Effect of practice procedure on skill acquisition

49 children in Grade 1 in an isolated community were assessed on their form and skill in making a basket for a one-step basketball lay-up following practice using a pseudoshaping, specific, or schema procedure. Analysis gave a significant form effect but no difference in success of making baskets.     

Stochastic independence,causal independence,and shieldability

The aim of the paper is to explicate the concept of causal independence between sets of factors and Reichenbach's screening-off-relation in probabilistic terms along the lines of Suppes' probabilistic theory of causality (1970). The probabilistic concept central to this task is that of conditional stochastic independence. The adequacy of the explication is supported by proving some theorems about the explicata which correspond to our intuitions about the explicanda.I am indebted to the referee for his most valuable report and to the editor for taking more trouble than usual, I fear.     

Effect of practice on the perception of temporal patterns

The effect of practice on the organization and the rate of identification of temporal patterns was investigated. The patterns involved a set of eight dichotomous left-right elements, repeated without interruption until the subject was able to identify the patterns. The patterns were presented in the auditory, tactual, or visual modalities, or in pairs of these modalities. In some conditions, all the pattern elements were presented in one modality; in other conditions, four elements were presented in one modality and the remaining four elements were presented in the second modality.

The results demonstrated that when all pattern elements were presented in one modality, naive subjects organized the sequence into a well-structured pattern; practiced subjects organized the sequence into a pattern beginning at the starting element. These patterns may be poorly-structured. When four pattern elements were presented in each of two modalities, naive subjects organized the elements in each modality separately; practiced subjects disregarded the modality structure and organized the sequence into a well-structured pattern.

These changes in organization suggest a hierarchy of perceptual modes; perception by modality (i.e. by sensations) is least complex, perception by pattern structure is intermediate, and perception by start point is most complex. Changes in the rate of pattern identification confirm this hierarchy. Furthermore, the changes in organization and identification found for highly practiced patterns were also found for novel patterns.     

Effect of practice on the identification of auditory sequences

Using a variant of the up-and-down method to establish duration thresholds for correct report of the order of sound sequences, six experiments were run with a practiced crew of three Ss. All showed striking improvement with practice, but substantial individual differences were observed. Two Ss found spaced sequences harder than simple cyclic ones and single presentations hardest of all, had increased difficulty when the component frequencies were brought closer together, and were disturbed by irregular timing. These variables made no difference to the third and most sensitive S, whose threshold reached 23 msec per component. All Ss displayed poorer performance if noise, additional signals, or a distrating activity occurred between the stimulus sequence and the response.     

Field independence and performance on ball-handling tasks

Subjects were administered the Children's Embedded Figures Test and four ball-handling tests. Pearson product-moment correlations were low between the measures. Girls scored significantly higher than boys on the embedded figures test while boys scored significantly higher than girls on the striking and throwing tests.     

Effect of practice on utilization of nonlinear rules in inference tasks

The effects of practice on subjects' ability to use nonlinear rules was investigated in five experiments. The first experiment showed that performance and transfer varied with the amount of practice given, the second that having to produce overt responses in training did not lead to better performance or transfer. The third and fourth experiment tested the hypothesis that the low transfer effects were due to interference, but since neither switching the order of test tasks nor an interpolated task affected performance, the hypothesis was rejected. The fifth experiment, finally, showed that practice decreased the nonsystematic error in the subjects' response systems, but did not affect the systematic features.     

Effect of response practice variables on learning spelling and sight vocabulary

Four experiments were conducted to examine variables associated with response practice as an instructional technique for individuals with intellectual disabilities. In Experiment 1, the effect of the cover component in the "cover write" method was evaluated, as were the comparative effects of written versus oral practice of spelling words by rehabilitation clients. The results showed that the cover procedure generally did not enhance performance over and above that produced by practice alone, and written practice generally was not superior to oral practice. Experiment 2 demonstrated that less response practice (i.e., five times) was as effective as more practice (i.e., 10 and 15 times) for teaching spelling to adolescents with developmental disabilities. Experiments 3 and 4 also showed that even less response practice (i.e., one time) was as effective as more practice (five times), and irrelevant practice following errors was as effective as relevant practice for teaching spelling and sight vocabulary to adolescents with behavior disorders and developmental disabilities, respectively. The findings suggest that a parsimonious procedure of limited response practice and positive reinforcement may be effective for the tasks and populations studied.     

Successive independence of multiple-schedule component performances

In three experiments, pigeons' responses were reinforced on two keys in each component of a series of multiple-schedule conditions. In each series, concurrent variable-interval schedules were constant in one component and were varied over conditions in the other component. In the first experiment both components arranged the same, constant total number of reinforcers, in the second the two components arranged constant but different totals, and in the third experiment the total was varied in one component and remained constant in the other. Relative reinforcer rate during the varied component was manipulated over conditions in all three experiments. In all these experiments, response and time allocation in the constant component were invariant when reinforcer ratios varied in the other component, demonstrating independence of behavior allocation in a multiple-schedule component from the relative reinforcer rate for the same alternatives in another component. In the two experiments which maintained constant reinforcer totals in components, sensitivity to reinforcement in the multiple schedules was the same as that in the concurrent schedules arranged during the varied component, with multiple-schedule bias in the experiment in which the totals were unequal.