Integrating Eye Tracking and Self-Report for Sensory–Emotion Evaluation of Red Bean and Coix Seed Water: A Complementary Validation Framework

To examine whether gaze behavior on the rating scale can complement conventional self-report, twenty-four volunteers evaluated three red bean and coix seed water beverages on sensory attributes, EsSense-based emotional terms, and preference, while their fixations on the response scale were recorded using a synchronous area-of-interest design. Two indices were extracted: the questionnaire rating (QR), reflecting the consciously selected score, and the eye tracking-derived rating (ETR), defined as the longest-fixated score option. QR and ETR were strongly correlated (ICC: 0.88–0.89) and produced an identical preference ranking (R1 > R2 > R3), yet the wide limits of agreement indicated that they are not interchangeable at the individual level. Across the sensory–preference, sensory–emotion, and emotion–preference layers, QR consistently yielded stronger correlations than ETR. Warmth and sweetness were positively associated with positive emotions and liking, and “Good-natured” was the most stable emotional correlate of liking. Gaze behavior thus provides a process-oriented complement to, rather than a replacement for, self-report.