Perceptual Processes: selecting, organizing, and interpreting information received by our senses. (McCornack, 78)

One of the central problems of vision is that the world we see is full of depth, but the retinal image is flat. Somehow, that missing dimension has to be reconstituted from the fragments of clues that the two-dimensional retinal image retains about the 3-D world from which it originated. (Stone, 114) The study of perception … has revealed many surprises in the form of processes of which we are unaware, though they can often be demonstrated … by  the phenomena of “illusions.” (OxfordMind, 707)

Perceptual Interpretation: the stage of perception in which we assign meaning to the information we have selected. For instance, Randy thinks a man running down the sidewalk hurries because he is late, but Shondra infers that the man is chasing someone. (McCornack, 81)

Perceptual Organization: the stage of perception in which we mentally structure selected sensory data into a coherent "pattern." (McCornack, 79)

Gestalt Theory: a holistic psychological approach that emphasizes the role of the organized ‘whole,’ as opposed to its parts, in mental processes such as perception. (Collin, 341) Gestalt psychologists identified several laws, or principles, that we tend to follow in grouping elements together to arrive at the perception of forms, shapes, and figures. (Hockenbury, 110) Also referred to as ‘Gestalt principals of organization.’

Figure-Ground Relationship: the figure is more memorable than the ground. The figure is seen as being in front of the ground. (Goldstein, 108) We automatically separate the elements of a perception into the feature that clearly stands out (referred to as the ‘figure’), and its less distinct background (referred to as ‘the ground’). (Hockenbury, 106) (Because of this phenomena), the same outline can be perceived as different alternative figures, with very different shapes. (OxfordMind, 373)

Law of Closure: states that our brains have the tendency to fill in gaps when objects are grouped together so that the grouping can be seen as a whole. (Kleinman, 83) To perceive an incomplete pattern or object as complete or whole. (MeSH) The brain’s capacity for dealing with inexplicable gaps in the visual image. 'Filling-in' occurs at several different stages of the visual process. Example – in seeing a rabbit behind a picket fence, the rabbit appears as a single rabbit instead of a series of rabbit slices. (Ramachandran, 88) Filling-in seems to occur at different speeds for different perceptual attributes like color, motion (twinkle) and texture. Motion takes longer to fill-in than color, and so on. (Ramachandran, 102-103) Also referred to as 'filling-in.' Editor's note - Dr. Ramachandran distinguishes between ‘conceptual filling in’ and ‘perceptual filling in.’

Law of Good Continuation: we perceive (we are more likely to recognize) the organization that interrupts the fewest lines. (OxfordMind, 373) Points, that when connected, result in straight or smoothly curving lines are seen as belonging together. (Goldstein, 106) The tendency to group elements that appear to follow in the same direction as a single unit or figures. (Hockenbury, 110)

Law of Proximity: states that when objects are near one another, people have the tendency to group them together. (Kleinman, 82) Things that are near each other appear to be grouped together. (Goldstein, 106) The tendency to perceive objects that are close to one another as a single unit. (Hockenbury, 110)

Law of Similarity: people tend to group together items that are similar. (Kleinman, 81) Tendency to perceive objects of a similar size, shape, or color as a unit or figure. (Hockenbury, 110)

Law of Simplicity: the central law of Gestalt psychology. (Goldstein, 105) We view objects in their simplest possible form. (Kleinman, 81) States that when several perceptual organizations of an assortment of visual elements are possible, the perceptual interpretation that occurs will be the one that produces the ‘best, simplest, and most stable shape.’ The implication is that our perceptual system works in an economical way to promote the interpretation of stable and consistent forms. The ability to efficiently organize elements into stable objects helps us perceive the world accurately. (Hockenbury, 110) Also referred to as the ‘law of Pragnanz’ and 'law of good figure.'

Perceptual Grouping: the process of actively organizing the elements to try to produce the stable perception of well-defined whole objects. This is what perceptual psychologists refer to as ‘the urge to organize.’ (Hockenbury, 110)

Shape Constancy: the tendency to perceive familiar objects as having a fixed shape regardless of the image they cast on our retinas. (Hockenbury, 115)

Size Constancy: the perception that an object remains the same size despite its changing image on the retina. (Hockenbury, 115)

Perceptual Selection: the stage of perception in which we focus our attention on specific sensory data, such as sights, sounds, tastes, touches, or smells. (McCornack, 78)

Perceptual Processing Time: the window of time required to process sensory data before it’s perceived. Allows the brain to create a ‘seamless world of now.’ Research indicates that these backward projections can be as long as 120 milliseconds. When a baseball player is hitting a fastball, it has been proven that the player has to start his swing before he can actually pick up the path of the ball. Yet players feel absolutely sure that they saw the ball, even though it is physiologically impossible. (In a conversation) we are usually anticipating what people are going to say before they say it. Since we tend to hear what we expect, we also fill in little gaps an ignore repeated words. (CampbellVA, 188)