Perception

Gestalt Tendency to make meaningful wholesTendency to make meaningful wholes “Whole is more than sum of parts”“Whole is more than sum of parts”

Figure-Ground We organize stimulus into figure seen against a backgroundWe organize stimulus into figure seen against a background Ambiguity shifts perceptionAmbiguity shifts perception

Gestalt Rules for Grouping Stimuli We perceive these as two continuous lines, AD and CB, rather than AB or CD 1) Proximity 2) Similarity 3) Continuity

Gestalt Rules for Grouping 3) Closure 5) Connectedness 6) Common fate (objects that move together in same direction, speed) mon-fate.php /time-example-common-fate/

Continuity

Binocular Depth Cues Retinal DisparityRetinal Disparity Convergence

Monocular Depth Cues – See textbook p.155 Relative height (in visual field)Relative height (in visual field) Relative sizeRelative size Linear perspectiveLinear perspective InterpositionInterposition ShadowingShadowing Relative motionRelative motion Texture gradientTexture gradient

Motion Perception Stroboscopic motion – presenting still images in rapid succession = motionStroboscopic motion – presenting still images in rapid succession = motion EX: Old cartoon animations, flip-booksEX: Old cartoon animations, flip-books

Motion Perception Phi PhenomenonPhi Phenomenon

Perceptual Constancy Aspects of object stay the same despite changes in contextAspects of object stay the same despite changes in context –Shape –Size –Brightness –Color

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Perceptual Interpretation Perceptual adaptation – we adjust to our perceptionsPerceptual adaptation – we adjust to our perceptions –In vision, we are able to adjust to an artificially displaced or inverted visual field

Perceptual Set Mental predisposition to perceive one thing & not anotherMental predisposition to perceive one thing & not another

Perceptual Set

Perceptual Set & Top-Down Processing

Perceptual Interpretation Context effectsContext effects Given stimulus may trigger different perceptions based on the context –Difference between “dye” or “die”, “pain” or “payne”, based on sentence/context –“eel is on the wagon” vs. –“eel is on the orange”

Perceptual Interpretation Motivation & emotionMotivation & emotion –Involves top-down processing –Ex: Walking destinations seem farther away when tired –Ex: Professional referees, when told a soccer team has history of aggression, will assign more penalty cards

McGurk Effect How we integrate visual speech into what we perceive to hearHow we integrate visual speech into what we perceive to hear Works with all language backgrounds, all agesWorks with all language backgrounds, all ages

Café Wall Illusion

Size Illusion – Ames Room

Muller-Lyer Illusion

Size Illusion – Context Effects on Perception