Radiology training involves being able to point out tiny details in medical imaging. (Gorodenkoff/Shutterstock)
In a nutshell
Radiologists and radiographers, who spend their careers examining medical images, are significantly less susceptible to common visual illusions than non-experts. This challenges the long-held belief that visual expertise remains confined to specific domains.
The ability of medical imaging experts to see through visual illusions likely comes from years of practice focusing on specific details while filtering out distracting elements in medical images. This skill transfers to judging sizes more accurately in everyday visual contexts.
Radiography students performed similarly to psychology students on the illusion tests, suggesting these enhanced perceptual abilities develop through years of professional training rather than innate talent. This highlights the brain’s remarkable capacity to adapt and specialize through intensive practice.
NORWICH, England — When radiologists examine medical scans, they look for subtle abnormalities that might indicate disease. This specialized training appears to have given them an unexpected advantage: they’re better at seeing through common visual illusions that trick most people.
A research team from several British universities found that medical imaging specialists were significantly less fooled by classic visual illusions than people without such training. The study, published in Scientific Reports, challenges what we thought we knew about how expertise works in the brain.
For decades, scientists believed that visual expertise was narrowly focused and that being great at one visual task wouldn’t help in other areas. A radiologist might excel at spotting lung tumors but wouldn’t necessarily have any visual advantages outside their specialty. This new research suggests otherwise.
Visual Superpowers Beyond Medical Imaging
The study tested radiologists, radiographers, and radiology trainees against psychology and medical students on four classic visual illusions. On average, the experts had worked with medical images for about 12 years and viewed roughly 79 medical images daily.
In this Ebbinghaus illusion of relative size perception, the orange circle on the left looks bigger than the one on the right – but it is actually 10 per cent smaller. In a new study, medical imaging experts were able to ‘see through’ the optical illusion. The research is the first to show that people can be trained to do better at solving visual illusions, which was previously thought to be near-impossible. (Credit: University of East Anglia)
The illusions included the Ebbinghaus illusion, in which identical circles appear different sizes when surrounded by larger or smaller circles; the Ponzo illusion, in which identical lines seem different lengths when placed between converging lines; the Müller-Lyer illusion, in which lines with different arrow endings appear unequal; and the Shepard Tabletops illusion, in which identical rectangles look different when rotated.
The medical imaging specialists outperformed the others on three of the four illusions. They were much less susceptible to the Ebbinghaus, Ponzo, and Müller-Lyer illusions. Both groups were equally tricked by the Shepard Tabletops illusion.
Visual illusions work by exploiting how our brains process visual information. Most of us integrate context when judging size or distance, which usually serves us well in the real world but backfires with these optical illusions. Somehow, medical imaging experts have developed the ability to judge size more accurately, regardless of misleading visual context.
How Years of Medical Training Reshape Visual Perception
The researchers believe this skill comes from years of examining medical images. Radiologists learn to focus intently on relevant areas while disregarding distracting background elements. They must detect small abnormalities amid visually complex images, such as a tiny tumor hidden in similar-looking tissue or a subtle fracture barely visible against surrounding bone.
The data demonstrates that intensive training alters how these professionals process visual information more fundamentally than previously thought. As they develop expertise, they may become better at filtering out visual noise and focusing on local details, which helps them see through illusions that trick most people.
This difference wasn’t present when comparing radiography students with psychology students, indicating the advantage isn’t something people are born with but develops through professional experience. It points to the brain’s remarkable adaptability. Intensive visual training in one area can reshape basic visual processing.
The Shepard Tabletops illusion was the exception. With this illusion, experts performed similarly to non-experts. Unlike the other illusions, the Shepard Tabletops doesn’t rely on misleading context but on orientation differences. Without irrelevant context to filter out, the experts’ specialized visual abilities didn’t give them an edge.
The study also found that men were less susceptible to the Ebbinghaus and Ponzo illusions than women across both groups, consistent with previous research showing sex differences in visual processing.
