Collaborative Research: Assessment of Infants' Object Concepts

婴儿和大一点的学步儿童是否能将世界上的物体划分为基本相似的类别，这个问题已经持续了几十年，主要是因为缺乏评估在各种年龄范围内都有效的分类方法。学龄前婴儿的概念必须通过独立于语言的技术来检查，而语言的产生和理解通常对幼儿早期概念的评估至关重要。确定年幼和年长的婴儿是否拥有相似类型的概念，与认知发展在多大程度上是连续或不连续有关。一方面，婴儿和大一点的学步儿童的类别扩展之间的差异可能是由于不同的评估方法或不同的经验水平的对象。即使在同一个年龄组中，婴儿也可能在不同的分类任务中产生不同的类别扩展模式，因为任务在注意和其他信息处理需求方面存在差异。另一方面，前语言婴儿和知道事物名称的大婴儿之间可能存在根本差异，因为他们拥有不同的表征系统。根据这种说法，组内分类的变化是因为不同的程序利用不同的分类过程而出现的。本研究将引入一种新的方法，一种联想概括的理解措施，旨在帮助确定婴儿期分类中组间和组内变化的基础。在这种方法中，偏好的外观将作为婴儿理解概念界限的指标，并将纠正与模仿和标签等基于生产的反应相关的方法问题。在整个项目的三个连续阶段中，将使用联想概括的理解测量来探索婴儿对早期分类研究中经常使用的玩具复制品作为相应真实物体的符号的理解，并区分概念出现的三种替代发展顺序：(1)领域优先；婴儿的早期概念在本质上是全局的（例如，在动物或交通工具的水平上），广义概念控制着婴儿对类别属性的联想；(2)基本优先：婴儿的初始概念处于基本层面（如狗、猫、汽车、卡车），通过基于生产的模仿任务获得的领域层面概括可归因于基本层面类别的过度扩展；(3)可变特异性：婴儿具有基本的知识，即不同类型的属性与不同特异性水平的类别相一致。最后一种方法意味着某些属性是在基本层面上一般化的，而其他属性是在领域层面上一般化的；这种意识将构成对阶级包容关系不对称的初步理解的证据。基于理解的模拟生产模仿措施的发展具有巨大的潜力，可以作为适合年幼婴儿的任务（例如，习惯化）和适合较大幼儿的任务（例如，命名，连续触摸）之间的方法学“桥梁”。这种工具将使研究人员能够灵敏地测试分类过程在生命的头两年保持稳定的程度，并将为旨在促进早期词汇发展的干预计划的发展提供有用的数据。

The question of whether infants and older toddlers differentiate the world of objects into fundamentally similar kinds of categories has persisted for decades, largely due to the absence of methods for assessing categorization that are effective across a wide variety of ages. The concepts of preverbal infants must be examined through techniques that are independent of language, while language production and comprehension typically are vital to the assessment of toddlers' early concepts. Determining whether younger and older infants possess similar types of concepts is relevant to broader questions concerning the degree to which cognitive development is continuous or discontinuous. On the one hand, differences between the category extensions of infants and older toddlers may be due to different methods of assessment or to different levels of experience with objects. Even within a single age group, infants may produce different patterns of category extension across different categorization tasks because the tasks vary in terms of attentional and other information-processing demands. On the other hand, fundamental differences may exist between prelinguistic infants and older infants who know names for things because they possess qualitatively different representational systems. By this account, within-group variations in categorization emerge because different procedures tap different categorization processes. This research will introduce a new method, a comprehension measure of associative generalization, that is intended to help determine the basis for between-group and within-group variations in categorization during infancy. In this method, preferred looking will serve as an index of infants' understanding of conceptual boundaries and will correct for methodological problems associated with production-based responses such as imitation and labeling. Throughout three consecutive phases of the project, the comprehension measure of associative generalization will be used to explore infants' understanding of the toy replicas often used in studies of early categorization as symbols for the corresponding real objects, and to differentiate among three alternative developmental sequences in the emergence of concepts: (1) Domain-first: Infants' early concepts are global in nature (e.g., at the level of animal or vehicle) and broad concepts control infants' associations of category properties; (2) Basic-first: Infants' initial concepts are at the basic level (e.g., dog, cat, car, or truck), and domain-level generalizations obtained through production-based imitation tasks are attributable to overextensions of basic level categories; and (3) Variable specificity: Infants possess rudimentary knowledge that different types of properties are aligned with categories at different levels of specificity. The last would imply that certain properties are generalized at the basic level, and others are generalized at the domain level; such awareness would constitute evidence for rudimentary understanding of the asymmetry of class inclusion relations.The development of a comprehension-based analog to productive imitation measures has tremendous potential to serve as a methodological "bridge" between tasks appropriate for younger infants (e.g., habituation) and tasks suitable for older toddlers (e.g., naming, successive touching). Such a tool will enable researchers to sensitively test the degree to which categorization processes remain stable throughout the first two years of life and will provide useful data for the development of intervention programs aimed at facilitating early lexical development.