When Mental Images Get in the Way: How Aphantasia Reveals a Hidden Advantage in Reasoning

When mathematicians kept walking up to Maël Delem and Damien Le Clézio at conferences saying, "I think I have aphantasia, and I think it's why I reason the way I do," the two young researchers started paying attention.

"That's something Francis Galton said in 1880, that Zeman proposed again in 2020," the researchers explain. "Many researchers said, yeah, but it's a bit too obvious, too much of a caricature. But actually, it seems to fit. It matches the observations, the pattern that seems to appear."

So they designed a study to test it. The question was deceptively simple: if you can't picture things in your mind, does that make you worse at reasoning—or could it actually make you better?

Their findings, published in collaboration with Merlin Monzel at Bonn University and conducted under the supervision of Professor Gaën Plancher at the EMC laboratory in Lyon, suggest something that runs counter to centuries of assumption: for certain kinds of thinking, mental images may not be a tool. They may be a speed bump.

A Debate That Goes Back to Aristotle

The question of whether mental images are essential to thought isn't new. It's ancient.

"There was essentially a divide between a group of imagery enthusiasts and a group of imagery skeptics," Maël and Damien explain. Plato was a skeptic. Aristotle was an enthusiast—and famously declared that "the soul never thinks without phantasma."

That debate resurfaced in the 1970s between Stephen Kosslyn, who argued that mental representations are stored in a pictorial, picture-like format, and Zenon Pylyshyn, who countered that all information—whether it feels visual or not—is actually stored in an abstract, symbolic, language-like code.

What makes aphantasia such a powerful tool for cognitive science is that it puts this debate to an empirical test. People with aphantasia clearly reason, remember, and solve problems. If they do it without mental images at all, then mental images can't be necessary for those processes. But how efficient are they? Are there things aphantasics do better—or worse—because of the absence of imagery?

As Maël and Damien note, this question had another personal dimension for researchers in the field: "Researchers' views were shaped by their own conscious experiences with imagery." A 2003 study by Reisberg, Pearson and Kosslyn found that psychologists who personally experienced vivid imagery were more likely to believe imagery was central to cognition. The theories we build tend to reflect the minds we have.

Aphantasia forces a reckoning with that bias.

The Visual Imagery Impedance Effect

Before aphantasia was even named, a researcher named Markus Knauff and his colleague Phil Johnson-Laird published a surprising finding in 2002. They asked people to solve deductive reasoning puzzles with three different kinds of relationships:

Visual problems ("A is cleaner than B")

Spatial problems ("A is above B")

Control problems ("A is faster than B")

The logical structure of all three was identical. Only the surface content differed. And yet—people solved the visual problems more slowly. Knauff and Johnson-Laird called this the visual imagery impedance effect: visual problems appeared to slow reasoning down, not speed it up.

To explain it, they drew on mental model theory, which Johnson-Laird had developed around the same time as the Kosslyn–Pylyshyn debate. Mental models are "small-scale reproductions of reality"—abstract representations that preserve the essential relationships between elements without being pictures themselves. You can build a visual image from a mental model, but the model itself sits underneath the image. And according to the theory, it's the model—not the picture—that does the actual reasoning.

"Mental models, and not mental images, underlie human reasoning," Maël and Damien explain. "This is what led them to the hypothesis that visual mental images are not necessary to reason—and that actually, they interfere with reasoning processes."

If that was right, Damien and Maël reasoned, people with aphantasia should have a quiet edge. With no visual images to take the detour through, their reasoning should stay on the faster, more direct route.

The Study

The team recruited participants across the imagery spectrum and had them complete two questionnaires: the VVIQ (Vividness of Visual Imagery Questionnaire), which measures visual imagery vividness, and the OSIVQ (Object-Spatial Imagery and Verbal Questionnaire), which separates people into three cognitive styles: visualizers, spatializers, and verbalizers.

Then came the reasoning task—27 problems inspired directly by Knauff and Johnson-Laird's original design. Nine visual, nine spatial, nine control. Participants had to read three premises and judge whether a conclusion followed logically.

After each session, participants rated how much they'd used each of five strategies: visual, spatial, verbal, semantic, or sensorimotor.

Crucially, rather than the usual two-group split (aphantasia vs. everyone else), the team ran the analyses three ways:

The classic VVIQ cut-off (aphantasia vs. typical imagery)

A finer split that separated complete aphantasia (VVIQ = 16, no imagery at all) from hypophantasia (VVIQ 17–32, weak or dim imagery)

Cognitive-style clusters (visualizer, spatializer, verbalizer) derived through a clustering algorithm

This last distinction matters more than it might sound. "Complete absence of visual imagery—complete aphantasia—is not hypophantasia," the researchers emphasize. "We should be wary of this difference."

What They Found

The results replicated the visual imagery impedance effect—but only in the groups you'd expect.

Typical imagers were about 2.4 seconds slower on visual problems than on spatial or control ones, and slightly less accurate. Just as Knauff and Johnson-Laird predicted.

Complete aphantasics showed a slowdown of only 1.3 seconds—statistically unclear. In other words, the impedance effect largely disappeared for people with no visual imagery at all.

Hypophantasics—people with some weak imagery—fell in between, with a 2.2-second slowdown.

The cognitive-style analysis told the same story. Visualizers were slowed by 2.7 seconds on visual problems. Spatializers and verbalizers barely showed the effect at all.

And the self-reported strategies matched perfectly. The groups most affected by the impedance effect were the ones who reported leaning most heavily on visual strategies to solve the problems.

"Mental images do seem to impact reasoning," Maël and Damien conclude, "but importantly, only for people who actually use mental images."

