Working memory is not fixed-capacity: More active storage capacity for real-world objects than for simple stimuli
Working memory is not fixed-capacity: More active storage capacity for real-world objects than for simple stimuli
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DOI：
10.1073/pnas.1520027113
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发表时间：
2016-07-05
影响因子：
11.1
通讯作者：
Alvarez, George A.
中科院分区：
文献类型：
--
作者：
Brady, Timothy F.;Stormer, Viola S.;Alvarez, George A.
视觉工作记忆是一种认知系统，它使视觉信息保持活跃，使其抵抗新的感知输入的干扰。关于简单刺激的信息——颜色和方位——被迅速编码到工作记忆中：在100毫秒内，工作记忆“填满”，显示出一个明显的容量限制。然而，对于现实世界的对象，同样的行为限制并不成立：随着编码时间的增加，人们存储更多的现实世界的对象，并以更详细的方式进行存储。人们通常认为，这种对现实世界物体表现的提升反映了一个单独的情景长期记忆系统的使用，而不是工作记忆。在这里，我们表明，这种对现实世界物体的能力的行为增加并不仅仅是由于使用单独的情景长期记忆系统。特别是，我们通过使用脑电图直接测量工作记忆任务延迟期间的神经活动，表明这种增加是工作记忆主动存储的结果。这些数据挑战了固定容量工作记忆模型，并表明工作记忆及其容量限制取决于我们现有的知识。
Visual working memory is the cognitive system that holds visual information active to make it resistant to interference from new perceptual input. Information about simple stimuli-colors and orientations-is encoded into working memory rapidly: In under 100 ms, working memory "fills up," revealing a stark capacity limit. However, for real-world objects, the same behavioral limits do not hold: With increasing encoding time, people store more real-world objects and do so with more detail. This boost in performance for real-world objects is generally assumed to reflect the use of a separate episodic long-term memory system, rather than working memory. Here we show that this behavioral increase in capacity with real-world objects is not solely due to the use of separate episodic long-term memory systems. In particular, we show that this increase is a result of active storage in working memory, as shown by directly measuring neural activity during the delay period of a working memory task using EEG. These data challenge fixed-capacity working memory models and demonstrate that working memory and its capacity limitations are dependent upon our existing knowledge.