Can you picture a red apple in your mind without looking at one?
If not, you might be one of the four percent of people who have aphantasia - a mind's eye that is blind.
Having a brain that's unable to conjure up mental imagery for "imagination" doesn't mean being less creative, says British neurologist Adam Zeman, who coined the term 'aphantasia' back in 2015.
People living with the condition include "highly creative and highly imaginative" types who invent new and useful things, like the 3D animation pioneer and former Pixar boss Ed Catmull.
"Many creative people do indeed use imagery in their creative thinking, but it doesn't seem to be the only route to creativity. Sensory imagery doesn't seem to be a requirement for creativity," Zeman tells Saturday Morning.
Computer scientist Ed Catmull is credited with revolutionising 3D animation, but has told the BBC that due to aphantasia, his "mind's eye" is blind.
Courtesy of Pixar
The inability to summon up mental imagery may make the ups and downs of life a bit easier for people with aphantasia, Zeman says, because they tend not to dwell on things for too long.
It seems people without visual imagery in their minds move on more easily from breakups, recover more quickly from grief and relocate with less angst, he says.
Without the ability to "picture" images of the future, people with aphantasia may just be less preoccupied with it, Zeman says, and able to live more in the moment.
"It seems that people with aphantasia are, in a sense, a little more present than those with very vivid imagery."
Whatever is or isn't going on in our heads, as perceiving human creatures, we use our imaginations constantly, Zeman says, when we remember the past, anticipate the future or enter a virtual world, aka watch Netflix.
"All of us are often absent from the here and now. We're often reminiscing, recollecting the past, and thinking about things that might happen in the future. We lose ourselves in a novel or in a film… in every one of those cases, we are engaging imagination."
Our imaginations are engaged every time we mentally enter a virtual world, says British neurologist Adam Zeman.
Andrea Piacquadio
In his new book The Shape of Things Unseen, Zeman dives into the science of visualisation, imagination and creativity - including the seemingly automatic yet creative "act" of perception.
"We tend to think of perception as a passive process, but actually it's a highly active, generative one that depends on both our huge accumulated knowledge of the world - hard-won over the course of our lives - and the ceaseless activity of our creative nervous system."
Although a powerful imagination isn't always on our side - maladaptive daydreamers neglect their daily lives and the newly widowed often see their departed spouse in hallucinations - the capacity seems crucial to our survival as a species, Zeman says.
"Human tradition, human artefacts, depend, ultimately, on individual acts of creativity, which we share with one another. So the sharing of our minds, the sharing of our imaginations, has been an absolutely key. Shared imagination has been at the heart of human evolution."
Thanks to our imaginative and creative skills, Zeman is hopeful that future humans will prove "pretty resilient" to technological domination thanks to this capacity.
"My guess is that our children are going to find imaginative and creative ways of using these technologies, and they won't be dumbed-down by them."
In the meantime, understanding that neuroplasticity is what enables our brains to be formed by the "arbitrary" set of traditions we happen to have been exposed to growing up is a strong argument against any form of fundamentalist thinking.
"Which particular set of traditions we were exposed to is rather arbitrary. It's rather a matter of chance. So, I think we can be both respectful of the importance of tradition and also very doubtful about claims that any particular tradition is superior to any other."
Adam Zeman came up with the term 'aphantasia' by combining the Greek word "phantasia" - imagination - with the prefix "a", indicating an absence or lack.
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