Patterns of Human Interlimb Coordination Emerge from the Properties of Non-Linear,Limit Cycle Oscillatory Processes

The present article represents an initial attempt to offer a principled solution to a fundamental problem of movement identified by Bernstein (1967), namely, how the degrees of freedom of the motor system are regulated. Conventional views of movement control focus on motor programs or closed-loop devices and have little or nothing to say on this matter. As an appropriate conceptual framework we offer Iberall and his colleagues’ physical theory of homeokinetics first elaborated for movement by Kugler, Kelso, and Turvey (1980). Homeokinetic theory characterizes biological systems as ensembles of non-linear, limit cycle oscillatory processes coupled and mutually entrained at all levels of organization. Patterns of interlimb coordination may be predicted from the properties of non-linear, limit cycle oscillators. In a set of experiments and formal demonstrations we show that cyclical, two-handed movements maintain fixed amplitude and frequency (a stable limit cycle organization) under the following conditions: (a) when brief and constantly applied load perturbations are imposed on one hand or the other, (b) regardless of the presence or absence of fixed mechanical constraints, and (c) in the face of a range of external driving frequencies from a visual source. In addition, we observe a tight phasic relationship between the hands before and after perturbations (quantified by cross-correlation techniques), a tendency of one limb to entrain the other (mutual entrainment) and that limbs cycling at different frequencies reveal non-arbitrary, sub-harmonic relationships (small integer, subharmonic entrainment). In short, all the above patterns of interlimb coordination fall out of a non-linear oscillatory design. Discussion focuses on the compatibility of these results with past and present neurobiological work, and the theoretical insights into problems of movement offered by homeokinetic physics. Among these are, we think, the beginnings of a principled solution to the degrees of freedom problem, and the tentative claim that coordination and control are emergent consequences of dynamical interactions among non-linear, limit cycle oscillatory processes.     

The Tat Newsletter

In this article, we argue that the student's first lessons in ethical decision making in personality assessment are in those assessment courses that have a practice component. In these courses, the student has an opportunity to experience in vivo how ethical problems are identified, addressed, and resolved. The faculty member's demonstration of a process wherein the ethical principles activated are highlighted and explored, will enable students to internalize a model for addressing future dilemmas. Four particular ethical situations are considered: (a) the students' procurement of personal experience with personality testing, (b) the identification of assessment participants, (c) the development of informed consent procedures for assessment participants, and (d) classroom presentations. This discussion does not provide concrete solutions to ethical problems but offers a consideration of the relevant ethical principles that any adequate solution must encompass.     

Embodied Knowing, Embodied Theology: What Happened to the Body?

As part of a larger project on human bodies and theological knowledge, this paper is a preliminary investigation into how biology and physicality shape human knowing. It asks whether, in the frequent use of the phrase embodied knowing or embodied theology, religion scholars have paid sufficient attention to actual bodies. It argues that there has been a lapse of attention to physical dimensions of bodies in the unreflective employment of such phrases, ironically among practical and pastoral theologians who have strong interest in understanding how theology operates on the ground. The paper traces evolving interest in embodiment across several disciplines, including theology, before exploring what might be learned from recent research on evolution, biology, and bodies in anthropology and the biological sciences.     

Genetic Counseling Supervisor Competencies: Results of a Delphi Study

Clinical supervision is a critical component of genetic counseling student preparation, yet empirically-determined competencies for genetic counseling supervisors are lacking. In this study a modified, two-round Delphi method was used to gain consensus about important genetic counseling supervisor knowledge, characteristics, and skills. Program directors and assistant directors of American Board of Genetic Counseling accredited genetic counseling programs in North America (N?=?33) were invited to participate and to recruit three experienced supervisors. Seventy-four individuals completed Round 1 and, of these, 61 completed Round 2. Approximately two-thirds were clinical supervisors from prenatal, pediatrics, cancer, and adult clinics; one-third were program directors. Participants rated the importance for genetic counseling supervisors of 158 items derived from supervision literature in allied health professions. They rated 142 items (89.9 %) as highly important. Content analysis of these items yielded six supervisor competency domains: Personal traits and characteristics; relationship building and maintenance; student evaluation; student centered supervision; guidance and monitoring of patient care; and ethical and legal aspects of supervision. The results provide a basis for training genetic counseling supervisors and for further research to refine and validate supervisor competencies.     

Children's binary prediction of partially learnable sequences followed by an all-correct procedure

Six groups of 20 subjects each were run individually in a binary prediction situation with each alternative occurring equally often. Two age groups were employed; subjects were either in second or sixth grades. For one-third of the subjects at each age level, the events occurred in runs of either two or six; another third observed events which occurred in runs of either five or six; the other subjects received a random sequence of events. All subjects then received an additional 50 trials in which every prediction was correct. The results indicated some sensitivity to run length characteristics. Fewer errors of all types were made in the prediction of 5–6 sequences. The verbal reports and all-correct trial protocols revealed that at least the sixth graders employed some simple run length structure rules, although many instances of runs other than those presented in training occurred, showing much processing error. The results were discussed in terms of a general limited-capacity model of information-processing.     

Sex,Education, Age,and Cautiousness: Implications for Counselors

A cross‐sectional study of educated men and women showed that cautiousness, as measured by perceived problem‐solving ability, does not increase with age. Sex differences were nonsignificant. The results are discussed in terms of R. Schultz and J. Heckhausen's (1996) Life Span Model of Successful Aging.     

Symposium on The Ego and the Id after fifty years. The past and future of ego psychology.

Having six roots in ordinary observation and introspection, ego psychology has a long pre-Freudian history, which influenced Freud's first usages of Ich. His works before 1923 contain much that is substantively ego psychology; The Ego and the Id was not a paradigm change but a consolidation of pre-existing ideas. The structural theory replaced a model (topographic) which Freud actually used very little, especially clinically, and he failed to remedy its gravest methodological faults. The ego-id model is an integral part of metapsychology, and will pass out of use as the latter dies, with no detriment to clinical psychoanalysis.