The "Fat Face" illusion: A robust adaptation for processing pairs of faces

Area of Science:

• Visual Perception
• Cognitive Psychology
• Social Neuroscience

Background:

• Humans excel at processing individual faces but rarely encounter them in isolation.
• Understanding how the visual system processes multiple faces simultaneously is crucial for real-world contexts.

Purpose of the Study:

• To investigate the visual processing of multiple faces using the
• Fat Face
• illusion.
• To determine the robustness and underlying mechanisms of this facial processing adaptation.

Main Methods:

• Utilized the
• Fat Face
• illusion with varied face stimuli (gender, race) and diverse participant groups (Canadian, Chinese, French).
• Assessed the illusion's stability across different task requirements and perceptual familiarity.
• Investigated the role of binocular vision by comparing performance with both eyes versus monocular vision.

Main Results:

• The
• Fat Face
• illusion proved stable and unaffected by face variations, participant nationality, or task demands.
• Binocular vision was essential for the illusion; it disappeared under monocular viewing conditions.
• The top face was perceived as more distant and smaller than the bottom face.

Conclusions:

• The visual system exhibits an adaptation for processing multiple faces, influencing perceived size and distance.
• This size overestimation of the lower face may serve a fundamental social function, directing attention to individuals closer to the self.