Why Do Images Slow Things Down?

If images aren't necessary to reason, why do they cause a detour in the first place?

Knauff and Johnson-Laird's fMRI follow-up studies offered a neurological answer. When typical imagers solve visual problems, their brains take a detour through the visual cortex. When they solve spatial or control problems, they don't. The image is doing something—but that something may be a memory aid, not a reasoning operation.

"Visual imagery would be a memory aspect," Maël and Damien explain. "You have to maintain the information, and then you have to manipulate it, reason about it. Visual imagery would be in the memory part. But the manipulation probably does not need this visual mental image."

There's also a basic architectural wrinkle. The brain processes visual properties (color, shape) through a different pathway than spatial properties (orientation, position)—the so-called ventral and dorsal streams. "They literally take different routes," the researcher said. "If spatial processes are the only ones that are necessary for reasoning, using both pathways would be too much. Whereas using only one—the only one that is necessary—would be faster, more precise."

For aphantasics, there's only one route available. And it turns out to be the one that matters.

The Dual Coding Question

During the discussion, Tom Ebeyer raised a parallel thread: the same logic might apply to dual coding theory, the 50-year-old idea that memory is strengthened when information is encoded both visually and verbally.

The researchers had been thinking along the same lines. "One hypothesis that just came to me," he said, "is that maybe dual coding theory—and the disadvantage of using only one of the two codes—is valid for people that actually have the two. But if you only use, say, only verbal, then adding or not adding an incentive for visual strategy doesn't have an impact. So dual coding theory would not be wrong, but only apply to a certain fraction of the population."

It's the same insight at the heart of the reasoning study. Cognitive theories built on the experience of visualizers may describe visualizers accurately—and quietly mislead us about everyone else.

As Tom put it: "When you start to look at individual differences and get a little more granular and nuanced, you get more clarity."

It's Not That Imagers Choose to Visualize

One question Tom raised in the discussion stuck: do typical imagers choose to visualize when they hear "A is cleaner than B," or does it just happen?

Maël, a self-described typical imager himself ("really black-and-white, sketch-drawing-like imagery"), thinks it's closer to a default.

"It's more a default than an automatic way to think," he says. People with vivid imagery fall into visual strategies because those strategies are right there, readily available. The cost of that convenience is invisible—until you compare them with people for whom visual strategies aren't an option, and realize those people aren't actually worse off. Sometimes, they're faster.

There's something quietly radical in that. It suggests imagery isn't a cognitive tool we choose to deploy. It's a lens we can't easily turn off—and the lens isn't free.

Not Deficits, Different Strategies

One of the most important reframing to come out of this work is the shift away from a deficit model.

"So much of the aphantasia research really has been focused on the deficits," Tom observed. "It's important scientifically, but it's also important for people who discover they have aphantasia to see a narrative that's maybe different from the I'm lacking story."

Maël and Damien agree. What's emerging instead is a picture of aphantasia as a distinct cognitive style—one that leans more heavily on semantic, abstract, or spatial representations. That style may carry genuine advantages: in deductive reasoning, in resisting false memories, and possibly in STEM fields, where a 2021 Zeman paper noted an over-representation of aphantasics.

"Aphantasia does seem to have potential benefits in reasoning that have to be investigated further," the researchers conclude. "That are likely tied to this abstract cognitive style that was hypothesized by Zeman and others before him."

A Constellation, Not a Category

During the Q&A, a member of Aphantasia Network raised a point that Maël and Damien were quick to validate: aphantasia isn't one thing. Some aphantasics have vivid imagery in other senses—auditory, tactile, motor. Others have no inner voice at all. Others still experience imagery in one modality but not another.

"We have a whole constellation of subtypes of aphantasia," said the researchers. A 2023 study by Dawes and colleagues in Australia used clustering algorithms on a large sample and found exactly this: a huge cluster of complete aphantasics in the middle, surrounded by a constellation of distinct sensory-imagery profiles.

The implication for researchers is that the VVIQ alone—while historically dominant—may be too narrow. Questionnaires like the Plymouth Sensory Imagery Questionnaire (PSIQ) measure imagery across all the senses and are increasingly being adopted by labs looking to capture the full spectrum of variation.

"Virtually everyone is different," says Maël and Damien. And that variation is precisely what makes aphantasia such a productive lens on the mind.

What's Next

The team is now extending the work with a series of follow-up studies, including one that uses purely abstract spatial reasoning problems to test whether aphantasics maintain their edge in contexts with no possible visual framing. They're also hoping to recruit more hyperphantasics to see whether the impedance effect scales with imagery vividness—the more imagery, the larger the slowdown.

If you'd like to take part, the team's ongoing studies are available at innerexperiencelab.com.

Why It Matters

For 50 years, cognitive psychology has worked from a quiet assumption: that visual imagery helps us think. Models of memory, reasoning, and learning have been built on foundations poured by researchers who could vividly picture what they were studying.

Aphantasia is, slowly, letting us check those foundations. What Damien and Maël's study suggests is that some of them describe a fraction of the population rather than the whole of it. For visualizers, imagery may help with memory. For everyone else, it was never doing that work in the first place.

It's a small correction, maybe. But it opens a larger door: the recognition that cognition comes in genuinely different flavors, and that what we've long called thinking has been, all along, a conversation among minds that don't all work the same way.

Learn More

Damien Le Clézio and Maël Delem are researchers at the EMC laboratory at the University of Lyon, working under the supervision of Professor Gaën Plancher. Their study, conducted in collaboration with Merlin Monzel of Bonn University, explores the impact of mental imagery on deductive reasoning in the aphantasic community. To participate in their ongoing research, visit innerexperiencelab.com.