Biomechanical motor patterns in normal walking

Motor patterns in normal human gait are evident in several biomechanical and EMG analyses over the stride period. Some of these patterns are invariant over the stride period with changes of cadence, whole others are closely correlated with speed changes. The findings for slow, natural, and fast walking are summarized: 1. Joint angle patterns over the stride period are quite invariant, and do not change with cadence; 2. Moment of force patterns at the ankle are least variable and quite consistent at all speeds; 3. A recently defined support moment is quite consistent at all speeds. 4. Moments at the knee and hip are highly variable at all cadences but decrease their variability as cadence increases; 5. Mechanical power patterns at all joints show consistent timing over the stride period; 6. EMG profiles of 5 muscles show consistent timing over the stride, but the amplitude increases as walking speed increases. Arguments are presented to support the concept that walking speed is largely controlled by gain and that the timing of the motor patterns, which is extremely tightly synchronized with the anatomical position, is under major afferent control.     

Measures of visual-auditory integration and their relations to reading achievement in early grades.

Several tests of visual-auditory integration were designed to represent the various tasks that have been found to correlate with reading achievement in the early grades. The battery of tests was administered to about 100 first, 84 second, and 110 third graders. Several questions were posed: (1) Do the various tests of integration measure the same underlying ability or are there separate abilities that are tapped by the various tests? (2) Are the various tests correlated with reading because they tap a common integrative ability that is related to reading or are there several abilities, each related to reading independently to the others? (3) To what extent are the relationships between the integrative abilities and reading separate from the relationship between reading and IQ? Results indicated that there are separate integrative abilities, and multiple regression analyses showed that several of the integrative measures were correlated with reading independently of the other measures. Further, several of the integrative measures accounted for significant reading variance beyond that accounted for by IQ tests. The results were discussed in the context of the need to differentiate adequately between various patterns of perceptual weakness in the diagnosis and remediation of perceptually based reading difficulties.     

Testing expectancy theory predictions using behaviorally based measures of motivational effort for engineers

Expectancy theory predictions were tested using a sample of engineers who had been rated on dimensions of work motivation or effort (in contrast to performance) using the behaviorally based rating scales designed by Landy and Guion (1970). It was found that the expectancy model was only weakly upheld for an older (41 or older) age subgroup, while few relationships were observed for a younger (below 41) age group. Also, the motivational behavior scales did not show any enhanced predictability when compared to a more global rating of job performance.     

Relation of the verbal transformation and the phonemic restoration effects

This study examined the relationship between illusory changes of repeated words (“verbal transformations” or VTs) and illusory presence of phonemes replaced by noise (“phonemic restorations” or PhRs). Separate groups of 20 subjects were each presented with one of four taped variations of the repeated stimulus word “magistrate”: stimulus intact (MAGISTRATE); speech sound “s” removed and replaced with a silent gap (MAGI TRATE); speech sound “s” removed and replaced with a louder extraneous sound (MAGI¹TRATE); syllable “gis” removed and replaced with a louder extraneous sound (MA⁷¹TRATE). The stimuli MAGI¹TRATE and MA⁷¹TRATE evoked PhRs, and with these stimuli, the phonetic changes corresponding to VTs were concentrated at the perceptually restored portions of the word. It is suggested that both PhRs and VTs are related directly to perceptual processes employed normally for the correction of errors and resolution of ambiguities in speech. Other effects of PhRs upon VTs are described and implications of these findings for mechanisms underlying speech perception are discussed.     

“Generalized imitation” on a nonimitative task: Effects of modeling and task history

Two experiments investigated characteristic generalized imitation procedures on a nonimitative successive visual discrimination task. In Experiment I, no discriminative behavior was obtained though a number of procedures designed to enhance discrimination were employed. The introduction of a differential modeling procedure after nine or 10 sessions of nondifferential performance was ineffective in producing differential responding for three of four Ss. In the second experiment, the differential modeling procedure was introduced as an initial manipulation and was successful in establishing discriminative performance in all Ss. After several sessions of differential responding, the observation of a model performing nondifferentially was relatively ineffective in altering the pattern of responding. These results suggest (1) that modeling may be functional in altering a S's behavior depending on what point in the procedures the manipulation is introduced and (2) that certain procedural variables may define a functional response class characterized by the failure to develop discriminative responding.