On a second occasion, after a procedure designed to orient children towards the use of predominantly visual rather than verbal memorising strategies, there was no significant difference between the groups.     

Stimulus generalization and the peak shift with movement stimuli

Stimulus generalization is suggested as an alternative method for examination of the "novelty" problem in motor learning. These experiments demonstrated that stimulus generalization occurs using simple movements as stimuli. The phenomenon of the "peak shift" in post-discrimination generalization gradients was also examined. The first experiment demonstrated that a peak shift occurred using linear movements as stimuli and that the magnitude of the peak shift increased as the difference between the training stimuli decreased. The second experiment showed similar results when the stimuli consisted of a range of movements rather than single movement length. The final experiment provided evidence that perception of movement length is influenced by the magnitude of an immediately preceding movement. The relevance of these studies to current motor-learning theory is discussed.     

Neuropsychological assessment of learning disabilities: a discriminant analysis

The neuropsychological test scores of 23 learning disabled children were compared with those of a matched population of normal children in the 9-1 to 13-1 age range. All children were administered the Wechsler Intelligence Scale for Children-Revised (WISC-R), a dichotic listening task involving both free and directed recall conditions, a handedness inventory, the Tactile Performance Test and the Category Test from the Halstead-Reitan Neuropsychological Test Battery. A multivariate analysis of variance resulted in a significant separation between groups (p less than .001) using these procedures. A stepwise discriminant function analysis revealed that both of the directed dichotic tasks contributed the most of all 13 measures to the significant group separation. In addition, other cognitive tasks found to discriminate normal from learning disabled children include general verbal processes, concept formation, and tactile memory. These findings suggest that the directed dichotic listening procedure and the WISC-R Verbal IQ measure are reasonably valuable clinical tools in the classification of learning disabilities.