Psychology 111- Chapter 4 Flashcards
sensation
happens first; interactions between sense organs and external stimuli, fairly objective (two people will have fairly similar sensations)
perception
second, brain’s interpretation and understanding of sensation, completely internally (in brain), much more subjective
Psychophysics
study of sensation and perception
just noticeable difference and Weber’s law
how much of a change in stimulus is required for you to notice a change (not a fixed response)
- weber’s law: JND is constant proportion of initial stimulus
absolute threshold
minimum amount of stimulus to say it exists
stimulus intensity
how strong a stimulus is
noise
other elements not associated with the stimulus
response criteria
how sure you have to be in order to say yes
hit
stimulus is present and you say stimulus is present
false alarm
no stimulus, but you respond like there is
correct rejection
no stimulus and respond like there is no stimulus
miss
there is a stimulus, but you respond like there isn’t
bottom-up processing theory
start with sensation and build understanding based on sensations (data driven processing of your experience)
top-down processing theory
expectations and assumptions guide your understanding, doesn’t require as many cognitive resources but leads you wrong more often-> less accurate, less resources
vision
strongest sense, used most often, can overrule other sensations
light vs. color
1) stimulus for sensation
2) interpretation of that sensation
light waves
larger- warmer colors, shorter-cooler colors, we only see a small section of light spectrum
amplitude
midpoint to highest point (how tall the wave is), tells us intensity/saturation of the wave (low amplitude- light, high amplitude- dark)
cornea
thin membrane that covers and protects the eye, protects from debris from pupil, allows light waves in
pupil
black part of eye, a hole
iris
color around pupil, muscle that changes the size of the pupil
lens
behind pupil, after light goes though pupil it goes to lens, helps focus light wave for the rest of light wave to process
accommodation
lens changes shape to do its focusing
retina
very back of the eye, image projected onto retina is upside down, where most of sensation occurs
fovea
strongest visual accuity (where you see the best), right behind the pupil
rods
operate in lower light- shades of grey and black, not a lot of fine detail
cones
fine detail, color vision, need a lot of light, most cones are in fovea
bipolar and ganglion cells
rods pool their info and send it to one of these types of cells, one cone sends info to one set of bipolar and ganglion cell
blindspot
where optic nerve leaves the eye, no rods/cones in this area (any light projected onto this area is not being sent to the brain)
blindspot
where optic nerve leaves the eye, no rods/cones in this area (any light projected onto this area is not being sent to the brain)
Sclera
whites of the eye, humans have a lot compared to other animals (probably because of social reasons- helps with communication)
trichromatic
3 types of cones (S-cone= short wave lengths, m-cone= medium wave lengths, H-cones= high wave lengths), can see 1 million different colors
tetrachromatic
4 types of cones, also have a cone that operates in yellow area, can perceive differences in colors between H and M cones, can see 100 million different colors
mantis shrimp
has 12 different types of cones, see much larger area of visual light
Herring’s Opponent Process
we have 3 cones, but the cones work in pairs of colors, when one is activated, the other is suppressed
colorblindness
one type of cone is not present or not very active, limited in amount of color you can see, can’t perceive as much of a difference, much more likely to happen in men than women
Stratton, 1896
wore glasses that flipped world upside down and backwards, wore for 8 days, by the end could successfully navigate his environment-> showed that our senses are good at adaptation
Visual pathway
retina-> optic nerve-> optic chiasm-> optic tract-> thalamus-> primary visual cortex