Staying Together: A Bidirectional Delay–Coupled Approach to Joint Action

To understand how individuals adapt to and anticipate each other in joint tasks, we employ a bidirectional delay–coupled dynamical system that allows for mutual adaptation and anticipation. In delay–coupled systems, anticipation is achieved when one system compares its own time‐delayed behavior, which implicitly includes past information about the other system’s behavior, with the other system’s instantaneous behavior. Applied to joint music performance, the model allows each system to adapt its behavior to the dynamics of the other. Model predictions of asynchrony between two simultaneously produced musical voices were compared with duet pianists’ behavior; each partner performed one voice while auditory feedback perturbations occurred at unpredictable times during live performance. As the model predicted, when auditory feedback from one musical voice was removed, the asynchrony changed: The pianist’s voice that was removed anticipated (preceded) the actions of their partner. When the auditory feedback returned and both musicians could hear each other, they rapidly returned to baseline levels of asynchrony. To understand how the pianists anticipated each other, their performances were fitted by the model to examine change in model parameters (coupling strength, time‐delay). When auditory feedback for one or both voices was removed, the fits showed the expected decrease in coupling strength and time‐delay between the systems. When feedback about the voice(s) returned, the coupling strength and time‐delay returned to baseline. These findings support the idea that when people perform actions together, they do so as a coupled bidirectional anticipatory system.     

Beyond medical ethics: New directions for philosophy and medicine

A unique relationship exists between physicians and philosophers — one that expands on the constructive potential of the liaison between physicians and, for example, theologians, on the one hand, or, social workers on the other. This liaison should focus in the scientific aspects of medicine, not just the ethical aspects. Philosophers can provide physicians with a perspective on both the philosophy and the history of medicine through the ages — a sense of how medicine has adapted to the social cultural and ethical needs of each period. This perspective, while emphasizing medicine asscience, should not be limited to matters of methodology, or to criteria for distinguishing science from other intellectual pursuits, but should be concerned also with the history, sociology and politics of science. Both physicians and philosophers stand to gain from a strengthening of their active liaison now as never before; but most of all, the public will be the beneficiary.     

Medical education: The training of ethical physicians

This paper suggests that medical education be revised to assist in diffusing potential ethical dilemmas that arise during health care provision. A revised medical education would emphasize the role of the humanities in the training of physicians, especially in light of recent critiques of the canonical scientific model in general, and more specifically in the use of that model for medical training and practice.I wish to thank Dr. Mary Ann Cutter and Melissa M. Amaro for their critical suggestions.     

Cost analysis of the utilization of new vascular grafts

A cost analysis of the utilization of new expensive vascular grafts is performed, applying the methodology of decision analysis to the theoretical case of a sixty year old male patient undergoing femoropopliteal grafting for limb threatening ischemia. The problem is presented graphically as a decision tree, uncertainties are quantified in terms of probabilities and end outcomes are evaluated in monetary terms. This informations is then utilized to calculate cost values associated with alternative actions. Based on initial cumulative patency figures of the new more expensive grafts and the known performance of the older grafts, the initial high expense for the new grafts is justified economically, if the saphenous vein is not available. This analysis, apart from giving an answer to a specific clinical problem, can be viewed as a general model for cost analysis of surgical procedures.     

Four methods of locating the egocenter: A comparison of their predictive validities and reliabilities

An attempt was made to identify the best method of locating the egocenter by comparing the predictive validity and reliability of the four methods introduced by Fry (1950), Funaishi (1926), Howard and Templeton (1966), and Roelofs (1959). To determine predictive validity, egocenters located by these methods were used to predict the responses of 14 subjects on three visual direction tasks; the correlation between the predicted and the actual responses on each task was computed. To determine reliability, the test-retest stability and the internal consistency were estimated for each method. All of the methods were reliable, but only the Howard and Templeton method predicted the results on all three of the visual direction tasks. The high reliability and predictive validity of the Howard and Templeton method is attributed to its high precision.