Tracking eye movements lets scientists figure out what we pay attention to in a scene. When people blink during such experiments, those few milliseconds are usually discarded as junk data. A new study finds that blinking might reveal important information, too. It turns out that the more we blink, the less focused is our attention. In kids with autism, blink patterns appear to offer clues about how they engage with the world around them.

During eye-tracking experiments with toddlers, Warren Jones, a pedia­trician at the Emory University School of Medicine, found that the children were strategic about when they blinked. While watching a recorded scene, the toddlers seemed to inhibit their blink­ing during the moments that sucked them in. “The timing of when we don’t blink seems to relate to how engaged we are with what we’re looking at,” Jones says.

He now uses this discovery as a tool to study attention in autistic children. In a paper published last December in the Proceedings of the National Academy of Sciences USA, Jones observed differences in the blinking patterns of autistic and develop­mentally normal children. Both groups watched a video that included moments of human emotion and sudden action. Developmentally normal children inhibited their blinking before emo­tional climaxes, as though they were following the narrative and predicting an outcome. Autistic children blinked right through those moments, sug­gesting they were not following the emotional arc of the story, but they responded sharply when an object suddenly moved.

The results confirm well-established observations of attention in autistic children—namely, they are more in­terested in action than in emotional phenomena. They also validate eyeblink studies as a powerful research tool, Jones says. The approach could be particularly helpful in exploring the minds of nonverbal children and may help define new subcategories of autism.

This article was published in print as "Think Before You Blink."