Close your eyes and picture an apple. Most people see something-a faint, slightly blurry image, less vivid than a real apple. A few, however, will see it as clearly as if it were sitting right in front of them. This ability is called hyperphantasia. Hyperphantasia, literally meaning "beyond imagination," refers to exceptionally vivid mental imagery. It is often described as the opposite of aphantasia, a condition in which people report little or no ability to form mental images.
Take the sur­prise some have expressed in recent years upon find­ing out that the expres­sion to "pic­ture" some­thing in one's head isn't just a fig­ure of speech. You mean that peo­ple "pic­tur­ing an apple," say, haven't been just think­ing about an apple, but actu­al­ly see­ing one in their heads? The inabil­i­ty to do that has a name: aphan­ta­sia, from the Greek word phan­ta­sia, "image," and prefix - a, "with­out."