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841.
In this paper we propose two interpretations for the discrimination parameter in the two-parameter logistic model (2PLM).
The interpretations are based on the relation between the 2PLM and two stochastic models. In the first interpretation, the
2PLM is linked to a diffusion model so that the probability of absorption equals the 2PLM. The discrimination parameter is
the distance between the two absorbing boundaries and therefore the amount of information that has to be collected before
a response to an item can be given. For the second interpretation, the 2PLM is connected to a specific type of race model.
In the race model, the discrimination parameter is inversely related to the dependency of the information used in the decision
process. Extended versions of both models with person-to-person variability in the difficulty parameter are considered. When
fitted to a data set, it is shown that a generalization of the race model that allows for dependency between choices and response
times (RTs) is the best-fitting model. 相似文献
842.
This paper focuses on model interpretation issues and employs a geometric approach to compare the potential value of using
the Grade of Membership (GoM) model in representing population heterogeneity. We consider population heterogeneity manifolds
generated by letting subject specific parameters vary over their natural range, while keeping other population parameters
fixed, in the marginal space (based on marginal probabilities) and in the full parameter space (based on cell probabilities).
The case of a 2 × 2 contingency table is discussed in detail, and a generalization to 2J tables with J ≥ 3 is sketched. Our approach highlights the main distinction between the GoM model and the probabilistic mixture of classes
by demonstrating geometrically the difference between the concepts of partial and probabilistic memberships. By using the
geometric approach we show that, in special cases, the GoM model can be thought of as being similar to an item response theory
(IRT) model in representing population heterogeneity. Finally, we show that the GoM item parameters can provide quantities
analogous to more general logistic IRT item parameters. As a latent structure model, the GoM model might be considered a useful
alternative for a data analysis when both classes of extreme responses, and additional heterogeneity that cannot be captured
by those latent classes, are expected in the population.
This work was supported by Award #1R03 AG18986-01 from the National Institute on Aging and NIH grant #1R01 CA94212-01. The
presentation of the ideas in this paper owes much to discussions with Stephen Fienberg and Brian Junker, Carnegie Mellon University.
The author thanks Jim Ramsay and two anonymous reviewers for their valuable comments on earlier drafts of this paper. 相似文献
843.
Both the speed and accuracy of responding are important measures of performance. A well-known interpretive difficulty is that
participants may differ in their strategy, trading speed for accuracy, with no change in underlying competence. Another difficulty
arises when participants respond slowly and inaccurately (rather than quickly but inaccurately), e.g., due to a lapse of attention.
We introduce an approach that combines response time and accuracy information and addresses both situations. The modeling
framework assumes two latent competing processes. The first, the error-free process, always produces correct responses. The
second, the guessing process, results in all observed errors and some of the correct responses (but does so via non-specific
processes, e.g., guessing in compliance with instructions to respond on each trial). Inferential summaries of the speed of
the error-free process provide a principled assessment of cognitive performance reducing the influences of both fast and slow
guesses. Likelihood analysis is discussed for the basic model and extensions. The approach is applied to a data set on response
times in a working memory test.
The authors wish to thank Roger Ratcliff, Christopher Chabris, and three anonymous referees for their helpful comments, and
Aureliu Lavric for providing the data analyzed in this paper. 相似文献
844.
We study a class of finite models for the Lambek Calculus with additive conjunction and with and without empty antecedents. The class of models enables us to prove the finite model property for each of the above systems, and for some axiomatic extensions of them. This work strengthens the results of [3] where only product-free fragments of these systems are considered. A characteristic feature of this approach is that we do not rely on cut elimination in opposition to e.g. [5], [9]. 相似文献
845.
We examine the influence of inferring interlocutors' referential intentions from their body movements at the early stage of lexical acquisition. By testing human participants and comparing their performances in different learning conditions, we find that those embodied intentions facilitate both word discovery and word-meaning association. In light of empirical findings, the main part of this article presents a computational model that can identify the sound patterns of individual words from continuous speech, using nonlinguistic contextual information, and employ body movements as deictic references to discover word-meaning associations. To our knowledge, this work is the first model of word learning that not only learns lexical items from raw multisensory signals to closely resemble infant language development from natural environments, but also explores the computational role of social cognitive skills in lexical acquisition. 相似文献
846.
Data from the first five waves of the National Youth Survey were used to test the applicability of the Developmental Pathways model to a nationally representative sample of girls. Overall, girls were less likely to be involved in all types of delinquent behavior, with the majority of girls reporting no delinquent involvement across the five waves of data collected. Using the Developmental Pathways model, similar developmental patterns of antisocial and delinquent involvement were found for girls as have been found for boys. Approximately 70% of involved girls followed most steps in each of the pathways. We also evaluated the relation of family and peer factors to specific pathways and found differences in those relations for boys and girls. For girls, only parental monitoring was related to involvement in one of the three pathways. For boys, specific relations were found between family and peer variables and each of the three developmental pathways. As with previous studies on girls involvement in disruptive behavior, these results suggest some general consistency in patterns with that of boys, although differences in frequency and predictors of risk. 相似文献
847.
Cooperation,Knowledge, and Time: Alternating-time Temporal Epistemic Logic and its Applications 总被引:8,自引:0,他引:8
Branching-time temporal logics have proved to be an extraordinarily successful tool in the formal specification and verification of distributed systems. Much of their success stems from the tractability of the model checking problem for the branching time logic CTL, which has made it possible to implement tools that allow designers to automatically verify that systems satisfy requirements expressed in CTL. Recently, CTL was generalised by Alur, Henzinger, and Kupferman in a logic known as Alternating-time Temporal Logic (ATL). The key insight in ATL is that the path quantifiers of CTL could be replaced by cooperation modalities, of the form , where is a set of agents. The intended interpretation of an ATL formula is that the agents can cooperate to ensure that holds (equivalently, that have a winning strategy for ). In this paper, we extend ATL with knowledge modalities, of the kind made popular in the work of Fagin, Halpern, Moses, Vardi and colleagues. Combining these knowledge modalities with ATL, it becomes possible to express such properties as group can cooperate to bring about iff it is common knowledge in that . The resulting logic — Alternating-time Temporal Epistemic Logic (ATEL) — shares the tractability of model checking with its ATL parent, and is a succinct and expressive language for reasoning about game-like multiagent systems. 相似文献
848.
大学生心理健康教育教学模式的构建与实践研究 总被引:9,自引:0,他引:9
采用自然教学实验法,探索提高大学生心理健康水平的有效途径与教学模式。结果表明(1)开设心理健康教育课程并辅以心理咨询是眼下提高大学生心理健康水平的有效措施之一;(2)不同系科心理健康教育的效果不同,心理健康教育课程应根据学生的个别差异有针对性地进行;(3)大学生心理健康教育课程的教学模式为“面上集中释疑,线上互相解疑,点上个别辅导”。 相似文献
849.
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
850.
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