Department of Experimental Psychology, University of Oxford, UK.
Cognition. 2013 Oct;129(1):123-37. doi: 10.1016/j.cognition.2013.06.009. Epub 2013 Jul 27.
There is emerging evidence that the encoding of visual information and the maintenance of this information in a temporarily accessible state in working memory rely on the same neural mechanisms. A consequence of this overlap is that atypical forms of perception should influence working memory. We examined this by investigating whether having grapheme-color synesthesia, a condition characterized by the involuntary experience of color photisms when reading or representing graphemes, would confer benefits on working memory. Two competing hypotheses propose that superior memory in synesthesia results from information being coded in two information channels (dual-coding) or from superior dimension-specific visual processing (enhanced processing). We discriminated between these hypotheses in three n-back experiments in which controls and synesthetes viewed inducer and non-inducer graphemes and maintained color or grapheme information in working memory. Synesthetes displayed superior color working memory than controls for both grapheme types, whereas the two groups did not differ in grapheme working memory. Further analyses excluded the possibilities of enhanced working memory among synesthetes being due to greater color discrimination, stimulus color familiarity, or bidirectionality. These results reveal enhanced dimension-specific visual working memory in this population and supply further evidence for a close relationship between sensory processing and the maintenance of sensory information in working memory.
有新的证据表明，视觉信息的编码以及工作记忆中对信息的临时访问状态的维持依赖于相同的神经机制。这种重叠的结果是，异常的感知形式应该会影响工作记忆。我们通过研究阅读或表示字母时是否会出现不由自主的颜色幻觉的文字-颜色联觉症（一种不由自主的体验颜色幻觉的病症），来检验这一点。这种病症是否会对工作记忆产生影响。有两个相互竞争的假设提出，联觉者的记忆之所以更好，是因为信息被编码在两个信息通道中（双重编码），或者是因为维度特定的视觉处理能力更强（增强处理）。我们在三个 n 回实验中区分了这些假设，对照组和联觉者观看了诱导物和非诱导物的字母，并在工作记忆中保持颜色或字母信息。对于这两种字母类型，联觉者的颜色工作记忆都优于对照组，而两组在字母工作记忆方面没有差异。进一步的分析排除了联觉者的工作记忆增强是由于更高的颜色辨别力、刺激颜色熟悉度或双向性所致的可能性。这些结果揭示了该人群中特定于维度的视觉工作记忆增强，并为感觉处理与工作记忆中感觉信息的维持之间的密切关系提供了进一步的证据。
