Picture a red apple and rate it from one, photo vivid, to five, nothing at all. Those who see nothing may have aphantasia, the absence of a mind’s eye. In 1880 Francis Galton asked distinguished scientists to picture their breakfast table, and many insisted mental imagery did not exist. In 1897 Théodule Ribot described a physiologist who saw the printed word dog instead of a dog. Interest returned in 2005 when Adam Zeman met Patient MX, who lost his imagery after minor surgery, and Zeman’s team named congenital aphantasia in 2015.

Most aphantasics cannot summon images on purpose but still dream in pictures. A March 2021 study found they showed no sweat response to a scary story, though they reacted to frightening photos like everyone else. They struggle with detailed visual recall but do well on spatial memory, and many also lack an inner voice, which researchers named anauralia in 2021. Yet Pixar co-founder Ed Catmull, Disney animator Glen Keane, Firefox co-creator Blake Ross and The Martian author Andy Weir all have it.

• A 2022 screening estimated 0.8 percent of people have no visual imagery and 3.9 percent only dim imagery
• Catmull surveyed 540 Pixar colleagues and found production managers visualized more vividly than the artists
• Aphantasics are slower at hidden object searches because they check a mental list of features
• Science writer Lynne Kelly uses memory palaces through spatial memory rather than pictures
• A 2024 University of Plymouth program improved imagery in most athletes after six weeks