Optical illusions: Tracing their origin and evolution
You may have come across many optical illusions while surfing the internet! They are both puzzling and entertaining. The beauty of an optical illusion lies in the fact that it might appear a certain way when you look at it for the first time or from a specific angle. However, the minute you start paying more attention to it or you change your viewing angle, its appearance changes entirely! Also known as visual illusions, they deceive the observer. You might be aware of the famous rabbit/duck illusion, where you see a duck head and a rabbit head in the same picture. Are you curious about the history and origin of optical illusions? Read on!
The earliest optical illusion was from ancient Greece
The origin of optical illusion is highly debated. However, experts mostly agree that the origin of optical illusion can be traced back to the art and architecture of ancient Greece. One of the earliest applications of optical illusion was found on Greek temple rooftops. The roofs were slanted but appeared curved to anyone viewing them from below the roof. This illusion baffled many Greek philosophers too! Soon, people became fascinated with decoding such illusions. During the 5th century BC, a Greek philosopher named Epicharmus tried to explain optical illusions. According to his theory, the brains were not at fault and could perceive the image clearly. It was our senses that betrayed us while viewing optical illusions. Protagoras, another Greek philosopher, had a different theory altogether. He postulated that our eyes had nothing to do with how we perceived optical illusions. The illusions were dependent on the environment in which they were viewed.
First known description of illusion by Aristotle
Amongst many philosophers, Aristotle (384–322 BC) too shared the descriptions of perceptual illusions and documented them in his book Parva Naturalia (short treatises on nature). His observations include illusions such as pareidolia (people seeing faces in meaningless visual patterns), afterimages (a visual image that outlives the exposure) and motion aftereffects (waterfall illusion). He also explained what we now know as the ‘Aristotle illusion.’ In this illusion, if you touch a small, round object such as a marble between the two fingertips, it feels like you are touching two different objects!
Centuries old optical illusions created in India
Now, apart from the Greeks, did you know that an optical illusion was also created 850 years ago here in India? We are talking about the ones in The Airavatesvara Temple. Located in Darasuram, Tamil Nadu, the historical temple is rich with architectural brilliance and heritage. It has captured the attention of vision scientists and historians alike for its sculptures with optical illusions. A sculpture in the temple contains one of the oldest examples of illusion in art! The creature depicted in the sculpture can be seen as a bull by some and an elephant by others! The city of Mahabalipuram houses another illusion, possibly built around 1300 years ago on a pillar. When you look at it for the first time, the sculpture appears to be of a cow and her calf. When you block the centre of the carving, it appears to be an adult and a baby elephant.