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A mechanical process resulting in the stimulation of the senses and the transmission of sensory information to the brain or spinal cord is called!

A.  perception. !B.  sensation. !C.  absolute threshold. !D.  dark adaptation.!

SOME KEY TERMS:!•  Sensation!•  Perception!•  Absolute threshold!•  Just noticeable

difference!•  Difference Threshold!•  Weber’s Constant!•  Fechner’s Law!•  Signal Detection

Theory!

•  Physics of waves: pitch, hue, etc. !

•  Sensory adaptation!– Sensitization!– Desensitization!

•  Afterimage (p. 169)!•  Primary colors: cannot be

created by mixing other colors (Red, Blue, Yellow)!

More Terms!•  Colors, as LIGHT =

ROYGBIV!•  Additive vs.

Subtractive!•  Top down

Processing!•  Bottom up

Processing!•  Phi phenomenon!

•  Monocular!•  Binocular !•  All the cues on p.

180!•  Hearing, Taste,

Smell !•  6th & 7th

sensations???!

After being in a dark room for a while, you can see much better than you could when you walked in. This is known as!A.  desensitization. !B.  sensitization. !C.  virtual stabilization. !D.  motion imaging.!

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There really isn�t an ABSOLUTE threshold, or vision would go from 0% to 100%"as shown by the black line. Rather, it is the level at which �there is a 50%

probability of detection�.!

Just Noticeable Difference and Weber�s Constant!

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Signal Detection Theory. Which one is best if a weak signal is present or absent?! The Mind wants the world to

make sense!

• Vision:!– Light!– Color!– Perception!

Light VS Color!

ADDITIVE! SUBTRACTIVE!

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Theories!•  Trichromatic: 3 types of cones!

– Red!– Blue!– Green!

•  Opponent Process: 3 types of cones!– Red/Green !– Blue/Yellow!– Light intensity!

PROBLEMS:!• Color blindness helps prove the �Opponent Process Theory� (really dichromats):!– Red/Green (weak in both or 1)!– Blue/Yellow (weak in both or 1)!

• Weak GR is most common!• Weak RD is 2nd!• Weak BL is RARE!

URL!

3 values of Light •  Wavelength and hue (color) •  Frequency and saturation (purity) •  Amplitude and brightness

–  Amplitude is measured in candelas per meter square (cd/m2)

The word HUE above is VIOLET,! I then increased its saturation, !And its brightness!

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Light •  Speed of light - 186,000 miles/sec •  Light tends to travel in straight lines •  Light is very abundant

–  Interacts w/ surface molecules of objects - reflects & absorbing

Two parts of the eye function to bend light into a more narrow focus. They are…! ! !!

A.  retina and lens!B.  foveae and retina!C.  cornea and lens!D.  cones and rods!

The opponent-process theory of color vision is based on the idea that the retina contains!A.  three types of simple receptors sensitive to red,

green, and blue.!B.  two types of receptors, one sensitive to color

and one to differences in brightness. !C.  three sets of cells responsive to brightness.!D.  three types of receptors responsive to

contrasting colors.!

Physical Structures!Jim sees only in white and black. After careful examination of his retina, the ophthalmologist concludes that Jim's _______________ have degenerated. ! !!A.  bipolar cells !B.  cones !C.  rods !!D.  ganglion cells!

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Internal Structure of the Eye

•  Lens - final bending of light –  Accommodation- allows focus

•  Cataract –  Reduced transparency

–  Ciliary muscles

Other stuff in the Eye

•  Aqueous humor- fluid behind cornea in front of lens –  Functions similar to blood

•  Glaucoma- gunky aqueous humor

–  Vitreous humor - behind lens •  floaters

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Retina!

Optic Nerve to!

Optic Chiasma to!

Thalamus!

Lateral Geniculate Nucleus and ! Superior Colliculus "

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Visual Cortex of the occipital lobe! !

FROM THE EYE TO THE BRAIN!

What it is?! Where it is?!

Lateral Geniculate Nucleus-LGN

•  80% come here •  Part of thalamus •  X cells and Y cells •  Shape perception •  Foveal Field information •  Color perception

Organization of Sensations!•  From the Primary Visual Cortex (feature

detectors) p 144 !•  To the Secondary Visual Cortex (p. 139)!•  Then on two separate paths:!

– Magnocellular (�where�)!– Parvocellular (�what�, esp. face recognition)!

•  On to the parietal/temporal and then the frontal lobes!

The Visual Pathway

•  Something on the left hand side is in the left visual field but processed by the right hand side of the retina, and is then processed in the right side of the brain

RED, BLACK, BLUE, GREEN, ORANGE, YELLOW, PINK, SILVER, RED, BLUE, YELLOW, ORANGE, PURPLE, GREEN, BLUE, PINK, BLUE!

The STROOP EFFECT "Say the color of the words:! The STROOP EFFECT"

Again--the color!VIRIDIS FULVUS CROCEUS!RUBER FUCUS PUNICEUS !CAERULEUS VIRIDUS FRIX!FLAVUS SPADIX DORIZ!!

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1. Bottom-up processing!

Which do you like more?!Women or saxophone players?!

2. GESTALT or Top-Down Organization!

SIX types of top-down processing!•  Foreground/Background!•  Closure !•  Proximity!•  Similarity!•  Continuity !•  Simplicity!

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1. Which is the background! Now?!

NOW?!2 . CLOSURE: The brain completes the missing parts!

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The perceptual tendency to separate objects from the surroundings is called!A.  figure-ground perception. !B.  closure. !C.  Gestalt rules of perception. !D.  trichromatic theory.!

3 Proximity: Nearness equals relationship!

•  4. Similarity: things are perceived in CONTEXT!

5. Continuity: things that appear continuous must be. (horizon broken by mountains)!

Continuity--Continued! 6. Simplicity!

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But how do we get from"""""""

to !

The Gestalt rule describing the perceptual tendency to see objects that are near each other as belonging to a set is termed!

A.  proximity. !B.  closure. !C.  continuity. !D.  similarity.!

DEPTH PERCEPTION!

•  Binocular cues!–  Convergence!–  Retinal disparity!

•  Monocular Cues!–  Motion Parallax!

–  Interposition!– Texture gradient!– Relative size!– Height in plane!– Light and shadow!– Linear perspective!

shading!

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If you are putting a puzzle together while looking at a picture of the completed project, this would illustrate _______________.!

A.  bottom-up processing !B.  top-down processing !C.  rule of continuity !D.  law of closure!

Which orange color is purer?!

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Brightness constancy!

Which Green squares are darker?!

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So:"!•  Is what you THINK you see what is actually

there?!•  Do you see the same things I see?!•  Why are you so absolutely sure you are

right when 3 other people saw something different?!

•  Are you going to stop arguing with others about what happened now that yo know this is true?!

The tendency to perceive an object as being just as bright in varying amounts of light is called!A.  an illusion. !B.  a monocular cue. !C.  brightness constancy. !!D.  color constancy.!

ILLUSIONS!

•  Müller-Lyer Illusion: !

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What�s wrong with this picture? What else?!

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Oh!! I see!

HOW MANY CUBES?!

STILL??! JUST A MATTER OF PERSPECTIVE!

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From this!And this!

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To this "M.C."

Escher!