Aphantasia: Some People Can't Picture Things While Awake, But See Them in Dreams

Picture someone you know well. You might be able to bring their face to mind, perhaps their smile or the way their hair falls. For some people, that familiar face never becomes a mental picture, however hard they try.

When they fall asleep, this can change. Faces and places may appear in their dreams, even though they cannot deliberately picture them during the day.

What allows those images to appear during sleep?

The inability to picture things at will is known as aphantasia. A study published in Scientific Reports explored the dreams of people who have it and found that the relationship between waking imagination and dreaming varies considerably from person to person.

The researchers looked beyond images, asking about sounds, smells, tastes, touch, the feeling of movement, and inner speech, the experience of hearing words in your mind.

Some people described similar sensory experiences while dreaming and imagining things awake. Others reported sensations in dreams that they could not deliberately summon during waking life.

The question had a personal beginning. Two of the researchers, Derek Arnold and Loren Bouyer of the University of Queensland in Australia, describe having lifelong aphantasia. Their dreams are not alike, and each felt that the sensations in their dreams reflected those they could imagine during the day.

They had previously described how their imaginations differ. Arnold can imagine sounds, while Bouyer can imagine sensations of touch. Neither can voluntarily form mental pictures.

Working with Merlin Monzel of the University of Bonn in Germany, they investigated how these experiences varied among a larger group.

The team analyzed online questionnaire responses from 205 people. Scores measuring visual imagination placed 84 participants in a visual aphantasia group and 121 in a comparison group.

Participants considered situations that might bring different senses to mind, such as remembering a social gathering. They ranked the imagined sensations they experienced and answered questions about everyday habits, including mentally rehearsing conversations or imagining how a movement would feel.

They also reported how often different sensations appeared in their dreams, with an option to say they were unsure.

Within the aphantasia group, 46 percent reported always having visual experiences in their dreams. About 8 percent reported never having them. Nobody in the comparison group reported experiencing visual dreams.

Among participants in the aphantasia group, the researchers found no evidence that stronger waking visualization went along with more frequent visual dreaming.

The connections were clearer for sounds and inner speech. Participants who reported these experiences more often in dreams also tended to report them more often while awake, although the associations were generally weak to moderate.

People in the aphantasia group who often heard sounds and conversations while dreaming also tended to report more frequent use of imagined sounds and inner speech in daily life, such as mentally rehearsing conversations before speaking.

Across the three questionnaires, participants were consistent in how closely their waking imagination matched their dreams. Some repeatedly reported a close match, while others described substantial differences.

Why a sensation would be available during sleep but not on demand while awake is still unclear. One possible explanation involves how brain regions involved in imagination work together. The researchers suggest that difficulties coordinating this activity might continue during sleep for some people, while changing for others.

Comparing brain activity in people with these different experiences could help test that idea. It could also reveal whether similar processes produce imagined sensations during waking life and dreams.

The study did not measure brain activity, so that explanation remains untested. The findings rely on participants describing their experiences and remembering their dreams. Those in the aphantasia group were also more likely to be unsure whether particular sensations occurred in their dreams. The group included some people with weak visual imagination alongside those reporting none.

Future sleep studies could bring researchers closer to the experience itself by waking participants immediately after dreams and asking what they remember.

Some people with aphantasia report images and sounds in dreams that they cannot call up while awake. For others, the sensations missing from waking imagination are also absent from their dreams.

The research has been published in Scientific Reports.