A Palaeolithic human fashioned a stone sculpture of a mammoth or bison 15,000 years ago in a corner of France.
Duncan Caldwell, its discoverer, believes this is the earliest optical illusion because of its resemblance to the rabbit-duck illusion, a drawing published in 1892 that is considered a pioneer in the study of visual illusions.
Despite its curiosity, optical illusions assist explain perception and cognition today.
MIT researchers claim to have uncovered the answer. One background seen as lighter was really darker in the researchers' modified simultaneous brightness contrast. Our judgment of their brightness would make the opposing figure darker than the second, although the contrary is true.
The study's director, computational neuroscientist said, “this result runs counter to the idea that high-level analysis of lighting conditions contributes to brightness estimation.”
Monkeys, other animals, fish, reptiles, and birds have been demonstrated to comprehend various optical illusions, suggesting that they do not require a complex human brain. It's astonishing that insects, with their diverse eyes and minds, have it too.
In 2017, vision scientist Adrian Dyer from RMIT University in Australia found that bees are susceptible to the Ebbinghaus illusion, where two equal figures appear different sizes based on their surroundings.
However, much remains unknown about our illusionary vision. According to psychologist Elena Nava of the University of Milano-Bicocca in Italy, children are less deceived by the Ebbinghaus illusion “because they are more accurate at discriminating size when the context is misleading.
Nava and computer scientist Ana Tajadura-Jiménez from the University Carlos III of Madrid study complex body illusions like the auditory Pinocchio illusion,
which makes us think a finger grows longer when we pull on it while listening to a pitch-rising sound. Once again, the two experts found that children are less sensitive.