Close your eyes and picture a beach. For most people, you can “see” it in your mind—water, sand, sunshine. For around 3 to 4% of the population, however, no image appears. The mental screen stays blank, and many of them spent years assuming everyone else was speaking metaphorically when they said, “picture this.” That condition is called aphantasia, and what’s really weird: a lot of people who have it still dream in full color.

A new study published in Scientific Reports set out to explain that contradiction and came back with something more complicated than a single answer. Researchers from the University of Queensland and the University of Bonn surveyed 205 participants, 84 of them classified as visual aphantasics, asking them to rate how vividly their waking imagination worked across six senses, then report how often those same senses appeared in their dreams. To add texture, participants also mentally revisited familiar scenarios—a dinner party, a sick day at home, a trip to the beach—and ranked which senses came through.

At the group level, the results pointed in one direction. Senses a person couldn’t summon while awake were more dulled in their dreams too, with the strongest links appearing for inner speech, hearing, and taste. Vision was the exception, which the researchers attribute to the fact that nearly everyone in the aphantasia group had little visual imagery to begin with, making it hard to measure variation. Aphantasia Probably Isn’t a Single Condition

The averages, though, are almost beside the point. The individual spread is where things get a bit wild. Some participants had virtually no waking sensory imagination and equally blank dreams. Others couldn’t picture, hear, or feel anything voluntarily while awake, yet all of it came flooding back once they fell asleep. Among the visual aphantasics in the study, 46% said they always dream in pictures. About 8% said they never do. What struck the researchers was that each person’s waking-to-dreaming relationship stayed consistent across senses—loose in one area, loose across all of them; tight in one, tight throughout. A stable personal signature, wildly different from one person to the next.

One possible explanation the researchers raise involves differences in how brain regions coordinate during sleep versus waking hours, which could account for why one person’s dreaming mind mirrors their conscious one while another’s runs completely free. Both lead authors have aphantasia themselves, which is what drew them to the question in the first place.

The study’s broader implication is that aphantasia has been treated as a single condition when the evidence suggests it’s more like a cluster of related ones. Two people can have the same diagnosis and, once the lights go out, inhabit completely different inner worlds.