A Neuroscientist's Journey Through Aphantasia

For years, Mac Shine studied people who saw things that weren't there. As a neuroscientist at the University of Sydney researching visual hallucinations in Parkinson's disease, he spent countless hours trying to understand how the brain could conjure vivid images from nothing. There was just one problem: he had no idea what that experience actually felt like.

The moment of discovery came during a lab discussion about imagination and perception. Shine was explaining his mental experience to a colleague when he realized something was profoundly different about how their brains worked.

"For her it was as if she was experiencing the world around her in a faded form," Shine recalls. "To me, I honestly when I first heard this just did not believe her. I believed that she was telling a lie or essentially making up some awful way of describing what it was."

But the more people he talked to, the more Shine realized the truth: there was a massive spectrum between his experience of complete mental darkness and his colleague's vivid internal cinema. And he wasn't alone on the dark end of that spectrum.

The Camera Metaphor We Need to Abandon

Shine's research challenges one of our most fundamental assumptions about how vision works. We typically think of the eye as a camera—light comes in, hits the retina, and projects an image into our brain like a movie screen. But this metaphor is fundamentally wrong.

"Perception is an active process," Shine explains. "Your visual system isn't like a camera, it's more like the way you would touch the world around you but with your eyes."

The anatomy backs this up. The brain has approximately four times as many connections feeding back to the primary visual areas than there are connections coming in from the retina itself. In other words, what you expect to see matters more than what's actually hitting your eyes.

This feed-forward and feedback loop between expectation and input is crucial for understanding both imagination and aphantasia. When you perceive the world, information flows forward from your eyes. When you imagine, you're driving that same system in reverse—using expectations and memories to activate visual areas without any actual visual input.

For people with aphantasia, that reverse gear simply doesn't engage.

The Hallucination Connection

Shine's work with Parkinson's patients revealed something fascinating: people who hallucinate are exceptionally good at "driving their visual system in reverse." They can prime their brains so effectively with expectations that they see things that aren't there.

In one study, Shine's team used ambiguous images that could be interpreted multiple ways. People with Parkinson's disease who experienced hallucinations were much better at spotting hidden images—but they also frequently saw things that weren't there at all. Their brains were constantly filling in gaps, making predictions, and sometimes getting carried away with those predictions.

"The ability to prime your system to essentially run the system in reverse, to imagine the world the way that you want it to be and not the way that it actually is, is really deeply related to hallucination," Shine explains.

In another clever experiment using binocular rivalry—where different images are shown to each eye—researchers found that people who imagined the color red before viewing the stimulus would see red longer before their perception switched. People with hallucinations were remarkably good at this mental priming.

The implication is striking: imagination and hallucination exist on the same spectrum, both involving the brain's ability to generate visual experiences from the top down rather than the bottom up.

The Aphantasic Advantage

Discovering his aphantasia helped Shine understand certain patterns in his own life and career. While he struggled with rote memorization, he excelled at deep understanding.

"I'm really really terrible at rote learning. I can't just look at a list of words and then recall it easily," he admits. "But I'm actually pretty good at taking things to a level where I understand them. When I have I can knit them into the fabric of my understanding of the rest of the system and then I can find my way back to them really easily."

This forced approach to understanding rather than memorizing may actually be beneficial for tackling complex problems in neuroscience. Rather than relying on mental lists and visual recall, Shine builds integrated frameworks of knowledge.

There's also an emotional component. Shine describes having "quite a lot of mental resilience" because he doesn't dwell on past failures. In academia, where rejection is constant—papers declined, grants denied, ideas scooped—this ability to move forward without repeatedly visualizing past disappointments becomes a genuine asset.

"I think my aphantasia allows me to kind of stroll through as you would with a bit of water off the duck's back," he says.

The Hidden Cost

But aphantasia isn't all advantages. Shine identifies one particularly painful downside: the inability to reconnect emotionally with loved ones through memory.

