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Previous work suggests that when speakers linearize syntactic structures, they place longer and more complex dependents further away from the head word to which they belong than shorter and simpler dependents, and that they do so with increasing rigidity the longer expressions get, for example, longer objects tend to be placed further away from their verb, and with less variation. Current theories of sentence processing furthermore make competing predictions on whether longer expressions are preferentially placed as early or as late as possible. Here we test these predictions using hierarchical distributional regression models that allow estimates of word order and word order variation at the level of individual dependencies in corpora from 71 languages, while controlling for confounding effects from the type of dependency (e.g., subject vs. object), and the type of clause (main vs. subordinate) involved as well as from trends that are characteristic of individual languages, language families, and language contact areas. Our results show the expected correlations of length with position and variation only for two out of six dependency types (obliques and nominal modifiers) and no difference between clause types. These findings challenge received theories of across-the-board effects of complexity on word order and word order variation and call for theoretical models that relativize effects to specific kinds of syntactic structures and dependencies. 相似文献
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习得性长时程突触增强在学习各阶段中的变化 总被引:4,自引:1,他引:3
应用慢性埋植技术以电生理学结合行为学的方法,观察大鼠海马CA_3区锥体细胞在明暗辨别反应的建立、巩固、消退和再建立的连续过程中,突触效应的变化规律。结果:在条件反应的建立过程中,产生突触效应长时程增强(LTP);在条件反应的巩固过程中,LTP继续保持;在条件反应的消退过程中,LTP消退;在条件反应的再建立过程中,再次产生LTP。而这种习得性LTP的发展和变化超前于习得性行为的产生和改变。这是在同一动物身上实现了以往多项工作的连贯性观察,表明在动物学习活动的连贯的迅速改变的各个阶段,海马CA_3区有相应的对条件性行为有制约作用的习得性LTP的发生和改变。它为论证习得性LTP可能是学习和记忆的神经基础之一,提供了新的有力证据。 相似文献
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颜色范畴知觉究竟是语言的还是知觉的, 或两者交互引起的认知冲突所致仍在探究与争议之中。本研究采用色觉疲劳和语义饱和操作分别独立地改变知觉或语义加工, 观察二者对颜色范畴知觉效应的即时影响, 以期探究语言和知觉对颜色范畴的作用。结果显示, 色觉疲劳操作导致范畴间颜色辨别反应时减少, 颜色范畴效应增强。语义饱和操作导致被饱和颜色词所属的范畴内颜色辨别反应时增加, 颜色范畴效应增强。说明单独改变知觉或语义加工能力均能影响CCP效应, 支持了语言标签对比模型, 即语言与知觉的交互作用引起颜色范畴知觉的观点。 相似文献
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不同发展阶段的习得性长时程突触增强对新学习的影响 总被引:1,自引:0,他引:1
在慢性实验条件下观察到大鼠由学习训练所产生的海马CA_3区习得性长时程突触增强,它的不同发展阶段对新学习任务的习得有不同的作用:(1)在它的形成阶段及巩固阶段对新学习均有易化作用,虽然两个阶段突触效应增强的程度都处于相同的高水平,但后者的易化作用相对要大些,提示这两个发展阶段突触的可塑性变化是有差异的;还有,新学习任务的训练并没有引起突触效应的进一步增强,表明突触效应的长时程增强有“饱和”现象。(2)在它消退后,对新学习任务的习得没有影响。上述结果提示学习的组织形式不同,可从突触机制上影响学习的效果,并进一步证明习得性长时程突触增强是学习和记忆的神经基础。 相似文献