Aphantasia

Figure 1. A quick and easy test to see if you have aphantasia.

Aphantasia is a condition characterized by the inability to generate on-demand visual mental images.

Prevelenace

People often don't realize they are aphantasic until they try psychedelics where they are supposed to see imagery which is often absent. One study estimates taht around 0.8% of the population is unable to form visual mental images, and 3.9% of the population are either unable to form mental images or have dim or vague mental imagery.

References