Unit 3: Sensation and Perception Flashcards
prosopagnosia
face blindness
sensation
process by which sensory receptors and the nervous system receive + represent environmental stimuli
perception
process bywhich sensory info is organized + interpreted so that we can recognize meaningful objects + events
top-down processing
info processing starting w/ higher level mental processes in the brain- constructs perceptions from sensory input
pereptions over sensation
occurs when we bring our expectations * prior knwoeldge to an enviro or stiatuion
bottom-up processing
starts at sensory receptors + works up to brain’s integration of sensory info
sensation over perception
occurs when we are unfaimilar with an enviro or situation
selective attention
focusing of conscious awareness on a particular stimulus
encompasses cocktail party effect, inattentional blindness, and change blindness
cocktail party effect
form of selective attention
pick out one voice from a sea of voices
inattentional blindness
form of selective attention
failure to see visible object when attention is directed elsewhere
change blindness
form of selective attention
failure to notice changes in environment
transduction
process of converting one form of energy (stimuli) into another that the brain can use (neural impulses)
How do our sensory systems function?
(rtd)
By:
receiving sensory stimuli through special receptors,
transforming stimuli into neural impulses, and
delivering neural info to the brain
psychophysics
study of relationship between physical characteristics of stimuli and our psychological experience of them
absolute threshold
minimum stimulus energy required to detect stimulus 50% of the time
ex:
specialist sends diff tones to determine pt where for any freq you hv that rate of detection
signal detection theory
assumes detection depends on alertness, not necessarily the absolute threshold
ex: a solider more likely to hear a noise at night while standing guard than a civilian is to hear that same noise when they’re watching tv at home
Does subliminal advertising work?
subliminal = below absolute threshold for conscious awareness
Yes if based on priming - we evaluate stimuli even when not consciously aware of it
No if just subliminal messaging to change our behavior - research shows it performs the same as a placebo
priming
unconscious activation of certain associations to predispose one to a particular perception / memory / response
difference threshold
min difference between 2 stimuli required for a 50% detection rate of that difference
once met, we experience it as a JND (just noticeable difference)
Weber’s Law
disscovered by Ernst Weber in late 1800s
for avg person to perceive a difference between 2 stimuli, they have to differ by a minmum constant PERCENTAGE, not amount.
ex: light, 8%. tones, 0.3%.
perceptual set
mental predisposition to perceive on ethings and not another - influences how we use top-down processing to interpret ambiguous situations
How do context, motivation, and emotion affect our perceptions?
ESP
Does it exist?
parapsychology
What does our perception of color depend on?
module 18
wavelength (distance from one wave peak to another … shorter wavelengths = more blue/violet = high frequency. long wavelengths = more red = low frequency)
How does light pass through the eye?
- Cornea
- Pupil
- Iris
- Lens
- Retina
a. rods/cones
b. bipolar cells
c. ganglion cells
d. optic nerve
e. thalamus
f. visual cortex
CPILR
cornea
clear, protective outer layer covering the pupil + iris
bends light to provide focus
pupil
small adjustable opening in the center of the eye through which light enters (after it hits cornea)
iris
ring of colored muscle tissue - dilates or constricts in response to light intensity, emotional stimuli
surrounds pupil + controls its size
lens
transparent structure behind the pupil that changes shape to focus images on the retina (in a process called accomodation)
The amount of light entering the eye is regulated by:
iris
accomodation
the process by which the curvature and thickness of the lens change - helps eye focus on near / far objects
retina
multilayered tissue on eye’s sensitive inner surface
contains receptor rods + cones that process info + forward impulses to the brain, which doesn’t “see” the whole image but rather reassembles visual info into an image we perceive
objects within the retina
- fovea, rods, and cones
- bipolar cells
- ganglion cells
- optic nerve
- blind spot
rods vs. cones
rods are used in peripheral, night, and grey scale vision
cones are used in fine detail and color vision - they cluster around the fovea
both convert light energy to neural impulses via transduction
upon hitting both, light triggers a photochemical reaction that activate the bipolar cells
fovea
central / focal point in the retina around which cones cluster
bipolar cells
activated by chemical reaction when light hits rods/cones
turns on ganglion cells by transmitting impulse from rods/cones to ganglion cells
ganglion cells
activated by bipolar cels
upon activation, their axons converge, forming the optic nerve
optic nerve
composed of the axons of ganglion cells
transmit impulses from eyes to thalamus (which sends to visual cortex)