Don’t Look At Me I’m Chewing (Don’t Worry, I Won’t)! Eye Language And The White Of Your Eyes
Christopher Philip
Researchers David Wu, Walter Bischof and Alan Kingstone in a paper published in Evolution and Human Behavior postulate that the human eye, with its dark iris set against a white sclera, evolved as a signaling device between people.
Unlike the eyes of nonhuman primates, the human eye has highly contrasting features. The darkness set against white, quickly, easily and efficiently tells others exactly where it is being aimed.
“Deictic” cues refer to the ability to point to the location of an object without the need to reference at it directly. This can be done with gestures, head turns and eye movements. People use them often in anticipation of moving to them and acting upon them in the near future.
Previous studies have shown that people involuntarily look at the eyes in an image and will shift their focus to the location in which those eyes are directed. People can also use head orientation to infer eye direction, such as when the eyes can not be seen directly.
However, science has found that eyes function more that just to point to objects, they also signal internal mental states.
In the current study, the experimenters wished to shift their focus away from the eye perceiver onto the eye informer.
It might not seem like a relevant distinction, however, take the example of a deer rustling in the leaves. To a wolf, the signal is relevant, but it does not imply that the deer is talking to the wolf and sending it a message. However, a poison frog with colouful markings, is signaling to other animals that it need not be bothered as it is a source of toxicity.
The difference between signal and cue hasn’t been tested in the context of gaze. However, much has been uncovered with respect to the how the perceiver engages with the signals.
In other words, the idea that we actively signal with our eyes such that others might pick up relevant signals, is a relatively unexplored concept.
In the current paper, the researchers aimed to explore the duality of gaze in a naturalistic setting – sharing a meal.
The researchers wanted to see if there was a real social norm that people should not stare at someone while they are chewing. Next, they wanted to verify if eye gaze would be broken just before putting food in their mouth. – a “potential signaling event.” Lastly, whether looking away would occur once eye contact was broken indicating that the message was correctly interpreted. That is, if looking away occurred, then we could assume that the other person received the message and understood that a bite was about to be taken.
The researchers looked for 1) Looking away while another person is biting 2) Look down at the food immediately prior to putting food in their mouth (i.e., a signaling event) 3) Whether the receiver of the signal of eyes down at food would be more likely to look away to indicate they received the message.
“In sum,” say the researchers “a gaze down at the food would be the signal for the upcoming action of taking a bite, which would trigger the perceiver to react in a norm-compliant manner by looking away from the informer while they are taking a bite.”
To set up the research, the participants were given a salad which they ate with another target. They were told they were being studied on taste perception, but unbeknownst to them, they were being filmed.
The results confirmed that people normally look away just as someone begins to take a bite. Targets were also significantly more likely to look down at their food 1-2 seconds before taking a bite. This happened much more often when they were eating with another person than when eating alone. Finally, they found that when a person looks down, the other person tends to look away, thus confirming that eye gaze signals and is read by others accurately to mean that a bit is coming.
“Our study shows that natural social attention between individuals is a two-way street,
where each person can signal and read gaze information, consistent with the idea that human eye morphology evolved to facilitate communication between conspecifics,” say the researchers in their paper.
“Evolutionary theory suggests that the high contrast human eye morphology developed to enable rapid and silent communication between individuals may also aid socially cooperative behaviors like group hunting.”
Eye gaze can signal intended direction of travel, or misdirection when performed by a magician.
Studies such as this one point out just how social we are as animals, and how adept we are at signaling to one another, most notably, at least in this study, is with respect to our eyes.
Not understood, however, is the reason we have a social norm of not looking at people as they chew. Perhaps, as the researchers suggest, it is to avoid appearing dominant as in the case of staring at an open mouth. Perhaps, it is simply a pro-social behaviour that is reinforced which strengthens bonds when it is followed.
While, on the scratch, this study might only seem to support the notion that we look away when taking a bit, in actual fact, it shows that eyes are used by people naturally to signal intent and that intent is received accurately from others.
No doubt, there are many other significant ways that people send and read signals from the eyes. More study is in order.
Resources
Wu, D.W-L.; Walter Bischof and Alan Kingstone. Natural Gaze Signaling in a Social Context. Evolution and Human Behavior. 2019. http://dx.doi.org/10.1016/j.evolhumbehav.2019.01.005