Department of Psychology, University of Chicago.
J Exp Psychol Gen. 2024 Jan;153(1):86-101. doi: 10.1037/xge0001479. Epub 2023 Sep 11.
The fundamental unit of visual working memory (WM) has been debated for decades. WM could be object-based, such that capacity is set by the number of individuated objects, or feature-based, such that capacity is determined by the total number of feature values stored. The present work examined whether object- or feature-based models would best explain how multifeature objects (i.e., color/orientation or color/shape) are encoded into visual WM. If maximum capacity is limited by the number of individuated objects, then above-chance performance should be restricted to the same number of items as in a single-feature condition. By contrast, if the capacity is determined by independent storage resources for distinct features-without respect to the objects that contain those features-then successful storage of feature values could be distributed across a larger number of objects than when only a single feature is relevant. We conducted four experiments using a whole-report task in which subjects reported both features from every item in a six-item array. The crucial finding was that above-chance recall-for both single- and multifeatured objects-was restricted to the first three or four responses, while the later responses were best modeled as guesses. Thus, whole-report with multifeature objects reveals a distribution of recalled features that indicates an object-based limit on WM capacity. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
视觉工作记忆 (WM) 的基本单元已经争论了几十年。WM 可以基于对象，其容量由个体对象的数量决定，也可以基于特征，其容量由存储的特征值总数决定。本研究旨在探讨基于对象或基于特征的模型哪个更能解释多特征物体（即颜色/方向或颜色/形状）是如何被编码到视觉 WM 中的。如果最大容量受个体对象数量的限制，那么超过机会的表现应该仅限于与单特征条件相同数量的项目。相比之下，如果容量由独立的特征存储资源决定，而不考虑包含这些特征的对象，那么特征值的成功存储可以分布在比只有一个特征相关的更多的对象上。我们进行了四项实验，使用全报告任务，其中被试在 6 个项目的数组中报告每个项目的两个特征。关键发现是，超过机会的回忆——无论是单特征还是多特征物体——都仅限于前三个或四个反应，而后面的反应则最好被建模为猜测。因此，多特征物体的全报告显示出回忆特征的分布，表明 WM 容量受到基于对象的限制。
