The direction of a person’s gaze is crucial in everyday social interactions. Our brain’s ability to quickly interpret this information is key for instant communication. A recent study published in the journal NeuroImage by a team from the University of Geneva (UNIGE) has provided new insights into how our brains detect gaze direction with unprecedented precision. These findings have significant implications for our understanding of autism.

Human faces are the most common and consistent visual stimuli that we encounter from the moment we are born. Our brains have developed the expertise to memorize and recognize faces and to interpret the messages they convey. For example, direct eye gaze signals a desire to engage in social interaction, while avoiding eye contact conveys the opposite message. However, there has been extensive research on how rapidly our brains can comprehend the gaze of others. Existing publications have mainly focused on studying the eye region in isolation, neglecting other factors like head orientation.

Cerebral analysis of gaze

A team from UNIGE introduced study participants to 3D avatars, each with different head and gaze directions. In the first task, volunteers were asked to indicate the orientation of the head, while in the second task, they had to identify the direction of the eyes. By analyzing brain activity using an electroencephalogram, the research team discovered that these two processes can be reliably decoded independently of each other.

“The experiment also shows a certain hierarchy in processing these two types of information. The brain first perceives the more general visual cues, such as the orientation of the head, from 20 milliseconds onwards, before focusing on the more specific information, such as the eyes, from 140 milliseconds onwards. This hierarchical organization then allows for the integration of eye region and head orientation information, ensuring accurate and effective judgment of gaze direction,” explained Domilė Tautvydaitė.

The study found that people were much more accurate at understanding where others were looking when they were specifically instructed to pay attention to the direction of their gaze. This shows that the context of a task affects how we perceive and interpret where someone is looking. According to Nicolas Burra, a senior lecturer at the Faculty of Psychology and Educational Sciences and director of the Experimental Social Cognition Laboratory (ESClab) at UNIGE, these results suggest that people are better and quicker at recognizing the intentions of others when they are actively engaged in a social interaction.

A cutting-edge method

The method used provides extremely accurate results for these two mechanisms. The research team integrated the analysis of neural activity using electroencephalography (EEG) with machine-learning techniques, allowing them to predict the decoding of gaze and head direction even before the participants were aware of it. Nicolas Burra adds, “This method represents a significant technical innovation in the field, allowing for a much more precise analysis than was previously attainable.”

In individuals with autism spectrum disorders, there may be difficulty in interpreting social cues, leading to a preference for avoiding eye contact. This is also observed in Alzheimer’s disease, where memory issues can impact relationships and cause social withdrawal. Therefore, it’s important to study the brain mechanisms involved in perceiving where others are looking.

The study results and the method used make a significant contribution to the early diagnosis of autism spectrum disorders in children. As Alzheimer’s disease progresses, one of the most striking symptoms is the inability to recognize faces, including those of family members.