Rationality,group choice and expected utility

In this paper I propose a view uniformly extending expected utility calculations to both individual and group choice contexts. By way of three related cases I discuss the problems inherent in applying expected utility to group choice cases. I show that the problem with such group cases does not essentially depend upon the fact that more than one agent is involved. A modified strategy is then devised allowing the application of the expected utility formula to these otherwise problematic cases. One case, however, leads to contradiction. But recognizing the falsity of the proposition.(1) If an agent x knows options A and B are both available, and x knows that were he to do A he would be better off (in every respect) than were he to do B, then doing A is more rational for x than doing B,allows the resolution of the contradiction and also allows my modified strategy to resolve otherwise paradoxical cases of group choice such as the Prisoners' Dilemma.This paper is dedicated to my parents, Arleen Eichengreen and Alvin Richter, for their encouragement, understanding, and financial support. Very special thanks also go to Daniel Hunter, Richard Sharvy, and Paul Horwich. In addition I owe a great deal to discussions and correspondence with Michael Ferejohn, John Ferejohn, Kit Fine, Allan Gibbard, Dale Jamieson, Gregory Kavka, David Lewis, J. Karel Lambert, Alice Perrin, Howard Pospesel, Brian Skyrms, J. Howard Sobel, and Michael Tooley.     

Hands up: attentional prioritization of space near the hand

This study explored whether hand location affected spatial attention. The authors used a visual covert-orienting paradigm to examine whether spatial attention mechanisms--location prioritization and shifting attention--were supported by bimodal, hand-centered representations of space. Placing 1 hand next to a target location, participants detected visual targets following highly predictive visual cues. There was no a priori reason for the hand to influence task performance unless hand presence influenced attention. Results showed that target detection near the hand was facilitated relative to detection away from the hand, regardless of cue validity. Similar facilitation was found with only proprioceptive or visual hand location information but not with arbitrary visual anchors or distant targets. Hand presence affected attentional prioritization of space, not the shifting of attention.     

A Conceptual Overview of the Self‐Presentational Concerns and Response Tendencies of Focus Group Participants

Focus group respondents are often requested to perform tasks that require them to convey information about themselves. However, despite the potential for respondents to have self‐presentational concerns, research on focus group productivity has virtually ignored extant scholarship on impression management. This shortcoming is addressed by presenting a conceptual overview of the effects of self‐presentational concerns on focus group participation. A product of this overview is a conceptual model that posits that the amount and nature of information that people convey about themselves to others is a function of their eagerness to make desired impressions and their subjective probabilities of doing so. According to the model, when focus group participants are highly motivated to make desired impressions, they may be reluctant to present unbiased images of themselves. However, they are not likely to deceive unless they are confident in their abilities to ascertain and enact desired images. Those who are motivated to make desired impressions but are doubtful of doing so are likely to protect themselves by concealing self‐relevant information or avoiding self‐relevant issues. Implications of this model for research and practice are discussed.     

Stress modulates the use of spatial versus stimulus-response learning strategies in humans

Animal studies provided evidence that stress modulates multiple memory systems, favoring caudate nucleus-based "habit" memory over hippocampus-based "cognitive" memory. However, effects of stress on learning strategy and memory consolidation were not differentiated. We specifically address the effects of psychosocial stress on the applied learning strategy in humans. We designed a spatial learning task that allowed differentiating spatial from stimulus-response learning strategies during acquisition. In 13 subsequent trials, participants (88 male and female students) had to locate a "win" card out of four placed at a fixed location in a 3D model of a room. Relocating one cue in the last trial allowed inferring the applied learning strategy. Half of them participated first in the "Trier Social Stress Test." Salivary cortisol and heart rate measurements were taken. Stressed participants used a stimulus-response strategy significantly more often than controls. Subsequent verbal report revealed that spatial learners had a more complete awareness of response options than stimulus-response learners. Importantly, learning performance was not affected by stress. Taken together, stress prior to learning facilitated simple stimulus-response learning strategies in humans-at the expense of a more cognitive learning strategy. Depending on the context, we consider this as an adaptive response.     

Can false memories be corrected by feedback in the DRM paradigm?

Normal processes of comprehension frequently yield false memories as an unwanted by-product. The simple paradigm now known as the Deese/Roediger-McDermott (DRM) paradigm takes advantage of this fact and has been used to reliably produce false memory for laboratory study. Among the findings from past research is the difficulty of preventing false memories in this paradigm. The purpose of the present experiments was to examine the effectiveness of feedback in correcting false memories. Two experiments were conducted, in which participants recalled DRM lists and either received feedback on their performance or did not. A subsequent recall test was administered to assess the effect of feedback. The results showed promising effects of feedback: Feedback enhanced both error correction and the propagation of correct recall. The data replicated other data of studies that have shown substantial error perseveration following feedback. These data also provide new information on the occurrence of errors following feedback. The results are discussed in terms of the activation-monitoring theory of false memory.     

Clinical significance of serum phenytoin level]

Phenytoin serum concentrations in 115 epileptics treated on an inpatient basis showed, in two groups, only relatively weak correlation with the dosage used. The range of variation was assigned a factor of 16. For individual patients there was observed a correlation between the dosage in mg/kg and the corresponding phenytoin serum concentration. The level of phenytoin serum concentration was not found to be related to the frequency of attacks. The effective phenytoin serum level showed interindividual differences and can be low as well as relatively high. Resulting from this is the need for determining, from the determination of serum concentrations, the effective serum concentration for each individual patient.