Brain study starts from scratch

It comes in many varieties and just as many degrees of irritation – there’s the woolly jumper one, the kids have got nits one and the nose one when your hands are in water. But who would have thought the humble itch could be so fruitful for scientific investigation?

It’s a well-known fact that you just need to glimpse someone else scratching for your skin to come over super-itchy. And you can’t fight it, you just have to scratch.

It has long been thought this phenomenon was down to a psychological response, to do with empathy. But researchers studying mice in the US have discovered that we don’t actually have a choice. This socially contagious activity is involuntary, an instinct. It is programmed into our brains.

Other behaviours that can be transmitted include everything from smiling, frowning and laughing to yawning and shivering. Then there is mass psychogenic illness, where people report feeling unwell after witnessing visible symptoms in others. Risk-taking such as gambling has also been found to be infectious, not to mention binge-drinking and eating habits, both bad and good.

Recent experiments show rudeness – particularly among workmates – can spread like a virus. It is a widely documented phenomenon that has been discussed as a factor in fuelling serious social disorder such as rioting and looting.

It’s hoped this new study may help scientists better understand the neural circuits that control such behaviours.

You may never scratch again without thinking of that deep primeval side of your nature that controls more of your brain than you might like to acknowledge.