Bayesian IRT Guessing Models for Partial Guessing Behaviors

According to the recent Nation’s Report Card, 12th-graders failed to produce gains on the 2005 National Assessment of Educational Progress (NAEP) despite earning better grades on average. One possible explanation is that 12th-graders were not motivated taking the NAEP, which is a low-stakes test. We develop three Bayesian IRT mixture models to describe the results from a group of examinees including both nonguessers and partial guessers. The first assumes that the guesser answers questions based on his or her knowledge up to a certain test item, and guesses thereafter. The second model assumes that the guesser answers relatively easy questions based on his or her knowledge and guesses randomly on the remaining items. The third is constructed to describe more general low-motivation behavior. It assumes that the guesser gives less and less effort as he or she proceeds through the test. The models can provide not only consistent estimates of IRT parameters but also estimates of each examinee’s nonguesser/guesser status and degree of guessing behavior. We show results of a simulation study comparing the performance of the three guessing models to the 2PL-IRT model. Finally, an analysis of real data from a low-stakes test administered to university students is presented.     

Contingent reliance on the affect heuristic as a function of regulatory focus

Results from four studies show that the reliance on affect as a heuristic of judgment and decision making is more pronounced under a promotion focus than under a prevention focus. Two different manifestations of this phenomenon were observed. Studies 1–3 show that different types of affective inputs are weighted more heavily under promotion than under prevention in person-impression formation, product evaluations, and social recommendations. Study 4 additionally shows that valuations performed under promotion are more scope-insensitive—a characteristic of affect-based valuations—than valuations performed under prevention. The greater reliance on affect as a heuristic under promotion seems to arise because promotion-focused individuals tend to find affective inputs more diagnostic, not because promotion increases the reliance on peripheral information per se.     

科学发展观是马克思主义世界观和方法论的最新体现

2004年年底,在中央经济工作会议上,胡锦涛同志指出:“科学发展观是指导我们抓住机遇、加快发展的世界观和方法论。”从本体论上讲,科学发展观首先是从人、社会和自然界的客观存在和相互联系中来谈发展问题的。以人为本,体现了人在社会和自然界中的至高无上的崇高主体地位,使地球上这一最高花朵显示出更加鲜艳的色彩。人的发展离不开人类社会,更     

字距在视觉干扰中作用的实验研究

本研究分别以字距和刺激呈现的时序为变量,采用同一异匹配作业和视搜寻范型,通过两个实验论证,字距因素是导致语境产生视觉干扰的一种必要而充分的条件。     

海马CA_3区在长时记忆的保持中的作用

本工作将M-胆碱能受体阻断剂东莨菪碱,r-氨基丁酸及其受体阻断剂印防己毒素,经埋植的慢性导管注入家兔双侧海马CA_3区,观察上述药物对已巩固的操作式食物性条件反应的影响。发现东莨菪碱(每侧45微克/5微升)、r-氨基丁酸(每侧3毫克/5微升)均使条件反应抑制;若注r-氨基丁酸之前先加注印防己毒素,则抑制时间缩短,且剂量愈大时间更为缩短。抑制期间动物的摄食和运动功能正常,抑制后条件反应皆恢复;注生理盐水作自身对照则均无抑制效应。这表明海马CA_3区在长时记忆的保持上起着重要作用,且此种作用有胆碱能突触和GABA能突触参与。     

超声诊断肝癌认识的扩展与深化

超声显像诊断肝癌经历了简单描述其回声特点、这些声学特征瑟病理的联系,阐述肝癌血供到从恶性肿瘤侵袭性的角度来理解肝癌原发和继发性超声征象等的认识层次不断深化扩展的过程。     

汉字的视知觉——知觉任务效应和汉字属性效应

本研究通过三个实验发现:1.在三种非速示的特定知觉任务下,认知汉字反应时的长短依次是;识别汉字两个部件的反应时>识别整体字的反应时>辨认字的结构方式的反应时,在错误率指标上也获得了同样的结果模式。这表明,在汉字的视知觉中存在知觉任务效应,而这些任务标志着不同复杂程度的加工水平。2.对于左右和上下结构的字,在辨认其结构方式上无差异。3.在命名整体字中,汉字的表层属性,如结构方式和表音特点对整体字的识别没有影响,这表明整体字是正常阅读条件下的知觉单位。4.在知觉分解整体字和命名识别其部件中,(1)字的结构方式有相当大的影响:上下结构字的反应时远远长于左右结构字的反应时。(2)字的表音特点对部件识别也极有影响,如形声字的反应时和错误率都远远短于和少于非形声字。(3)在误操作中,存在着大量整体字的命名现象。以上表明的汉字属性效应,都是发生在汉字知觉的分解过程中,它们反映了整体对部分的强烈影响。     

Glutamatergic activation of anterior cingulate cortex mediates the affective component of visceral pain memory in rats

Studies of both humans and animals suggest that anterior cingulate cortex (ACC) is important for processing pain perception. We identified that perigenul ACC (pACC) sensitization and enhanced visceral pain in a visceral hypersensitive rat in previous studies. Pain contains both sensory and affective dimensions. Teasing apart the mechanisms that control the neural pathways mediating pain affect and sensation in nociceptive behavioral response is a challenge. In this study, using a rodent visceral pain assay that combines the colorectal distension (CRD)-induced visceromotor response (VMR) with the conditioning place avoidance (CPA), we measured a learned behavior that directly reflects the affective component of visceral pain. When CRD was paired with a distinct environment context, the rats spent significantly less time in this compartment on the post-conditioning test days as compared with the pre-conditioning day. Effects were lasted for 14 days. Bilateral pACC lesion significantly reduced CPA scores without reducing acute visceral pain behaviors (CRD-induced VMR). Bilateral administration of non-NMDA receptor antagonist CNQX or NMDA receptor antagonist AP5 into the pACC decreased the CPA scores. AP5 or CNQX at dose of 400 mM produced about 70% inhibition of CRD-CPA in the day 1, 4 and 7, and completely abolished the CPA in the day 14 after conditioning. We concluded that neurons in the pACC are necessary for the "aversiveness" of visceral nociceptor stimulation. pACC activation is critical for the memory processing involved in long-term negative affective state and prediction of aversive stimuli by contextual cue.     

《恒先》的气论——一种新的万物生成动力模式

<正>在近年公布的出土文献中,上海博物馆藏战国楚竹书《恒先》①备受中国哲学界的关注。这篇文献虽然只有13简,510字,但极富研究价值。首先,其他出土文献或多或少存在残损,而《恒先》保存基本完整,没有缺简,没有残断,字迹也十分清晰,不需要做太多增补、推测,保障了文本的可信性。其次,这篇亡佚了两千多年的文献保存了许多独特的思想,其中涉及到宇宙论、道论、气论、