Question

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 use this excerpt from the why are yawns contagious? we asked a scientist article to answer the question. based on the information in the article, make a logical inference about why yawns are contagious. in 3–5 sentences, provide specific evidence from the text to support your inference and explain why your reasoning is logical and valid. (4 points) short answer rubric (4 points) points awarded criteria

Explanation:

To determine why yawns are contagious, we analyze the article. Douglas Parham notes tiredness leads to less deep breathing, causing carbon dioxide buildup, and a yawn is a special respiration that quickly increases oxygen and expels carbon dioxide. James Giordano mentions excess carbon dioxide and chemical changes (like oxygen drop or adenosine increase) act as "yawn gates" that trigger yawning. When one person yawns, it may indicate their body has these chemical triggers, and seeing a yawn could prompt others’ bodies (with similar chemical imbalances from tiredness) to respond with a yawn to regulate their oxygen - carbon dioxide levels, as the yawn is an effective way to do so. This is logical as the article links chemical changes to yawning, and contagious yawning could be a social - biological response to shared physiological needs.

Answer:

Yawns are contagious likely because of physiological and chemical triggers. When a person yawns, it may signal their body has excess carbon dioxide (from tiredness - induced shallow breathing, per Parham) or other chemical changes (like adenosine increase, per Giordano) that trigger yawning. Seeing a yawn can prompt others with similar tired - related chemical imbalances to yawn, as yawning efficiently regulates oxygen - carbon dioxide levels. This is valid as the article ties chemical changes to yawning, and contagious yawning would help groups address shared physiological needs.