Researchers Explain Why Eyes Widen During Fear
The response of eyes to fear and disgust aided human survival, according to a new study.
It's a common observation that eyes expand when we are afraid and constrict when we are disgusted. But, why do the eyes change their shapes?
According to Cornell University neuroscientist, wide eyes during a fear response gather more light and send more data to the brain. And, a constricted pupil during disgust narrows our field of vision and helps us focus more on the object of our loathing.
The study shows that eyes didn't evolve solely as a means of social communication. The ability to widen eyes probably helped our ancestors scan the environment to spot a potential threat such as a lion lurking amid the bushes. Their research supports Charles Darwin's 19th century theories on the evolution of emotion.
"These opposing functions of eye widening and narrowing, which mirror that of pupil dilation and constriction, might be the primitive origins for the expressive capacity of the face," said Adam Anderson, professor of human development in Cornell's College of Human Ecology. "And these actions are not likely restricted to disgust and fear, as we know that these movements play a large part in how perhaps all expressions differ, including surprise, anger and even happiness."
It is also worth noting that our emotions already control our perception of the world even before our brains actually receive data about the environment.
"We tend to think of perception as something that happens after an image is received by the brain, but in fact emotions influence vision at the very earliest moments of visual encoding," Anderson said in a news release.
The study, "Optical Origins of Opposing Facial Expression Actions," published in the March 2014 issue of Psychological Science.