Perception l The process of integrating organizing and

Perception l. The process of integrating, organizing, and interpreting sensation

l Perceptions Influenced by: ----motivation ----Values ----Expectations ----Experience ----Culture ----Cognitive Style ----Personality

Perception l. Selective Attention focus of conscious awareness on a particular stimulus

l. Visual Capture ltendency for vision to dominate the other senses

l. Grouping lthe perceptual tendency to organize stimuli into coherent groups

Gestalt Psychology l. We perceive whole objects, not isolated bits or pieces.

Gestalt l The “whole, ” or the organizational patterns that we tend to perceive l Gestalt psychologists stressed that the whole is greater than the sum of its parts. l By breaking experiences into their basic parts, something important is lost.

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A Gestalt

Figure- Ground relationship lorganization of the visual field into object (figures) that stand out from their surroundings (ground)

Figure-Ground l The perceptual tendency to organize stimuli into objects (the figures) that stand out from their surrounding (the ground) l The figure is the object (s) that stands out or draws one’s attention. l The ground is the background.

What is the figure, and what is the background here?

Grouping lthe perceptual tendency to organize stimuli into coherent groups l. Patterns, shapes, forms

Grouping l Several principles of grouping include: l Similarity l Proximity l Closure l Continuity

Grouping - Similarity l The tendency to place items that look similar into a group

Grouping - Proximity l The tendency to place objects that are physically close to each other in a group

Grouping – Closure l The tendency to look at the whole by filling in gaps in a perceptual field

Grouping – Continuity l The tendency to perceive that movement of an object continues once it appears to move in a particular direction

Depth Perception lability to see objects in three dimensions lallows us to judge distance

Module 10: Perception Depth Perception: Binocular Depth Cues

Binocular Cues l Depth cues that require the use of both eyes

Retinal Disparity l. A binocular depth cue resulting from slightly different images produced by the separation of the retinas in the left and right eye l Is most effective when the item is quite close to the person

Binocular Depth Cues: Finger Sausage

Convergence l. A binocular depth cue related to the tension in the eye muscles when the eyes track inward to focus on objects close to the viewer l The more tension in the eye muscle, the closer the object is l Works best at close distances

Module 10: Perception Depth Perception: Monocular Depth Cues

Monocular Cues l Depth cues that require the use of only one eye l Monocular depth cues include: relative size, relative motion, interposition, relative height, texture gradient, relative clarity, and linear perspective.

Monocular Cues lrelative size lsmaller image is more distant

Monocular Depth Cues – Relative Size l Using the perceived size of a familiar object to determine depth l The larger the object appears, the closer the object is to the viewer

Monocular Depth Cues – Relative Motion l. A person who is moving can determine depth by focusing on a distant object. l Objects further away than the object of focus will appear to move in the same direction as the subject is moving.

Monocular Depth Cues – Relative Motion l Objects closer than the object of focus will appear to move in the opposite direction.

Relative Motion

l. Interposition/ Overlap lcloser object blocks distant object

Interposition

Monocular Depth Cues – Relative Height l Method of determining depth by noting that distant objects appear higher in your field of vision than do closer objects

ltexture gradient l coarse --> close fine --> distant l(Look at the floor beneath you, and then across the room)

Monocular Depth Cues – Texture Gradient l Method of determining depth by noting that distant objects have a smoother texture than nearby objects

Monocular Depth Cues – Relative Clarity Method of determining depth by noting that distant objects are less clear than nearby objects l Tends to work outdoors l

Monocular Depth Cues–Linear Perspective Method of determining depth by noting that parallel lines appear to converge in the distance l The lines appears to eventually merge on the horizon. l

lrelative clarity/ Aerial Perspective lhazy object seen as more distant l(Look out window at the trees close to the window and the trees in the distance)

llinear perspective lparallel lines converge with distance

Motion l. Stroboscopic Motiontimed flashing lights that gives the illusion of movement

Perceptual Constancy l perceiving objects as unchanging despite changes in retinal image l. Color/ brightness lshape lsize

The door changes shape, but you know that it doesn’t really change

Muller- Lyer Illusion l Which area is longer?

How about these ?

Which monster and line segment is larger?