Have you ever sensed that someone might be watching you? You get a prickly feeling at the back of your neck and turn to see a stranger staring at you across the room. It sometimes seems that we can feel a person’s gaze as a physical sensation. And, from a single glance, we can tell a lot about a person, such as their moods, intentions and focus. Is their gaze dangerous, interesting or attractive? Do they stare directly or glance to the side? If “eyes are the window into the soul,” then a glance reveals far more than we know.

Recent studies demonstrate that humans attribute gaze with physical properties. We create tacit mental schemes in which the visual attention of others is computed as a forceful beam emitted from the viewer’s eye and directed at the object of interest. These mental schemes allow us to take cognitive shortcuts to process peoples’ visual attention quickly and efficiently.

Gaze is an elemental form of communication that can coordinate activities and convey social dynamics without a gesture or spoken word. It requires a rapid interpretation of the meaning behind another’s gaze, but the trade-off for the speed of that interpretation is the mistaken understanding of gaze as something that can move things in our environment. These studies show that this interpretation is subconscious and automatic, and that it occurs even in those who would consciously deny that vision exerts any force.  

You might expect that such an erroneous interpretation would be detrimental. In fact, while there seem to be few if any adverse consequences these findings may underlie rich and diverse cultural references to the outward force and power of the gaze. The results of the experiment demonstrate an ancient human idea linking gaze with physical properties. This notion, as old as the Greeks, is known as the “extramission” theory of vision. Extramission literally means “sending out,” and the extramission theory is the belief that vision is a force emitted from the eye. It is an intuitive understanding of vision common among children that persists among many adults. In contrast, the modern visual theory is called “intromission,” and is based on the notion that vision results from light entering the eyes. 

Using a series of ingeniously simple experiments in one study, researchers found that subjects associate gaze with a physical force. Subjects viewed a computer display that had an image of a tube, roughly the size of the end of the paper towel roll, standing vertically on a table. At one end of the table was an image of a face gazing at the tube (researchers dubbed the face avatar Kevin). Subjects were instructed to tilt the tube towards Kevin’s image using specific keys on a keyboard until they felt the tube had reached the critical angle at which it would tip over. The critical angle reported by subjects depended upon whether Kevin was blindfolded. If Kevin was perceived as gazing at the tube, the critical angle was greater than when Kevin was blindfolded, suggesting that his gaze was impressing some force upon the tube that needed to be overcome for the tube to fall.

Likewise, in a second experiment, subjects were presented with the image of Kevin either gazing at the tube or gazing away in the opposite direction and asked to report the critical angle of the tube before toppling. Once again, the angle depended on Kevin’s perceived gaze and was much greater when Kevin gazed straight at the tube compared to when Kevin was turned away. Finally, in a third experiment subjects were told that Kevin was either looking directly at the tube or focused beyond the tube at a wall at the other end of the table. Once again, the critical tilt angle was greater if subjects thought Kevin was gazing at the tube rather than the wall.

Participants in this study were screened for belief in extramission beforehand and those who expressed such a belief were excluded. So, it is remarkable that all remaining participants intuited a force based upon gaze, even while they disavowed any belief in such a force emanating from the eye. What has emerged in this study is an implicit, unrecognized cognitive shortcut employed by humans to rapidly process gaze, but which leads us to comprehend it as something that affects objects in the world.

To test this theory, researchers employed brain imaging methods to demonstrate that gaze perception activates brain regions associated with motion. In this case, subjects were presented images of moving dots or an image of a face gazing at a tree. Brain activity was measured using functional magnetic resonance imaging (fMRI), which detects brain activity by measuring local brain oxygen consumption. Areas of the brain involved in processing visual motion (the right middle temporal cortical areas) and in understanding the thoughts and intentions of others (the right temporal parietal junction) were involved in processing the face’s gaze when staring at the tree. However, just as with the blindfolded Kevin, these fMRI signals halted when the face in these studies was blindfolded. Here, the brain processes the gaze as movement even when no movement occurs, again showing an extraordinary misapprehension of reality.

Belief in the power of gaze appears in stories and myths throughout the centuries. Medusa turned people to stone with her gaze. The catoblepas and, more famously, the basilisk, both described by Pliny the Elder, could kill with the single glance. In Shakespeare’s Venus and Adonis, Venus complains of the pain caused by Adonis’ glance: “Thine eye darts forth the fire that burneth me.” While in John Donne’s The Ecstasy, the glances of the lovers intertwine and bind them as if they were their clasped hands. And, of course, no list of cultural references to gaze would be complete without mention of the Jedi master or Superman.

Gaze is a powerful element of social interaction. It reveals where a person is focusing their attention, and, when directed at us, it can have a strong emotional effect. Gaze can play a role in social organization, with a direct gaze demonstrating social dominance and gaze aversion indicating passivity. Eye contact can elicit alertness and bodily awareness, while indifference or aversion to eye contact can signal emotional or neurological disorders. When we direct our gaze at something or someone, others who notice subconsciously direct their gaze in the same manner. We can take advantage of this tendency to deliberately influence the gaze of others. Magicians take advantage of the ability to redirect gaze and attention to enhance their sleight of hand. Visual artists can manipulate attributes of a work of art such as luminosity in order to direct visual gaze to specific features of a painting. In dance, gaze can be used to convey the power dynamics between the characters on stage, while musicians rely upon gaze as an essential means of communication, using it to help in cuing and synchronization during the performances of orchestras and choirs. 

Gaze is a means of communication that impacts us in many ways, subconsciously and quickly, so quickly and energetically that one investigator described the effects of gaze as “exuberant.” And while magicians may know how to manipulate gaze to enhance their illusions, the illusion of gaze as a physical force is magic enough.