Luck S J, Vogel E K
Department of Psychology, University of Iowa, Iowa City 52242-1407, USA.
Nature. 1997 Nov 20;390(6657):279-81. doi: 10.1038/36846.
Short-term memory storage can be divided into separate subsystems for verbal information and visual information, and recent studies have begun to delineate the neural substrates of these working-memory systems. Although the verbal storage system has been well characterized, the storage capacity of visual working memory has not yet been established for simple, suprathreshold features or for conjunctions of features. Here we demonstrate that it is possible to retain information about only four colours or orientations in visual working memory at one time. However, it is also possible to retain both the colour and the orientation of four objects, indicating that visual working memory stores integrated objects rather than individual features. Indeed, objects defined by a conjunction of four features can be retained in working memory just as well as single-feature objects, allowing sixteen individual features to be retained when distributed across four objects. Thus, the capacity of visual working memory must be understood in terms of integrated objects rather than individual features, which places significant constraints on cognitive and neurobiological models of the temporary storage of visual information.
短期记忆存储可分为用于言语信息和视觉信息的不同子系统，并且最近的研究已开始描绘这些工作记忆系统的神经基础。尽管言语存储系统已得到充分表征，但视觉工作记忆对于简单的阈上特征或特征组合的存储容量尚未确定。在此我们证明，视觉工作记忆一次仅能保留关于四种颜色或方向的信息。然而，也有可能保留四个物体的颜色和方向，这表明视觉工作记忆存储的是整合的物体而非单个特征。的确，由四个特征组合定义的物体与单个特征物体一样能够很好地保留在工作记忆中，当分布在四个物体上时可允许保留十六个单独的特征。因此，视觉工作记忆的容量必须从整合的物体而非单个特征的角度来理解，这对视觉信息临时存储的认知和神经生物学模型施加了重大限制。
