拓广分部评分模型下计算机自适应测验变加权选题策略

摘要: 在计算机自适应测验中, 对0-1评分模型按a-分层选题是高效安全的策略,但多级评分模型的项目难度/步骤参数有多个而无法直接应用这种选题策略。信息函数能够很好地综合项目所有参数及能力参数,但最大信息量选题策略会影响考试安全。本文提出一种变加权选题策略,它通过调用一个与信息量相关联的函数,该函数与信息量成正比,与区分度的某个幂函数成反比,从而达到既能综合项目所有参数又按a分层的效果。在GPCM模型下用蒙特卡罗实验进行比较研究,结果显示新的选题策略总体效果比已有相关结果好。     

Distinguishing genuine from spurious causes: a coherence hypothesis

Two opposing views have been proposed to explain how people distinguish genuine causes from spurious ones: the power view and the covariational view. This paper notes two phenomena that challenge both views. First, even when 1) there is no innate specific causal knowledge about a regularity (so that the power view does not apply) and 2) covariation cannot be computed while controlling for alternative causes (so that the covariation view should not apply), people are still able to systematically judge whether a regularity is causal. Second, when an alternative cause explains the effect, a spurious cause is judged to be spurious with greater confidence than otherwise (in both cases, no causal mechanism underlies the spurious cause). To fill the gap left by the traditional views, this paper proposes a new integration of these views. According to the coherence hypothesis, although a genuine cause and a spurious one may both covary with an effect in a way that does not imply causality at some level of abstraction, the categories to which these candidate causes belong covary with the effect differently at a more abstract level: one covariation implies causality; the other does not. Given this superordinate knowledge, the causal judgments of a reasoner who seeks to explain as much as possible with as few causal rules as possible will exhibit the properties that challenge the traditional views. Two experiments tested and supported the coherence hypothesis. Both experiments involved candidate causes that covary with an effect without implying causality at some level, manipulating whether covariation that implies causality has been acquired at a more abstract level. The experiments differed on whether an alternative cause explains the effect.     

Selection demands versus association strength in the verb generation task

Neuroimaging and neuropsychological data from Thompson-Schill and colleagues (Thompson-Schill, D’Esposito, Aguirre, & Farah, 1997; Thompson-Schill et al., 1998) showed that in the verb generation task, the left inferior frontal gyrus (left IFG) was more involved in a high-selection condition, in which the noun had two verb responses of equal association strength, than in a low-selection condition, in which the noun had only one strongly associated verb. They proposed that the left IFG was involved in selecting semantic information from competing alternatives. The present study compared verb generation in two high-selection conditions that varied in the association strength of the most frequently produced verbs. The results from neurally intact participants and a patient with a lesion that included the left IFG indicated that association strength between nouns and the most frequently produced verb, rather than competition during verb selection, affected verb generation. The degree of involvement of the left IFG may depend on the difficulty of verb retrieval as reflected in association strength.     

Tortured families: a Coordinated Management of Meaning analysis

Torture is known to affect both the individual and the family. The aim of the present study was to reach a better understanding of the significance of communication and information about parental exposure to violence in torture-surviving families. The theoretical background is Social Constructionism and Coordinated Management of Meaning (CMM). In-depth interviews were carried out with 14 members of 3 Middle Eastern refugee families living in Denmark in which the father had been exposed to torture. The 3 families experienced their life stories and situations as refugees in very different ways, ranging from meaninglessness, discontinuance, and alienation to a sense of community, solidarity, and openness. Communications about past events were related to such meaning-providing contexts. The way in which parents talk with their children about torture and organized violence can be understood in terms of "stories told" and "stories lived." When stories told (e.g., the experience of torture and organized violence) are in contradiction to stories lived, a situation of ambiguity and uncertainty is created. The meaning-providing contexts for making sense of the family history of violence and exile can be more or less coherent or contradictory, and might result in a strengthened relationship or confusion, powerlessness, and action paralysis. Clinicians can help traumatized families deal with their past histories of violence by paying attention to such ambiguities and contradictions.     

Relationships between physiological and psychological stress and salivary immunoglobulin A among young female gymnasts

We investigated whether psychological and physical stress induced by training or competition influence the secretory immune system among 12 highly trained young female gymnasts. Salivary levels of secretory IgA and cortisol responses to gymnastic training session or competition were assessed a total of 10 times, immediately before and after two training sessions which had different intensities and just before and after a major competition. These parameters were also measured on two non-training days. The Brunel Mood Scale was also used to assess the gymnasts's overall mood on each test day. IgA:Protein ratio was calculated. Significant decreases in this ratio were found after each exercise session, related to the physiological and psychological stress induced by exercise. Over the 5-mo. training period the presession IgA:Protein ratios were unchanged. Gymnasts registered any episodes of upper respiratory tract infection. Bouts of exercise induce transitory effects on the immune system in relation to the workload and the stress induced by the exercise without any relation to increased susceptibility to illness in children.     

