Wagar Brandon M, Dixon Mike J
Department of Psychology, University of Waterloo, Waterloo, Ont., Canada N2L 3G1.
Brain Cogn. 2005 Apr;57(3):248-56. doi: 10.1016/j.bandc.2004.08.054.
The nature of object representation in working memory is vital to establishing the capacity of working memory, which in turn shapes the limits of visual cognition and awareness. Although current theories discuss whether representations in working memory are feature-based or object-based, no theory has considered the role of past experience. However, work with humans and non-human primates suggests that once participants learn which features are important for category membership, these diagnostic features become more salient than non-diagnostic features in long-term memory and object recognition. Critically, the brain areas involved in this diagnosticity effect are also recruited during working memory tasks. We report two experiments testing whether a diagnosticity effect exists in working memory; and whether it is present when visual information is encoded into working memory, or if it is the result of maintenance within working memory. Results showed a diagnosticity effect which was present at encoding. Maintenance did not influence the nature of object representation in working memory. These findings show that the meaning we glean from our past experience has a profound influence on the nature of object representation in working memory.
工作记忆中客体表征的本质对于确定工作记忆的容量至关重要，而工作记忆的容量又反过来塑造了视觉认知和意识的界限。尽管当前的理论探讨了工作记忆中的表征是基于特征还是基于客体，但尚无理论考虑过往经验的作用。然而，针对人类和非人类灵长类动物的研究表明，一旦参与者了解哪些特征对于类别归属很重要，这些诊断性特征在长期记忆和客体识别中就会比非诊断性特征更加突出。至关重要的是，在工作记忆任务中也会调用涉及这种诊断效应的脑区。我们报告了两项实验，测试工作记忆中是否存在诊断效应；以及当视觉信息被编码到工作记忆中时该效应是否存在，或者它是否是工作记忆中维持的结果。结果显示在编码时存在诊断效应。维持过程并未影响工作记忆中客体表征的本质。这些发现表明，我们从过往经验中收集到的意义对工作记忆中客体表征的本质有着深远的影响。
