Afantasia makes it harder to visualize your past and future, study shows

A rare condition that leaves people unable to visualize images in their imaginations may have more far-reaching effects on the mind than we knew about, scientists report.

Aphasia, sometimes referred to as “blind in the mind,” has been known since the 1800s, but it has only attracted much scientific attention in recent years.

Those studies tell us more about how fantasy manifests in humans, while also revealing new insights about how important mental images are as part of other brain functions, such as memory.

In 2020, a team of researchers led by cognitive neuroscientist Alexei Dawes of the University of New South Wales (UNSW) in Australia found that people with afantasia had a diminished ability to remember the past and imagine the future, in addition to remembering. of fewer dreams (and often with fewer details).

Now, in a new study, some of the same scientists have uncovered new evidence of the impact of afantasia on our memory and imagination of the future.

“Episodic memory and future perspective are functionally similar,” said Dawes, now a researcher at the RIKEN Center for Brain Science in Japan, explains in a Twitter thread about the new findings.

“Both are everyday cognitive processes involving the reconstructive simulation of events and scenes, usually accompanied by anecdotally vivid online sensory repetition (or ‘preplay’) in the form of visual images.”

While these inner visual images are something that constantly conjures up our minds, there’s still a lot we don’t know about how these images contribute to our ability to actually remember episodes from the past.

To investigate, Dawes and fellow researchers conducted an experiment with about 60 participants, half of whom experienced fantasy, and the other half people without the condition, acting as a control group.

In the experiment, participants completed a modified version of the autobiographical interview, a test given to assess components of autobiographical memory in adults.

In the version performed here, participants were asked to remember six life events (real memories) and imagine six hypothetical future events based on word clues, with detailed written descriptions of each.

The results showed that aphantasic participants generated significantly less episodic detail than participants in the control group, both for past and future events.

This included significantly weaker visual images, object images and scene images, the researchers found, but noted that people with aphantasia scored similarly to the controls on spatial imagery ability.

Most importantly, the current study provides the first robust behavioral evidence that the absence of visual imagery is associated with a significantly reduced capacity to simulate the past and construct the future.

“Aphantasic participants generated significantly less internal detail than controls, regardless of temporal direction, indicating that their event descriptions were less episodic rich and specific than participants with visual imagery.”

While we can’t estimate the magnitude of the impact yet, the researchers say it’s clear that the ability to generate visual images is important for the mental construction of events, whether reconstructing real-life memories or making up scenarios that didn’t happen.

The fact that both past memories and imaginary future anticipations are affected in the same way could provide support for what is called the constructive episodic simulation hypothesis, which states that future prospecting is a cognitive process that collects fragments of past memories in order to to paint a picture of possible future events.

“According to this account, internal ‘re-experiencing’ and ‘pre-experiencing’ events must both involve the recombination of stored perceptual, spatio-temporal and conceptual information, and thus rely on similar cognitive processes — including mental images,” the researchers explain.

Of course, this doesn’t mean that people with aphasia can’t do that to remind past events or imagine future events, the researchers note.

But it seems their ability to construct or reconstruct these internal scenes is diminished compared to people without the condition, whose ability to rely on a greater amount of mental visual images seems to give them an advantage in tapping into memories.

There’s still so much we don’t know about how this condition works, but studies like this one help fill in the details — and not just about afantasia, but about how memory and visual images intersect (or don’t) in all of our heads. .

“The interactions between visual imagery, episodic event construction, and autobiographical memory are likely complex and further complicated by the myriad individual differences that moderate each of these cognitive processes,” the researchers write.

“However, Aphantasia offers a unique model to explore these interactions and build a broader taxonomy of cognitive simulation in the human brain.”

The findings are reported in Cognition

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