by Katherine Gombay, McGill University

Experiment 1 design and results. A Example instruction display for the gazers. Gazers sat in front of a computer screen at an approximate distance of 60 cm with their face and torso filmed using a camera centered on top of the screen. They first saw an instruction for 4000 ms informing them how they should direct their eyes by displaying either ‘Choose’ or ‘Left/Right’ message. Next, a peripheral placeholder dot was presented on each left and right side of fixation, and the gazers were instructed to look towards and remain looking at a chosen or instructed location dot for an additional 4000 ms. B Example response display for observers. Observers viewed a clip of the gazer making eye movements. The gazer first looked straight ahead for 2000 ms and at T0 started their eye movement, at which point the video was paused. Observers responded by indicating the direction (left or right) of the gazer’s upcoming eye movement. C Experiment 1 results. Box plot showing Median Response Time (RT; solid horizontal line) as a function of Gaze intentionality (Self-chosen gaze vs. Computer-instructed gaze; N = 81 participants). Boxes encompass data points between the 25th and 75th percentiles, with whiskers indicating the larger minimum value and the smaller maximum value. Points represent individual participant’s data. Credit: Communications Psychology (2024). DOI: 10.1038/s44271-024-00137-x

McGill researchers have demonstrated something long assumed: that glances can transmit information about one's mental state to others without a single word being exchanged. They speculate that this primal ability may have played a role in assuring the survival of human society at times when making a sound could have attracted predators.

The research is published in the journal Communications Psychology.

"Humans have a long history of living in complex groups and social situations. It has been theorized that this has led our brains to develop a heightened ability to focus on social cues from faces, and especially from eyes, " said Jelena Ristic, a professor in McGill's psychology department. She has been working in the field for over 20 years. "It's a system that has evolved to support very quick exchanges of complex social information."

"Gaze-following is thought to provide a foundation for our social development and behavior. It helps us to understand what others are thinking, looking or wanting, as well as to connect with them mentally, so we follow where others are looking quickly and spontaneously. Even young human infants and primates do it, " she said.

Able to glean intentions by looking at eyes

Ristic is the senior author of the research paper describing a series of seemingly simple experiments in which participants viewed videos in which people on screen looked either right or left. Sometimes the subjects on screen had been instructed to look in one direction or the other, and other times they were allowed to choose where to look. Videos were paused just before the subjects moved their eyes, and the observers were asked to predict the direction that the subjects were going to look next.

The researchers discovered that when the people on screen were free to choose the direction of their gaze—what the researchers called "intentional looks"—the observers' rate of accuracy was not affected. However, those who predicted correctly were able to do so more quickly.

In other words, the observers were able to glean intentions in the eyes before any action had taken place.

"The speed of the observers' responses suggests that they implicitly recognize and respond more quickly to intentional eye movements. It also told us how sensitive we are to information about the mental state and intentions conveyed by the eyes, " said Florence Mayrand, a Ph.D. candidate in the Department of Psychology and the paper's first author.

Characteristics of eye movements may provide clues about intentions

To try to understand why observers were able to guess eye-shift direction more quickly when people on screen had been left free to choose the direction in which they would look, the researchers analyzed the amount of motion available in the eye movement video. More movement was found in the area near the eyes right before the gaze shift, when the gazers could choose freely where to look, than when they had been told which way to look. This suggested to the investigators that intentional looks are marked by specific movement patterns.

To further understand whether intentional looks have any special physical properties to which people are inherently sensitive, the researchers are currently measuring the speed, trajectory, duration and the number of blinks and blink characteristics for intentional and directed looks in a new sample of study participants.

Following this, they plan to examine whether these fundamental properties differ according to the intentions of the person looking in one direction or the other; for example, whether they are intending to deceive or help; how the ability to read intentions from eye gaze develops; what the underlying brain mechanisms are; and whether there are any differences in sensitivity to intentions in gaze for groups with social difficulties, such as adults or children with autism or ADHD.

More information: Florence Mayrand et al, Intentional looks facilitate faster responding in observers, Communications Psychology (2024). DOI: 10.1038/s44271-024-00137-x  Journal information: Communications Psychology