Assessment of Stimulus Similarity using Event-related Potential

Abstract

This study aims to develop a system for assessment of stimulus similarity using event-related potential (ERP). First, we investigated whether one of ERPs, P3 can assess visual stimulus similarity with regard to physical and affective aspects. Visual stimuli are Landolt rings for physical stimuli and facial expressions of emotion for affective stimuli. For each stimulus set, participants engaged in the target detection task, in which they counted target stimuli silently in a sequence of the stimuli during the measurement of electroencephalogram (EEG). To quantify stimulus similarity from EEG data, we applied linear discriminant analysis (LDA) to ERP amplitudes to discriminate targets from non-targets. To visualize stimulus similarity, we applied multi-dimensional scaling (MDS) to discriminant scores. We obtained MDS mappings that reflect physical similarity, suggesting that our system can be available for assessment of physical similarity. Further research is needed to examine whether our system can represent affective similarity.