Our brain can communicate without words, a glance is enough 👀

Researchers at McGill University have confirmed a long-standing hypothesis: a simple glance can convey information about a person's state of mind without a single word being spoken. They suggest that this primitive ability may have played a key role in human survival during times when making a sound could have attracted predators.


"For a very long time, humans have lived in complex groups and social structures. We believe this is why the brain has developed the ability to focus on social cues transmitted by faces, particularly the eyes," explains Jelena Ristic, a professor in McGill University's Department of Psychology, who has been working in this field for over 20 years. "It's a system that evolved to allow rapid exchanges of complex social information."

"The ability to follow gaze is considered a fundamental pillar of social development and human behavior. It helps us understand what others are thinking, looking at, or desiring, as well as establish a mental connection with them. This is why we spontaneously and quickly look in the same direction as someone else's gaze. Even young children and primates do this," she adds.

The ability to decipher intentions in a gaze

Jelena Ristic is the lead author of a scientific paper describing a series of seemingly simple experiments. Participants watched videos in which people looked either to the right or left. Sometimes, these individuals were instructed to look in a specific direction, while other times, they were free to choose where to look. The videos were paused just before the individuals moved their eyes, and observers had to predict the direction of the next gaze.

The study reveals that when people freely directed their gaze (a phenomenon the researchers termed "intentional gazes"), the accuracy of observers' predictions remained unchanged. However, observers who correctly predicted the direction of the gaze did so more quickly.

In other words, observers were able to perceive intentions in the gaze before the action was even carried out.

"The speed of responses suggests that observers take less time to recognize and react to intentional eye movements. These findings also show just how sensitive we are to information about mental states and intentions conveyed by gaze," explains Florence Mayrand, a PhD student in the Department of Psychology and the paper's lead author.

Eye movement characteristics may provide clues about intentions

To understand why observers guessed the direction of gaze more quickly when people were free to choose, the researchers analyzed the movements visible in the videos. They noted more movements around the eyes just before the gaze shifted when people freely chose where to look compared to when they followed an instruction. The researchers concluded that intentional gazes are characterized by specific patterns of eye movements.

To determine whether intentional gazes have unique physical properties that people are naturally sensitive to, the researchers are currently measuring—with a new sample of participants—the speed, trajectory, duration, number, and blink characteristics associated with intentional and non-intentional gazes.

Once this data is collected, they will investigate whether these fundamental properties vary depending on the intention of the person looking in a direction (e.g., whether they are trying to deceive or help someone else). They will also study the development of the ability to perceive intentions in gaze, as well as the underlying brain mechanisms.

Additionally, they will examine whether individuals with social difficulties, such as autistic adults or children, or those with attention deficit hyperactivity disorder (ADHD), are more or less sensitive to intentions in gaze.

The study

The paper "Intentional looks facilitate faster responding in observers," by Florence Mayrand, Sarah D. McCrackin, and Jelena Ristic, was published in Communications Psychology.
DOI: https://doi.org/10.1038/s44271-024-00137-x