类别学习中分类学习与推理学习的对比研究

本研究对类别学习中分类学习与推理学习进行了对比.实验中要求被试从成对呈现的项目中选择一个更典型的A,并且要求被试将典型的A和典型的B画出来.测试中所呈现项目诊断性程度或典型性程度不同.研究结果表明,分类学习者主要受诊断性信息的影响,而推理学习者主要受典型性信息的影响.即,分类学习者关注类别间信息,而推理学习者关注类别内信息.     

类别学习中两种学习模式的比较研究：分类学习与推理学习

采用学习迁移任务范式,使用基于单一特征的类别判断技术,比较了非线性分离结构下,分类学习和推理学习的学习效率、学习过程与策略和学习结果。结果表明：在学习效率上,分类学习比推理学习更好地习得了含有较多样例的类别知识,分类学习的速度上显著快于推理学习。在学习的过程与策略上,推理学习比分类学习更为关注类别内不同特征的相关,但在分类策略的运用上不如分类学习灵活。在学习的结果上,推理学习倾向于原型记忆,分类学习倾向于进行样例记忆,分类学习比推理学习更好地掌握了类别原型     

三水平特征的家族相似性类别结构的分类和推理学习

采用学习迁移任务范式,使用基于单一特征的类别判断技术,比较了三水平特征的家族性似性类别结构下,分类学习和推理学习的学习效率、学习过程与策略和学习结果.结果表明:在学习效率上,分类学习在达标率上优于推理学习,而在速度上,两者差异不显著.在学习的过程与策略上 ,推理学习相对较快地从单维度策略转向使用规则加例外策略,而分类学习表现出一定程度的潜伏学习, 并在高水平的信息整合策略使用上,赶上了推理学习.在学习的结果上,分类学习比推理学习更好掌握了类别的原型.     

两种学习模式下类别学习的结果：原型和样例

利用“学习－迁移”的任务范式和单一特征类别判断技术,探讨了分类和推理两种类别学习模式的结果,比较了两种学习模式的效果和策略。研究表明：两种学习模式产生了不同的结果,分类学习的结果是样例,推理学习的结果是原型;在学习效果方面,分类学习比推理学习在达标比例上更高,但在进度上差异不显著;在策略运用方面,分类学习比推理学习更快地使用单维度策略,而在高水平策略的运用上,两者差异不显著     

不同类别学习方式的对比研究

55名被试被随机分配到两个组,分别通过分类学习与推理学习来学习两个类别,之后,两组被试对新的测试项目进行典型性评定,考察类别学习方式对类别表征的影响。研究结果表明,分类学习者仅仅依据项目的诊断性程度来评定,而推理学习者主要依据项目的典型性程度来评定。所以,诊断性信息在分类学习者的类别表征中占有重要位置,典型性信息在推理学习者的类别表征中占有重要位置,即分类学习与推理学习导致的类别表征不同。     

类别学习的机制:基于类别中心学习假设的解释

为了区分推理学习是学习类别内部结构还是学习类别对应特征的规则,该研究使用眼动仪研究了22名大学生被试在类别学习过程中的眼动情况。被试被随机分为相等的两组,一组进行分类学习,另一组进行推理学习。实验分为学习、测试两阶段,在学习阶段被试三个连续单元的正确率为90%或者30个单元做完则结束学习,在测试阶段检验学习的效果。结果表明推理学习者在学习过程中关注的是类别内部特征之间的关系,而不是类别对应特征的规则。     

类别特征推理的认知机制与神经基础

分类及类别特征推理是类别知识的两大重要功能。研究表明, 两种任务之间存在本质差异。因此, 探讨类别特征推理的认知及神经机制对于拓展类别相关理论非常重要。已有研究发现, 类别标签、典型性程度以及类别特征间的因果关系都会影响类别特征推理任务, 而且, 类别特征推理任务与分类任务的神经基础不同。未来研究方向应当关注类别标签以及类别特征间的因果关系分别与典型性程度之间的交互作用, 在未来神经机制方面的进一步研究应当设计更符合自然情境下的特征推理任务范式。     

