The dimensionality of movement trajectories and the degrees of freedom problem: A tutorial

A framework for investigating the degrees of freedom problem (how the large number of degrees of freedom (dfs) at micro-levels of analysis are compressed to the smaller number of dfs at the macro-level of behavior) is discussed. The discussion centers around the use of dynamical systems as models of coordinative structures. Dimensionality analysis, a technique for assessing the dfs of an observable behavior, is explained both intuitively and in detail. By measuring the dfs being produced by actors, we can constrain our dynamical models of how actors produce coordinated behavior.     

Teaching gender-related material: The effect of group sex composition on perceptions of a female instructor

This study investigated how group sex composition affects female and male students' perceptions of female instructors who teach in the area of counseling women. Three components of person perception were assessed: cognitive, affective, and behavioral. The cognitive domain included evaluations of the instructor and the subject matter presented; the affective domain included emotional responses to the instructor and the subject matter; and the behavioral domain included actions in response to the instructor, operationalized as the number of questions asked by students. Students with some interest in a career in the helping professions viewed one of two videotapes either with a group of same-sex peers or in a group in which they were the only male or female. One tape described a gender-neutral topic (psychology and the law) and the other described a female gender-related topic (sex bias in counseling women). The same female instructor made both presentations. Students then completed the measures. As predicted, the sex composition of the student group affected person perception, especially in the affective and behavior domains. Recommendations are made for future research.This study was supported by a small grant from the University Research Institute, University of Texas at Austin. Appreciation is expressed to Sherry Fowler, Bob Haverstick, and Kathy Thomas for help with data collection and to Carolyn Bates and Ken Wilgus for coding the open-ended responses. A paper based on this research was presented at the meetings of the American Psychological Association, August 1987.     

Illness and the paradigm of lived body

This paper suggests that the paradigm of lived body (as it is developed in the works of Merleau-Ponty, Sartre and Zaner) provides important insights into the experience of illness. In particular it is noted that, as embodied persons, we experience illness primarily as a disruption of lived body rather than as a dysfunction of biological body. An account is given of the manner in which such fundamental features of embodiment as bodily intentionality, primary meaning, contextural organization, body image, gestural display, lived spatiality and temporality, are disrupted in illness causing a concurrent disorganization of the patient's self and world. The paradigm of lived body has important applications for medical practice. It provides a fuller account of illness than does the prevailing reductionist Cartesian paradigm of body, more directly addresses the existential predicament of illness, and orients the clinical focus around the personhood of the patient.     

Space-time behavior of single and bimanual rhythmical movements: data and limit cycle model

How do space and time relate in rhythmical tasks that require the limbs to move singly or together in various modes of coordination? And what kind of minimal theoretical model could account for the observed data? Earlier findings for human cyclical movements were consistent with a nonlinear, limit cycle oscillator model (Kelso, Holt, Rubin, & Kugler, 1981) although no detailed modeling was performed at that time. In the present study, kinematic data were sampled at 200 samples/second, and a detailed analysis of movement amplitude, frequency, peak velocity, and relative phase (for the bimanual modes, in phase and antiphase) was performed. As frequency was scaled from 1 to 6 Hz (in steps of 1 Hz) using a pacing metronome, amplitude dropped inversely and peak velocity increased. Within a frequency condition, the movement's amplitude scaled directly with its peak velocity. These diverse kinematic behaviors were modeled explicitly in terms of low-dimensional (nonlinear) dissipative dynamics, with linear stiffness as the only control parameter. Data and model are shown to compare favorably. The abstract, dynamical model offers a unified treatment of a number of fundamental aspects of movement coordination and control.     

TRAINING COUNSELING SKILLS: AN EXPERIMENTAL ANALYSIS AND SOCIAL VALIDATION

A community development perspective suggests the value of using local resources to solve local problems. Two low-income staff of a community service center served as nonprofessional counselors after receiving a training program consisting of written instructions, practice, and performance feedback. The effects of the 40-hour training program were positive for both counseling and problem-solving skills. There was also evidence of generalization of counseling performance across clients, problems, and time. In addition, expert judges' ratings of performance were obtained as a measure of social validity. These findings suggest that the training procedures are effective in enhancing the counseling and problem-solving skills of low-income nonprofessionals.     

KOHLBERG'S THEORY OF MORAL DEVELOPMENT: CRITICAL ANALYSIS OF VALIDATION STUDIES WITH THE DEFINING ISSUES TEST

This paper evaluates studies that have used the Defining Issues Test for validating Kohlberg's theory of moral stage development. Although this test was introduced to overcome inadequacies with Kohlberg's procedure, it too encounters serious methodological and conceptual difficulties. Its limitations include truncation of the stages and age range assessed. The validation studies, both cross-sectional and longitudinal, have used a correlational design and confounded age with other variables. Threats to internal and external validity obviate support claimed for Kohlberg; moral reasoning thus measured seems a function of education, IQ, direct moral training, and cultural values rather than maturation. Nor is the stage model upheld by longitudinal data, which fail to reveal sequential stepwise change and belie occasional regression. Attempted redefinition of the stage concept to salvage these data has not rescued Kohlberg's proposal, which remains to be validated empirically.     

The development of a child assessment interview for research and clinical use

The Child Assessment Schedule (CAS) was developed to address the need for a standardized child interview that could be used for research and clinical purposes. The CAS has several distinguishing characteristics: (1) Questions and responses are standardized, (2) the format was designed to enhance rapport with the child, and (3) information necessary for DSM III childhood diagnoses is explicitly solicited. The CAS was administered to 32 child outpatients, 18 inpatients, and 37 normal controls. Derived scores were obtained for total psychopathology, 11 content areas, and 9 symptom complexes. Interrater reliability for the total CAS score was quite high. The CAS was able to discriminate among the three groups in total score indicating degree of psychopathology, on 9 of the 11 content areas, and on 8 of the 9 symptom complexes. Significant correlations were found between the CAS and maternal report of child behavior and between the CAS and child selfreport of internal affects. It was concluded that the CAS has adequate reliability and validity, although further research is indicated.     

Learning of a serial task by different age groups

In a serial learning task given to subjects whose ages ranged from twenty to seventy, a decline in performance showed itself as a loss of speed in the thirties, a loss of accuracy in the forties, and a marked loss of both speed and accuracy in the fifties and sixties. Experiments on recall and reorganization of material verified that older subjects were forgetting more quickly than younger, but that one of their main difficulties was an inability to substitute new reponses in an already mentally formed sequence.

Older subjects were not introducing new learning features but accentuating normal tendencies, such as the repetition of the same error at the same serial position. In so far as subjects learned their repeated errors, final learning involved unlearning, with the often observable phenomenon of the previously learned error serving as the cue for the more recently learned correct response. In terms of schematic concepts of mental functions, serial learning difficulty was not so much the formation of a general “scheme” but its subsequent amendment. Preformed habits influenced both the learning procedure and its results, particularly in the constraints and expectancies which the making of one serial response had upon another.     

Different thresholds for recognition—further experiments on interpolated recall and recognition

Three experiments are described which have attempted to identify some of the difficulties in recognition after interpolated recall. In the first, complex picture material was used, and, though subjects were able to recognize the original after interpolated recall, they did in fact recognize fewer items. This posed the query, why should the recall of some items depress the recognition of other unrecalled items? The second experiment showed that in recognition the stronger (correct) memory has an inhibitory effect on a weaker (also correct) memory. The third experiment therefore examined the hypothesis that the juxtaposition of better and worse known items raises the threshold of recognition of the worse known, and confirmed that the threshold of recognition for an item varies according to its context. The theoretical significance of this finding is briefly indicated.