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Speech-to-Song Illusion

Students listen to an auditory illusion that blurs the line between speech and song.

This is an illusion discovered by Dr. Diana Deutsch at the University of California, San Diego. Some researchers spend their entire academic careers studying how the brain misinterprets information, leading to illusions.

Exactly why this illusion occurs is not fully understood, but it does suggest a strong link between speech and music. In Dr. Deutch's study, even professional vocalists with years of musical training and a well-tuned ear hear a melody where no melody exists. Her observations tell us that although the ear may hear the same words with no variation, the brain can transform the information into more than one result, such as spoken words or a melody.


  • Understand that auditory information is processed in the brain.


  • Per Class:
    computer or mobile device with speakers (or headphones if using as a station)
    audio link to the Diana Deutsch’s Speech-to-Song Illusion

Key Questions

  • How does the statement “sometimes behave so strangely” change from the beginning to the end of the demo?
  • At what point did the spoken phrase appear to transform into song?

What To Do

  1. Ask students to close their eyes.
  2. Play the clip “Sound Demo 1”.
  3. Ask the class to repeat/sing the phrase they heard.
  4. If anyone in the class only heard the phrase as spoken, and not sung, either play “Sound Demo 1” again, or play “Sound Demo 3”.
  5. When everyone can hear the phrase as sung, sing the phrase as a class again.
  6. Play “Sound Demo 2”.
  7. Discuss what they heard.


Other Resources

ASAPScience | Can you trust your eyes (Auditory Illusion)