类别学习的双系统模型

概念和类别学习是认知心理学研究的核心问题之一,以往的理论主要基于类别学习的单系统理论假设,而近十多年来概念和类别的研究关注类别学习的双重系统问题。目前双系统模型不仅得到了行为学实验的支持,更重要的是得到了临床神经心理和认知神经研究的广泛支持,本文回顾了双系统模型的非行为学研究证据,并指出了今后概念和类别研究应该注意的问题。     

类别验证任务中否定加工的ERP研究

有研究提出了否定加工的两阶段模拟假说,认为否定加工的第一阶段是模拟被否定的状态,第二阶段是整合否定以模拟真实状态.为了对该假说进行检验,本研究采用ERP技术探讨了20名被试完成类别验证任务时的脑内时程动态变化.任务有4种条件：肯定类别对（例如,蔬菜-白菜）,肯定无关对（例如,蔬菜-蜜蜂）,否定类别对（例如,蔬菜-蜜蜂）和否定无关对（例如,蔬菜-白菜）.其中类别上画有一横线表示＂不是该类别的事物＂,例如,蔬菜表示＂不是蔬菜＂.结果表明,否定类别对比否定无关对和肯定类别对都引发了更负的N400,这说明,否定加工中建立了被否定状态的表征,支持了两阶段模拟假说.此外,肯定类别对比否定类别对引发了更正的LPC,这一结果揭示了两阶段模拟假说中第二阶段即整合否定模拟真实状态的神经机制.可能是因为肯定类别关系的加工涉及再认和记忆信息的提取,而否定类别关系的加工如两阶段模拟假说所预期的包含两个阶段,涉及推理过程,因而前者比后者引发了更正的LPC.     

基于相似性的类别学习ERPs研究

目的:研究类别学习过程中,基于类别相似性的不同时间限制下被试分类学习脑激活机制.方法:通过对15名被试采用事件相关电位技术(ERPs),使用2相似程度不同(高相似vs低相似)×3呈现时间不同(10ms vs 200ms vs 600ms)的多因素实验设计,探讨不同相似程度及刺激呈现时间不同下的类别学习脑机制.结果:类别高相似的脑激活机制更加复杂,激活的脑区更多;刺激呈现时间为10ms的时候被试的波形图与200ms和600ms类似,但是其潜伏期更短,决策速度更快;三种时间条件下都激活了N400,可能存在语义加工.结论:类别学习在视觉加工阶段就已经发生;类别学习过程并非全或无的竞争机制,而是内隐和外显综合加工的结果.     

概率类别学习的认知神经机制

概率类别学习是探讨人们如何习得线索与结果之间的"概率"关系.研究者借助天气预报等任务,探讨了概率类别学习的认知策略、无意识性及其与工作记忆和注意的关系,并借助脑成像技术和脑损伤病人,探讨了基底神经节、内侧颞叶、前额叶和顶叶等脑区在概率类别学习中的作用.但是,由于概率类别学习涉及内隐和外显学习系统的分离问题,目前对其相关研究结果和理论解释还存在很大争议,概率类别学习的认知神经机制仍有待进一步研究.     

类别学习的脑机制研究现状和展望

本文主要探讨类别学习的脑机制。首先介绍类别学习的基本过程及主要研究范式。其次从脑损伤和脑成像两方面探讨此过程中的脑机制,主要包括额区、内侧颞叶、基底神经节的激活。再次,介绍了ERP研究类别学习过程的方法和结果,主要相关成分包括N1、P1、N2、P2、N300、P3、P450。最后对类别学习的脑机制进行小结和展望,认为ERPs和脑成像技术的结合可使此研究深化。     

类别决策中情景标签效应的神经机制

目的:类别决策是人类重要的认知方式之一,情景对类别决策的准确性具有重要影响,但并没有引起足够的重视,对其研究也较少。方法:本研究选取大学生被试,通过ERPs对大学生被试电生理水平探讨情境标签的作用。结果:在基于情境标签下的分类活动激活了更多的大脑区域,基于情景标签下被试分类的潜伏期更短,判断更加快速准确。结论:类别决策过程中情景标签有重要的作用,通过情景标签能提高类别决策能力。     

认知神经科学类别学习研究进展

文章回顾了认知神经科学关于类别学习的研究进展.认知神经科学关于类别学习的模型包括样例模型、原型模型、边界模型、SUSTAIN和COVIS模型,研究范式包括以规则为基础的范式、天气预报范式和原型变形范式.认知神经科学的类别学习研究揭示了类别学习的神经机制,发现类别学习由不同神经系统共同调节,不同脑区负责不同类别学习.认知神经科学的类别学习研究揭示了不同神经疾病患者类别学习缺陷的生理机制,为临床医疗康复提供了重要启示.     

