Here is how and how quickly the brain interprets others' gaze

The ability to perceive the direction of a gaze is crucial for everyday social interactions. Our brain quickly decodes eye direction to facilitate communication.

A recent study from the University of Geneva (UNIGE), published in NeuroImage, has pinpointed the exact moment our brain detects this direction. This discovery is significant for understanding conditions such as autism and could offer treatment prospects for Alzheimer's disease.


Since birth, faces are the most frequently encountered visual stimuli. The brain excels at memorizing faces and interpreting their signals. Direct eye contact signals social interest, while avoiding gaze conveys a different message. However, most previous research has focused solely on the eyes, neglecting factors like head orientation.

UNIGE researchers employed 3D avatars to study participants' perception of head and gaze orientations. In one task, participants had to identify head orientation, and in another, eye direction. Using electroencephalogram (EEG), the team managed to independently decode these processes.

The study demonstrated that the brain first processes head orientation at 20 milliseconds, then eye direction at 140 milliseconds. This hierarchy allows for the integration of both cues for accurate gaze perception. Domilė Tautvydaitė, a postdoctoral researcher at the Faculty of Psychology and Educational Sciences of UNIGE, explains that this hierarchical organization facilitates information integration.

The research utilized advanced methods combining EEG and machine learning to accurately predict head and gaze direction perception, even before participants were aware of it. According to Nicolas Burra, this method represents a significant advancement in understanding these cognitive processes.

In autism spectrum disorders, individuals may have difficulty interpreting gaze direction and avoid eye contact. Similarly, Alzheimer's disease can impair memory and lead to social withdrawal, affecting relationships. Understanding how the brain detects gaze direction is crucial to addressing these challenges.

These findings and methods could help diagnose autism earlier in children. Regarding Alzheimer's, difficulty recognizing faces, even those of close relatives, is a notable symptom. Research by UNIGE's ESClab and McGill University aims to further understand these neural processes in social interactions and memory.