An ERP-based Icon Contour Similarity Perception Research

The paper uses ERP to observe the cognitive process of icons in different similarity conditions. Icons are compared across three similarity levels (high, medium, and low) by varying four factors: curvature, proportion, orientation, and line style. The EEG performance of the subjects in discriminating similar icons is observed using the Oddball paradigm. The behavioral data shows significant differences in response time and accuracy across similarity conditions. There is a greater reduction in similarity when there are differences in the contours of two or more features of the icon, facilitating the identification of differences. The EEG results show that three similarity levels all evoke N100, N200 and P300 components. Icons with low similarity evoke greater N100 amplitude, indicating selective attention to the stimuli; N200, which is associated with pattern matching, also shows greater amplitude in the low similarity condition; and since the amplitude of P300 is proportional to the amount of mental resources invested, icons with high similarity evoke greater amplitude. It is suggested that N100, N200 and P300 can all be used to reflect differences in similarity discrimination.