That is, children were unlikely to look at the toy if Brooks's eyes were closed, but very likely to do so when her eyes were open. This rules out the notion that head movement in and of itself sort of drags infants' attention to where someone else is looking. The fact that they know you are using your eyes to find something in the room is a clue that 12-month-olds recognize that you have distinct thoughts and ideas, and that these thoughts can be shared.
"Then sometimes they'll even point at it," Brooks says. "And it's sort of as if to say, ‘Oh, it's over there! We're doing this together!' And kids get really excited about doing things with another person. It's a beginning, I think, of children beginning to understand that we share attention, that we're interested in things together."
Beyond pointing, Brooks and her colleague, Andrew Meltzoff, also noted that children would tend to babble more when Brooks looked at the toy with open eyes.
"And it's that package of children's actions— where they point and talk and look— that really conveys that they're beginning to understand that we're sort of having a conversation. That we're indeed having a social interaction," Brooks says.
Understanding when these stages of development occur can help parents understand at what age they can expect their children to take in another person's point of view. And it's important in helping establish a baseline for what is normal in child development. Theory of mind is a concept that children with disorders like autism find hard to grasp, and the lack of acquiring this important building block of development— realizing the importance of eyes— may be an early indicator of a social disorder.
Brooks says she next hopes to do similar studies in even younger children, to see how early this behavior is present. Her work was published in the journal Developmental Psychology, and was funded by the National Institute of Child Health and Human Development, the Talaris Research Institute, and the Apex Foundation.