Some people have lost a large stretch of the brain tissue that first receives what the eyes send in, and yet, when they close their eyes and try, they can still call up a picture of a face or a room. Such patients sit awkwardly beside an influential idea about how imagination works, one that treats the mind’s eye as ordinary seeing run backward through the same hardware. A new review in the journal Consciousness and Cognition , written by Derek Arnold, Loren Bouyer, Blake Saurels and Samuel Schwarzkopf, argues that this backward-seeing picture has run out of road, and that the people best placed to show why are those who can’t form mental pictures at all . Their condition is called aphantasia, from the Greek phantasia, a piece of information drawn from the senses, and it describes a lifelong inability to imagine sights, and often sounds, smells, tastes or touch as well.…