London - It's a tried and tested method for helping you drift off when you’re struggling to sleep.
But counting sheep doesn’t come easily to everyone, and now scientists believe they have figured out why.
If you find it impossible to picture things in your head – such as sheep jumping over a fence – you may have aphantasia, otherwise known as no “mind’s eye”.
Up to one in 50 people are thought to have the condition, meaning they cannot visualise faces, landscapes or any other images. As a result, descriptive passages in books are rendered meaningless and careers in which a ‘vision’ is required, such as architecture, are closed off.
The condition can also be distressing, with aphantasics unable to remember the faces of loved ones who have died.
The name aphantasia was coined by scientists from the University of Exeter in a study published earlier this year. Dame Gill Morgan, former permanent secretary to the Welsh government, was one of 21 aphantasics who took part in the research.
“I became more aware of it when my mom died, as I can’t remember her face,” she said.
“I now realise that others can conjure up a picture of someone they love, and that did make me feel sad, although of course I remember her in other ways. I can describe the way she stood on the stairs for a photo for example, I just can’t see it.”
Niel Kenmuir from Lancaster, who also took part, first realised he had no mind’s eye when he was a child. He told the BBC: “My stepfather, when I couldn’t sleep, told me to count sheep. I tried to do it and I couldn’t. I couldn’t see any sheep jumping over fences, there was nothing to count.”
Kenmuir, 39, works in a bookshop and enjoys reading – but says he avoids novels with vivid landscape descriptions as he cannot visualise the scenes.
Professor Adam Zeman, who authored the study, said aphantasia was first noted more than a century ago but remained nameless until now. He believes that up to two percent of the population could have the condition.
Writing in the journal Cortex, Professor Zeman said people can be born with aphantasia or develop it as a result of damage to the parts of the brain involved in visualisation. Curiously, sufferers are still able to “see” faces and landscapes in their dreams.
He added: “People who have contacted us say that they are really delighted that this has been recognised and has been given a name, because they have been trying to explain to people for years that there is an oddity that they find hard to convey.”
To test for aphantasia, psychologists ask a series of questions such as “How clearly can you imagine a sunrise?”.
Daily Mail