Johns Hopkins University.
Psychol Sci. 2013 Oct;24(10):2038-47. doi: 10.1177/0956797613484938. Epub 2013 Aug 12.
In the ongoing debate about the efficacy of visual working memory for more than three items, a consensus has emerged that memory precision declines as memory load increases from one to three. Many studies have reported that memory precision seems to be worse for two items than for one. We argue that memory for two items appears less precise than that for one only because two items present observers with a correspondence challenge that does not arise when only one item is stored--the need to relate observations to their corresponding memory representations. In three experiments, we prevented correspondence errors in two-item trials by varying sample items along task-irrelevant but integral (as opposed to separable) dimensions. (Initial experiments with a classic sorting paradigm identified integral feature relationships.) In three memory experiments, our manipulation produced equally precise representations of two items and of one item.
在关于视觉工作记忆是否能记住三个以上项目的持续争论中，人们已经达成共识，即记忆精度会随着记忆负荷从一个增加到三个而下降。许多研究报告称，对于两个项目的记忆精度似乎比一个项目的更差。我们认为，对于两个项目的记忆似乎不如一个项目的精确，仅仅是因为当只有一个项目被存储时，两个项目会给观察者带来对应性的挑战，而当只有一个项目被存储时，这种挑战不会出现——即需要将观察结果与相应的记忆表示相关联。在三个实验中，我们通过沿着与任务无关但整体（而不是可分离）的维度变化样本项目，在两个项目的试验中防止了对应错误。（在一个经典的分类范式的初步实验中确定了整体特征关系。）在三个记忆实验中，我们的操作产生了对两个项目和一个项目的同样精确的表示。
