The word "bioethics": its birth and the legacies of those who shaped it

Extensive historical sleuthing reveals that the word "bioethics" and the field of study it names experienced, in 1970/1971, a "bilocated birth" in Madison, Wisconsin, and in Washington, D.C. Van Rensselaer Potter, at the University of Wisconsin first coined the term; and André Hellegers, at Georgetown University, at the very least, latched onto the already-existing word "bioethics" and first used it in an institutional way to designate the focused area of inquiry that became an academic field of learning and a movement regarding public policy and the life sciences. A further comparison of the Potter and the Hellegers/Georgetown understandings of bioethics and the relative acceptance of the two views will appear in the March 1995 issue of this journal.     

Multimethodological approach to examining risk-taking

Research on risk-taking behavior has shown to yield inconsistent findings. Three studies were conducted using four different analysis techniques. The first study used a phenomenological approach and qualitative analysis to gain an understanding of risk-taking. A model of factors relating to risk-taking was developed and tested in a second study. The third study was conducted to develop scales of risk and used magnitude estimation and multidimensional scaling techniques. Results from the studies confirmed the multidimensionality of the construct of risk-taking. Also indicated was a gender difference in risk-taking behavior and perception. These studies expand our knowledge of risk-taking behavior in that 1) a method of categorizing risks was developed, 2) gender similarities and differences in risk-taking were explored, and 3) perceived magnitude and underlying dimensions of risk were developed.     

Meaning dominance norms for 120 homographs

Over the past two decades, homographs have been used in psychological experiments aimed at testing a variety of theoretical issues concerning memory and language. Often, such research requires prior knowledge of the dominance relations among various meanings of the homographs. Previously available homograph meaning norms are limited because they are now more than 10 years old, and they have typically reported only the two most dominant meanings even though many homographs have three or more common meanings. This paper presents normative data on 120 homographs from a relatively large, heterogeneous sample of subjects (N = 100). Meaning dominance was assessed by having subjects write the first definition that came to mind for each homograph. Definition responses were grouped by similarity, and the resulting meaning categories were verified against dictionary meaning classifications. The number of distinct meanings varied from two to six for the homographs investigated, and frequency of response is reported for all definition categories.     

Teaching the Rescorla-Wagner model using STELLA-II

Although the Rescorla-Wagner model is widely taught in learning courses, most textbooks present a simplified version that does not contain all of its parameters. On the basis of Rescorla and Wagner 1972) and the Turbo PASCAL program by Lachnit, Schneider, Lipp, and Kimme! (1988), we created a simulation using STELLA-II, an icon-based program by High Performance Systems, Inc. We argue that this simulation facilitates teaching the complete Rescorla-Wagner model. Using trans-switching (Kimmel & Ray, 1978; Lachnit, 1986; Murrin & Kimmel, 1986) as an example, we demonstrate the effectiveness of the STELLA-II version of the Rescorla-Wagner model as a heuristic tool.     

Hinton diagrams: Viewing connection strengths in neural networks

A graphical analysis similar to that used by Hinton and Shallice (1991) was applied to the hair cells of a simulated auditory transducer. The graphical analysis made it apparent that there were hair cells that responded to a narrow range of frequencies, as would be predicted by the tonotopic organization of the real physiology. In short, this study demonstrates the efficacy of using graphic techniques to examine the nature of the autopoetic organization of the hidden layer of back-propagation networks.     

Characterization of state transitions in spatially distributed,chaotic, nonlinear,dynamical systems in cerebral cortex

The neurons of cerebral cortex are largely autonomous and generate activity that is manifested in trains of microscopic axonal action potentials. The neurons interact by sparse but numerous synaptic connections to generate macroscopic dendritic activity patterns that are observed in electroencephalographic (EEG) waves. The macroscopic patterns are constructed by the populations and they shape the output of cortical neurons in parallel arrays. Sensory cortexes receive sensory information in the form of microscopic action potentials, which induce state transitions in population dynamics. Each state transition transforms sensory information to perceptual meaning. The EEG reflects both kinds of activity. The sensory input is accessed by time ensemble averaging, whereas the perceptual output is found by spatial ensemble averaging. Spatial phase gradients in the EEG are useful for identifying EEG segments in a sequence of state transitions in response to sensory input. The rapidity and flexibility with which they take place give strong reason to postulate that the mechanism for the construction of these sequences of patterns is a dynamical system operating in a chaotic domain.     

Measuring and predicting the effects of alcohol consumption on contrast sensitivity for stationary and moving gratings

Contrast sensitivity was measured for 12 healthy young males while sober, after ingestion of an alcohol placebo, and after ingestion of alcohol (95% grain alcohol; mean estimated blood alcohol level = .088%). Observations were made for both stationary gratings and gratings that traveled through a circular path and required pursuit eye movements. The significant alcohol-related reduction in contrast sensitivity was 2.6 times greater for moving (.29-log-unit reduction) than for stationary gratings (.11-log-unit reduction). The loss in contrast sensitivity for the moving gratings of high spatial frequency (12 cpd) was particularly severe (.37 log unit). Estimated blood alcohol level was correlated with the loss in contrast sensitivity for moving gratings (r = .61), but not with the loss for stationary gratings. Estimated blood alcohol level was strongly correlated with the difference between the loss in contrast sensitivity to moving and stationary gratings (r = .75). These results are consistent with reports that alcohol consumption degrades the ability to make pursuit eye movements. Subjects’ perceived intoxication level was not a reliable predictor of any index of visual performance.     

Matching components of self-report and peer-nomination personality measures

Two common methods of measuring personality variables are examined with respect to the ways in which they control respondent biases. A form of the mental-test theory model is developed which makes explicit differences in score components that result from different methodological constraints imposed by the two methods. From the model, it is possible to specify the operations necessary to provide equivalent information from the two sets of data. Performance of these operations in an empirical test supports the model by producing generally higher correlations between the variables having score components which are more closely matched.