Optical illusions captivate a wide audience who find great pleasure in them, as do scientists who are trying to explain how the brain works when faced with visual stimuli. A recent study, published in the journal Scientific Reports, explores the ability of humans to overcome these illusions without succumbing to them. The results show that this is entirely possible, but under certain conditions.
Humans are prone to optical illusions because the brain analyzes images and visual scenes based on specific contexts. The eye does not perceive objects in isolation; rather, the brain focuses on all the elements of an image. A typical example is the "Ebbinghaus illusion," named after the German psychologist Hermann Ebbinghaus.
The Ebbinghaus Illusion
When observing this illusion, we see two groups of gray circles, each surrounding a central orange circle. At first glance, these orange circles do not appear to be the same size, although they are actually identical. This is explained by the influence of the surrounding gray circles, which alter the perception of the image. This is because the brain analyzes objects in their overall context and not in isolation.
The perception of optical illusions varies from person to person depending on several factors. Studies show that women are more susceptible to these illusions than men, likely because they rely more on contextual and narrative cues. Similarly, young children do not perceive these illusions because their brains have not yet learned to interpret contextual cues.
Neurological and cultural factors also play an important role. People with autism or schizophrenia are less prone to optical illusions because they focus more on individual elements rather than their surroundings.
Culturally, individuals from East Asian cultures, such as Japan, are more prone to optical illusions because their perception tends to be more global. In contrast, people from Western cultures, which favor a more analytical and isolated perception of objects, such as those in the United Kingdom, are less prone to them, according to the study's findings.
Can optical illusions be overcome with training?
Many researchers assume that the tendency to be influenced by optical illusions is innate and uncontrollable. However, the recent study contradicts this assumption by suggesting that training can reduce the brain's reliance on deceptive visual cues.
The study compared two groups: one of radiologists and the other of young medical and psychology students. The results showed that radiologists were significantly less susceptible to optical illusions. This difference is likely explained by their years of intensive training, which allows them to focus on critical details of medical examinations while ignoring distracting elements in the background.
Participants were exposed to different variations of the Ebbinghaus illusion. In one experiment, the orange circle on the left was slightly smaller than the one on the right, but most participants had the opposite impression. However, the radiologists were better at identifying the actual sizes, suggesting that their visual training allowed them to overcome the illusion. Interestingly, radiologists in the early stages of training did not show this ability, indicating that the ability to overcome these illusions develops with time and experience.
Is learning possible?
The study suggests that this ability to learn and improve is not limited to a specific field. For example, mastering chess does not necessarily strengthen problem-solving skills in other disciplines. However, training in a specific field, such as radiology, can improve general perceptual abilities, including resistance to optical illusions.
This discovery opens new perspectives in several professions requiring precise visual perception. Researchers are wondering if similar training could be designed for pilots, surgeons, and police investigators. If so, developing specialized programs to strengthen visual perception could improve performance in these critical areas.
Additionally, scientists are currently exploring whether training in optical illusions themselves could sharpen perceptual skills, in the same way that physical exercise strengthens muscles. They emphasize that this would require methodical and intensive training. However, the findings could be beneficial in helping individuals better process misleading visual information and improve their perception, whether in everyday life or in professional environments.
