Identification

involves organization, rules, recognition in the nervous system

Contour

abrupt change in luminance

Picked up by both rods and cones; goes to magnocellular and parvocellular in LGN → blobs in V1 → interstripes in V2 → form is processed in V3

Brain looks at environment and tries to make enclosed areas; it finishes incomplete or obstructed objects

a visual field with no contours; eventually you will feel like you are completely blind, because receptors are not getting information about contours

everything is pure white, and eventually your vision will go completely black

no matter where your eye moves, the same image lies on the same part of your retina

eyes are constantly quivering so that even if you are staring at the same image, it strikes different receptors

Temporal factors

⅕ of a second to register contour; if an object and a mask are shown within 100 milliseconds of each other, the observer will see both as one object

integrated unit we perceive as a thing

The Rubin face/vase thing; you can’t see both simultaneously

always seems to be in front of the background; background contains unformed material, this has higher spatial frequency

these kinds of objects are seen as figures

curving out or bulging outward

looks more like figure

if things are small, they are the figures

things that are vertical or horizontal are figures

farther apart, two objects are seen

shades help determine form

makes forms more noticeable; more likely to appear three-dimensional

cannot tell figure from ground

whole > sum of parts

Common fate: we all group elements the same way

objects that are close together are grouped together

objects that look alike are grouped together

areas that are enclosed by lines are seen as a thing

our brain continues lines and fill in spaces, and we group things wherever we can extend lines

the brain tries to make things as simple as possible; stable, consistent, and simple

The brain reduces ambiguity and increases simplicity

objects do not change size, even when the retinal image does (when things get closer and farther away)

objects remain constant shape, even when

measured in degrees, minutes, and seconds

things do not change color, even if ambient light changes

Hue

Reflectance of pigment (brain only pays attention to this)

Wavelength of illumination (brain ignores this)

things do not change brightness, even if less light is being reflected

how bright the ambient light is; our brain does not pay attention to this

amount of light being reflected off the object; brain only judges brightness based on this

a stationary object is staying in the same position even if the viewer is moving

egocentric direction doesn’t change; stationary objects change direction when the viewer moves

mathematical formula that allows the brain to tell how far away you are based on the retinal image

cross-eyed, straight ahead; brain knows which one, so it can judge how far away

the brain makes decisions about size based on images surrounding it

a perception that has no base in reality

based on size constancy; we perceive that the horizon is much farther away than overhead

Apparent distance: not reality, but how far away something appears to be

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faulty judgement of apparent distance

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brain makes things that are far away bigger

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bottom-up-- your attention is not contingent upon knowledge of the object; the outside stimulus is sufficient on its own

top-down; ex. Abstract image, shown image of a cow, and the abstract looks like a cow; reading

test hypothesis by searching for features

retina records the image and brain compares it to models we have for different objects

Image stage: rods and cones record the image; divides image into lines, movement, color, etc.

Feature stage: in V1; simple, complex, hypercomplex; 

Cognitive stage: what is it? V1 → V2 → inferotemporal cortex

Decision stage: decide what exactly the object is