“…Three types of 3D face features (distance-between-eyes, nose width and chin width) were used for human reaction elicitation and four EEG-based response signals (excitement, frustration, engagement/boredom and meditation) were observed and analyzed in previous research [46]. Analysis of the results has shown that all three types of the 3D face feature have triggered similar human reaction signals, accordingly distance-between-eyes was selected and used as a dynamic 3D face feature in further research [24], [26], [28]. From observed four EEG-based response signals, excitement is the most variable signal.…”