DOES EFFORT PLAY A ROLE IN THE EFFECT OF RESPONSE REQUIREMENTS ON DELAYED MATCHING TO SAMPLE?

The possible role of "effort" in the accuracy of pigeons' performance on a delayed matching-to-sample procedure was investigated by examining the effects of response requirements that accompanied a trial-initiating stimulus and that accompanied a sample stimulus. In the first experiment, the effect of varying the size of a fixed-ratio requirement for responses during an initiating stimulus was compared to that of varying a similar requirement for responses during the sample stimulus. Accuracy increased reliably with increases in the ratio scheduled during the sample stimulus, but was not significantly affected by increases in the ratio scheduled on the key during the initiating stimulus. In another phase of Experiment 1, sample duration was held constant while the ratio requirement was varied during the initiating stimulus. Again, accuracy of matching to sample was not significantly affected by the size of the ratio scheduled during the initiating stimulus. Experiment 2 provided a systematic replication of these results in another group of pigeons and included a more detailed analysis of responding. These results support the view that increases in sample-response requirement facilitate accuracy of delayed matching by increasing the durations of exposure to the sample stimuli, and do not support a role of effort in the sample-response effect. In Experiment 3, the facilitative effect of responses on the sample but not of those on the initiating stimulus was replicated using a simultaneous matching-to-sample procedure. This finding provides further evidence against an interpretation of response-requirement effects that appeals to effort; the finding also suggests that sample exposure might affect initial discrimination of the sample rather than remembering the sample.     

A Realist Analysis of the Relationship between Logic and Experience

I undertake to explain how the well known laws of formal logic – Barbara Syllogism, modus ponens, etc. – relate to experience by developing Edmund Husserl's critique ofFormalism and Psychologism in logical theory and then briefly explaining his positive views of the laws of logic. His view rests upon his understanding of the proposition as a complex, intentional property. The laws of formal logic are, on his view (and mine), statements about the truth values of propositions as determined by their formal character and relationships alone. The laws thus understood explain how algorithms set up to mirror them can accomplish what they do to advance knowledge, even though they operate purely mechanically. Further, they explain the proper sense in which formal laws "govern," and may guide, processes of actual thinking. Husserl's theory is a realist theory in the sense that, on his interpretation, the laws of pure or formal logic hold true regardless of what any individual, culture or species may or may not think, or even if no thinking ever occurs. This revised version was published online in June 2006 with corrections to the Cover Date.     

Analog scale,magnitude estimation,and person trade‐off as measures of health utility: biases and their correction

Subjects judged the disutility of health conditions (e.g. blindness) using one of them (e.g. blindness+deafness) as a standard, using three elicitation methods: analog scale (AS, how bad is blindness compared to blindness+deafness?); magnitude estimation (ME, blindness+deafness is how many times as bad as blindness?); and person trade‐off (PTO, how many people cured of blindness is as good as 10 people cured of blindness+deafness?). ME disutilities of the less bad condition were smallest, and AS was highest. Interleaving PTO with ME made PTO more like ME. AS disutilities were inconsistent with direct judgments of differences between pairs of conditions. ME and PTO judgments were internally inconsistent: e.g. the disutility of one‐eye‐blindness relative to blindness+deafness was larger than predicted from comparison of each to blindness. Consistency training reduced inconsistency, increased agreement between AS and PTO, and transferred from one method to the other. The results support the use of consistency checks in utility elicitation. Copyright © 2001 John Wiley & Sons, Ltd.     

Caring for decisionally incapacitated elderly

Although treating the elderly occasion the same kinds of ethical issues as treating other patients, specific problems do arise when making decisions for persons, once competent, who no longer can express their values. I examine the problem of decisional incapacity and offer a critique of the principles, such as substituted judgment, and the instruments, such as advance directives, living wills, other instructional directives, as well as surrogate decision-makers.     

On "risk" and reward: investigating state anhedonia in psychometrically defined schizotypy and schizophrenia

Anhedonia, defined as dysfunction in the experience of pleasant emotions, is a hallmark symptom of the schizophrenia spectrum. Of interest, it is well documented that patients with schizophrenia, at least as a group, do not show reductions in their state experience of pleasant stimuli. However, there is emerging evidence to suggest that individuals with schizotypy--defined as the personality organization reflecting the latent vulnerability for schizophrenia--do show these state deficits. This is paradoxical in that schizophrenia reflects a more pathological state in virtually every conceivable domain as compared with schizotypy. The present study examined self-reported affective reactions to neutral-, bad-, and good-valenced stimuli in individuals with psychometrically defined schizotypy and schizophrenia. Two separate control groups were also included, comprising psychometrically defined controls and stable outpatients with affective disorders. With no exceptions, the schizotypy group reported significantly less pleasant affect for each of the three conditions than each of the other groups. Conversely, the schizophrenia group did not statistically differ from the control groups for any of the conditions. Within both the schizotypy and schizophrenia groups, severity of negative symptoms/traits was associated with less pleasant report. We found that individuals with prominent negative symptoms and traits from the schizophrenia and schizotypy groups resembled each other in terms of state anhedonia. The present findings did not appear to reflect comorbid depression or anxiety. Our discussion centers on this apparent paradox in the schizophrenia spectrum--that individuals with schizotypy exhibit state anhedonia, whereas patients with schizophrenia do not.