DISCRETE VERSUS CONTINUOUS MODELS OF VISUAL PERCEPTION

认知心理学中最基本的假设之一是 执行决策或“选择反应时间”(RT)任务 使用一系列不同的心理过程或“阶段”，如 感知、决策和响应执行。传统上，这一领域 试图识别和描述这样的阶段，在 其输入信息、执行的操作和输出的术语 制作。最近，许多研究人员开始问，这些阶段是如何 适合执行复杂的任务，以及它们如何与人进行沟通 又一个。两种完全不同类型的模型，通常称为 已经提出了离散和连续的概念(例如，McClelland，1979； Sternberg，1969)。 关键是要确定这些模型中哪一个能更好地描述 在人类信息处理任务中的表现。的发展。 正常认知过程的复杂模型是 理解认知缺陷，包括那些由衰老引起的认知缺陷， 受伤和疾病。目前，这种模式的发展受到以下因素的阻碍 关于离散模型还是连续模型更多的基本不确定性 准确描述正常认知。尽管这两款车型都是 与现有的关于人类表现的证据相一致，它们是 在操作上完全不同，他们开出的处方也非常不同 进行新实验和解释结果的策略。 这项拟议的研究将调查两个关键的差异 离散模型和连续模型。其一是离散模型需要 各阶段严格按顺序运行。每个阶段开始 当它接收到输入时，进行处理，直到它完成，然后 将单个输出传输到处理序列中的下一个阶段。 相反，连续模型允许连续的阶段在 游戏时间(即，与一些“时间重叠”)，即使当输出 一个阶段是下一个阶段的输入。一个阶段传递初步信息 部分输出到它的后继者，从而允许后期 在前面的那个完成之前就开始。第二个关键差异 涉及从一个阶段传输到另一个阶段的产出的性质。 根据离散模型，输出是离散的(“全有或全无”) 范畴内部表征的激活。根据 连续模型，然而，阶段输出逐渐变化的强度或 “激活水平”，可能在其他方面也是如此。 这项研究的直接目的是开发寻找 是否(1)在执行选择性RT任务时使用的不同阶段 严格按顺序运行，以及(2)每级的输出为 要么全有要么全不，而不是分级。所提出的方法使用收敛 反应时间、反应力和心理生理学的测量 源于脑电活动的测量，将被用来检查人类 信息处理中的一些重要科学认知 任务，尤指涉及注意力的任务。

One of the most basic assumptions in cognitive psychology is that speeded decision making or "choice reaction time" (RT) tasks are carried out using a sequence of distinct mental processes or "stages" like perception, decision, and response execution. Traditionally, the field has attempted to identify and describe such stages, specifying each in terms of its input information, operations performed, and output produced. Recently, many researchers have begun to ask how these stages fit together to perform complex tasks, and how they communicate with one another. Two quite different types of models, commonly referred to as discrete and continuous, have been suggested (e.g., McClelland, 1979; Sternberg, 1969). It is crucial to determine which of these models better describes performance in human information processing tasks. The development of sophisticated models for normal cognitive processes is a prerequisite for understanding cognitive deficits, including those resulting from aging, injury, and disease. At present, such model development is hindered by fundamental uncertainty about whether discrete or continuous models more accurately describe normal cognition. Although both models are compatible with available evidence about human performance, they are fundamentally different in operation, and they prescribe very different strategies for conducting new experiments and interpretating the results. The proposed research will investigate two critical differences between discrete and continuous models. One is that discrete models require stages to operate in a strictly sequential manner. Each stage begins when it receives input, processes until it is finished, and then transmits a single output to the next stage in the processing sequence. Conversely, continuous models allow successive stages to operate at the game time (i.e., with some "temporal overlap"), even when the output of one stage is the input to the next. A stage transmits preliminary partial output to its successor, thereby allowing the later stage to begin before the earlier one is finished. The second critical difference concerns the nature of the outputs transmitted from stage to stage. According to discrete models, outputs are discrete ("all-or-none") activations of categorical internal representations. According to continuous models, however, stage outputs vary gradually in strength or "activation level", and possibly in other respects as well. The immediate aims of this research are to develop methods for finding out whether (1) the different stages used in performing choice RT tasks operate in strict sequence, and (2) the output of each stage is all-or-none rather than graded. The proposed methods use convergent measures of response time, response force, and psychophysiological measures derived from EEG activity, and will be used to examine human information processing in a number of scientifically important cognitive tasks, especially those involving attention.