Reaction time as a function of the intensity and probability of occurrence of vibrotactile signals

Three Ss made judgments of the presence or absence of a burst of 60-cps vibration onthe index fingertip.The probability of S’s reporting the presence of a signal was found to be influenced by signal probability and signal intensity. Mean reaction time for reporting the presence of a signal decreased as a function of signal intensity and signal probability whereas mean reaction time for reporting the absence of a signal increased as a function of signal intensity and signal probability. On trials where no signal was presented mean R T for reporting a signal decreased with increases in the signal probability whereas mean RT for reporting the absence of a signal increased with increases in signal probability. The results were interpreted as support for the hypothesis that S’s decision time was longer the closer on the sensory continuum a particular observation was to his criterion.     

Limiting the role of the family in discontinuation of life sustaining treatment

In matters of discontinuation of life-sustaining treatment, traditional role of the family to speak on behalf of the incompetent patient is questionable. We explore the reasons why physicians perceive patient autonomy to be transferrable to family members. Principle of patient autonomy may not suffice when futile treatment is demanded and may serve to erode the ethical integrity of medical profession. An enhanced role for bioethics committees is proposed when physicians propose to discontinue life-sustaining treatment against the wishes of the patient or their families.     

No attentional bias for pictoral stimuli in spider-fearful subjects

A number of experiments have shown that (spider) fearful subjects direct their attention to fear-relevant words, even when these words are irrelevant to the completion of a target task (e.g., color naming). The present study examined whether subjects with an intense fear of spiders also display such attentional bias for a fear-relevant pictoral stimulus. Female spider-fearful (n=13) and control subjects (n=13) saw neutral patterns (i.e., horizontal and vertical bars). One pattern served as target for a reaction time, while the other pattern served as nontarget. Targets and nontargets were accompanied by either fear-relevant or neutral pictoral material (i.e., a picture of a spider or a picture of a flower, respectively). The fear-relevant picture did not selectively delibate reaction time performance of spider-fearful subjects. Thus, no evidence was found for an attentional bias for fear-relevant pictoral material in subjects with an intense fear of spiders. Instead, fearful subjects exhibited a general inhibition of performance which became stronger over trials. This suggests that the fear-relevant picture induced a state of anxious arousal or defensive withdrawal that interfered with reaction time performance on both fear-relevant and neutral trials.     

Grading the ‘cultural literacy’ project

The essay examines the argument advanced by E.D. Hirsch, Jr., for instituting ‘cultural literacy’ as a fundamental priority of schools. A number of confusions and equivocations in Hirsch's reasoning are identified, and the propensity of his project to indoctrinate is exposed. Among the features of Hirsch's argument shown to be troubling are his shifting construal of ‘language’, his inconsistency about the requirements of cultural literacy, and his uncritical relation to traditional images of the American past and present. The upshot is to raise the question why Hirsch's project has elicited wide support and praise.     

Saccadic reaction times of dyslexic and age-matched normal subjects

Saccadic reaction times (SRT) were measured in a simple task: subjects had to make saccades from a central fixation point to peripheral targets, which appeared randomly 4 deg to the left or to the right. In the first test the fixation point went off before the target appeared (gap trials); in the second test it remained on the screen (overlap trials). The distribution of SRTs for trained normal adults (N = 4), untrained normal adults (N = 11), untrained normal children (aged 9-11 years, N = 9), untrained normal teenagers (aged 15-17 years, N = 8), dyslexic children (aged 9-11 years, N = 15), and dyslexic teenagers (aged 15-17 years, N = 5) were compared, with special emphasis on the number of express saccades, ie saccades with extremely short reaction times (100-120 ms, under the present conditions). In normal adults with the gap paradigm, the distribution of reaction times typically exhibits two or three modes (express saccades, fast regular saccades, and very few slow regular saccades), whereas in the overlap paradigm only one or two modes (few fast regular saccades and many slow regular saccades) are obtained. On average, normal children produce more express saccades than naive normal adults. Dyslexic children produce more express saccades than the normal age-matched controls. Among the dyslexic children, four different types of abnormalities in their reaction times were encountered. The group of dyslexic teenagers was characterized by a larger number of express saccades at the expense of fast regular saccades in gap trials and by fewer express saccades and fewer fast regular saccades in overlap trials when compared to the age-matched control group. It is concluded that the abnormal patterns of saccadic reaction times reflect defects in the system of visual attention and/or in its control over the oculomotor system, rather than indicating a defect in the oculomotor system itself. In this context, symptoms of dyslexia appear as a combination of attentional deficits and irregular timing of saccadic eye movements.     

Referenzsemantik in der Partnermodellierung

How can we explain that an assertion on something perceived can be understood in the same manner by somebody who cannot perceive that scene? This problem bases the interest in computational linguistics in how listener modeling could possibly be harmonized with reference semantics. Mental images substituting real perception appear as a way out. The architecture of the listener model has to be adapted to the creation and use of such pictorial data structures. Furthermore, the relation between the latter and a verbal (i. e., propositional) representation must be understood. The resulting architecture of a listener model with reference semantics can be employed to solve communicational problems from three general classes in a better way, as is demonstrated by an example implementation.     

Procuring organs from a non-heart-beating cadaver: commentary on a case report

Procurement of organs from non-heart-beating cadaver donors raises concerns. Standards for optimal patient care during withdrawal of life-sustaining therapy are evolving and continue to be debated and studied. Consensus on specific procedures and methods has not been attained, however, and protocols for the procurement of organs from patients following the withdrawal of life-sustaining therapies may compromise the evolving standards and harm the patient and the attendant family. In addition, there is little evidence to suggest that such protocols will significantly increase the number of organs procured. "Non-heart-beating cadaver" protocols that do not give comprehensive attention to optimal patient/family care at the time of withdrawal of life-sustaining therapy ought not to be endorsed.     

The judgment-choice discrepancy: Noncompatibility or restructuring?

The study examines the relative merits of a noncompatibility and a restructuring explanation of the recurrent empirical finding that a prominent attribute looms larger in choices than in judgments. Pairs of equally attractive options were presented to 72 undergraduates who were assigned to six conditions in which they performed (1) only preference judgments or choices, (2) preference judgments or choices preceded by judgments of attractiveness of attribute levels, or (3) preference judgments or choices accompanied by think-aloud reports. The results replicated the prominence effect for choices, but a prominence effect was also found for preference judgments. In accordance with the restructuring explanation, the think-aloud protocols indicated that options were more often restructured in choices than in preference judgments. However, restructuring could not explain the prominence effect observed for preference judgments. A modified compatibility hypothesis is offered as an alternative explanation.