Whites of their eyes: Study finds infants respond to social cues from sclera

October 27, 2014

Humans are the only primates with large, highly visible sclera - the white part of the eye.

The eye plays a significant role in the expressiveness of a face, and how much sclera is shown can indicate the emotions or behavioral attitudes of a person. Wide-open eyes, exposing a lot of white, indicate fear or surprise. A thinner slit of exposed eye, such as when smiling, expresses happiness or joy. Averted eyes, as well as direct eye contact, can mean several things. So the eye white, or how much of it is shown and at what angle, plays a role in the social and cooperative interactions among humans.

Adult humans are well-attuned to social cues involving the eye and use them, along with a great range of other facial and body features, to respond appropriately during social interactions. This sensitivity to eye cues is hard-wired into the brain of adults as they respond to social eye cues even without consciously seeing them.

But it is unclear whether the ability to unconsciously distinguish between different social cues indicated by the eyes exists early in development and can therefore be considered a key feature of the human social makeup.

A new University of Virginia and Max Planck Institute study, published online this week in the journal Proceedings of the National Academy of Sciences, finds that the ability to respond to eye cues apparently develops during infancy - at seven or so months.

"Our study provides developmental evidence for the notion that humans possess specific brain processes that allow them to automatically respond to eye cues," said Tobias Grossmann, a University of

Virginia developmental psychologist and one of the study's authors.

Grossmann and his Max Planck Institute colleague Sarah Jessen used electroencephalography, or EEG, to measure the brain activity of 7-month-old infants while showing images of eyes wide open, narrowly opened, and with direct or averted gazes.

They found that the infants' brains responded differently depending on the expression suggested by the eyes they viewed, which were shown absent of other facial features. They viewed the eye images for only 50 milliseconds - which is much less time than needed for an infant of this age to consciously perceive this kind of visual information.

"Their brains clearly responded to social cues conveyed through the eyes, indicating that even without conscious awareness, human infants are able to detect subtle social cues," Grossmann said.

The infants' brain responses displayed a different pattern to sclera depicting fearful expressions (wide-eyed) to non-fearful sclera. They also showed brain responses that differed when viewing direct gaze eyes compared to averted gaze.

"This demonstrates that, like adults, infants are sensitive to eye expressions of fear and direction of focus, and that these responses operate without conscious awareness," Grossmann said. "The existence of such brain mechanisms in infants likely provides a vital foundation for the development of social interactive skills in humans."

The infants in the study wore an EEG cap, like a small hat, which included sensors that could detect brain signals. Infants were sitting in the laps of their parents during the testing.
-end-
The study was conducted at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany where Grossmann directs the Early Social Development Group.

University of Virginia

Related Brain Articles from Brightsurf:

Glioblastoma nanomedicine crosses into brain in mice, eradicates recurring brain cancer
A new synthetic protein nanoparticle capable of slipping past the nearly impermeable blood-brain barrier in mice could deliver cancer-killing drugs directly to malignant brain tumors, new research from the University of Michigan shows.

Children with asymptomatic brain bleeds as newborns show normal brain development at age 2
A study by UNC researchers finds that neurodevelopmental scores and gray matter volumes at age two years did not differ between children who had MRI-confirmed asymptomatic subdural hemorrhages when they were neonates, compared to children with no history of subdural hemorrhage.

New model of human brain 'conversations' could inform research on brain disease, cognition
A team of Indiana University neuroscientists has built a new model of human brain networks that sheds light on how the brain functions.

Human brain size gene triggers bigger brain in monkeys
Dresden and Japanese researchers show that a human-specific gene causes a larger neocortex in the common marmoset, a non-human primate.

Unique insight into development of the human brain: Model of the early embryonic brain
Stem cell researchers from the University of Copenhagen have designed a model of an early embryonic brain.

An optical brain-to-brain interface supports information exchange for locomotion control
Chinese researchers established an optical BtBI that supports rapid information transmission for precise locomotion control, thus providing a proof-of-principle demonstration of fast BtBI for real-time behavioral control.

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.

Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.

Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.

Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.

Read More: Brain News and Brain Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.