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771.
This paper attempts to explain why in obsessive-compulsive disorder (OCD) checkers distrust in memory persists despite extensive checking. It is argued that: (1) repeated checking increases familiarity with the issues checked; (2) increased familiarity promotes conceptual processing which inhibits perceptual processing; (3) inhibited perceptual processing makes recollections less vivid and detailed and finally; (4) reduction in vividness and detail promotes distrust in memory. An interactive computer animation was developed in which participants had to perform checking rituals on a virtual gas stove. Two separate experiments were carried out with n=39 (Experiment I) and n=40 (Experiment II) healthy participants. In both studies, the control group and the experimental group were given the same pre-test and post-test on the virtual gas stove. In between, the experimental group engaged in 'relevant checking', i.e. checking the gas stove, while the control group engaged in 'irrelevant checking', i.e. checking virtual light bulbs. In both experiments there were powerful effects of repeated 'relevant checking': while actual memory accuracy remained unaffected, the vividness and detail of the recollections were greatly reduced. Most pertinently, in both experiments relevant checking undermined confidence in memory. No such effects were observed in the control group. One might argue that the pre-test/post-test design may have made the control group anticipate a memory assessment at the post-test and that this artifact made them relatively alert producing memory confidence at post test that was artificially high. A third experiment was carried out (n=2 x 20) in which no pre-test was given while, other than that, Experiment III was identical to the first two experiments. Results confirmed earlier findings: compared to the irrelevant checking control group, recollections in the relevant checking group were non-vivid, non-detailed while confidence in memory was low. The theory and data suggest an answer to the question 'why memory distrust persists despite repetitive checking'. In people who check extensively, memory distrust may persist as a result of repetitive checking. OCD checking may be motivated by the wish to reduce uncertainty, but checking appears to be a counter-productive safety strategy. Rather than reducing doubt, checking fosters doubt and ironically increases meta-memory problems. 相似文献
772.
In earlier experiments using interactive computer animation with healthy subjects, it was found that displaying compulsive-like repeated checking behavior affects memory. That is, checking does not alter actual memory accuracy, but it does affect 'meta-memory': as checking continues, recollections are experienced as less vivid and less detailed while confidence in memory is undermined. This procedure provides a model of OCD checking and suggests that checking is a counterproductive strategy to reduce memory distrust. The present experiment was carried out to specify the phenomenological quality of memory distrust after checking and to see if repeated checking produces a shift in the memory source that is used to decide about the outcome of checking: from 'remembering' to 'knowing' (Tulving, 1985). Using the same interactive computer-animation, the earlier findings on vividness, detail and confidence were replicated. In addition, it was found that checking made participants endorse quotations from OCD patients (Reed, 1985) expressing a specific ambivalence about memory: 'It is as though the memory is there, but is isn't definite enough', 'I remember doing it in a way, but it's all fuzzy....' And 'I can remember that I've done it. But the memory isn't clear somehow'. This finding adds to the validity of the experimental model. Furthermore, after checking subjects' beliefs about the outcome of checking became based on (general) knowing instead of (specific) remembering. It is suggested that OCD checkers feel a general and relatively strong need to be certain about the veracity of recollections and that they have high standards for memory performance. This may explain earlier findings that OCD checkers have a general tendency to distrust their episodic memory. A need for certainty and a critical attitude towards memory performance may not be problematic or abnormal. It is suggested that clinical problems arise when the patient tries to fight memory distrust by repeated checking. The latter does not reduce distrust but rather increases distrust and the patient may get trapped in a spiral of mutually reinforcing checking behavior and memory distrust. 相似文献
773.
The present study explored whether cognitive factors specified in the Ehlers and Clark model (Behav. Res. Ther. 38 (2000) 319) of posttraumatic stress disorder (PTSD) predict chronic PTSD in children who had experienced a road traffic accident. Children were assessed at 2 weeks, 3 months, and 6 months after the accident. Data-driven processing during the accident, negative interpretation of intrusive memories, alienation from other people, anger, rumination, thought suppression and persistent dissociation at initial assessment predicted PTSD symptom severity at 3 and 6 months. On the basis of sex and stressor severity variables, 14% of the variance of PTSD symptoms at 6 months could be explained. The accuracy of the prediction increased to 49% or 53% when the cognitive variables measured at initial assessment or 3 months, respectively, were taken into account. 相似文献
774.