部分呈现条件下类别分类学习中的信息表征机制

先前研究者普遍认为, 类别推理学习条件下可以同时表征诊断性信息和非诊断性信息, 而类别分类学习条件下中只能表征诊断性信息, 不能表征非诊断性信息。而最近又有研究者发现部分呈现条件下的类别分类学习可以表征非诊断性信息。本研究通过两个实验系统比较了全部呈现和部分呈现条件下类别分类学习的结果, 进一步探讨了分类学习条件下信息的表征情况, 并进一步探讨了部分呈现条件下的分类学习能够表征非诊断性信息的原因。实验1发现全部呈现6个特征、缺失1个特征(即部分呈现5个特征)、缺失2个特征(即部分呈现4个特征)3种条件下都能表征诊断性信息, 但只有部分呈现条件下能表征非诊断性信息。实验2发现全部呈现7个特征、缺失2个特征(即部分呈现5个特征)、全部呈现5个特征3种条件下都能表征诊断性信息, 但只有部分呈现条件下能表征非诊断性信息。总的实验结果表明：全部呈现条件下的分类学习只能表征诊断性信息, 而部分呈现条件下的分类学习能够同时表征诊断性信息和非诊断性信息, 并且部分呈现条件下表征非诊断性信息的原因是被试进行了推理学习, 而非注意广度的变化。     

工作记忆容量与内容相关性对类别学习的影响

类别学习是通过不断地分类练习,学会如何将类别刺激进行归类的过程。采用2(工作记忆容量:高、低)×4(内容相关性:方向、宽度、亮度、控制组)被试间实验设计,通过两个实验探讨工作记忆容量与内容相关性对基于规则类别学习和信息整合类别学习的影响。结果显示:(1)对基于规则类别学习来说,在高工作记忆容量条件下,当关注相关维度时,类别学习的成绩更好;(2)对基于信息整合类别学习来说,不管工作记忆容量如何,只要关注相关维度类别学习的成绩更好。     

非监控类别学习的分类策略与表征

类别学习是人类对不同类别加以归类的过程。类别信息的表征、分类策略运用的特点一直是类别学习研究的重点。非监控类别学习可分为直接的非监控类别学习和间接的非监控类别学习。直接的非监控类别学习(非限制任务, 限制任务)中被试的分类策略具有分类“单维度倾向”策略特点,类别变异程度会影响类别表征; 间接的非监控类别学习更倾向形成相似性表征, 直接的非监控类别学习则为基于规则表征。现有的非监控类别学习的理论对分类策略和表征的解释仍显薄弱, 不同学习任务下类别迁移和知识效应的研究还存在不足, 未来研究还需要进一步验证知识效应对非监控类别学习的认知加工过程的影响、探索影响类别表征形成的因素等问题。     

Learning nonlinearly separable categories by inference and classification

Previous research suggests that learning categories by classifying new instances highlights information that is useful for discriminating between categories. In contrast, learning categories by making predictive inferences focuses learners on an abstract summary of each category (e.g., the prototype). To test this characterization of classification and inference learning further, the authors evaluated the two learning procedures with nonlinearly separable categories. In contrast to previous research involving cohesive, linearly separable categories, the authors found that it is more difficult to learn nonlinearly separable categories by making inferences about features than it is to learn them by classifying instances. This finding reflects that the prototype of a nonlinearly separable category does not provide a good summary of the category members. The results from this study suggest that having a cohesive category structure is more important for inference than it is for classification.     

Classification versus inference learning contrasted with real-world categories

Categories are learned and used in a variety of ways, but the research focus has been on classification learning. Recent work contrasting classification with inference learning of categories found important later differences in category performance. However, theoretical accounts differ on whether this is due to an inherent difference between the tasks or to the implementation decisions. The inherent-difference explanation argues that inference learners focus on the internal structure of the categories—what each category is like—while classification learners focus on diagnostic information to predict category membership. In two experiments, using real-world categories and controlling for earlier methodological differences, inference learners learned more about what each category was like than did classification learners, as evidenced by higher performance on a novel classification test. These results suggest that there is an inherent difference between learning new categories by classifying an item versus inferring a feature.     

Diagnosticity and prototypicality in category learning: a comparison of inference learning and classification learning

Category knowledge allows for both the determination of category membership and an understanding of what the members of a category are like. Diagnostic information is used to determine category membership; prototypical information reflects the most likely features given category membership. Two experiments examined 2 means of category learning, classification and inference learning, in terms of sensitivity to diagnostic and prototypical information. Classification learners were highly sensitive to diagnostic features but not sensitive to nondiagnostic, but prototypical, features. Inference learners were less sensitive to the diagnostic features than were classification learners and were also sensitive to the nondiagnostic, prototypical, features. Discussion focuses on aspects of the 2 learning tasks that might lead to this differential sensitivity and the implications for learning real-world categories.     

