Department of Psychology, Harvard University, William James Hall, 33 Kirkland Street, Cambridge, Massachusetts 02138, USA.
Nat Commun. 2012;3:1229. doi: 10.1038/ncomms2237.
Working memory is a mental storage system that keeps task-relevant information accessible for a brief span of time, and it is strikingly limited. Its limits differ substantially across people but are assumed to be fixed for a given person. Here we show that there is substantial variability in the quality of working memory representations within an individual. This variability can be explained neither by fluctuations in attention or arousal over time, nor by uneven distribution of a limited mental commodity. Variability of this sort is inconsistent with the assumptions of the standard cognitive models of working memory capacity, including both slot- and resource-based models, and so we propose a new framework for understanding the limitations of working memory: a stochastic process of degradation that plays out independently across memories.
工作记忆是一种心理存储系统，可在短暂的时间内保持与任务相关的信息，其容量非常有限。不同人之间的工作记忆容量存在显著差异，但对于特定个体而言，工作记忆容量被认为是固定的。在这里，我们表明，个体的工作记忆表示质量存在很大的可变性。这种可变性既不能归因于注意力或觉醒程度随时间的波动，也不能归因于有限心理资源的不均匀分布。这种类型的可变性与工作记忆容量的标准认知模型的假设不一致，包括插槽和资源模型，因此我们提出了一个新的框架来理解工作记忆的局限性：一种独立于各个记忆的随机退化过程。
