Authors

Bharat Vyas, Trinity College Dublin, Dublin, Ireland, vyasb@tcd.ie

Pisut Wisessing, CMKL University, Bangkok, Thailand, pisut@cmkl.ac.th

Rachel McDonnell, Trinity College Dublin, Dublin, Ireland, ramcdonn@tcd.ie

teaser image

Conference

Presented at ACM Symposium on Applied Perception (SAP) 2025, Vancouver, Canada

Abstract

Virtual humans are increasingly used in games, films, and interactive media. Yet, understanding the role of emotional intensity remains critical for expressive character design. This work investigates the gaze behavior in expressive virtual avatars with varying levels of facial expression intensity and light colors. Using eye tracking, we analyzed visual attention patterns as participants viewed avatars displaying three emotions (anger, disgust, and joy) at four intensity levels (neutral, low, medium, and high) under three light colors (white, red, and blue). Participants rated the perceived intensity of each expression while their gaze data was recorded. Results indicate that participants consistently distinguished between intensity levels, with higher ratings corresponding to more intense expressions. The eye region received the highest number of fixations and visits, though gaze distribution across facial features varied by emotion. Additionally, lighting color significantly affected pupil diameter.

Key Findings

  1. Participants rated high-intensity expressions as more emotionally intense.

  2. The eye region consistently received the most visual attention across all emotions and lighting conditions.

  3. Lighting color (especially blue) significantly increased pupil size, indicating arousal—but did not alter gaze allocation.

  4. Gaze behavior varied subtly by emotion and expression intensity, especially in the mouth and nose regions.

  5. Static images of avatars were used to precisely control visual cues; future work will explore dynamic expressions and immersive environments.

Why this work is important?

As virtual humans become more common in games, storytelling, and VR, understanding how users perceive their emotions is essential. This work shows how subtle design choices like expression intensity and lighting can shape user perception and engagement.

Explore Heatmap

Use the dropdowns below to explore how gaze behavior changes based on different emotions, lighting colors, and avatar characters. The slider compares the original image with its corresponding gaze heatmap.

Downloads

Coming Soon …..

Citation

Coming Soon …..

Contact

For questions, data access, or collaborations, email me @ vyasb@tcd.ie