Zimmer Hubert D, Fischer Benjamin
Brain & Cognition Unit, Department of Psychology, Saarland University, Saarbrücken, Germany.
International Research Training Group "Adaptive Minds", Saarland University, Saarbrücken, Germany.
Front Psychol. 2020 Apr 17;11:516. doi: 10.3389/fpsyg.2020.00516. eCollection 2020.
People unfamiliar with Chinese characters show poorer visual working memory (VWM) performance for Chinese characters than do literates in Chinese. In a series of experiments, we investigated the reasons for this expertise advantage. Experiments 1 and 2 showed that the advantage of Chinese literates does not transfer to novel material. Experts had similar resolution as novices for material outside of their field of expertise, and the memory of novices and experts did not differ when detecting a big change, e.g., when a character's color was changed. Memorizing appears to function as a rather abstract representation of word forms because memory for characters' fonts was poor independently of expertise (Experiment 3), though still visual. Distractors that were highly similar conceptually did not increase memory errors, but visually similar distractors impaired memory (Experiment 4). We hypothesized that literates in Chinese represent characters in VWM as tokens of visual word forms made available by long-term memory. In Experiment 5, we provided novices with visual word form knowledge. Participants subsequently performed a change detection task with trained and novel characters in a functional magnetic resonance experiment. We analyzed set size- and training-dependent effects in the intraparietal sulcus (IPS) and the visual word form area. VWM for trained characters was better than for novel characters. Neural activity increased with set size and at a slower rate for trained than for novel characters. All conditions approached the same maximum, but novel characters reached the maximum at a smaller set size than trained characters. The time course of the bold response depended on set size and knowledge status. Starting from the same initial maximum, neural activity at small set sizes returned to baseline more quickly for trained characters than for novel characters. Additionally, high performers showed generally more neural activity in the IPS than low performers. We conclude that experts' better performance in working memory (WM) is caused by the availability of visual long-term representations (word form types) that allow a sparse representation of the perceived stimuli and make even small changes big because they cause a type change that is easily detected.
不熟悉汉字的人在处理汉字时，其视觉工作记忆（VWM）表现比会读写中文的人要差。在一系列实验中，我们探究了这种专业技能优势的原因。实验1和实验2表明，中文读写者的优势并不能迁移到新的材料上。对于专业领域之外的材料，专家和新手的分辨能力相似，并且在检测大的变化（例如，一个汉字的颜色发生改变）时，新手和专家的记忆表现并无差异。记忆似乎起到了一种相当抽象的文字形式表征的作用，因为无论专业程度如何，对汉字字体的记忆都很差（实验3），不过仍然是视觉层面的。概念上高度相似的干扰项不会增加记忆错误，但视觉上相似的干扰项会损害记忆（实验4）。我们推测，会读写中文的人在VWM中把汉字表征为长期记忆中可用的视觉文字形式的符号。在实验5中，我们为新手提供了视觉文字形式知识。随后，参与者在功能磁共振实验中对经过训练的汉字和新的汉字执行了变化检测任务。我们分析了顶内沟（IPS）和视觉词形区中与集合大小和训练相关的效应。对经过训练的汉字的VWM表现优于新的汉字。神经活动随着集合大小的增加而增强，并且对于经过训练的汉字，其神经活动增强的速率比对新汉字慢。所有条件下都接近相同的最大值，但新汉字在比经过训练的汉字更小的集合大小时就达到了最大值。粗体响应的时间进程取决于集合大小和知识状态。从相同的初始最大值开始，对于经过训练的汉字，小集合大小时的神经活动比新汉字更快地回到基线。此外，表现优秀者在IPS中的神经活动总体上比表现较差者更多。我们得出结论，专家在工作记忆（WM）中表现更好的原因是视觉长期表征（文字形式类型）的可用性，这些表征允许对感知到的刺激进行稀疏表征，并且即使是很小的变化也会显得很明显，因为它们会导致易于检测的类型变化。
