| Similarity judgment and difference judgment play important roles in cognition and classification study. Previous research usually focuses on the relationship of similarity judgment and difference judgment. Earlier research suggests that similarity judgment and difference judgment are inverses of one another. More recently, researchers found that similarity and difference judgments are not simply inverses. In certain cases, the perception of similarity is not inversely related to the perception of difference. Geometric figures stimulus used in previous similarity judgment studies has been proven successful in separating the visual classification process, we combine ERPs and behavioral measures in this study to investigate visual classification based on the similarities and differences. This study includes two experiments.In experiment 1, participants were asked to make similarities and differences judgment on single dimension feature of geometric figures(stripe orientation) in different blocks. The results showed no significant difference in reaction time and accuracy when the participants were respectively asked to and judge whether the stripe orientation of two figures are the same or different.In experiment 2, 2(similarity vs. difference judgment)×2(1feature vs. 2features) within subjects design was adopted. The results showed that reaction time of the task "to find the same features" was significantly shorter than the task "to find the different features", and the accuracy was higher when the experiment task is "to find the same features". ERP data analysis results showed that the four kinds of experiment conditions successfully induced the related ERP components: N1, P2 and P3, of which the main effect of experiment task of P2 is significant. The above experiments results together concluded that visual classification process is roughly divided into three stages: selective attention, perception processing and comparative analysis. The conclusions are highly consistent with predecessors’ research conclusions. |
