Sensation and Perception Flashcards
sensation
basic/primitive mental state corresponding to environmental energies; experience of world
perception
mental state corresponding to properties of environmental objects and events; knowledge of world
Light is…
electromagnetic radiation.
Electromagnetic spectrum is arranged from…
shortest to longest wavelength.
Light intensity indicates…
brightness.
Light wavelength indicates…
color.
Retina consists of…
receptors, bipolar cells, and ganglion cells.
receptors
contain rods and cones
Filtration of light through the eyes?
Light enters pupil; Passes through eyeball to retina; Through ganglia/bipolars/etc; Strikes receptors
optic nerve
bundle of axons of ganglion cells that leads out back of eye to brain (leaving blind spot)
fovea
central depression in retina where cones are most densely packed; most acute vision
rods
very sensitive; black/white (achromatic); night vision; mostly in periphery; 120,000,000
cones
less sensitive; color (chromatic); daytime vision; mostly in fovea; 6,000,000
photoreceptors
light-sensitive neurons in retina of eye that produce action potentials when stimulated by light
Two types of photoreceptor cells are…
rods and cones.
The three types of cone cells are sensitive to…
different wavelengths of light.
Short-wavelength cone cells are most sensitive to…
blueish light.
Medium-wavelength cone cells are most sensitive to…
greenish light.
Long-wavelength cone cells are most sensitive to…
redish light.
Cone cells send action potentials to….
opponent process cells.
opponent-process theory
theory of color vision proposing three pairs of color antagonists: red-green, blue-yellow, and white-black. Excitation of neurons sensitive to one member of a pair automatically inhibits neurons sensitive to other member.
Opponent processes are…
excitation and inhibition.
Three types of opponent process cells in visual system are…
black/white, red/green, and blue/yellow.
Trichromatic theory suggests…
all colors would be mixtures of blue/green/red based on response of cone types.
The peak response of short wavelength cones is…
440 nm.
The peak response of medium wavelength cones is…
530 nm.
The peak response of long wavelength cones is…
560 nm.
Activation of short/medium/long wavelength cones may…
excite or inhibit Opponent Process cells.
Opponent process cells may be…
ganglion cells or cells in thalamus or cortex.
lateral inhibition
feedback from neighboring receptor cells tends to inhibit each other using inhibitory interneurons connecting them
Result of lateral inhibition is…
the exaggeration of contrasts (dark looks darker).
brightness contrast
neighboring regions of different brightness have boundaries sharpened as their brightness/darkness difference is increased