"If I travel and I'm lying down to bed in a hotel in some foreign country, it's really quite often you feel quite lonely because you can't reimagine your wife and child's eyes and think of their faces as you go to bed," he reflects. "You sit there with a feeling of them but not really that rich experience."

This points to a fundamental trade-off in aphantasic brains. While the inability to replay painful memories in vivid detail may offer protection from trauma, it also means losing access to the rich sensory replay of positive memories and beloved faces.

What's Actually Happening in Aphantasic Brains

Working with Adam Zeman, Shine's team has begun scanning the brains of people with aphantasia to understand what's different at a neural level. The preliminary findings are revealing.

When people with aphantasia try to imagine something, large networks in the temporal lobe, cingulate cortex, and frontal cortex become hyperconnected—but areas in the parietal lobe show reduced connectivity. The network is performing quite differently than in people with typical imagination, even though aphantasic individuals can still access information about what they're "imagining."

This explains the classic aphantasia paradox: you can count the windows in your house with your eyes closed, navigating mentally through each room, but you don't actually see your house. The information is there; the visual replay isn't.

"The question then becomes why is it that I'm still able to do all the other things that I can do?" Shine asks. "Why is it I can still imagine the number of windows around my house but I don't have that visual perception?"

His hypothesis involves information encoding capacity. Early results suggest that people with aphantasia may not be capable of encoding as much detailed information in their visual cortex, which could explain why the system can't be fully reactivated during imagination.

The Unexpected Connection to AI

In a surprising twist, Shine argues that large language models like ChatGPT might actually function more like aphantasic brains than typical human imagination.

These AI systems can access and process information without any form of internal experience or imagery. They provide elaborate responses by manipulating patterns and relationships rather than by "seeing" or "experiencing" anything. This feed-forward architecture—information in, processing, response out—resembles how aphantasic individuals often describe accessing knowledge without sensory replay.

"The kinds of computations that these large language models are capable of are really very different than the kinds of computations that are happening in our brain, particularly for aphantasics," Shine notes. "But they're actually a little bit more like aphantasics I think than typical imagining humans because the large language models can give you access to information without necessarily perceiving it."

The Research Continues

Shine emphasizes that understanding aphantasia remains a work in progress. While we now know that aphantasic brains show different patterns of connectivity and activation, the complete picture of why some people can drive their visual systems in reverse while others cannot is still emerging.

The research raises fundamental questions about consciousness, perception, and the nature of thought itself. If we can think, reason, remember, and create without mental imagery, what does that tell us about the role imagery plays in typical cognition? Is visualization merely one tool among many, or does its absence fundamentally reshape how we process the world?

For Shine, these questions aren't just academic. They're deeply personal explorations of how his own mind works and why it works that way.

What This Means for Aphantasics

Shine's journey from studying hallucinations to understanding his own aphantasia illustrates a crucial insight: the absence of mental imagery isn't a deficit—it's a different configuration of the same neural machinery everyone else uses.

Your brain still has visual areas. They still activate when you think about visual information. The connections are just arranged differently, preventing the top-down reactivation that creates mental images while preserving access to spatial, factual, and conceptual information.

"We need to work on some of those subtleties," Shine acknowledges. "Why is it that as an aphantasic I can't make my visual system become active in the way that my imagining colleagues can but I still have access to all the other information?"

As research continues unraveling these mysteries, one thing becomes clear: understanding aphantasia isn't just about understanding a quirk of some brains. It's about understanding how all brains construct reality, how we separate perception from imagination, and how consciousness emerges from coordinated neural activity.

The invisible differences in how we experience our inner mental worlds—whether pitch dark or vividly illuminated—are windows into the extraordinary diversity of human consciousness. And that diversity, as Shine's own career demonstrates, might be exactly what we need to solve the hardest problems we face.

When Your Brain Runs in Reverse: A Neuroscientist's Journey Through Aphantasia