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Do Mental Pictures Slow Reasoning Down?
Damien Le Clézio and Maël Delem, Université Lumière Lyon 2
When you work through a logic puzzle, do pictures in your head help or get in the way?
Researchers have found a visual impedance effect: people take longer on reasoning puzzles built on words that are easy to picture, like “cleaner” or “dirtier”, than on words about position, like “left of”, or words that are hard to picture, like “braver”. The researchers who first found it proposed that easy-to-picture words call up images full of detail the puzzle doesn’t need.
If mental pictures cause the slowdown, people with aphantasia shouldn’t show it. Do they?
What the study found
Damien Le Clézio and Maël Delem tested this with their colleagues in “The impact of mental images on reasoning: A study on aphantasia”, published in the journal Neuropsychologia in 2026.
In all, 104 French speakers did the puzzles online: 47 with aphantasia, 30 of them with no visual imagery at all and 17 with faint imagery, and 57 typical imagers.
Each solved 27 puzzles about the letters A to D. Three statements, such as “A is cleaner than B”, came one at a time, then a conclusion to judge true or false. A third of the puzzles used easy-to-picture words, a third words about position and a third words that are hard to picture.
Typical imagers took about 2.4 seconds longer on the easy-to-picture puzzles than on the others. That repeated the original finding.
People with aphantasia may have slowed down too, by about 1.7 seconds, but the evidence was unclear either way.
Split further, those with faint imagery seemed to slow down more than those with none, though that difference wasn’t certain either.
Accuracy didn’t clearly differ between the groups or the kinds of puzzle.
Asked how they solved the puzzles, people with aphantasia said they relied mostly on strategies other than pictures.
So the easy-to-picture puzzles slowed typical imagers. Whether mental pictures are the cause, the study couldn’t settle: the slowdown may be smaller in aphantasia, or there may be no difference at all, and then something other than pictures would be at work.
The test ran online at each person’s own pace, which adds noise, and these are group results, so they can’t tell you about any one person.
What you’ll take away
- What the visual impedance effect is, and when pictures may cost time
- Why “aphantasia makes you reason faster” goes further than the evidence
- Why faint imagery and no imagery may not work the same way
About Damien and Maël
Damien Le Clézio and Maël Delem are PhD students in the Inner Experience Lab, part of the Laboratoire d’Étude des Mécanismes Cognitifs (EMC) at Université Lumière Lyon 2 in France. The lab studies how inner experience, such as mental images, an inner voice and a sense of space, relates to abilities like memory and reasoning. Maël’s thesis is on how people with aphantasia think, and what their brain activity shows.