Aphantasia is a relatively unknown – and only recently discovered – condition that affects 2% of the population, and both genders equally, says Adam Zeman, professor of cognitive and behavioural neurology at the University of Exeter. “People with aphantasia can think about an apple, or a front door or a loved one perfectly well, but they just can’t bring to mind the visual image of that thing or person.”In some people, aphantasia not only leaves them without any visual imagery, but they have no sensory recall at all. Alan Kendle, an engineer and the author of Aphantasia: Experiences, Perceptions and Insights, says he cannot recreate any of his five senses in his mind. “I can’t hear anything in my head unless it comes through my ears. I’ve got no inner voice. It’s absolute silence in there.”