“大范围优先”对象形成的神经关联：前颞叶

知觉对象是什么？这事看起来很简单,却是认知科学许多领域中最核心的问题,日前为止还没有公认的解答。“大范围优先”的拓扑学方法把知觉对象的定义严格地联系到拓扑变换下的不变量。知觉对象的直观概念—形状改变时其整体一致性得以保持一可以精确地被拓扑不变量,如连接组分和洞,所刻画。知觉对象的拓扑学定义已经被大量的行为学实验所验证。这些实验一致表明,虽然对象的一致性能够在非拓扑变换下得以保持,却会被拓扑变换所破坏,从而一个新的对象被感知到。特别是进一步的功能磁共振成像实验揭示,前颞页区参与拓扑知觉和知觉对象的形成,而这一脑区本来是形式视觉通路的终点。行为学上“大范围优先”的结果与视觉通路神经解剖学结果的悖逆,提示我们应该注意对象表征形成的问题和更广泛的意义上,知觉到底在何处发生的基本问题。     

"大范围优先"对象形成的神经关联:前颞叶

知觉对象是什么?这事看起来很简单,却是认知科学许多领域中最核心的问题,目前为止还没有公认的解答."大范围优先"的拓扑学方法把知觉对象的定义严格地联系到拓扑变换下的不变量.知觉对象的直观概念-形状改变时其整体一致性得以保持-可以精确地被拓扑不变量,如连接组分和洞,所刻画.知觉对象的拓扑学定义已经被大量的行为学实验所验证.这些实验一致表明,虽然对象的一致性能够在非拓扑变换下得以保持,却会被拓扑变换所破坏,从而一个新的对象被感知到.特别是进一步的功能磁共振成像实验揭示,前颞页区参与拓扑知觉和知觉对象的形成,而这一脑区本来是形式视觉通路的终点.行为学上"大范围优先"的结果与视觉通路神经解剖学结果的悖逆,提示我们应该注意对象表征形成的问题和更广泛的意义上,知觉到底在何处发生的基本问题.     

运动对时距知觉的影响及其神经机制

在运动过程中,时距知觉的能力非常重要,能帮助个体对时长进行判断及对事件的发生做出预测和准备.近年来,越来越多的研究发现运动本身会直接影响个体的时距知觉.本文分别从运动参数、运动阶段、视觉运动刺激和运动有关的个体因素四个方面梳理了运动对时距知觉产生影响的行为学证据.目前已经有大量研究从不同角度证明,大脑运动系统组成了支持...     

Species: the concept, category and taxon

The term species by itself is vague because it refers to the species concept, the species category and the species taxon, all of which are distinct although related to one another. The species concept is not primarily a part of systematics, but has always been an integral part of basic biological theory, It is based on evolutionary theory and applies only to sexually reproducing organisms. The species concept and the phyletic lineage concept are quite distinct although they are related to one another. The important aspect of the species concept is lack of gene flow between different species, and hence the defining criterion of the species is genetic isolation. The species concept is often considered as non‐dimensional, both in time and space. Species possess three different major properties, namely genetic isolation, reproductive isolation and ecological isolation; these properties evolve at different times and under the effect of different causes during the speciation process. Speciation requires an external isolating barrier during the initial allopatric phase in which genetic isolation evolves and must reach 100% efficiency. The subsequent sympatric phase of speciation occurs after the disappearance of the external isolating barrier when members of the two newly evolved species can interact with one another and exert mutual selective demands on one another. Much of the reproductive and ecological isolation evolves during this secondary sympatric phase. The species category is a rank in the taxonomic hierarchy and serves as the basis on which the diversity of organisms is described; it is not the same as the species concept. The species category applied to all organisms, sexually and asexually reproducing. The species taxon is the practical application of the species category in systematics with the recognition of species taxa requiring many arbitrary decisions. No single set of rules exist by which the species category can be applied to all organisms. Recognition of species taxa in asexually reproducing organisms is based on amount of variation and gaps in the variation of phenotypic features associated with ecological attributes of these organisms as compared with similar attributes in sympatric species taxa of sexually reproducing organisms. Species taxa are multidimensional in that they exist over space–time and often have fuzzy borders. Because recognition of species taxa, including those in sexually reproducing organisms, depends on many arbitrary decisions especially when dealing with broad geographical and temporal ranges, species taxa cannot be used as the foundation for developing and testing theoretical concepts in evolutionary theory which can only be done with the non‐dimensional species concept.     

