A recent study found that eye blinking may be an early cue for autism diagnosis (abstract). The Marcus Autism Center at Emory University, with help from Dr. Warren Jones, the Director of Research at the Marcus Autism Center, and Dr. Sarah Shultz, an Emory graduate student and the first author on the PNAS-published paper, have written a blog post for ASF which summarizes the study’s findings.
One of the central goals in autism research is to better the needs and experiences of individual children on the autism spectrum, even and especially children who may not be able to easily communicate those experiences. Researchers hope that doing so will provide an inroad into helping those children and also into understanding the condition as a whole. That goal would initially appear to have very little to do with eye blinking. But researchers at the Marcus Autism Center at Emory University, together with a graduate student in Psychology at Yale University, have discovered a new way to use this information to actually measure how engaged people are with what they’re watching. And they can even use this technique to learn from children who, like those with autism, have difficulties communicating their interests to others. The results are reported in the December 12th online Early Edition of the Proceedings of the National Academy of Sciences.
The new method relies on measuring the precise timing of when people blink, and when they don’t. The research reveals that people unconsciously inhibit their blinking at precise moments. Why would people blink at some moments but not at others? “When we blink, we lose visual information,“ says Sarah Shultz, a graduate student in the Psychology Department at Yale University. “Our eyelids close. We’re not conscious of the timing of our blinks, but they still impact the visual information we take in.” While measuring what 2-year-olds look at when watching videos of other children playing, Shultz made an interesting observation: she noticed that the children blinked less while the videos were playing than they did before or after the videos. This led Shultz and her colleagues at the Marcus Autism Center, Ami Klin and Warren Jones, to wonder whether the rate of blinking might go down or up on a moment-to-moment basis, depending on whether viewers perceived a scene to be more or less important. The researchers tested the hypothesis by letting 93 two-year-old children watch a video. The video showed a simple scene of a boy and girl playing together. About half the children watching had Autism Spectrum Disorders. The researchers measured when children blinked and when they didn’t, and the results were surprising. “Typically-developing 2-year-olds inhibited their blinking at the same moments in the video. And they were more likely to inhibit their blinking when watching more emotional moments, and when looking at the faces of onscreen characters,” said Shultz. Toddlers with autism, however, were more likely to inhibit their blinking when looking at physical objects, and at physical objects in motion. Toddlers with autism also inhibited their blinking after actions happened, whereas typically-developing toddlers inhibited their blinking early. This suggests that typically-developing toddlers were anticipating the unfolding of the social interactions they watched, while toddlers with ASD were reacting, after the fact, to physical actions that had already happened.
“While we knew about young children with autism paying less attention to social cues and information, this is a new insight into understanding what kids engage with and what they perceive to be most important,” said Jones. “Even if they’re looking at the same thing, different children may perceive it differently. For a two-year-old with language delays, or even an 8 or 10 year-old who struggles to communicate, this kind of measure can tell us about that child’s experience and, with that information, hopefully improve our efforts to help that child learn.” This method is now being applied to investigate the experiences of other children with ASD. When children with ASD look at different kinds of visual information, or at faces and eyes and information that might be useful when trying to understand other people’s actions, are children with ASD actually engaged with those stimuli to the same extent as their typical peers? Do children with ASD perceive those stimuli and their adaptive value in the same way? Because engagement with socially relevant stimuli may be critical for other aspects of neural and behavioral development—such as the acquisition of speech and language skills, and the specialization of brain function—this is a critical question. And the timing of when children blink may hold new answers.
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