中文摘要：

本文首先介绍了相似性判断和差异性判断不对称性的行为研究及理论解释。其次，根据事件相关电位研究的结果，阐述了图-词信息的双编码模型对相似性判断的影响。接着分析和介绍了相似性判断的双编码过程及其时问进程。最后，提出有待深入研究的几个问题：（1）差异性策略在分类和推理中的应用；（2）相似性双编码过程的实证研究及应用；（3）从发展认知神经科学的角度探讨不对称的认知神经机制。

英文摘要：

Similarity serves as a central construct in theoretical accounts of many cognitive processes, such as perception, classification, learning, memory and reasoning. Previous research has suggested that similarity judgment and difference judgment are inverses of one another. The philosopher James Mill said： ＂distinguishing differences and similarities is the same thing; a similarity being nothing hut a slight difference＂. That is, as similarity increases, difference will decrease to the same extent. For instance, if wolves and dogs have a similarity rating of 4 on a 1 - to - 5 scale, they ought to have a difference rating of 2. However, studies have found that similarity and difference judgments are not necessarily logical opposites. These results were mainly found in situations when both features and structural relations, or both thematic and taxonomic relations were considered. At first, in addition to shared features, the relationships among features also influence similarity judgments, and features and relationships may have different roles in similarity and difference judgments. Secondly, thematic relations also have an effect on similarity, and the thematic relationships are more salient for similarity than for difference. In these cases, the similarity judgment and difference judgment are not logical opposites, either. Behavioral studies suggest that the mechanism of this non - inversion can be explained by the contrast model, structural alignment model and the dual process model to some extent. Event related potential （ERP） studies suggest that the effect of pictures and words in- formation on similarity judgment may be different. Furthermore, the similarity could be divided into perceptual similarity and conceptual similarity based on the dual - coding model of the picture - word information, which may be considered complementary as they were viewed in the earlier literatures, rather than mutually exclusive, which reflect the essence of this cognitive process. The dual - proces- ses of similarity