Control theories in motor behavior

The goal of contemporary motor control theorist is the delineation of the “language” of movements. That is, in what unambiguous code are the parameters of movement specified, given the composition of the human body? In this pursuit not only are the elements of the language of movement sought, but the rules of combination or syntax of movement are also to be derived. This paper compares a number of motor control theories according to the form of control they exhibit and according to their ability to address issues in the area. Recurring theoretical trends in motor control are examined and the evidence for each is reviewed, emphasizing their explanatory power in the classical problems of control: motor equivalence (Hebb 1949), complexity (Bernstein 1967), and variability (Glencross 1980; Schmidt 1975, 1976).     

Deviation from hierarchical structure in recall: Is there an “optimal” structure?

Past research has suggested that proportionally more superordinate than sub-ordinate propositions are recalled from expository texts, following a hierarchical analysis of the text structure. Since free recall has typically followed this hierarchical pattern, several researchers have assumed that the related memory structures are isomorphic to the text structure. However, few of these studies have examined how individual differences and text structure interact to affect free recall. In two experiments, the assumption of hierarchical patterns of children's recall of expository text was tested. In Experiment 1, high- and average-ability fourth graders (9 years old) were asked to read and recall a passage. Experiment 2 was a replication and extension of Experiment 1. In this experiment, fourth and sixth graders (9 and 11 years old) read and recalled a different passage. The combined results of both experiments support the notion that there is probably no one optimal hierarchical structure for storage and retrieval of expository text.     

QUANTUM PHYSICS AND FREEDOM IN A WHITEHEADIAN PERSPECTIVE

This paper attempts to demonstrate the critical significance of early advances in quantum physics for Alfred North Whiteheads development of the categories of his metaphysics and to illustrate the capacity of his system to serve as a bridge between the sciences and the humanities by relating specific Whiteheadian categories to concrete microphysical behavior with special reference to the notion of freedom.     

Direct and continuous measurement of relational learning in human pavlovian conditioning

Three experiments were conducted employing a continuous measure of conditional stimulus/unconditional stimulus (CS/US) contingencies as perceived by the subject (i.e., subjective contingency or SC). It is argued that direct measurement of relational learning, as indexed by SC, can lead to a better understanding of Pavlovian conditioning processes. The first two experiments applied this approach to a methodologic controversy, raising the debate from a procedure-based argument to testing what the subject actually learns about CS/US relationships. While the issue was not resolved, testable hypotheses for future research were generated from the data. The third experiment contrasted the contingency stimulus-stimulus (S-S) account of Pavlovian conditioning with an earlier stimulus-response (S-R) continguity-reinforcement account. In this experiment, both SC and skin resistance were measured. Evidence for the existence of both cognitive-propositional and response-learning processes in conditioning was obtained.     

Entry-Level Employment Prospects for Women in College-Student Personnel Work

Women are no longer underrepresented in student-personnel preparation programs. Although this situation is noteworthy, it may not be without potentially frustrating consequences for the increased number of female master's degree graduates who are seeking a limited number of entry-level positions. Whether the increase in women will have deleterious effects on placement remains to be seen. In the meantime, women (and men) should be made aware of the inherent free-market employment risks when contemplating a career in student-personnel work.     

Assessment of human obesity: The measurement of body composition

The most common methods of assessing degree of obesity in humans are reviewed. These include anthropometry, somatotyping, bodyweight, skinfold calipering, densitometry, and several nondensitometric procedures. The evidence suggests that bodyweight may often be an unreliable and invalid index of obesity. The parameters influencing its inaccuracy are discussed. These include age, height, sex, muscularity, and degree of obesity or amount of recent weight loss. The most reliable and valid measures of human bodyfat are generally the most complicated and impractical. Compromise assessment procedures involving nonintrusive measurement of subcutaneous fat and selected anthropometric dimensions may offer an incomplete but welcome improvement over sole reliance on bodyweight as an index of obesity.     

Stimulus context and duration discrimination

The ability of human observers to discriminate duration was assessed in two types of tasks: (1) pulse tasks, in which the observer compared the duration of two brief increments in an ongoing sinusoid, and (2) gap tasks, in which the observer compared the duration of two brief interruptions in an ongoing sinusoid. Performance in these tasks was assessed in three different contexts: noise alone, noise plus continuous sinusoids, and noise plus continuous sinusoids chosen to induce a pitch segregation effect. Performance in the pulse task was independent of the changes in context; however, performance in the gap task changed as a function of context condition. There was a large decrement in the observers’ ability to discriminate duration when the stimulus ensemble induced the pitch segregation effect. The results are discussed in terms of the relationship between duration discrimination and stimulus variations which do not carry duration information.     

Self-monitoring and self-reinforcement processes in a pre-transsexual boy

Young boys with normal male physical status who manifest feminine gender-role behavior and verbalize a cross-gender identity are high-risk for later adult sexual adjustment problems, e.g., transsexualism and homosexual conflicts (Bakwin, 1968; Lebovitz, 1972; Stoller, 1968; Zuger, 1966). In the only published experimental treatment studies on child gender disturbance in which replication procedures were used, Rekers and his colleagues empirically demonstrated external stimulus control and reinforcement control over pronounced feminine behavior in young boys with serious gender identity and behavior disturbance (Rekers and Lovaas, 1974; Rekers, Lovaas and Low, 1974; Rekers, Willis, Yates, Rosen and Low, in press; Rekers, Yates, Willis, Rosen and Taubman, 1976). To potentially minimize the previously reported stimulus specificity of the extrinsic reinforcement effects, this study introduces, for the first time, behavioral self-control strategies to decrease feminine behavior in a cross-gender identified boy. A 6-year-old boy was taught to self-monitor his own sex-role behavior, and then to self-reinforce gender-appropriate responding. A behavioral cueing procedure was used during the initial phases of the training of self-monitoring.