u05 Perception Slides

8/8/2019 u05 Perception Slides

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Perceptionm1617


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Perception

Perception

The process of organizing

and interpreting sensory

information.

Selective AttentionThe focusing of conscious

awareness on a particular

stimulus.


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Selective Attention


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McGurk Effect


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Perceptual Illusions

Franz Muller-Lyer Illusion.

Which segment is longer? AB or BC?

Text

AB is one-third longer than BC.


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Perceptual IllusionsSize-DistanceRelationship

Illusions help usunderstand perception.


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Size-Distance Relationship


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Are the horizontal lines parallel?


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Perceptual OrganizationVisual Capture

Tendency for vision to dominate the other senses.

Grouping

The perceptual tendency to organize stimuli into

coherent groups.

Gestalt

Tendency to integrate pieces of information into a

meaningful whole.


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Form Perception:Figure and Ground

The organization ofthe visual field intoobjects (the figure)

that stand out fromtheir surroundings (theground).


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Form Perception:Grouping


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Depth PerceptionDepth Perception

The ability to see objects in three dimensions.

Allows us to judge distances.

Sources of Depth Perception

Binocular Cues

Monocular Cues


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Depth Perception:Binocular Cues

Retinal Disparity

Images from two eyes differ.

The closer the object, thegreater the difference.

Eg MagicEye

Convergence

The extent to which the eyesconverge when looking at anobject.


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Depth Perception:Monocular Cues

Interposition - Closerobject blocks distantobject.

Relative Size - Smallerimage is more distant.

Relative Clarity- Hazyobject seen as more

distant.

Texture Gradient -Coarse = close and Fine =distant.

Relative HeightObjects higher in ourvision seem farther.

Relative Motion Thenearer an object, the fasterit moves.

Linear Perspective

Parallel lines seem toconverge at the horizon.

Light and ShadowFurther objects seem moredim.


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Motion PerceptionAs an object movesacross our field ofvision, it is detected byopposing visualcortices.

Phi Phenomenon marquees.

StroboscopicMovement 24 framesper second.


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Phi Phenomenon


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Perceptual ConstancyPerceiving objects asunchanging despite

changes in retinal image.

Color

Shape

Size


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Perceptual ConstancySize-Distance Relationship

Linear Perspective uses context cues to tell

distance based on relative size.


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Perceptual Constancy


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Perceptual Constancy

Lightness Constancy

Relative luminance: the

amount of light an object

reflects relative to its

surroundings.


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Perceptual InterpretationSensory Deprivation.

There is a critical period

for developing featuredetector cells.

If deprived of a stimuliover a long period oftime, the brain loses theoriginal ability to processthat stimuli.

Eg Blakemore and Cooper,1970.


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Perceptual Interpretation

Perceptual AdaptationThe visual ability toadjust to an artificiallydisplaced visual field.

E.g. Prism glasses.


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What doyou see onthe bottle?

You see whatyou want to

see


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Extrasensory PerceptionESP

The controversial claim thatperception can occur apartfrom sensory input.

A reproducible ESPphenomenon has never beendiscovered, nor has anyoneproduced any individual who

can convincinglydemonstrate psychic ability.

Telepathy

Mind-to-mind

communication.

Clairvoyance

Perceiving remote events.

Precognition

Perceiving future events.

Documents

u05 Perception Slides