Perceptual and Cognitive Processes in Category Learning

这项由该奖项资助的研究将调查人们如何学习感知对象和事件的新类别。分类是一个至关重要的认知过程，所有人每天都会进行无数次。它允许人们阅读，选择安全的食物，使用环境中的物体和工具，以及识别朋友和亲人。不幸的是，这也是一个脆弱的过程，从某种意义上说，许多正常和病理条件已被证明会导致分类学习缺陷。这些疾病包括正常衰老、重度抑郁症、帕金森病、阿尔茨海默病、亨廷顿病、中风和精神分裂症。以往的分类学习理论主要是在健康大学生的分类数据上进行检验的。要了解这些被忽视的人群中的类别学习，需要了解调节这一重要技能的大脑结构和途径。为此，本研究将测试和扩展第一个关于类别学习的神经心理学理论，称为COVIS（言语和内隐系统之间的竞争；Ashby, Alfonso-Reese,Turken, & Waldron, 1998, Psychological Review, 105, 442-481），该理论假设类别学习是独立的外显和内隐分类系统之间的竞争。外显系统处于意识控制之下，并参与假设检验或基于规则的推理的系统过程。内隐系统是一种程序性学习，它在很大程度上是有意识意识所无法接触到的。阿什比等等。（1998）开发了一个正式版本的COVIS，可以对各种各样的分类任务进行精确的定量预测，同时还开发了一个神经心理学版本，描述了被认为是调解类别学习的潜在神经机制和途径。目前的研究包括在COVIS理论的推动下对健康年轻人进行的许多新实验。一些实验将验证covis的假设，即正常的类别学习是功能独立的外显和内隐系统之间的竞争。许多实验将分离显性系统并研究它的特性，包括控制它如何学习的规则，有或没有关于反应准确性的逐次反馈。最后，许多类似的实验将尝试用隐式系统实现相同的目标（即，隔离它并研究它的性质）。这些研究的完成不仅将为COVIS提供严格的测试，而且无论结果如何，它还将为感知和认知过程以及潜在的神经机制和途径提供有价值的新见解，这些神经机制和途径介导了所有人类行为中最基本的行为之一-按类别对环境中的物体和事件进行分组。

The research funded by this award will investigate how people learn newcategories of perceptual objects and events. Categorization is a cognitiveprocess of fundamental importance that all people perform countless timesevery day. It allows people to read, to select foods that are safe to eat,to use objects and tools in the environment, and to recognize friends andkin. Unfortunately, it is also a fragile process, in the sense that anumber of normal and pathological conditions have been shown to causecategory learning deficits. These include normal aging, major depression,Parkinson's disease, Alzheimer's disease, Huntington's disease, strokes,and schizophrenia. Previous theories of category learning were testedprimarily on categorization data from healthy university students. Tounderstand category learning in these neglected populations requires anunderstanding of the brain structures and pathways that mediate thisimportant skill. Toward this end, this research will test and extend thefirst neuropsychological theory of category learning, called COVIS(COmpetition between Verbal and Implicit Systems; Ashby, Alfonso-Reese,Turken, & Waldron, 1998, Psychological Review, 105, 442-481), which assumesthat category learning is a competition between separate explicit andimplicit categorization systems. The explicit system is under consciouscontrol and engages in a systematic process of hypothesis testing orrule-based reasoning. The implicit system, which is largely not accessibleto conscious awareness, engages in a form of procedural learning. Ashby etal. (1998) developed a formal version of COVIS that makes precisequantitative predictions in a wide variety of categorization tasks, andalso a neuropsychological version that describes the underlying neuralmechanisms and pathways that are assumed to mediate category learning. Thecurrent research includes many new experiments with healthy young adultsthat were motivated by the COVIS theory. Some experiments will test theCOVIS assumption that normal category learning is a competition betweenfunctionally separate explicit and implicit systems. Many of theexperiments will isolate the explicit system and investigate itsproperties, including the rules that govern how it learns, both with andwithout trial-by-trial feedback about response accuracy. Finally, manyanalogous experiments will attempt to achieve the same goals with theimplicit system (i.e., isolate it and investigate its properties). Thecompletion of these studies will not only provide a rigorous test of COVIS,but regardless of their outcome, it will also provide valuable new insightsinto the perceptual and cognitive processes and the underlying neuralmechanisms and pathways that mediate one of the most basic of all humanacts - grouping objects and events in the environment by category.