DISCRETE VERSUS CONTINUOUS MODELS OF VISUAL PERCEPTION

认知心理学中最基本的假设之一就是 进行决策或“选择反应时间”（RT）任务 使用一系列不同的心理过程或“阶段”， 感知、决策和响应执行。 传统上， 试图识别和描述这些阶段，详细说明每一个阶段， 其输入信息、执行的操作和输出的术语 制作。 最近，许多研究人员开始询问这些阶段是如何 如何配合执行复杂的任务，以及它们如何与一个 另 两种完全不同的模型，通常被称为 离散的和连续的，已经被提出（例如，McClelland，1979年; 斯滕贝格，1969年）。 确定哪种模型更好地描述了 人类信息处理任务的表现。 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， 伤害和疾病。 目前，这种模式的发展受到阻碍， 关于离散模型还是连续模型的基本不确定性 准确描述正常认知。 虽然这两种模式都是 与现有的关于人类表现的证据相一致，它们是 在操作上有着根本的不同， 进行新实验和解释结果的策略。 拟议的研究将调查两个关键的差异， 离散和连续模型。 一个是离散模型需要 以严格的顺序方式操作。 每一阶段开始 当它接收到输入时，处理直到完成，然后 将单个输出传输到处理序列中的下一级。 相反，连续模型允许连续的阶段以 游戏时间（即，有一些“时间重叠”），即使当输出 一级是下一级的输入。 一个阶段， 部分输出到其后继者，从而允许后一级 开始在前一个完成之前。 第二个关键区别是 涉及从一级到另一级传输的输出的性质。 根据离散模型，输出是离散的（“全有或全无”） 分类内部表征的激活。 根据 然而，连续模型的阶段输出在强度或 “激活级别”，并且也可能在其他方面。 这项研究的直接目的是发展出一种方法， 是否（1）在执行选择RT任务时使用的不同阶段 严格按顺序操作，（2）每级的输出是 全或无，而不是分级。 所提出的方法使用收敛 反应时间、反应力和心理生理指标 从EEG活动中获得的测量，并将用于检查人类 信息处理在一些科学上重要的认知 任务，尤其是涉及注意力的任务。

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.