Cognitive processes underlying coping flexibility: differentiation and integration

This study investigates how individuals formulate flexible coping strategies across situations by proposing differentiation and integration as two stress-appraisal processes. Results showed that participants who coped more flexibly adopted the dimensions of controllability and impact in differentiating among different stressful situations. They also deployed an integrated strategy: the deployment of more monitoring in situations perceived as controllable but less of this strategy in situations perceived as uncontrollable. Participants who coped less flexibly did not adopt any given dimensions and tended to use more monitoring regardless of situational characteristics. These results suggest that individuals with different extents of coping flexibility differ in the cognitive processes. Individuals who cope more flexibly display a greater extent of differentiation and integration than do those who cope less flexibly. These findings are translated into strategies for stress management workshops.     

Trace fear conditioning is reduced in the aging rat

Auditory trace fear conditioning is a hippocampus-dependent learning task that requires animals to associate an auditory conditioned stimulus (CS) and a fear-producing shock-unconditioned stimulus (US) that are separated by an empty 20-s trace interval. Previous studies have shown that aging impairs learning performance on hippocampus-dependent tasks. This study measured heart rate (HR) and freezing fear responses to determine if aging impairs hippocampus-dependent auditory trace fear conditioning in freely moving rats. Aging and Young rats received one long-trace fear conditioning session (10 trials). Each trial consisted of a tone-CS (5 s) and a shock-US separated by an empty 20-s trace interval. The next day rats received CS-alone retention trials. Young rats showed significantly larger HR and freezing responses on the initial CS-alone retention trials compared to the Aging rats. A control group of aging rats received fear conditioning trials with a short 1-s trace interval separating the CS and US. The Aging Short-Trace Group showed HR and freezing responses on the initial CS alone retention trials that were similar to the Young Long-Trace Group, but greater than the Aging Long-Trace Group. A second aging control group received unpaired CSs and USs, and showed no HR or freezing responses on CS-alone retention trials. These data show that HR and freezing are effective measures for detecting aging-related deficits in trace fear conditioning.     

Improving measurement precision of test batteries using multidimensional item response models

A conventional way to analyze item responses in multiple tests is to apply unidimensional item response models separately, one test at a time. This unidimensional approach, which ignores the correlations between latent traits, yields imprecise measures when tests are short. To resolve this problem, one can use multidimensional item response models that use correlations between latent traits to improve measurement precision of individual latent traits. The improvements are demonstrated using 2 empirical examples. It appears that the multidimensional approach improves measurement precision substantially, especially when tests are short and the number of tests is large. To achieve the same measurement precision, the multidimensional approach needs less than half of the comparable items required for the unidimensional approach.     

Cross-serial dependencies in dutch: Testing the influence of NP type on processing load

We tested the cross-linguistic generalizability of three models of sentence processing complexity--Lewis (1996), Gibson (1998, 2000), and Gordon (Gordon, Hendrick, & Johnson, 2001; Gordon, Hendrick, & Levine, 2002)--by investigating the on-line processing of cross-serial dependencies in Dutch. The number of subject-verb relations in a clause was manipulated, as well as type of noun phrase (indexical pronouns vs. proper names or full definite NPs). Several of our findings diverged from Gibson's model: Processing difficulty at the verbs was not affected by the use of proper names versus first- and second-person pronouns; an increase at the first verb was seen for full NPs versus pronouns in 3-verb constructions, which was predicted by the Gibson model, but is in contrast to Lewis's model. These findings are best explained within the framework of similarity-based inference models (Gordon et al., 2001; Gordon et al., 2002), according to which the number of similar NPs affects processing difficulty at the point of retrieval, and not specifically their discourse status or syntactic function.     

Factorial structure of the kidcope in Hong Kong adolescents

The Kidcope (A. Spirito, L. J. Stark, & C. Williams, 1988), a brief screening measure of coping strategies for children and adolescents, was subjected to exploratory and confirmatory factor analyses in a sample of adolescents in Hong Kong. A 2-factor model was found to fit the data when only the 2 emotional regulation items were treated separately and were allowed to load on the 2 different factors. Further analyses showed that factor loadings, factor variances, and factor covariance were invariant across age and gender. On the basis of the factor analyses, the authors created 2 composite scores, representing control-oriented and escape-oriented coping strategies. Implications for the use of the Kidcope in research and preventive intervention are discussed.