The Psychological Science of Taking Friendlier Selfies
Upper eye bias makes humans (and dogs) less threatening when the head is tilted.
Posted Dec 28, 2018
A slight tilt of the head to the left or right makes human beings—including an image of the Mona Lisa—and other species less off-putting and more approachable by focusing attention to the upper eye, according to a new study by researchers at the University of California, Santa Cruz. These findings, “The Upper Eye Bias: Rotated Faces Draw Fixations to the Upper Eye,” were published Dec. 27 in the journal Perception.
Previous research on the face-processing task revealed a phenomenon called “left-gaze bias” (Guo et al., 2009). This research showed that when viewing faces, human adults display a left-gaze bias towards the right side of someone’s face and inspect this visual field for longer and more intensely. Left-gaze bias isn't uniquely human; it appears to be widespread in the animal kingdom. Interestingly, the researchers found that domestic dogs only demonstrate a left-gaze bias when viewing human faces, but not towards other dog faces.
For the recent study on upper eye bias, lead author Nicolas Davidenko was curious to see if left-gaze bias still occurs in rotated faces, where the tilt of the head causes someone's eyes to appear at different heights. Using advanced eye-tracking technology, Davidenko and colleagues found that left-gaze bias completely disappears when the head is tilted a few degrees off center.
When someone's head was rotated, the researchers found that upper eye bias dominates left-eye bias. For example, when you look at this rotated Mona Lisa image, upper eye bias directs your gaze to her right eye, which is higher in the visual field than her left eye. "People tend to look first at whichever eye is higher," Davidenko said in a statement. "A slight tilt kills the left-gaze bias that has been known for so long. That's what's so interesting. I was surprised how strong it was."
Davidenko et al. also discovered that upper eye bias appears to be more robust when head rotation is 45 degrees and dissolves if someone's head is tilted completely sideways to a 90-degree rotation. "Ninety degrees is too weird," Davidenko said. "People don't know where to look, and it changes their behavior totally."
That said, the sweet spot of upper eye bias has a relatively wide range. The authors found that upper eye bias completely dominated left-gaze bias in ±45° faces but also across a range of rotated face orientations of ±11.25 degrees, ±22.5 degrees, and ±33.75 degrees.
One of the most interesting aspects of this study is that it may help to explain why the tilted head of a dog evokes such a warm-and-fuzzy emotional response in most humans. "Across species, direct eye contact can be threatening. When the head is tilted, we look at the upper eye more than either or both eyes when the head is upright. I think this finding could be used therapeutically," Davidenko said.
The next phase of Davidenko’s research will focus on other aspects of social cognition. For example, he speculates that people with autism spectrum disorders (ASD) might be more at ease when engaging with rotated faces that elicit upper eye bias.
The latest research (Davidenko et al., 2018) suggests that tilting your head may be a simple way to make yourself seem more approachable and friendly during face-to-face social interactions and in photographs or selfies.
Nicolas Davidenko, Hema Kopalle, Bruce Bridgeman. "The Upper Eye Bias: Rotated Faces Draw Fixations to the Upper Eye." Perception (First published: December 27, 2018) DOI: 10.1177/0301006618819628
Kun Guo, Kerstin Meints, Charlotte Hall, Sophie Hall, Daniel Mills. "Left Gaze Bias in Humans, Rhesus Monkeys and Domestic Dogs." Animal Cognition (First published online: October 17, 2008) DOI: 10.1007/s10071-008-0199-3