When children with autism speak they sound different from most people. Their speech usually follows one of several characteristic patterns: Some talk in a flat, toneless voice, others in an exaggerated, hyper way that doesn’t match the subject matter. Still others may sound robotic; their speech doesn’t flow but comes in clipped bursts.
A recent study of nearly 100 children with autism and 100 typically developing peers conducted by Joshua Diehl, Notre Dame assistant professor of psychology, and colleagues at Yale and Harvard universities suggests the speech difficulty may be because children with autism understand meaning differently as it’s communicated through tone of voice, not because they have trouble reproducing the speech patterns, as has been thought.
“It isn’t a hearing issue,” Diehl says. “It’s not that they have trouble producing changes in tone of voice. It’s that they have problems understanding it and how it’s meaningfully used.”
In the study, Diehl tested children with autism to see if they could understand shifts in meaning based on subtle changes in tone of voice. For instance in the sentence, “You can feel the frog with the feather,” the emphasis on the word frog makes the sentence mean to use the feather to feel the frog.
However, if the emphasis shifts to “You can feel the frog with the feather,” the meaning shifts to you can touch a frog that is holding a feather. Typically, such changes in meaning based solely on tone of voice are a source of confusion for children with autism.
Interestingly, Diehl discovered that younger children with autism will make the proper interpretation the first time they encounter a certain verbal construction, but later, if the tone of voice shifts it to a new meaning, they’ll have trouble.
“They get stuck on the initial interpretation,” he says. “The way they first heard it is how they’ll process it whenever they encounter it again. If you can’t flexibly alter your interpretation during a conversation as the context changes, that becomes a problem.”
Future therapies should expand beyond teaching bare-bones communication skills, as is current practice, Diehl says. “We need to give children with autism the tools to understand the social aspects of communication, that meaning isn’t always set in stone and how to detect when it shifts. Most of us learn this naturally, but these kids have to be taught explicitly.”
John Monczunski is an associate editor of Notre Dame Magazine.