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Teaching Guide
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Tickling in the Lab
Investigating the Yawn
Frozen Droplets
Image of person yawning

In the segment "Laughing Matters ," Robert Provine discusses the contagious nature of laughter. When humans hear laughter- even the canned, laugh-track variety- we invariably laugh in response. Provine concludes this reaction is an evolved, hard-wired reflex, perhaps a primitive version of human speech. Provine's research also encompasses another hard-wired reflex, yawning. Why do we yawn?

For years, scientists believed that yawning was a response to lowered levels of oxygen. By yawning, we open up our respiratory tract and more easily replenish our depleted oxygen stores. Today, this theory is discounted. Rather, Provine emphasizes yawning's role as a social signal. He believes the yawn may have evolved from a behavior during which animals showed their teeth to indicate that it was time for the pack to settle down for the evening. Although no one knows for certain, it is a behavior that is certainly contagious.

note to educators



These activities will offer:

  • an experience in observational psychology
  • an opportunity for a dramatic performance as you deliver an essay on communication
  • an opportunity to induce yawning in others


  • Copy of this essay (with the yawn cues)


  1. This observational investigation is designed to be presented at home. You will be reading the essay below aloud to your friends or family to test their response to yawning. However, the essay needs to be performed without your subjects becoming aware of its true intent. Therefore, don't tell your family or friends what you are really testing. Refrain from discussing the SCIENTIFIC AMERICAN FRONTIERS segment on yawning.
  2. Before you present this essay, you'll need to practice it. Like an actor reviewing lines, you'll need to know where to seamlessly insert your actions. Remember not to read your yawning cues! The more you practice, the easier it will become. So practice, practice, practice-but don't let anyone hear you! HINT: You might borrow an actor's trick and practice delivering this essay in front of a mirror.
  3. When you are ready, explain that your homework assignment requires five minutes of assistance from friends or family. Gather this group in one room. Explain that you are going to read an essay from a science book and you need to test their retention of the major concepts.
  4. Begin reading. Observe the reactions of others. Specifically be aware of any yawning.
  5. As you read, follow the cues. Keep observing your audience.
  6. When you are done, present the following questions to your audience.

Essay to be Read and Performed

"People can communicate in many different ways. Most often, our communication is spoken. We reply on our voices to convey our thoughts to others.

Sometimes, however, our communication is non-verbal. Through actions and appearance (yawn here), we communicate to others.

Most people have heard of body language. If you stand up straight, you are likely to communicate a forceful and assertive attitude. If you slouch (yawn here), you may suggest a more patient and resigned approach. But body language goes beyond posture.

Think of animals (yawn here). Have you ever watched a dog "stare-down" another dog? It's a non-verbal challenge. The dominant animal conveys its (yawn here) position without speaking.

But did you realize that yawning is also a type of communication. When we see another human yawn (large yawn here), we get the urge to yawn. Want to see that again? (large yawn again) Although scientists don't understand (yawn here) it fully, they do know that it is a behavior that is contagious. When you see someone yawn, (yawn again), you want to yawn. Yawn, yawn, yawn, yawn and yawn (one final long yawn)."



  1. At this moment, who feels like yawning? Are you tired? If not, why do you want to yawn?
  2. Is watching someone yawn contagious?
  3. Is hearing about yawning contagious?
  4. Think about yawning. Do these thoughts make you want to yawn?


A Contagious Dose

How much of a yawn is contagious? Do you need to see the entire face or are limited facial clues sufficient to induce a desire to yawn? Think about it. How would you develop an inquiry strategy that would test how much of the face needs to be exposed in order to induce yawns in others? Do you think that the region above the mouth is necessary for a yawn to be communicated as a contagious behavior? How many yawns do you need to observe to attain the peak desire to yawn? Develop an experiment that would explore any of these aspects of yawning behavior. With your instructor's approval, use your strategy to investigate yawning.

Cross-Species Contageon

Can the contagious nature of yawns be transmitted across species? If you own a dog, cat or hamster, you may have observed the animal's natural yawn behavior. Do you think you can induce a yawn in these animals. With your parents' approval, yawn in front of these animals. How do they respond? Are they interested in your behavior? Do they yawn as well? Record and compare your observations with your classmates.


Fantastic site on yawning - includes interactive elements

Theories on yawning and suggestions for student inquiry


The activities in this guide were contributed by Michael DiSpezio, a Massachusetts-based science writer and author of "Critical Thinking Puzzles" and "Awesome Experiments in Light & Sound" (Sterling Publishing Co., NY).

Academic Advisors for this guide
Corrine Lowen, Science Department, Wayland High School, Wayland, MA
Suzanne Panico, Science Department, Fenway High School, Boston, MA

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