Xiao Xiaoqian, Dong Qi, Chen Chuansheng, Xue Gui
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, PR China; Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing, PR China.
Department of Psychology and Social Behavior, University of California, Irvine, United States.
Cortex. 2016 Jun;79:99-111. doi: 10.1016/j.cortex.2016.03.016. Epub 2016 Mar 31.
It has been consistently shown that words representing living things are better remembered than words representing nonliving things, yet the underlying cognitive and neural mechanisms have not been clearly elucidated. The present study used both univariate and multivariate pattern analyses to examine the hypotheses that living words are better remembered because (1) they draw more attention and/or (2) they share more overlapping semantic features. Subjects were asked to study a list of living and nonliving words during a semantic judgment task. An unexpected recognition test was administered 30 min later. We found that subjects recognized significantly more living words than nonliving words. Results supported the overlapping semantic feature hypothesis by showing that (a) semantic ratings showed greater semantic similarity for living words than for nonliving words, (b) there was also significantly greater neural global pattern similarity (nGPS) for living words than for nonliving words in the posterior portion of left parahippocampus (LpPHG), (c) the nGPS in the LpPHG reflected the rated semantic similarity, and also mediated the memory differences between two semantic categories, and (d) greater univariate activation was found for living words than for nonliving words in the left hippocampus (LHIP), which mediated the better memory performance for living words and might reflect greater semantic context binding. In contrast, although living words were processed faster and elicited a stronger activity in the dorsal attention network, these differences did not mediate the animacy effect in memory. Taken together, our results provide strong support to the overlapping semantic features hypothesis, and emphasize the important role of semantic organization in episodic memory encoding.
一直以来的研究表明，与代表无生命事物的词汇相比，代表有生命事物的词汇更容易被记住，但其中潜在的认知和神经机制尚未得到清晰阐释。本研究使用单变量和多变量模式分析来检验以下假设：有生命的词汇更容易被记住是因为（1）它们吸引了更多注意力，和/或（2）它们共享更多重叠的语义特征。在语义判断任务期间，要求受试者学习一组有生命和无生命的词汇列表。30分钟后进行一次意外的识别测试。我们发现，受试者识别出的有生命词汇明显多于无生命词汇。结果支持了重叠语义特征假设，具体表现为：（a）语义评级显示，有生命词汇比无生命词汇具有更高的语义相似性；（b）在左侧海马旁回（LpPHG）后部，有生命词汇的神经全局模式相似性（nGPS）也显著高于无生命词汇；（c）LpPHG中的nGPS反映了评级的语义相似性，并且介导了两个语义类别之间的记忆差异；（d）在左侧海马（LHIP）中，有生命词汇比无生命词汇表现出更大的单变量激活，这介导了有生命词汇更好的记忆表现，并且可能反映了更强的语义上下文绑定。相比之下，尽管有生命词汇的处理速度更快，并且在背侧注意力网络中引发了更强的活动，但这些差异并未介导记忆中的生命性效应。综上所述，我们的结果为重叠语义特征假设提供了有力支持，并强调了语义组织在情景记忆编码中的重要作用。
