Some People Cannot Picture Things Awake but See Them in Dreams
People with aphantasia cannot call up a mental picture on purpose, yet many of them still see faces and places in their dreams.
Most people can shut their eyes and bring a familiar face to mind, maybe a smile or the way someone's hair falls. Some people cannot do this at all, however hard they try. The everyday name for that is aphantasia: the inability to picture things at will. The odd part comes at night. In a study of 205 people, many who cannot picture anything on purpose while awake still reported seeing pictures in their dreams.
Two of the researchers live with it
The question started with the scientists themselves. Derek Arnold and Loren Bouyer, at the University of Queensland in Australia, have had aphantasia all their lives. Neither can deliberately form a mental picture. Their dreams are not alike, though. Arnold can imagine sounds, while Bouyer can imagine the feeling of touch. Each felt that the sensations in their dreams matched the ones they could imagine during the day.
Working with Merlin Monzel of the University of Bonn in Germany, they set out to see whether other people with aphantasia had the same experience. Aphantasia is not always only about pictures. Earlier work found that about 26 percent of people with aphantasia report no imagined experience of any kind, and other researchers have sorted people into groups, including those who cannot imagine in any sense and those whose only gap is pictures.
What the 205 people reported
The team looked at online questionnaire answers from 205 people. Scores for visual imagination placed 84 of them in a visual aphantasia group and 121 in a comparison group. Participants were asked about imagined sounds, smells, tastes, touch, the feeling of movement, and inner speech, which simply means hearing words in your mind. They also reported how often those sensations showed up in their dreams, with the option of saying they were unsure.
Within the aphantasia group, 46 percent said they always had visual experiences in their dreams, and about 8 percent said they never did. The researchers found no evidence that stronger waking visualization went along with more frequent visual dreaming.
Sounds and inner speech behaved differently. People who heard sounds and conversations in their dreams also tended to use imagined sounds and inner speech in daily life, such as mentally rehearsing a conversation before speaking. Those links were generally weak to moderate. Across the three questionnaires, people were consistent about how closely their waking imagination matched their dreams. Some repeatedly described a close match, while others described substantial differences.
Why a picture can appear in sleep and not on demand
That is still unclear. One possible explanation involves how the brain regions used in imagination work together. The researchers suggest that trouble coordinating this activity might continue during sleep for some people, while changing for others. The study did not measure brain activity, so that idea remains untested.
There are other limits to keep in mind. The findings rely on people describing their own experiences and remembering their dreams. Those in the aphantasia group were also more likely to be unsure whether a particular sensation had occurred in a dream. The group included some people with weak visual imagination alongside those reporting none at all.
Future sleep studies could get closer to the experience itself by waking participants immediately after a dream and asking what they remember.