Ever wondered why yawning is so damn contagious? We may have an answer.

Yawn.

Yawn. Yawn.

Yawn. Yawn. Yawn.

Are you yawning yet? No? How about now?

I thought so. All we have to do is utter the word yawn, or actually yawn, to know the act is entirely contagious. The same goes for scratching, which has long been considered another ‘socially contagious’ behaviour – the minute someone starts to scratch, why do we then feel the need to itch?

It’s a strange one, and one that’s seemed to baffle scientists for years. The rest of us just accepted our body’s innate reactions as a fact of life and went about our days.

But the question still does remain: Why do our bodies, and our minds, find certain behaviours so contagious? And is there anything we can do to stop them?

In a paper in leading journal Science, researchers found in a study of mice that the mere act of seeing another scratch prompted the brain to release a chemical. This chemical then helps communicate an “itch” signal from the skin to the spinal cord, coercing you to start scratching yourself.

By putting a group of mice in the experiment who had chronic itching issues with a group that didn’t, the researchers found that mice are hard-wired to feel the need to itch when watching someone else scratch. Which means no, there’s probably nothing you can do to control it.

Dr Zhou-Feng Chen, director of the Washington University Centre for the Study of Itch, said contagious itching has physical origins and not mental ones, according to The Independent.

“Itching is highly contagious. Sometimes even mentioning itching will make someone scratch,” he said.

“Many people thought it was all in the mind, but our experiments show it is a hard-wired behaviour and is not a form of empathy.

“It’s an innate behaviour and an instinct. 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.”

So what does this have to do with yawning? The findings may help scientists understand brain circuits that control other socially contagious behaviours too.

So yawning may well be outside our control after all.

But seriously, how many times did you yawn reading this?