INTERRELATING NATURE, HUMANITY, AND THE WORK OF GOD: SOME ISSUES FOR FUTURE REFLECTION

Abstract. This essay suggests some future items for an agenda about human viability, defined as survivability with meaning and purpose, by exploring interrelations between nature, humanity, and the work of God. It argues for intrinsic and creative value in nature, so there is a value kinship, as well as a factual kinship, between humans, nature, and God-working. It considers humans as "webs of culture, life, and cosmos" and suggests some implications of this notion of human nature for viability. And it asks what human fulfillment can be in light of the awesome creative-destroying-recreative activity that seems to be the ground of an evolving universe.     

Virtual Time-to-Collision and Human Postural Control

This article is a report on 3 experiments designed so that the role of virtual time-to-collision (VTC), which specifies the spatiotemporal proximity of the center of pressure to the postural stability boundary in the regulation of posture in upright stances, could be examined. Virtual time-to-collision was estimated for normal upright stance with different bases of support, and for postural oscillations in which the speed of movement and instructional constraints on the coordination mode used were manipulated. The results showed that virtual time-to-collision was predictably reduced as (a) the base of support was reduced, (b) the speed of the postural oscillation was increased, and (c) the number of biomechanical degrees of freedom regulated in the coordination mode increased. Over a range of task conditions, the coefficients of variation of the VTC time-series were significantly lower than the coefficients of variation for the velocity and acceleration time series of the center of pressure. The absolute values of VTC increased with the increment of the ground reaction forces a performer generated to avoid falling while approaching the stability boundary. These findings are consistent with the proposition that VTC may serve as an organizing informational control parameter for posture.     

The Ketamine Model of the Near-Death Experience: A Central Role for the N-Methyl-D-Aspartate Receptor

Near-death experiences (NDEs) can be reproduced by ketamine via blockade of receptors in the brain for the neurotransmitter glutamate, the N-methyl-D-aspartate (NMDA) receptors. Conditions that precipitate NDEs, such as hypoxia, ischemia, hypoglycemia, and temporal lobe epilepsy, have been shown to release a flood of glutamate, overactivating NMDA receptors and resulting in neurotoxicity. Ketamine prevents this neurotoxicity. There are substances in the brain that bind to the same receptor site as ketamine. Conditions that trigger a glutamate flood may also trigger a flood of neuroprotective agents that bind to NMDA receptors to protect cells, leading to an altered state of consciousness like that produced by ketamine.     

Visual control of discrete aiming movements

An experiment is reported which investigated the visual control of discrete rapid arm movements. Subjects were required to move as rapidly as possible to several target width-movement distance combinations under both visual and non-visual conditions. The movement time (MT) data were supportive of Fitts' Law in that MT was linearly related and highly correlated to the Index of Difficulty (ID). MT was also similar for different target width-distance combinations sharing the same ID value. The error rate analysis, which compared visual to non-visual perfromance, indicated that vision was only used, and to varying degrees, when MT exceeded 200 ms (3.58 ID level). There was some evidence that vision was differentially used within target width-distance combinations sharing the same ID. Estimates of endpoint variability generally reflected the results of the error rate analysis. These results do not support the discrete correction model of Fitts' Law proposed by Keele (1968).     

A 64-station computer-assisted teaching and research facility

A 64-subject computer-controlled laboratory for use in research and as a teaching aid is described. The laboratory hardware includes an 8K minicomputer, a 64-channel input multiplexor, and a video display generator. The software includes a complete operating system and an easy-to-use programming language. The entire laboratory, including the computer, was built for under $12,000.     

Signal identification: The comparison of two competitive theories

Attention, Perception, & Psychophysics - On each of a series of random trials, 10 observers had to identify which of two possible tones of different amplitude had been presented. Two theories...     

PROSS: A process control programming language

PROSS, a programming language for small- and medium-scale process control computers, is presented. The PROSS language, whose structure and syntax were expressly designed for ease of use by psychologists, is summarized and exemplified in a sample procedure. The structure of an existing PROSS compiler is briefly summarized.     

A test of the assumptions of multidimensional scaling by separating sensitivity and response bias

Summary This study investigates one of the main assumptions underlying multidimensional scaling models. It is tested whether the violation of decomposability found in previous studies can be explained by variation in sensitivity or in response bias. Rectangles of different shape served as stimuli in an experiment using a matching procedure. In addition the probability for presenting pairs of identical stimuli was varied. The data were analysed by a model separating response bias and sensitivity. Six versions of the model with different numbers of parameters were applied. The results suggest that the violation of decomposability comes from variation in sensitivity and not in response bias.This research was supported by a grant from the Deutsche Forschungsgemeinschaft to the first author. All computing was done on the Telefunken TR 440 of the Deutsches Rechenzentrum Darmstadt.     

On counteradaptation

Often adaptation to artificially altered stimulation takes place because veridical stimulation that produces the same perceptual property that is produced by the altered stimulation is also received. In these cases, an assimilation of the two perceptual processes produced by the two different stimulations (the altered and the veridical) is supposed to be responsible for the adaptation that is achieved. This hypothesis, which was formulated by Wallach and Karsh (1963), would be confirmed by demonstrating a modification of the perceptual process produced by veridical stimulation rather than the one produced by the altered stimulation. We demonstrated this by having S observe in the dark for 20 min a luminous figure that objectively expanded as it moved toward S and contracted as it moved away. But instead of testing for changes in size perception as such, we tested for a change in the relation between accommodation and convergence on the one hand and registered distance on the other. In one experiment, such a change was measured by obtaining estimates of perceived size and depth before and after the adaptation period. Highly significant changes of size and significantly greater changes of stereoscopic depth were obtained. Inasmuch as stereoscopic vision was totally absent from the adaptation conditions, the change in stereoscopic depth that was larger than the size change can only be ascribed to a change in registered distance. In another experiment, we tested for a change in distance by having S point from the side to a vertical line, before and again after the adaptation period, under conditions where only accommodation and convergence could serve as distance cues. Significant changes in the pointing distance were measured, indicating more directly a change in the relation between these oculomotor adjustments and perceived distance. We propose the term counteradaptation for such modification of a perceptual process away from veridicality.