Understanding how specialized training enhances visual abilities might improve training programs for medical professionals. It could also benefit other fields requiring fine visual discrimination, from security screening to satellite image analysis.
Rewiring the Brain Through Professional Training
The human visual system is incredibly adaptable. The researchers propose that through years of practice focusing on specific details in medical images while filtering out distractions, radiologists develop a “local processing bias” that transfers to other visual tasks. Rather than seeing the illusion as a whole, as most people do, they focus more on the specific elements being judged.
It’s a powerful example of neuroplasticity, showing how the brain reorganizes itself through experience. Just as a musician develops finer auditory discrimination or a sommelier refines their sense of taste, radiologists appear to fine-tune their visual systems after years in the field.
Paper Summary
Methodology
The experiment was designed as a forced-choice task. Participants viewed paired images on laptop screens and had to select which element was larger or longer. For example, with the Ebbinghaus illusion, they chose which of two central circles was larger. For each illusion, participants completed 24 trials of varying difficulty, where the actual size differences between elements changed. The researchers included control trials where the context helped rather than hindered perception, allowing them to identify participants who weren’t paying attention. They excluded participants who performed poorly on these control trials. Using specialized statistical methods, they analyzed how accurately each group judged the illusions, with higher scores showing less susceptibility to being fooled.
Results
The data showed clear differences between experts and non-experts. With the Ebbinghaus illusion, experts scored an average of 0.49 out of 1 across trials, while non-experts averaged just 0.29, showing experts were much less fooled. For the Ponzo illusion, experts averaged 0.61 compared to non-experts’ 0.52. The Müller-Lyer illusion revealed an interesting pattern—both groups performed similarly when size differences were small, but experts (0.96) significantly outperformed non-experts (0.87) when size differences were larger, suggesting they were better at seeing through the illusion when the actual differences became more noticeable. For the Shepard Tabletops illusion, both groups performed similarly. The researchers also compared radiography students with psychology students and found no significant differences, indicating the perceptual advantage develops through professional experience rather than being an innate ability.
Limitations
The research had some limitations. The expert group included people with varying experience levels, from trainees to seasoned radiologists, which might have introduced variability. Testing conditions weren’t completely standardized—some participants were tested in quiet cubicles, while others were tested in busier settings during a radiology conference. The study looked at differences between experts and non-experts at one point in time rather than tracking how these abilities develop over years of training. The comparison between radiography students and psychology students included only 12 people in each group, which is relatively small. The study also didn’t examine whether other visual experts, like artists or photographers, might show similar advantages, which would help determine if this effect is unique to medical imaging or applies to other types of visual expertise.
Discussion and Key Takeaways
The researchers think medical imaging experts develop a stronger local processing bias—they become better at focusing on specific details while filtering out distracting information. This skill likely develops through years of examining medical images where they must focus on relevant areas while ignoring irrelevant parts. This ability then transfers to judging sizes in visual illusions where misleading context normally tricks perception. The findings challenge standard theories of expertise, which claim enhanced perceptual abilities remain confined to specific domains. The researchers suggest that both knowledge-based skills and perceptual filtering abilities develop simultaneously through intensive training. Future research could explore whether other visual experts show similar advantages and whether different specialties within radiology affect visual perception differently.
Funding and Disclosures
The researchers reported no competing interests. They acknowledged Maha Sweetha Shanmugam and Tom Mcmutry for helping with data collection. The study received ethical approval from Lancaster University. No specific funding sources were mentioned. The article is published with open access, making the findings freely available for future research.
Publication Information
The study, “Specific visual expertise reduces susceptibility to visual illusions,” was published in Scientific Reports (volume 15, article 5948) in 2025. The authors include Radoslaw Wincza, Calum Hartley, Tim Donovan, Sally Linkenauger, Trevor Crawford, Debra Griffiths, and Martin Doherty from Lancaster University, University of Central Lancashire, Cumbria University, and the University of East Anglia. The paper was received on September 12, 2024, accepted on January 24, 2025, and published on March 13, 2025.