What is perception? Perception is the conclusions made from sense perception and one's own judgment. Judgment is crucial to perception, and is what separates it from sight, hearing, touch, and the other senses. Because perception includes one's own judgment, one could visually perceive more or less than is actually seen (Britannica student Encyclopedia).
The principles of perceptual organization is organizing raw sensory stimuli into meaningful experiences involves cognition, a set of mental activities that includes thinking, knowing, and remembering. Knowledge and experience are extremely important for perception, because they help us make sense of the input to our sensory systems. You could probably read the text, but not as easily as when you read letters in their usual orientation. Knowledge and experience allowed you to understand the text. You could read the words because of your knowledge of letter shapes, and maybe you even have some prior experience in reading text upside down.
Without having knowledge of letter shapes, you would perceive the text as meaningless shapes. We see perceptual constancy as we view an object, the image it projects on the retinas of our eyes changes with our viewing distance and angle, the level of ambient light, the orientation of the object, and other factors. Perceptual constancy allows us to perceive an object as roughly the same in spite of changes in the retinal image. Psychologists have identified a number of perceptual constancies, including lightness constancy, color constancy, shape constancy, and size (Critical thinking Across the Curriculum Project).
ÃÂÃ ÃÂÃ ÃÂÃ ÃÂÃ ÃÂÃ ÃÂÃ ÃÂÃ ÃÂÃ Lightness constancy means that our perception of constancy. An object's lightness or darkness remains constant despite changes in illumination. To better understand lightness constancy, I tried the following demonstration using an exercise I read. First, I took a plain white sheet of paper into a brightly lit room and noted that...