The role of proprioception in action recognition 总被引:1,自引:0,他引:1
This study aimed at evaluating the role of proprioception in the process of matching the final position of one's limbs with an intentional movement. Two experiments were realised with the same paradigm of conscious recognition of one's own limb position from a distorted position. In the first experiment, 22 healthy subjects performed the task in an active and in a passive condition. In the latter condition, proprioception was the only available information since the central signals related to the motor command were likely to be absent. The second experiment was realised with a deafferented patient who suffers from a complete haptic deafferentation, including loss of proprioception. The results first argue in favour of a dominant role of proprioception in action recognition, but they also stress the possible role of central signals. The process of matching the final position of one's limbs with an intended movement and thus of action recognition would be achieved through a comparison process between the predicted sensory consequences of the action, which are stored in its internal model, and the actual sensory consequences of that action. 相似文献
775.
Liechty, Pieters & Wedel (2003) developed a hidden Markov Model (HMM) to identify the states of an attentional process in an advertisement viewing task. This work is significant because it demonstrates the benefits of stochastic modeling and Bayesian estimation in making inferences about cognitive processes based on eye movement data. One limitation of the proposed approach is that attention is conceptualized as an autonomous random process that is affected neither by the overall layout of the stimulus nor by the visual information perceived during the current fixation. An alternative model based on the input-output hidden Markov model (IOHMM; Bengio, 1999) is suggested as an extension of the HMM. The need for further studies that validate the HMM classification results is also discussed. 相似文献
776.
777.
Silvers A 《Theoretical medicine and bioethics》2003,24(6):471-487
Disagreement about the properattitude toward disability proliferates. Yetlittle attention has been paid to an importantmeta-question,
namely, whether ``disability' isan essentially contested concept. If so, recentdebates between bioethicists and the disabilitymovement
leadership cannot be resolved. Inthis essay I identify some of the presumptionsthat make their encounters so contentious.
Much more must happen, I argue, for anydiscussions about disability policy andpolitics to be productive. Progress depends
onconstructing a neutral conception ofdisability, one that neither devaluesdisability nor implies that persons withdisabilities
are inadequate. So, first, I clearaway the conceptual underbrush that makes usthink our idea of disability must bevalue-laden.
Second, I sketch someconstituents of, and constraints upon, aneutral notion of disability.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
778.
对变化/分割模型的检验(Ⅱ) 总被引:3,自引:0,他引:3
在前一报告的基础上设计了两个实验,对变化/分割模型做进一步的检验,实验3控制目标时距和该时距内的填充数字系列的分割段数以及段的持续时间,操纵段内的项目数;结果显示,数字系列的分割段数明显影响延迟操作条件下的时距估计,而段内的项目数则不影响对时距的估计,实验4控制目标时距和该时距内填充数字系列的分割段数以及段内的项目数,操纵的持续时间,结果显示,对时距的估计取决于被试所傅物时间标尺,四个实验结果表明 相似文献
779.
780.
Four pigeons were trained on eight or nine pairs of independent concurrent variable-interval schedules. The range of reinforcement ratios included extreme ratios (up to 532 to 1). Large samples of stable performance were gathered. Contrary to the findings of Davison and Jones (1995), the generalized matching law described choice more accurately than a contingency-discriminability model. Taking small samples (5 to 10 sessions) and applying a more liberal stability criterion used by Davison and Jones only increased the unsystematic variance in the data and in estimates of generalized-matching-law sensitivity. Because changing to dependent scheduling and inserting a changeover delay had no systematic effect, the deviations from generalized matching reported by Davison and Jones probably arose from imperfectly discriminated stimuli. Analysis of visits revealed that visits to the nonpreferred alternative were brief and approximately constant. When choice between the preferred (rich) and nonpreferred (lean) alternatives, regardless of position, was analyzed according to the generalized matching law, sensitivities approximated 1.0, with bias in favor of the lean alternative. This bias, which arose from an excessive frequency of visits to the lean alternative, explains undermatching as the result of fitting one line to a choice relation that consists of two displaced lines, both with a slope of 1.0. The pattern of deviation from the generalized matching line confirmed this account. The findings suggest an alternative analysis of choice that focuses on probability of visiting the lean alternative as the dependent variable. This probability was directly proportional to ratio of reinforcement. Matching, undermatching, and overmatching may all be explained by a view of concurrent performance based on foraging theory, in which responding occurs primarily at the rich alternative and is occasionally interrupted by brief visits to the lean alternative. 相似文献