A central idea of the excerpt is that yawning serves multiple physiological functions and is a behavior that can be triggered socially among animals, including humans. The question-and-answer structure of the text develops this idea by presenting various scientific perspectives on the reasons for yawning, such as its role in regulating brain chemistry and its potential to cool the brain. For instance, Douglas Parham explains that yawning could help clear out carbon dioxide and increase oxygen levels in the body, while James Giordano discusses the concept of yawn “gates” linked to changes in chemical levels, illustrating the complexity of yawning's functionality. Additionally, the mention of yawning being contagious reinforces the idea of social behavior through the reference to "social mirroring," enhancing our understanding of how deeply intertwined yawning is in both physiology and social interaction.
"Why are yawns contagious? We asked a scientist"
by Teresa Carey
One theory argues that when humans are tired, we stop taking deep breaths, which causes a build-up of carbon dioxide in the body, said Douglas Parham, a speech scientist at Wichita State University. A yawn might be a special kind of respiration, Parham said. It builds up oxygen quickly, while expelling carbon dioxide, even more than a deep breath.
Excess carbon dioxide and other chemical changes, such as a drop in oxygen or increase in a compound called adenosine, could also act as “yawn gates,” said James Giordano, a neuroethicist and neuroscientist at Georgetown University. These chemicals send out a signal that triggers a yawn. By yawning, we compress the muscles of the face, driving oxygen-enriched blood to the brain, Giordano said.
Other proposals state the purpose of yawning is to cool the brain, or to stretch internal organs like tissues and lungs, helping the body to liven up.
Despite being a fundamental part of our lives, information on yawning is thin, said Thomas Scammell, a neurologist at Harvard Medical School who studies sleep. But he added that yawning is a primitive reflex among many animals that originates in the brain stem.
Because the brain stem of humans is similar to other mammals (and birds and reptiles too), it makes sense that most animals yawn, Scammell said. Indeed, birds, reptiles, mammals and some sharks can yawn — and animals with bigger brains tend to yawn longer.
“That puts a little bit of support back in the theory that what yawning is really doing is changing the brain chemistry,” Giordano said, adding that scientists are still trying to investigate the reasons why.
What is known is that the behavior is contagious. The likelihood of yawning increases sixfold, according to one study, after seeing someone else yawn.
As for yawn contagion, Giordano said it may be related to a phenomenon called social mirroring, where organisms imitate the actions of others. Other behaviors fall into this category, such as scratching, leg crossing and laughing.
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Question
Use the excerpt from the article to answer the question.
In 3–5 sentences, identify a central idea and analyze how the question-and-answer text structure develops this idea. Provide specific evidence from the text to support your answer.
(4 points)
Short Answer Rubric (4 points)
Points Awarded Criteria
4
The answer is very clear.
The answer is fully supported by details.
There may be a few errors in grammar, usage, or mechanics. Errors do not interfere with meaning.
3
The answer is mostly clear.
The answer is supported by mostly relevant details.
There are a few errors in grammar, usage, or mechanics. Errors do not interfere with meaning.
2
The answer is somewhat clear.
Details are weak or not related.
There are some errors in grammar, usage, and mechanics. Errors interfere with meaning.
1
The answer is not clear.
There are few or no supporting details.
There are many errors in grammar, usage, and mechanics. Errors interfere with meaning.
0 The question is not answered.
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