Imagine not being able to imagine anything -- you can't visualize your thoughts, produce mental images, or see any type of imagery in your head. This is the experience of individuals with a condition known as aphantasia. People with aphantasia often struggle to recognize faces, and may also have a weak memory. And while they can't picture images, they do have knowledge of the features that make up those images. For instance, people with aphantasia may not be able to picture a face, but they know that there's a nose, two eyes, and a mouth that make up a face. In many instances, people who are afflicted with the condition do not even realize that they're different from other people in this way.