PerceptionPerception

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Inattentional BlindnessInattentional BlindnessChallenge:Challenge:

Count the number of passes the white shirts pass!Count the number of passes the white shirts pass!

Video (2mins) (2mins)

Type of Type of selective attentionselective attention

Failing to see visible objects when your attention is Failing to see visible objects when your attention is directed elsewheredirected elsewhere

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Change BlindnessChange Blindness• You fail to notice a difference in a stimulus (ex. You fail to notice a difference in a stimulus (ex.

the person) from just a moment agothe person) from just a moment ago

• Focusing on the task (relevant), not the person Focusing on the task (relevant), not the person (irrelevant)! (irrelevant)!

• British video (4 mins)

• Daniel Simons (4 mins)

© 1998 Psychonomic Society Inc. Image provided courtesy of Daniel J. Simmons.

Do you see what I see?Do you see what I see?

Constantly filtering info in

ways that make sense to us

Gestalt: German meaning “whole”

or “form”

When given a cluster of

sensations, we tend to

organize them using gestalt

Figure-ground relationship:Define the figure (focused object) from the ground (its surroundings)

Relationship is continuously reversible

The same stimulus can trigger more than one perception

Does this most closely resemble Does this most closely resemble 6 lines 6 lines or or 3 groups of 23 groups of 2??

Proximity: We group nearby figures togetherProximity: We group nearby figures together

Do you see vertical or horizontal Do you see vertical or horizontal lines?lines?

Similarity: group similar objects togetherSimilarity: group similar objects together

How do you draw an How do you draw an XX??

Continuity: perceive smooth, Continuity: perceive smooth, continuous patterns rather than continuous patterns rather than discontinuousdiscontinuous

How many?How many?

Connectedness: if uniformed and Connectedness: if uniformed and linked, we perceive each set of two linked, we perceive each set of two dots and lines as a single unitdots and lines as a single unit

This is a _______??This is a _______??Closure: we fill Closure: we fill in gaps to create in gaps to create a complete a complete whole objectwhole object

We assume the We assume the circles are circles are complete and complete and just blocked by just blocked by a trianglea triangle

BBinocular Cuesinocular Cuescues that depend on using cues that depend on using BOTHBOTH eyes eyes

Retinal disparityRetinal disparity

You see two angles of every objectYou see two angles of every object

ConvergenceConvergence

When objects get closer to your When objects get closer to your face, you cross your eyes to face, you cross your eyes to continue using your foveacontinue using your fovea

Monocular CuesMonocular CuesRelative sizeRelative size

InterpositionInterposition

Relative motionRelative motion

Texture gradientTexture gradient

Relative heightRelative height

Linear perspectiveLinear perspective

ShadowingShadowing

Depth cues that Depth cues that DO NOT DO NOT require both eyesrequire both eyes

Monocular CuesMonocular CuesWhich pencil is closer?Which pencil is closer?

Relative SizeRelative Size: if we assume two objects are the same size, : if we assume two objects are the same size, we perceive the smaller retinal image as farther awaywe perceive the smaller retinal image as farther away

Which letter is the closest?Which letter is the closest?

InterpositionInterposition: objects that block the view of : objects that block the view of other objects must be the closestother objects must be the closest

Relative MotionRelative Motion: :

distant objects seems to move distant objects seems to move with you while nearby objects with you while nearby objects go by rapidlygo by rapidly

Smaller objects appear to go Smaller objects appear to go faster than larger objects faster than larger objects moving at the same speedmoving at the same speed

Monocular CuesMonocular CuesTexture GradientTexture Gradient

Surface quality of an Surface quality of an object; we see less object; we see less texture on something texture on something that is farther away.that is farther away.

Relative HeightRelative Height

Distant objects Distant objects appear relatively appear relatively higher in your field of higher in your field of vision than close vision than close objects.objects.

Monocular CuesMonocular Cues

Linear PerspectiveLinear Perspective

Distance cue; parallel Distance cue; parallel lines converge, as they lines converge, as they move away from usmove away from us

ShadowingShadowing

Given two identical objects, Given two identical objects, the dimmer one will seem the dimmer one will seem farther awayfarther away

Gives clues about depthGives clues about depth

Gives clues about movementGives clues about movement

(1:01-2:50)(1:01-2:50)

Motion PerceptionMotion PerceptionStroboscopic effect Stroboscopic effect (flip book effect)(flip book effect)

FilmFilm is not motion! At 24 slides per second we perceive as motion is not motion! At 24 slides per second we perceive as motion

When the information is limited, the brain often makes assumptions When the information is limited, the brain often makes assumptions based on what it knows. In the case of spinning rims, the relative based on what it knows. In the case of spinning rims, the relative position of the individual spokes and the light source which makes position of the individual spokes and the light source which makes them visible can combine to create an optical illusion of backwards them visible can combine to create an optical illusion of backwards motion.motion.

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forza motorsport 5 (2:15)

Perceptual Perceptual IllusionsIllusions

Julian BeeverJulian Beever(3:00)(3:00)

Motion PerceptionMotion Perception

Phi Phenomenon: Phi Phenomenon: blinking lights make it look like blinking lights make it look like light is jumping from one point to another creating light is jumping from one point to another creating

the illusion of motion.the illusion of motion.

Lightness Constancy

Which is a darker shade

of gray?

A or B?

Perceived color depends on the amount of light an object reflects relative to its surroundings.

Perceptual InterpretationPerceptual Interpretation

When we are unfamiliar with the size of an object, monocular cues When we are unfamiliar with the size of an object, monocular cues (linear perspective) tricks us in perceiving the false size of the (linear perspective) tricks us in perceiving the false size of the

object.object.

The monster farther away is larger, right?The monster farther away is larger, right?

Perceptual InterpretationPerceptual Interpretation

The moon looks huge when it’s near the horizon, The moon looks huge when it’s near the horizon, but it’s actually always the same size!but it’s actually always the same size!

We have no perspective of how far away the We have no perspective of how far away the moon is in high sky since we donmoon is in high sky since we don’’t have a horizon t have a horizon to compare it to.to compare it to.

Moon Illusion

Perceptual InterpretationPerceptual Interpretation

Perception HighlightsPerception HighlightsStart at 8:00-15:00Start at 8:00-15:00

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