Find Out Why Itching and Yawning Are Contagious Behaviors

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Mar 15, 2017 07:14 AM EDT

Itching and yawing are well-known behaviors that when you see someone doing it, you might mimic what they are doing. However, a recent study revealed the reason behind the mystery of this "contagious behavior."

A lot of people thought that itching and yawning are all in the mind. However, in a research study of Dr. Zhou-Feng Chen, a scientist at Washington University's Center for the Study of Itch showed that in the experiment they made, that contagious behavior is a hardwired behavior and it is "not a form of empathy."

For the sake of studying these well-known contagious behaviors -- itching and yawning --, researchers conducted an experiment on mice. Chen and his team found out when they showed a video of another mouse scratching, in a matter of seconds, the mice started scratching. According to Chen, this is really surprising knowing that mice have poor vision and use smell and touch only.

Researchers explained that how yawning and itching have been a contagious behavior by observing the brain activity of the mice. An area of the brain called suprachiasmatic nucleus (SCN) - part of the hypothalamus that controls sleeps and wakes up - is highly active at the time when mice watching the video. The SCN releases a chemical called gastrin-releasing peptide (GRP), which will transmit an itch signal from the brain to the spinal cord. The researchers tried to block GRP in traveling and found that the mice no longer scratched themselves when they see others doing it.

In this way, Chen and his team's study enlightened how itching and yawning were considered to be contagious behaviors. "The next time you scratch or yawn in response to someone else doing it, remember it's really not a choice nor a psychological response; it's hardwired into your brain," he explained.

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