基于特征属性的中国自然保护区分类体系

基于114个自然保护区典型样本的特征属性,采用聚类分析方法建立了新的中国自然保护区分类体系.结果表明:与现行的国家分类标准相比,新的分类体系更具简明性和实用性;同时,新体系中的C1、C2、C3、C4类型分别与世界自然保护联盟(IUCN)分类体系中的Ⅰ、Ⅱ、Ⅳ、Ⅴ类保护区相对应.新体系保持了分类标准和尺度的一致性,一定程度上避免了主观分类的偏差,为中国自然保护区的分类提供了量化依据.     

An artificial environment is often a noisy environment: auditory scene analysis and speech perception in noise

Our auditory system has to organize and to pick up a target sound with many components, sometimes rejecting irrelevant sound components, but sometimes forming multiple streams including the target stream. This situation is well described with the concept of auditory scene analysis. Research on speech perception in noise is closely related to auditory scene analysis. This paper briefly reviews the concept of auditory scene analysis and previous and ongoing research on speech perception in noise, and discusses the future direction of research. Further experimental investigations are needed to understand our perceptual mechanisms better.     

Acoustic versus phonetic representation of speech as reflected by the mismatch negativity event-related potential

The concept of categorical perception of speech and speech-like sounds has been central to models of speech perception for decades. Event-related potentials (ERPs) provide a neurophysiologic perspective of this important phenomenon. In the present experiment the mismatch negativity (MMN) event-related potential, which is sensitive to fine acoustic differences, was recorded in adults. Of interest was whether the MMN reflects the acoustic or categorical perception of speech.The MMN was elicited by stimulus pairs (along a continuum varying in place of articulation from /da/ to /ga/) which had been identified as the same phoneme /da/ (within category condition) and as different phonemes /da/ and /ga/ (across categories condition). The acoustic differences between these two pairs of stimuli were equivalent.The MMN was observed in all subjects both in the within and across category conditions. Furthermore, the MMN did not differ in latency, amplitude or area within and across categories. That is, the MMN indicated equal discrimination both across and within categories. These results suggest that the MMN appears to reflect the processing of acoustic aspects of the speech stimulus, but not phonetic processing into categories. The MMN appears to be an extremely sensitive electrophysiologic index of minimal acoustic differences in speech stimuli.     

材料性质和专业对解决四卡片问题影响的眼动研究

目的：探讨实验材料性质和专业背景等因素对四卡片推理问题解决的影响。方法：使用ASL-504眼动记录仪,以16名大学生为被试,采用2（材料性质）×2（专业）的二因素被试间设计。结果：材料性质主效应不显著,但材料性质在相对注视时间、相对注视次数和瞳孔直径上呈现显著差异;专业因素主效应显著,专业因素在平均注视时间和平均眼跳距离上差异显著,二因素交互作用不显著;＂如果子句＂和＂那么子句＂在所有眼动指标上不存在显著差异。结论：（1）抽象程度高的材料在理解四卡片问题时需要更多的加工,包括条件句及其组成部分;（2）不同专业背景对理解条件句有不同的影响;（3）条件句各组成部分在理解时得到同等重要的加工。     

Brain function and higher nervous activity

Some actual problems of higher nervous activity have been analysed on the peculiarities of brain states in the course of different types of conditioning and reactivity of the nervous structures which depend on the brain state have been considered. A concept of brain state as a specific mechanism of each temporal connection forming during the learning process has been formulated for the first time. The authors suggest that the brain represents the dynamic system with changeable structure which reveals itself in multitude nervous set constellation during various types of activity. This concept is presented to be the theoretical basis for integral evaluation of functional capacities of central nervous system.     

The Mobility of The Coordinates of a Subjective Semantic Space As a Manifestation of Categorical Set

The perception and objective semantic interpretation of an object depend on categorical set. Categorical set is the readiness of the subject to interact with objects of a specified category. A multitude of experimental evidence confirms the existence of categorical set. This evidence can be divided into three groups: (a) data indicating that perception depends on experimental instructions; (b) data indicating that perception depends on the category to which the preceding stimulation belongs; and, finally, (c) data indicating that perception depends on individual differences in motivation, which are a priori with regard to the experiment. The reasons for the appearance of sets vary; but in the end they all lead to one and the same result: the evocation of diverse expectations (hypotheses) in different subjects in the same situation, or in the same subject at different moments in time (Bruner, 1977).