Visual short-term memory, response delay, and age

Recall and recognition memory performance of 12 young (M = 19 yr.) and 12 older (M = 72 yr.) females was studied in relation to response delay (5, 25, and 125 sec.) and stimulus complexity (6.1 and 13.7 bits of information). The subjects were matched on verbal IQ, visual acuity, and educational levels. Stimuli were abstract, black and white, 4 X 4 square matrices. Age-related decrements in memory performance were associated with stimulus complexity but not with response delay. Older subjects also reported experiencing encoding difficulties during the registration phase. The results were discussed with reference to the locus of age-related decrements in visual short-term memory.     

Specific and varied practice of motor skill

To assess the potential effect of specific and varied practice on the development of motor schema, 64 children in two age groups (8 yr. and 12 yr.) were tested on a simple throwing task at the beginning and end of a 12-wk. physical education program. For the throwing test the children were assigned to either a specificity or a schema group (varied practice). The task was performed without visual feedback, but knowledge of results was given after each trial. Prior to both tests at the criterion target, the specific group was given practice throws using the criterion target distance, whereas the schema group practiced on two other targets. No differences were found between the two groups at the beginning of the program but on the posttest those children receiving a variety of practice on the throwing task performed significantly better than the specific-practice group. Thus it was suggested that a varied practice schedule may facilitate the initial formation of motor schema, and this process may be enhanced by participation in a physical education program.     

Tests of symmetry in three-way contingency tables

Three-dimensional contingency tables are analyzed, with one variable (e.g., sex) as a factor, and with a natural relation between the other variables (e.g. left and right eye vision). Models of special interest, like symmetry and proportional symmetry between the related variables, and homogeneity across the factor levels, are investigated. Maximum likelihood estimators of parameters and partitions of chi-square goodness-of-fit statistics are explicitly presented; the independence of certain models is noted, and an example is discussed.     

The dimensionality of vocational commitment: An empirical assessment of Ramsay's three-factor model with trainee nurses

The validity of Ramsey's three factor model of vocational commitment – consisting of ego-involvement (ranging from altruism to self-orientation), pre-dispositions, and occupational possibilities – is examined Although no data is provided relevant to the altruism end of the ego-involvement continuum, analyses of data from a sample of trainee nurses indicated that the three measures of self-orientation, predispositions, and occupational possibilities possessed satisfactory internal consistency and discriminant validity, thus providing support for the three-dimensional model.     

Electromyographic indications of laryngeal-area activity during stuttering expectancy

Using surface electrodes, mean microvolt values of laryngeal-area muscle activity were determined for 13 male and 6 female stutterers during 10-sec periods in which single words were silently read and stuttering expectancy was indicated. No significant differences in levels of laryngeal-area muscle activity were found between periods of fluency expectancy and stuttering expectancy preceding both fluent and stuttered speech. The results were interpreted as being nonsupportive of the hypothesis that a breakdown in stutterers' laryngeal-area muscle activity occurs during moments of stuttering expectancy. In addition, the results suggest that the most common rationale for the utilization of laryngeal biofeedback procedures to enhance fluency should be questioned.     

Visual laterality patterns for pure- versus mixed-list presentation

In Experiment 1, an overall left visual field advantage for nonverbal form recognition was found in a pure list of forms, but an overall right visual field form recognition advantage was found when the form trials were randomly intermixed with word recognition trials. Form complexity also influenced the form recognition laterality pattern, but the complexity effects were independent of (i.e., additive with) those produced by randomly mixing forms with words. Experiment 2 found that the mixed-list laterality pattern was unchanged by a pretrial cue indicating whether a word or form would follow. Experiments 3 and 4 demonstrated that holding two nouns in memory on each trial in a pure list of forms has much the same effect on laterality pattern as mixing forms with words but that the combined effect of these two variables is no larger than the effect of either variable alone. The entire pattern of results suggests that (a) laterality patterns are caused by the interaction of several factors, (b) the effects of random mixing and concurrent verbal memory are both caused by selective left-hemisphere activation, and (c) the form-complexity effects are caused by some other mechanism--perhaps subtle difference in stimulus codability.