Why do visual illusions occur
People see things with the help of the eyes. But, there are cases when our very own eyes tend to deceive us, thus the popular phrase seeing is deceivingÃ¢â‚¬Â which occurs in a phenomena called visual illusion, or commonly known as optical illusion.
Visual illusion can be described as the misinterpretation of objects in its original form that are perceived in a different way through the sense of sight. There are three major kinds of visual illusion: the actual visual illusion that produces pictures which are different from the original objects that constitute them, the physiological visual illusion that affects the perception of the eyes and processing of the brain due to the absorption of extreme stimulations, and cognitive visual illusion wherein both the brain and the eye creates unconscious assumption because of a learned set of patterns, or familiarity of objects.
There are also three main factors that causes visual illusion and it primarily begins with the way the eyes perceive an object or its surroundings. The human eye is packed with two kinds of nerve cells, the rods and cones. The rod cells are responsible for detecting light changes whereas the cone cells are responsible in detecting color. Together, they change the light into neural signals which are then carried over to the brain that interprets it. However, the rods and cone cells are not equally distributed within the human eye. On the circumference of the retina, there are more rods than cone cells while its center only has cone cells. Because of this, the sight of things from the corner of the eyes is proven to be misleading, also known as the blind spotÃ¢â‚¬Â.
Having said these, the light that helps eyes to see things also played a major role in creating visual illusion. When the eyes are bombarded with different stimulus (that includes color, brightness, movement, pattern, tilt, and the likes), it affects the way the eyes perceive things.
And, the last factor relies on the way the brain interprets the received visual information that is based on its past experiences which contradicts with the reality of the object seen, thus creating visual illusion.