4. SENSATION & PERCEPTION Flashcards
Define: sensation
stimulation of sense organs by absorption of energy (ie. light, sound, etc.)
Define: perception
selection, organization, interpretation of sensory input
How are sensation and perception related
perceptions deals with how somebody interprets the sensations they have experienced
Define: amplitude (light)
height of the light waves, affects perception of brightness
Define: wavelength (light)
distance between peaks, affects perception of color
Define: purity (light)
how varied the mix of different wavelengths of light is
Define: saturation (vision)
richness of colors, refers to the relative amount of whiteness in a color
As whiteness declines, saturation ___
increases
Function: cornea
acts as a transparent “window” that lets light into the eye, works with the lens to form an upside down image of objects on the retina and adjust focus of the image
Function: lens
a transparent film that focuses the light rays falling on the retina
Define: accomodation
curvature of the lens adjusts to alter visual focus
When you focus on a close object, the lens of your eye accommodates to become ____ to give you a clear image.
thicker
When you focus on a distant object, the lens of your eye accommodates to become ____ to give you a clear image.
flatter
Define: pupil
opening in the center of the iris that helps regulate the amount of light coming in
List two things the pupil does in response to bad lighting.
Pupil dilates, image loses sharpness
List two things the pupil does in response to bright lighting.
Pupil constricts, image becomes/stays sharp
Function: retina
light absorption, image processing, transmits visual info to the brain
Define: fovea
a tiny spot in the center of the retina that only contains cones (point where visual acuity is the greatest)
Define: iris
colored ring of muscle surrounding pupil
Define: optic nerve
nerve situated in the retina that transmits visual information to the brain
What is another name for the optic disk
blind spot
Define: trichromatic theory
the human eye has three types of receptors (R, G, B) with differing sensitives to different light wavelengths and our eyes mix the three colors together to make all those that we can see
Define: rods
“black and white” visual receptors
Define: cones
visual receptors that are able to detect color, high visual acuity, found mainly in the center of the retina
Primary flow of info from retina to brain
optic nerve -> optic chiasm -> thalamus (lateral geniculate nucleus) -> occipital lobe (primary visual cortex) -> feature detectors process input -> dorsal stream (where the object is)/ventral stream (what an object is)
Define: sensory adaptation
when individuals adapt to repetitive senses over time
List three examples of sensory adaptations
- Sound of loud music appears to have become quieter over a long period of exposure
- Smell of a restaurant seems to fade as you are eating
- Feeling of jewelry is no longer noticed
Define: feature detectors
neurons that respond selectively to very specific features of more complex stimuli
At what level does the visual cortex process information
highly specialized (ex. a single neuron may only be able to process one type of line)
Problem with trichromatic theory of color vision
Does not explain complementary afterimages (after looking at a bright object for a long time and looking away, you will see an “afterimage” in complementary colors, ie. the sun)
Define: opponent process theory
color perception depends on receptors that make antagonistic responses to three pairs of colors (red/green, yellow/blue, black/white)
Evidence for trichromatic theory
color blindness, ability to make all colors from basic R,G,B
Evidence against trichromatic theory
complementary afterimages
Evidence for opponent process theory
complementary afterimages, color blindness (dichromats)
