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61.
To investigate whether learning to discriminate between visual compound stimuli depends on decomposing them into constituting features, hens were first trained to discriminate four features (red, green, horizontal, vertical) from two dimensions (colour, line orientation). After acquisition, hens were trained with compound stimuli made up from these dimensions in two ways: a separable (line on a coloured background) stimulus and an integral one (coloured line). This compound training included a reversal of reinforcement of only one of the two dimensions (half-reversal). After having achieved the compound stimulus discrimination, a second dimensional training identical to the first was performed. Finally, in the second compound training the other dimension was reversed. Two major results were found: (1) an interaction between the dimension reversed and the type of compound stimulus: in compound training with colour reversal, separable compound stimuli were discriminated worse than integral compounds and vice versa in compound training with line orientation reversed. (2) Performance in the second compound training was worse than in the first one. The first result points to a similar mode of processing for separable and integral compounds, whereas the second result shows that the whole stimulus is psychologically superior to its constituting features. Experiment 2 repeated experiment 1 using line orientation stimuli of reversed line and background brightness. Nevertheless, the results were similar to experiment 1. Results are discussed in the framework of a configural exemplar theory of discrimination that assumes the representation of the whole stimulus situation combined with transfer based on a measure of overall similarity. 相似文献
62.
This article reports on the feasibility of using interactive voice response (IVR) technology to obtain daily reports of attitudes
toward alcohol and tobacco use among children 9–13 years of age. Two studies were conducted. The first was an investigation
of the use of IVR technology to obtain daily data from a sample of primary school children over a period of 8 weeks. The second
was an extension of the research to a large sample of primary and secondary school children in urban and rural areas who provided
daily data over a 4-week period. Retention and compliance rates comparable to those obtained with adults were evident in both
studies, supporting the feasibility of this technology with children. The results are discussed in relation to the benefits
of this methodology for health research, particularly for studies of sensitive topics conducted with children and adolescents. 相似文献
63.
We tested the influence of two horizontally aligned visual landmarks on pointing movements to memorized targets, to investigate whether the visuomotor system can make use of an egocentric representation unaffected by visual context. The endpoints of pointing movements were systematically distorted toward the nearest visual landmark, indicating that spatial representations included both target and nontarget information. These distortions were not due to the presence of the landmarks during the movement but, rather, to their presence in the encoding phase. Qualitatively similar distortions were present even with the shortest possible retention phase, when the target was extinguished at movement onset. Finally, we found the same pattern of distortion when participants were forced to remember the target within an allocentric frame of reference. We argue that even early memory representations for pointing movements are influenced by visual information in the surrounding visual field. 相似文献
64.
This study examines the public's and physicians' willingness to support deception of insurance companies in order to obtain necessary healthcare services and how this support varies based on perceptions of physicians' time pressures. Based on surveys of 700 prospective jurors and 1617 physicians, the public was more than twice as likely as physicians to sanction deception (26%versus 11%) and half as likely to believe that physicians have adequate time to appeal coverage decisions (22%versus 59%). The odds of public support for deception compared to that of physicians rose from 2.48 to 4.64 after controlling for differences in time perception. These findings highlight the ethical challenge facing physicians and patients in balancing patient advocacy with honesty in the setting of limited societal resources. 相似文献
65.
When a chromatic (eg light-blue) annulus surrounds the central gap of an Ehrenstein figure so as to connect the inner ends of the radial lines, a striking new lightness effect emerges: the central white disk has both a self-luminous quality (brighter than in the regular Ehrenstein figure) and a surface quality (dense, paste-like). Self-luminous and surface qualities do not ordinarily appear co-extensively: hence, the brightness induction is called anomalous. In experiment 1, subjects separately scaled self-luminous and surface properties, and in experiment 2, brightness was nulled by physically darkening the central gap. Experiments 3 and 4 were designed to evaluate the importance of chromatic versus achromatic properties of the annulus; other aspects of the annulus (width or the inclusion of a thin black ring inside or outside the chromatic annulus) were tested in experiments 5-7. In experiments 8-12, subjects rated the brightness of modified Ehrenstein figures varying the radial lines (number, length, width, contrast, arrangement). Variation of these parameters generally affected brightness enhancement in the Ehrenstein figure and anomalous brightness induction in a similar manner, but was stronger for the latter effect. On the basis of these results, anomalous brightness induction is attributed to a surface induction process triggered by an interaction between illusory brightness enhancement (due to the radial lines) and border ownership (due to the blue annulus). 相似文献
66.
67.
Intravenous injection of histamine to rabbits was used as a prototype in an investigation of the mechanism of sudden death due to anaphylaxis and other causes. The "dive" reflex, bradycardia due to activation of the ophthalmic branch of the fifth cranial nerve, was induced in thirty-seven of the animals while they inhaled a very small amount of cigarette smoke. Associated with the resulting bradycardia were lowered blood pH and increased serum content of lactic acid and potassium and increased peripheral arterial constriction with elevation of diastolic blood pressure. Intravenous injection of 1 ml of histamine in the presence of the dive reflex induced potentially fatal ventricular arrhythmia, but no cardiac disturbance when administered while the dive reflex was inactive, thereby strongly suggesting that sudden death in anaphylaxis may involve an overzealous response to a normally protective neural reflex. 相似文献
68.
Susan Wolf 《The Journal of Ethics》1999,3(3):203-223
According to one influential conception of morality, being moral is a matter of acting from or in accordance with a moral point of view, a point of view which is arrived at by abstracting from a more natural, pre-ethical, personal point of view, and recognizing that each person's personal point of view has equal standing. The idea that, were it not for morality, rational persons would act from their respectively personal points of view is, however, simplistic and misleading. Because our nonmoral reasons cannot all be adequately captured as falling within any single, unified and coherent point of view, morality cannot be adequately understood as a matter of abstracting from such points of view and taking them all equally into account. After considering several ways of modifying the initial conception of morality in a way that accommodates the variety of nonmoral reasons that do not have their source in a personal point of view, the paper concludes with the suggestion that we free ourselves more thoroughly from the grip of the metaphor that takes morality as a whole to be a matter of acting in accordance with the judgments of a single unified and coherent point of view. 相似文献
69.
70.