GPCM模型项目参数估计程序的开发与研究

该文对GPCM的项目参数估计的方法进行较为深入的探讨,特别对容易混淆的参数初值计算以及项目参数分两步进行估计的原因进行了阐述。并且基于MMLE／EM算法,开发了相应的项目参数估计程序。通过大量的蒙特卡洛模拟,与国外专业软件PARSCALE比较,本程序的步骤参数估计值更好,区分度参数估计值相当,具有较好的应用价值。     

Distorted distance estimation induced by a self-relevant national boundary

Six experiments explored the possibility that the categorization of self versus not-self can distort visual estimations of distance. In Experiments 1-3, Americans overestimated the distance between a U.S. location and a foreign location relative to a visually equidistant U.S. location. In Experiment 4, Canadians overestimated foreign relative to Canadian locations. Experiment 5 showed that this effect occurs even when the domestic context is not physically contiguous. Experiment 6 showed that distance distortion occurs only when crossing one’s own border to a foreign location, not when crossing borders from one foreign location to another. Thus, crossing the psychological boundary between self and not-self creates a visual illusion that distorts on-line distance estimates.     

Statistical models of syntax learning and use

This paper shows how to define probability distributions over linguistically realistic syntactic structures in a way that permits us to define language learning and language comprehension as statistical problems. We demonstrate our approach using lexical‐functional grammar (LFG), but our approach generalizes to virtually any linguistic theory. Our probabilistic models are maximum entropy models. In this paper we concentrate on statistical inference procedures for learning the parameters that define these probability distributions. We point out some of the practical problems that make straightforward ways of estimating these distributions infeasible, and develop a “pseudo‐likelihood” estimation procedure that overcomes some of these problems. This method raises interesting questions concerning the nature of the data available to a language learner and the modularity of language learning and processing.     

Facteur d’impact et mondialisation culturelle

In the present article, we recall the principle of articles consummation as defined by the ISI creator (Institute for Scientific Information). That principle justifies the impact factor (IF) used as a measure of a journal scientific value, of a researcher or of a researcher group… We expose some assumptions that support the IF validity. Further we demonstrate that, on the one hand, these assumptions are not very well established and, on the other hand, that principle and the IF success bias the scientific activity. We consider next two shapes that this bias could take: at best a phenomenon of fashions, at worst, an ideological war having as purpose the American way of thinking domination.     

Experiencing past and future personal events: functional neuroimaging evidence on the neural bases of mental time travel

Functional MRI was used in healthy subjects to investigate the existence of common neural structures supporting re-experiencing the past and pre-experiencing the future. Past and future events evocation appears to involve highly similar patterns of brain activation including, in particular, the medial prefrontal cortex, posterior regions and the medial temporal lobes. This result seems to support the view of a common neurocognitive system, which would allow humans to mentally travel through time. Past events recollection was associated with greater amplitude of hippocampal and anterior medial prefrontal hemodynamic responses. This result is discussed in terms of the involvement of the self in the conscious experience of past and future events representations. More generally, our data provide new evidence in favour of the idea that re- and pre-experiencing past and future events may rely on similar cognitive capacities.     

Recovering a Probabilistic Knowledge Structure by Constraining its Parameter Space

In the Basic Local Independence Model (BLIM) of Doignon and Falmagne (Knowledge Spaces, Springer, Berlin, 1999), the probabilistic relationship between the latent knowledge states and the observable response patterns is established by the introduction of a pair of parameters for each of the problems: a lucky guess probability and a careless error probability. In estimating the parameters of the BLIM with an empirical data set, it is desirable that such probabilities remain reasonably small. A special case of the BLIM is proposed where the parameter space of such probabilities is constrained. A simulation study shows that the constrained BLIM is more effective than the unconstrained one, in recovering a probabilistic knowledge structure.     

测量估计研究:回顾与展望

测量估计是算术估计的一种常见形式,被看作个体数量能力早期获得的重要渠道,也可为物理测量教学提供一条有效途径。论文简要回顾了测量估计研究的发展历程,讨论了测量估计能力的发展及其影响因素,分析了个体常用的测量估计策略种类以及相关的教学训练方式,最后指出了现有研究的缺陷和今后的发展方向。     

Crossover by Line Length and Spatial Location

It is well known that line length has a systematic influence on line bisection error in neglect. Most patients with neglect misbisect long lines on the same side of true center as their brain lesion but then cross over on short lines, misbisecting them on the opposite side (i.e., crossover by line length). What is less recognized is that the spatial location of lines relative to the viewer can similarly induce a crossover effect when one considers line bisection error scores that have been averaged across individual line lengths. Patients with right hemisphere injury and neglect classically make averaged line bisection errors that fall right of true center on lines located either at midline or to the left of the viewer; however, we observed that the averaged line bisection error can fall left of true center when lines are located to the right of the viewer (i.e., crossover by spatial location). We hypothesized that crossover by both line length and spatial location stem from systematic errors in magnitude estimation, i.e., perceived line length. We tested predictions based on this hypothesis by examining how the crossover effect by line length is altered by the spatial location of lines along a horizontal axis relative to the viewer. Participants included patients with unilateral lesions of the right and left cerebral hemispheres and age-appropriate normal subjects. All groups demonstrated a crossover effect by line length at the midline location but the effect was altered by placing lines to the right and left of the viewer. In particular, patients with right hemisphere injury and neglect crossed-over across a broader range of line lengths when the lines were located to the right of the viewer rather than at either midline or left of the viewer. It is proposed that mental representations of stimulus magnitude are altered in neglect, in addition to mental representations of space, and that traditional accounts of neglect can be enhanced by including the psychophysical concept of magnitude estimation.     

项目反应理论中潜在心理特质“填补”的参数估计方法及其演变

在心理与教育测量中, 项目反应理论(Item Response Theory, IRT)模型的参数估计方法是理论研究与实践应用的基本工具。最近, 由于IRT模型的不断扩展与EM (expectation-maximization)算法自身的固有问题, 参数估计方法的改进与发展显得尤为重要。这里介绍了IRT模型中边际极大似然估计的发展, 提出了它的阶段性特征, 即联合极大似然估计阶段、确定性潜在心理特质“填补”阶段、随机潜在心理特质“填补”阶段, 重点阐述了它的潜在心理特质“填补” (data augmentation)思想。EM算法与Metropolis-Hastings Robbins-Monro (MH-RM)算法作为不同的潜在心理特质“填补”方法, 都是边际极大似然估计的思想跨越。目前, 潜在心理特质“填补”的参数估计方法仍在不断发展与完善。     

不同干扰刺激对成人数量估计的影响

研究采用自行设计的图形材料,考察了不同干扰刺激(纯靶刺激;干扰刺激与靶刺激数量相同;干扰刺激是靶刺激数量的2倍)对成人完成数量估计任务的影响.30名硕士生参加了本实验.行为数据和口头报告资料分析显示:1)反应时随数量估计任务难度的增加而不断增长;2)干扰刺激越多,任务越复杂,成人估计的误差率越高,准确性越低;3)成人存在多重数字表征形式,完成数量估计任务时主要采用线性表征,但随着干扰刺激物的增加,运用对数表征的趋势愈加明显.