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The sound of laughter

Image by Jon Gilbert Fox

DMS assistant professor of psychiatry William Hudenko

There's laughter, and then there's pure, unrestrained joy. What William Hudenko, Ph.D., found is that it's easy to tell the difference—and that people generally prefer to hear the latter kind. But for most people, as they grow older, they use more and more "unvoiced" laughter, such as a chuckle in response to a bad joke, instead of "voiced" laughter, which is the pure, unrestrained kind produced spontaneously. And the laughter of children with autism tends to be of the voiced variety. In other words, their laughter is genuine, not a forced response to social cues. They laugh because they think something is funny, not because they think they're expected to laugh. The clips below are short examples of different kinds of laughter. Two clips are of unvoiced laughter in children without autism, one is voiced laughter in a child without autism, and two are the laughter of children with autism. Because of the quality of the recordings, it is not easy to make out exactly the sound of the first two clips—but the difference in the type of laughter between those two and the other clips is clear. For more on this topic, read the article "Autism study is no laughing matter (or is it)?" from the Winter 2011 issue of Dartmouth Medicine.

Hear more

• Unvoiced laughter (a snort) in a typically developing child
  
  
• Unvoiced laughter (a grunt) in a typically developing child
  
  
• Voiced laughter in a typically developing child
  
  
• Voiced laughter in a child with autism (1)
  
  
• Voiced laughter in a child with autism (2)