Bigrams and the richness of the stimulus

Recent challenges to Chomsky's poverty of the stimulus thesis for language acquisition suggest that children's primary data may carry "indirect evidence" about linguistic constructions despite containing no instances of them. Indirect evidence is claimed to suffice for grammar acquisition, without need for innate knowledge. This article reports experiments based on those of Reali and Christiansen (2005) , who demonstrated that a simple bigram language model can induce the correct form of auxiliary inversion in certain complex questions. This article investigates the nature of the indirect evidence that supports this learning, and assesses how reliably it is available. Results confirm the original finding for one specific sentence type but show that the model's success is highly circumscribed. It performs poorly on inversion in related constructions in English and Dutch. Because other, more powerful statistical models have so far been shown to succeed only on the same limited subset of cases as the bigram model, it remains to be seen whether stimulus richness can be substantiated more generally.     

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.     

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、     

小学儿童数学态度与数学成就的纵向联系：学业拖延和数学元认知的作用

为深入探讨小学儿童的数学态度、学业拖延、数学元认知与数学成就之间的纵向联系及内在作用机制,对515名三、五年级小学生进行为期半年的追踪研究。结果表明:(1)学业拖延在儿童的数学态度与数学成就之间发挥着即时和纵向中介作用;(2)不同水平数学元认知个体在纵向中介模型中“数学态度→数学成就”这一路径上存在差异。这意味着较积极的数学态度有利于减少小学儿童的学业拖延行为,进而提高其数学成就,而高数学元认知则能够监控和调节个体的数学态度,使其发挥积极作用,从而提高数学成就。该发现为有效促进儿童的数学学习提供了重要实践启示。     

Moderators of the association between exercise identity and obligatory exercise among participants of an athletic event

Previous research has connected exercise identity with obligatory exercise, yet to date no empirical studies have identified moderator variables of this association. The current study included participants of an athletic event (full marathon, n = 582; half marathon, n = 1,106; shorter distance, n = 733) who completed questionnaires about exercise behaviors, obligatory exercise, and internalization of both the thin-ideal and athletic-ideal body shapes. General linear model analyses were conducted to examine the exercise identity–obligatory exercise relationship; moderator variables included gender, internalization of the thin-ideal body shape, and internalization of the athletic-ideal body shape. After controlling for the effects of body mass index, age, and distance group, the three-way interaction of exercise identity, gender, and internalization of the athletic-ideal body shape predicted obligatory exercise. Findings suggest that women who report high identification with exercise and high value on having an athletic physique may be vulnerable to obligatory exercise.