It is widely believed, and accepted by practitioners, that when an image appears in an external environment, its appearance is altered by other elements, including the environment itself. As I described previously, when you change an image’s shape, you change its relative position in space. Similarly, when you switch an image’s direction, you control where (or how much) in space it appears within.
What’s really unusual about illusions is that they alter how we see (i.e. how we evaluate) what we view. In psychology, this is referred to as “illusionification.”
If you were to imagine that you could turn a piece of paper upside down without moving it, you might perceive that the paper was rotated (e.g. by shifting the orientation of the top half of the page). This is often called a “mirrored illusion.” You are more likely to perceive a reversed image if you consider the image’s position relative to you, rather than to its appearance on the page’s surface.
How do the visual illusions of the visual mind and the eye influence reality?
The perception of a visual or auditory stimulus is based on the way our brains interpret the signal arriving from our eyes or ears. When we hear the sound of thunder, our brain interprets it in a certain way based on how the brain’s internal auditory representation of the stimulus fits into the brain’s internal model of sound. When the auditory signals from our eyes arrive, our brains interpret them “back into reality”, which is based on how our brains are internally wired to act.
This is why a sound that strikes you, and which is perceived for about half a second, doesn’t seem to have any effect. We aren’t really consciously aware that we are hearing two sounds simultaneously, and our brains have no way of integrating them into one image. In order to do so, our brain relies on an illusion in our brain’s internal model of sound.
Why does this apply to people, not just animals?
I have a very personal reason for getting into the illusion-making business: my own eye sight. For years, I experienced very poor vision from an undiagnosed optic nerve degeneration, called optic neuropathy, that rendered part of my visual cortex permanently dark. Eventually, all that was left were these distorted images, which I thought were all part of a dreamy or psychedelic experience. It seemed like the world had been turned upside down, and I felt a great sense of liberation.