Toddlers with autism may focus on co-occurring sounds and motions: as a result, the kids may neglect cues to social interaction.

When 2-year-olds with autism look at someone's face, they may crave synchronized detection rather than social connection. Toddlers with this developmental condition track sounds and sights that occur together, such as a mother's lips moving in time with sounds coming out of her mouth, rather than social cues, such as that same mother's smile, a new study suggests.

Locked in a world of co-occurring sound and motion, youngsters with autism neglect social signals that critically contribute to mental and brain development, propose Ami Klin of Yale University's Child Study Center and his colleagues. "Our findings lead us to the rather sad hypothesis that a toddler with autism might watch a face but not necessarily experience a person, since so much of that experience involves mutual eye gaze," Klin says.

The new study, published online March 29 in Nature, indicates that by age 2, kids with autism Day no attention to the array of cues indicating that a body is moving. Non-autistic children do so within days of birth. Young animals in many species monitor signs of others' movements as cues to initiate social contact.

While earlier studies have suggested that children with autism often don't look at other people's eyes, it's been unclear why. Few studies have included toddlers or infants with autism because they are difficult to diagnose and study.

"For the first time, this study has pinpointed what grabs the attention of toddlers with autism spectrum disorders," Thomas Insel, director of the National Institute of Mental Health in Bethesda, Md., said in a statement.

[ILLUSTRATION OMITTED]

Klin's study employed point-light cartoons based on data from actors playing children's games. Each animation, consisting only of bright dots positioned at body joints, played normally on one side of a computer screen. On the other side, the animation played upside-down and in reverse. (Children with no developmental problems have difficulty discerning movement made by inverted figures.) An accompanying sound track played with each pair of cartoons.

Eye-tracking devices determined that 39 typically developing toddlers and 16 toddlers with non-autistic developmental delays preferred to look at upright animations, tracking biological motion. In contrast, 21 toddlers with autism tended to look back and forth at both upright and reversed animated figures, suggesting that these children paid no attention to whole-body movement--denying them a key to unlocking social understanding.

But toddlers with autism made an exception for a video with a cartoon that featured a game of patty-cake, where colliding dots representing two hands repeatedly produced a clapping sound. This physical synchrony existed only for the upright figure; the inverted figure played in reverse, so its motions didn't match the sound track.

An analysis of other sound-motion synchrony in the five cartoons indicated that sensory pairings frequently drew the attention of toddlers with autism.

It's too early to say for sure whether autism really involves a focus on audiovisual synchronies, since a broader mental trait could explain Klin's new findings, cautions psychologist and autism researcher Mark Strauss of the University of Pittsburgh. An intense focus on details may partly explain a tendency of kids with autism to ignore moving bodies while focusing on synchronized events (SN: 7/7/07, p. 4), Strauss suggests. Greater difficulty in detecting subtle eye movements versus larger mouth movements may also contribute to this pattern, he notes.

Questions remain about the extent to which kids with autism make eye contact. Klin's team reported last year that 2-yearolds with autism mainly look at people's mouths. But in another study, Strauss' group finds that 8- to 12-year-olds with autism look others in the eyes as much as their non-autistic peers.

Klin's group now plans to see whether children with autism become more social after receiving training that directs attention away from synchronized sights and sounds and toward signs of biological motion.