Why you itch when another person scratches in front of you? Behaviour is hardwired in the brains, rather than a form of empathy with the original scratcher.
Ever wondered why you itch when another person scratches in front of you? Scratching, just like yawning, is socially contagious and not a psychological response. According to researchers, itching is highly contagious. Sometimes even its mention could make someone scratch.
"Many people thought it was all in the mind, but our experiments show it is a hardwired behaviour and is not a form of empathy," said lead investigator Zhou-Feng Chen, director at the Washington University School of Medicine in St. Louis, US.
In the study, conducted on mice, the researchers found a chemical in the brain that makes them want to scratch when seeing someone else do it.
Further, the findings, published in the journal Science showed that the behaviour is hardwired in the brains, rather than a form of empathy with the original scratcher.
The chemical, GRP (gastrin-releasing peptide) -- a key transmitter of itch signals between the skin and the spinal cord -- caused mice to scratch when they saw others doing it. When it was blocked, they stopped.
"The mouse doesn’t see another mouse scratching and then think it might need to scratch, too. Instead, its brain begins sending out itch signals using GRP as a messenger," Chen said.
Advertisement
However, when the GRP receptor were blocked in the mice’s brains, they did not scratch when they saw others scratch.
Advertisement
Source-IANS