would not survive for long. In fact, many species of animals have evolved exquisite sensory and perceptual systems that aid their survival. PRINCIPLES OF PERCEPTUAL ORGANIZATION 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 knowledge of letter shapes, you would perceive the text as meaningless shapes, just as people who do not know Chinese or Japanese see the characters of those languages as meaningless shapes. Reading, then, is a form of visual perception. Note that in the example above, you did not stop to read every single letter carefully. Instead, you probably perceived whole words and phrases. You may have also used context to help you figure out what some of the words must be. For example, recognizing upside may have helped you predict down, because the two words often occur together. For these reasons, you probably overlooked problems with the individual letters—some of them, such as the n in down, are mirror images of normal letters. You would have noticed these errors immediately if the letters were right side up, because you have much more experience seeing letters in that orientation. How people perceive a well-organized pattern or whole, instead of many separate parts, is a topic of interest in Gestalt psychology. According to Gestalt psychologists, the whole is different than the sum of its parts. Gestalt is a German word-meaning configuration or pattern.GESTALT LAWS OF GROUPING The three founders of Gestalt psychology were German researchers Max Wertheimer, Kurt Koffka, and Wolfgang Köhler. These men identified a number of principles by which people organize isolated parts of a visual stimulus into groups or whole objects. There are five main laws of grouping: proximity, similarity, continuity, closure, and common fate. A sixth law, that of simplicity, encompasses all of these laws. Although most often applied to visual perception, the Gestalt laws also apply to perception in other senses. When we listen to music, for example, we do not hear a series of disconnected or random tones. We interpret the music as a whole, relating the sounds to each other based on how similar they are in pitch, how close together they are in time, and other factors. We can perceive melodies, patterns, and form in music. When a song is transposed to another key, we still recognize it, even though all of the notes have changed. 1) PROXIMITY The law of proximity states that the closer objects are to one another, the more likely we are to mentally group them together 2) SIMILARITY The law of similarity leads us to link together parts of the visual field that are similar in color, lightness, texture, shape, or any other quality 3) CONTINUITY The law of continuity leads us to see a line as continuing in a particular direction, rather than making an abrupt turn 4) CLOSURE According to the law of closure, we prefer complete forms to incomplete forms.This tendency allows us to perceive whole objects from incomplete and imperfect forms. 5)COMMON FATE The law of common fate leads us to group together objects that move in the same direction . 6) Simplicity Central to the approach of Gestalt psychologists is the law of prägnanz, or simplicity. This general notion, which encompasses all other Gestalt laws, states that people intuitively prefer the simplest, most stable of possible organizationsFIGURE & GROUND Not only does perception involve organization and grouping, it also

Some topics in this essay:
PERCEPTION Depth, CONSTANCY Color, Relative Height, James Gibson, INTRODUCTION Perception, Wolfgang Köhler, CONSTANCY Lightness, SIZE CLUES, POSITION Probably, Figure Ground, binocular disparity, retinal image, size constancy, depth perception, lightness constancy, depth cue, perceive object, motion perception, color constancy, monocular cues, constancy color constancy, single three-dimensional image, size objects experience, explanation motion perception, person moves front,