Medical image experts demonstrated superior perceptual accuracy in response to visual illusions compared with a control group, according to recent research.
The finding offers new evidence of how expertise and training may impact mechanisms underpinning visual perception, noted lead author Radoslaw Wincza, PhD, a behavioral scientist at Lancaster University in the U.K., and colleagues.
“Overall, these data are the first to demonstrate that professional visual expertise may induce changes in visual perception that extend beyond a specific domain,” the group wrote. The study was published March 13 in Scientific Reports.
Only two previous studies have addressed the issue of whether enhancements in visual perception abilities of radiologists are a product of specialist professional training, with mixed results, the authors explained.
To explore the issue further, the researchers compared responses to visual illusions among 44 experts in medical image interpretation (reporting radiographers, trainee radiologists, and certified radiologists) and a control group consisting of 107 psychology and medical students. Participants were presented with the Ebbinghaus, Ponzo, Müller-Lyer, and Shepard Tabletops visual illusions via forced-choice tasks.
The Ebbinghaus illusion: The central circle surrounded by smaller outer circles is usually perceived as bigger. Image and caption available for republishing under Creative Commons license (CC BY 4.0 DEED, Attribution 4.0 International) and courtesy of Scientific Reports.
For the Ebbinghaus illusion, for instance, participants had to select the larger circle by pressing the corresponding key on the keyboard. They were instructed not to try to ‘see through the illusions’ and respond based on their first impression as quickly and accurately as they could. The difference between the two targets varied by 2%, 6%, 10%, 14%, and 18%.
Participants received a score of 1 for correctly identifying the longer/larger stimuli, while identifying the incorrect stimuli was scored 0. Thus, participants could score a maximum of 20 correct answers per illusion (excluding control trials), with higher scores indicating lower susceptibility.
Across groups, participants were more likely to respond accurately as differences between stimuli increased, yet experts were more likely to respond accurately across difficulty levels than nonexperts. Experts had mean scores of 0.49 versus 0.29 on the Ebbinghaus illusion and mean scores of 0.61 versus 0.46 on the Ponzo illusion, for instance.
In addition, further analysis showed that medical radiography students performed similarly to psychology students, which indicates that it is unlikely that these differences in visual illusion susceptibility are due to preexisting visual abilities, the researchers noted.
“These findings present evidence that expertise in perceiving specific kinds of visual stimuli may afford domain-general benefits to visual perception,” the group wrote.
Ultimately, the results diverge from previous literature and existing models of perceptual expertise, which claimed that proficiency does not transfer beyond the specific domain of expertise, the researchers noted.
Future studies should include other groups considered experts in visual perception, such as chess players, as well as conduct comparisons between different sub-domains of radiology expertise, which could elucidate whether different sub-domains of expertise (e.g., chest imaging versus mammography) and their associated training differentially affect visual perception, they wrote.
“Our research advances theoretical understanding of how expertise and training impact fundamental mechanisms underpinning visual perception,” the researchers concluded.
The full study is available here.