Seeing is more than just translating optical signals into nerve impulses. The brain analyzes the information, organizes it piece by piece and understands it.
The visual system
Ultimately, the perception of the present is an individual experience that is influenced by many different factors. Sight is certainly our most important sensory perception. We receive around 80 percent of the information about the environment through our eyes. A flood of information about the environment continually flows into the various interconnected parts of the central nervous system, all of which are involved in vision, whenever the eyelids are open. This allows us to recognize shapes, contours, differences in brightness, movements, objects and people.
But what is more astonishing is how the visual system creates connections. The visual data is repeatedly converted, filtered, analyzed, re-sorted and evaluated. This goes far beyond mere sensory impressions. Only when this visual information is linked to existing knowledge what is seen becomes meaningful.
Learning plays a big role in this because we can only perceive many things because we know them and have a certain amount of prior knowledge. For example, “back-translating” a two-dimensional image into three dimensions: Theoretically, various three-dimensional objects can be hidden behind the two-dimensional image of an object. The brain often chooses the simplest or most familiar interpretation. In addition to experience, it also takes into account facts such as the incidence of light and shadows.