Sensation and Perception Flashcards
Idealism-
minds make reality. We are constantly experiencing delusion–optical illusion example
Sensation
Sensation is process by which important changes in state of world create changes in state of brain
Perception
Perception is process by which changes in state of brain give rise to conscious experience of world
Sensation vs perception in the ex: blindsight
Usually they come as one. Sometimes they’re separate (ex: blindsight, condition that blind, but aware of visual field;
“All they see is darkness” but can guess correctly whether horizontal or vertical, can avoid objects–they have sensation but not perception
Brain injury that blocked perception but the motor systems can access sensation
So ppl with blindsight–info gets to visual cortex but doesnt get to frontal cortex–no chance to get to frontal cortex and be processed
Five senses–
Olfaction Vision Audition Touch Taste
vision process
Occipital lobe (vision in the back) takes 30-40% of cortex/way more than other senses
Info flow in brain (vision)
Light flows thru eye→ thalamus–(all sensory info goes there) then → occipital lobe/visual cortex (far away as possible from eyes) → what/where pathways→ frontal cortex (conscious experience of info)
retinotopic maps
Scientists discover brain organizes visual info in a way that preserves how that info is organized in world (looking at expanding circle vs moving in circle processed that way)
“retinotopic maps”–visual processing corresponds to reality
neurons LOOK LIKE what we visually process
CLOCKWISE IMAGE=CLOCKWISE NEURONS
LINEAR IMAGE=LINEAR NEURONS
Jack gallant
developed machine learning technique–u can use fmri to look at blood flow thru visual cortex and while person is watching video computer will create image of what it thinks person is looking at
Relatively good job
What and where pathways
Info processed in two diff pathways
Info travels from visual cortex back thru two ways
What pathway
identifying objects and what they are (thru temporal lobe lobe → frontal lobe)
Damage–visual agnosia (can’t identify an object)
Can describe rose but cant figure out that it is rose
Can work out what to do with object
Where pathway
identifying them in space (thru parietal lobe → frontal lobe)
Sensation as change detection and Weber’s law
What changes are our brains looking for
Contrast
Change over time (motion)
Senses detect relative (not absolute) change (weber’s law)
5 pounds in humans seem less important than 4 pounds in dog
color constancy/contrast
Change blindness
Perception process
Reality → Sensory apparatus→ computation → experience
Mcgurk effect–
eyes helping ears interpret what we’re hearing/also like lip reading
perception fill ins–Expectancy effect
Blind spot
sound/phonemic restoration
ames room
depth, color constancy
If apple, whether or not we see apple or something else, theyre both illusions
Where do we get expectations?? (ex: M-I illusion)
Role of experience
Mueller-lyer illusion (which line is longer) doesn’t work on people who didnt grow up in industrialized societies
We learn!! (another example–ppl who grow up in rainforests cant interpret size=distance)
Hemispatial neglect
if damage only on one side of the brain to where pathway ppl ignore half of world (draw half clock, shave half beard…if damage to left side of brain ignore right side of world)
Amount also varies based on damage
Mueller-lyer illusion
(which line is longer)
Change blindness
the finding that observers often fail to notice large changes to objects or scenes when the change coincides with a brief visual disruption bc it’s so outside of ur expectations
phonemic restoration
brain fills in sound due to expectation
What we decide the noise is is based on context
blind spot
Eyes continuously scanning
retina cant receive info in the spot where it connects to optic nerve–but brain compensates so u dont notice
ames room
Effect when we see people at diff distances and interpret at diff sizes
depth/color constancy
snowball doesn’t change color in and outside/movement
Eyes and brain correct for change in light
contrast
u interpret smthn as diff colors when they’re the same bc of contrast–ex if it’s in shadow
Fixating vision color change
Brain shifts color perception to keep u from getting overwhelmed by color
Eyes continuously scanning so if u fixate on one color it counteracts
