When most people imagine walking on a beach at sunset, their mind will likely conjure up a picture such as this. For some it will be vivid, others a little hazier, but they will envisage the scene.
But recent studies have found that 2% to 5% of people will see nothing at all; they have aphantasia, or “mind-blindness”.
Australian research, published in the journal Scientific Reports, has discovered aphantasia could have broader ramifications for important thought processes, making it hard to remember the past, picture the future and even dream.
“The human mind is like an expert simulation device, allowing us to mentally travel through time in order to forecast the future and re-experience the past,” says lead author Alexei Dawes from the University of New South Wales.
“For most of us, mental imagery seems to form much of the rich and vivid content of these simulations. It gives colour, shape and light to our inner worlds.”
It’s much more than seeing pretty pictures or summoning up memories; Dawes and colleagues note visual imagery can help people interpret events, plan and make decisions.
For their experiment, they compared more than 250 people with aphantasia with around 400 controls who can visualise to test their “cognitive fingerprint”.
Participants completed questionnaires measuring their ability to use imagery, memory and imagination, response to stressful life events, mind-wandering, dreaming and spatial abilities.
For the imagery scales, a question might ask participants to rate statements on a scale, like, “When I imagine the face of a friend, I have a perfectly clear and bright image”, or for spatial imagery, “I am a good Tetris player”.
Among the findings, mind-blindness was associated with difficulty remembering the past, such as a special event.
“Most of us will remember these events by ‘picturing’ the scene in our mind’s eye,” says Dawes, “adding colour, shape, shadow, tone and movement to the images, almost like they are being projected onto a screen in our minds.”
“We might see the blinding white of the clouds, the soft green of the grass, the movement of shadows across a tree branch.”
People with aphantasia lack this rich sensory detail, so they can recall things that happened, but don’t see it in their mind’s eye.
“They don’t see the pattern of the icing on the birthday cake, or the wedding crowd cheering as the fiancés share their first kiss, or the bright red of the sun as it sets over the horizon,” says Dawes. “Instead, it’s like a blank slate in there – just black.”
This might also be true for other cognitive processes. Without visual imagery, how do you visualise numbers to solve a maths problem, or dream without seeing the video-like images play out or plan for a future that you can’t see?
“In the case of aphantasia, we’re really talking about widespread differences in any mental process that requires us to simulate an event or scene using sensory detail – the mental journeys we take inside our minds every day.”
Mind-blindness also extended to other senses, and a quarter had a total lack of multi-sensory imagery.
So those who couldn’t visualise the beach scene at sunset would, to varying degrees, struggle to imagine the sound of the waves, the feeling of sand between their toes as they walk, and the taste or smell of the sea air.
People with mind-blindness also reported having fewer dreams, and those they did have lacked sensory detail and were rated weaker and less vivid.
However, supporting other research, they didn’t seem to have impaired spatial imagery, the ability to picture distance or the spatial relationships between things. They wouldn’t therefore have trouble imagining how a shape would fit into something or remember how to get from A to B.
The research is observational, so the researchers are extending it and replicating their findings with objective measurements, which are so far aligning well with their current predictions.
They also are looking for people to join the Australian Aphantasia Database and potentially be a part of the research. Information is available from the Future Minds website.
Natalie Parletta is a freelance science writer based in Adelaide and an adjunct senior research fellow with the University of South Australia.
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