chapter 4 Flashcards
sensation
stimulation of sense organs
perception
interpretation of sensory input
psychophysics
how physical stimuli are translated into psychological experience (used to measure threshold)
gustav fechner
discovered the concept of threshold
absolute threshold
minimal amount of stimulus that can be detected 50% of the time
threshold
at what point do we detect stimulus
JND
smallest difference detectable between 2 stimuli
Websters Law
Size of JND is proportional to size of original stimulus ex: 30-31, 60-62 etc
signal detection theory
detection of sensory information is influenced by sensory processes and decision processes– hit, false alarm, miss, correct rejection
“hit”
stimulus present and subjects response is present
miss
stimulus present but subject response is absent
absent
stimulus is absent but subject believes it is present
correct rejection
stimulus is absent and subject believes it is absent
Perception without awareness
advertising** used to influence buyers without buyers noticing
subliminal perception
stimulus presented just beyond our threshold
sensory adaptation
stimulus is present and doesn’t change but our reaction has changed– decline in sensitivity, overtime we become less sensitive to the stimulus
synaesthesia
condition in which perceptual/cognitive activities trigger special experiences–senses overlap (ex see colour over math)
Graphemes
numbers and letters have colour
light
electromagnetic radiation
brightness of light
amplitude (height of light wave)
colour of light
wavelength, distance from one peak to the next, long-red, short-blue
purity
mixture of wavelength in the light
saturation
richness of colour, amount of whiteness in a colour impact saturation
pure vs not pure (aka saturation)
pure- one wave
not pure- a bunch of wavelength
retina
neural tissue at the back of our eye
cornea
where light waves begin to penetrate our eyes, transparent
anterior chamber,
filled with a fluid called aqueous humor, flows through canals, constantly being replaced, blockage in the canal leads to build up of pressure in the eye–> glaucoma, leads to blindness
lens
lens refract the light waves when it enters the eye, bending the light waves causes it to be flipped and backwards
little muscles relax: lens fattens, near
little muscles flex: lens becomes thin, far
vitreous humor
jelly like substance in the posterior chamber, developed as a fetus, leftover proteins are squiglys
pupil
gap, changes in size in order to control the amount of light that is let in
iris
coloured part of the eye, ring of muscle that control the contraction of pupil
fovea
dip at the back of the eye, crispest vision
saccade
tiny eye movements we are constantly making, constantly moving to fill the blind spot
nearsighted
myopia, less round, more football shape, focus point falls in front of the retina
far sighted
hyperopia, see further away, focus point behind retina
presbyopia
happens when we get older the shape of our lens does not change as much as before, begin to have problems seeing things that are close to us
photoreceptor cells
cones and rods
rods
night vision, respond well to dim lighting , more, peripheral vision, no colour information
cones
need lots of light, bright will be most active during the day, what gives us our colour vision
dark adaption
rods react to darkness and increase sensitivity
receptive fields
retinal area that affects firing of cell, ganglion is reactive to pinpricks of light
no light: action potential firing at a normal baseline
light in centre: basically turns on the cell, INCREASING firing rate
light in the surrounding: DECREASING firing rate
computer vision function
computer models function the same way our receptor fields work, to find out what kind of information we can obtain from this, at the initial level our ganglions are receiving information on where the edges are