Optical illusions work by using color, light, patterns and other variables to form pictures that deceive the brain. The eyes collect information that the brain attempts to understand, and the misleading information produces a perception that’s different from the objective reality.
Perception refers to an individual’s understanding of what he sees through the sense of sight. People usually see deceptive visual effects in physiological optical illusions, which are illusions resulting from a physical method.
Cognitive illusions, also called mind games, are illusions that happen when the brain instantly makes a perception according to the information received from the eyes. Some cognitive illusions are ambiguous, which means the objects in the illusions can be interpreted in different ways. Distortion of cognitive illusions involves various techniques to present objects of the same size or length in a contorted picture. Paradox illusions refer to images and objects that cannot occur in reality.
Many illusions are created by the refraction of light, which passes through substances at considerably different speeds. Light bends as it travels through a transparent channel, such as air, to another medium, such as water. For example, a pencil placed in a container filled with water appears bent at the surface, and a log that’s partly immersed in the water looks like it’s deformed.