新颖语义联结形成的右半球优势效应

Right hemispheric dominance in forming novel semantic associations

新颖语义联结形成是创造性思维的重要加工过程。采用谜题型歇后语为材料,直接操控语义联结的新颖性,通过两个实验考察汉语新颖语义联结形成的神经机制。实验1采用fMRI记录谜题型歇后语阅读理解过程的神经活动,结果显示相对于寻常语义关联条件,新颖语义关联条件更强地激活了右侧颞上回,该脑区可能与新颖语义信息的激活有关。实验2采用ERP技术在语义关联性判断任务中考察新颖语义联结形成神经加工的时空特征,结果显示相对于寻常语义关联条件,新颖语义关联条件在右侧颞区和右侧额区诱发了更正的晚期正成分,可能分别反映了新颖语义信息的激活以及选择与整合。研究结果支持了新颖语义联结形成的右半球加工优势效应。

Forming novel associations is one of the key subprocesses in creative thinking. According to the generation-selection model of creativity and the theory of coarse semantic coding in right hemisphere, the right brain may play a dominating role in forming novel associations. However, this inference is only supported by half of the neuroimaging studies, and the others emphasize the role of left hemisphere or both. The disagreement among previous studies might result from different materials and different task requirements they used. The right hemispheric dominance in forming novel semantic associations may be more easily detected in the tasks of comprehending creative language. In the current study, the Chinese two-part allegorical sayings as well as fMRI and ERPs were used to explore the temporal and spatial features of neural processing in forming novel semantic associations.Two experiments were conducted in this study.In Experiment 1,participants were asked to read silently some Chinese two-part allegorical sayings and keep them in mind.For half of the experimental materials,the semantic association between the two parts was novel,while for the other half,it was normal.The neural activity was recorded by fMRI.In Experiment 2,the experimental materials were similar with those in Experiment 1,except for some filling materials in which there was not semantic association between the two parts.Participants were asked to judge whether the first part was associated with the second part in meaning,and the neural activity was recorded by ERP.The result of Experiment 1 showed that compared with normal semantic association,novel semantic association activated more in right superior temporal gyrus,which was related to the retrieval of novel semantic information.Results of Experiment 2 showed that novel semantic association induced a more positive late positive component（650~900 ms after the onset of target words）over the right temporal sites and right frontal sites,which might reflect the retrieval as well as selection and integration of novel semantic information respectively.In summary,the current results support the right hemispheric dominance in forming novel semantic associations,and indicate that its timing may be at the late period of processing.