Read the given passage and answer the questions that follow.
Most people can readily conjure images inside their head - known as their mind's eye. Scientists have described a condition, aphantasia, in which some people are unable to visualise mental images.
Niel Kenmuir, from Lancaster, has always had a blind mind's eye.
He knew he was different even In childhood. "My stepfather, when I couldn't sleep, told me to count sheep, and he explained what he meant, I tried to do it and I couldn't," he says. "I couldn't see any sheep jumping over fences, there was nothing to count."
Our memories are often tied up in images, think back to a wedding or first day at school. As a result, Niel admits, some aspects of his memory are "terrible", but he is very good at remembering facts.
And, like others with aphantasia, he struggles to recognise faces.
Yet he does not see aphantasia as a disability, but simply a different way of experiencing life. Ironically, Niel now works in a bookshop, although he largely sticks to the non - fiction aisles. His condition begs the question what is going on Inside his picture-less mind. I asked him what happens when he tries to picture his fiancée.
"This is the hardest thing to describe, what happens in my head when I think about things," he says.
"When I think about my fiancée there is no image, but I am definitely thinking about her, I know today she has her hair up at the back, she's brunette.
"But I'm not describing an image I am looking at, I'm remembering features about her, that's the strangest thing and maybe that is a source of some regret."
The response from his mates is a very sympathetic: "You're weird."
But while Niel is very relaxed about his inability to picture things, it is a cause of distress for others.
One person who took part in a study into aphantasia said he had started to feel "isolated" and 'alone" after discovering that other people could see images in their heads.
Being unable to reminisce about his mother years after her death led to him being "extremely distraught".