Observed attention allocation processes in category learning

In two empirical studies of attention allocation during category learning, we investigate the idea that category learners learn to allocate attention optimally across stimulus dimensions. We argue that “optimal” patterns of attention allocation are model or process specific, that human learners do not always optimize attention, and that one reason they fail to do so is that under certain conditions the cost of information retrieval or use may affect the attentional strategy adopted by learners. We empirically investigate these issues using a computer interface incorporating an “information-board” display that collects detailed information on participants' patterns of attention allocation and information search during learning trials. Experiment 1 investigated the effects on attention allocation of distributing perfectly diagnostic features across stimulus dimensions versus within one dimension. The overall pattern of viewing times supported the optimal attention allocation hypothesis, but a more detailed analysis produced evidence of instance- or category-specific attention allocation, a phenomenon not predicted by prominent computational models of category learning. Experiment 2 investigated the strategies adopted by category learners encountering redundant perfectly predictive cues. Here, the majority of participants learned to distribute attention optimally in a cost–benefit sense, allocating attention primarily to only one of the two perfectly predictive dimensions. These results suggest that learners may take situational costs and benefits into account, and they present challenges for computational models of learning that allocate attention by weighting stimulus dimensions.     

Observed attention allocation processes in category learning

In two empirical studies of attention allocation during category learning, we investigate the idea that category learners learn to allocate attention optimally across stimulus dimensions. We argue that "optimal" patterns of attention allocation are model or process specific, that human learners do not always optimize attention, and that one reason they fail to do so is that under certain conditions the cost of information retrieval or use may affect the attentional strategy adopted by learners. We empirically investigate these issues using a computer interface incorporating an "information-board" display that collects detailed information on participants' patterns of attention allocation and information search during learning trials. Experiment 1 investigated the effects on attention allocation of distributing perfectly diagnostic features across stimulus dimensions versus within one dimension. The overall pattern of viewing times supported the optimal attention allocation hypothesis, but a more detailed analysis produced evidence of instance- or category-specific attention allocation, a phenomenon not predicted by prominent computational models of category learning. Experiment 2 investigated the strategies adopted by category learners encountering redundant perfectly predictive cues. Here, the majority of participants learned to distribute attention optimally in a cost-benefit sense, allocating attention primarily to only one of the two perfectly predictive dimensions. These results suggest that learners may take situational costs and benefits into account, and they present challenges for computational models of learning that allocate attention by weighting stimulus dimensions.     

Language evolution by iterated learning with bayesian agents

Languages are transmitted from person to person and generation to generation via a process of iterated learning: people learn a language from other people who once learned that language themselves. We analyze the consequences of iterated learning for learning algorithms based on the principles of Bayesian inference, assuming that learners compute a posterior distribution over languages by combining a prior (representing their inductive biases) with the evidence provided by linguistic data. We show that when learners sample languages from this posterior distribution, iterated learning converges to a distribution over languages that is determined entirely by the prior. Under these conditions, iterated learning is a form of Gibbs sampling, a widely-used Markov chain Monte Carlo algorithm. The consequences of iterated learning are more complicated when learners choose the language with maximum posterior probability, being affected by both the prior of the learners and the amount of information transmitted between generations. We show that in this case, iterated learning corresponds to another statistical inference algorithm, a variant of the expectation-maximization (EM) algorithm. These results clarify the role of iterated learning in explanations of linguistic universals and provide a formal connection between constraints on language acquisition and the languages that come to be spoken, suggesting that information transmitted via iterated learning will ultimately come to mirror the minds of the learners.     

Learning about the internal structure of categories through classification and feature inference

Previous research on category learning has found that classification tasks produce representations that are skewed toward diagnostic feature dimensions, whereas feature inference tasks lead to richer representations of within-category structure. Yet, prior studies often measure category knowledge through tasks that involve identifying only the typical features of a category. This neglects an important aspect of a category's internal structure: how typical and atypical features are distributed within a category. The present experiments tested the hypothesis that inference learning results in richer knowledge of internal category structure than classification learning. We introduced several new measures to probe learners' representations of within-category structure. Experiment 1 found that participants in the inference condition learned and used a wider range of feature dimensions than classification learners. Classification learners, however, were more sensitive to the presence of atypical features within categories. Experiment 2 provided converging evidence that classification learners were more likely to incorporate atypical features into their representations. Inference learners were less likely to encode atypical category features, even in a “partial inference” condition that focused learners' attention on the feature dimensions relevant to classification. Overall, these results are contrary to the hypothesis that inference learning produces superior knowledge of within-category structure. Although inference learning promoted representations that included a broad range of category-typical features, classification learning promoted greater sensitivity to the distribution of typical and atypical features within categories.