Sensation and Perception Flashcards
Psychophysics
study of how physical energy relates to psychological experience
sensation
detection of physical energy and encoding it as neural signs
perception
interpretation of senses
bottom up processes
perception of sensory level to brain
top down processes
brain to location of stimulus
from past to present
habituation
decrease in response to a repeated stimulus
sensitization
responding to a weak stimulus due to preparation of strong stimulus
adaptation
occurs in which cells threshold goes up
signal detection
prediction about how quickly you notice a new stimulus
speed impacted by alertness, importance, expectation
sensitiveness of senses example
candle light from 30 miles away on a clear dark night
receptor cells
cells designed to respond to one particular form of energy
absolute threshold
minimum intensity of physical energy required to produce any sensation
difference threshold
smallest amount of change that can be detected 50% of the time
webers law
thresholds for detecting differences are roughly constant proportion to the size of the original stimulus
subliminal
beneath the threshold
back masking does nothing
vision
most important human sensory system
cornea
transparent protective coating over front of eye
pupil
opening of iris where light enters
iris
colored part of eye
lens
focus on light
vitreous
fluid inside eye giving its shape
retina
lining on back interior of eyeball
have light sensitive receptor cells
firing of these cells allow light
fovea
place where you see most clearly
order: cornea, pupil, lens, vitreous, iris, fovea
*inside retina: rods
respond to light
night vision
cones
respond to color
found mainly in fovea
bipolar cells
specialized neuron with only one dentrite and one axon
rods and cones fire into bipolar cells which then connect to the optic nerve
hue
aspect of color that corresponds to the name
saturation
vividness of hue
brightness
nearness to white
how do we see color?
not enough cones for every color
cones combine their messages
results in color through mixing
additive color mixing
mixing of light adds additional wavelengths
end result: white
subtractive mixing
colors mixed to form a black/brown color
doesnt reflect back to your eye
The Trichromatic Theory
Hermann von Helmholtz
3 primary colors form to form any hue
used to be no red but red is primary color
the opponent process theory
Edward Herring
pairs of color receptors
after image: stimuli of 1/2 of pair causes other receptor to fire easier
monchromats
people most seriously color blind
Dichromats
people blind to either red/green or blue/yellow
10% Male 1% Female
steps of hearing
sound waves enter the outer ear and travel to the ear drum
vibrating ear drum causes the bones of middle ear (hammer, anvil, stirrup) to hit each other to amplify vibrations
vibrations carried from stirrup to oval window and then to the fluid in cochlea
fluid in cochlea causes movement of basilar membrane, also moving the organ of corti. Organ of corti houses tiny fibers that move causing the receptor cells to fire
movement of the fibers causes firing of cells that have a message carried from Auditory nerve into the brain
pitch
hertz
higher frequency, higher pitch
volume
decibles
determined by size of amplitude
overtones
accompanying sound waves that are different multiples of the frequency of the basic tone
timbre
quality of sound caused by overtones
cheap vs expensive instrument
smell
more sensitive then taste
activated by odorant binding protein produced by nasal gland
smell receptors located in olfactory epithelium
neurons in epithelium fire directly at olfactory bulb and then go to amygdala
pheromone communication
hormones that are carried to another person through smell
sensed by receptors in the vomeronasal organ
flavor
combo of taste and smell # of taste buds decrease as you get older
papillae
bumps on tongue that hold taste buds
taste
assembled in parietal bone and limbic system
psychological
kinesthetic senses
info about speed and direction of body’s movement in space
vestibular senses
info about orientation in space
vestibular organ
inner ear
fluid movement inside semicircular canals sends info about orientation of head
vestibular sacs
tells you up and down
cutaneous senses
sensitive to pressure, temp, pain
the gate control theory
“gate” in the spinal chord controls the transmission of impulses to the brain
pain
can be managed with a placebo
meditation
focuses awareness away from the pain or it can close the gate
perception
top down way or brain organizes and interprets info and puts it into context
perceptual set
psychological factors that determine how you perceive your environment
figure-ground relationship
the organization of the visual field into objects that stand out from their surroundings
depth perception
ability to see objects in 3 dimensions although it is 2d
binocular cues
depth cues that depend on two eyes
monocular cues
things that are far away
one eye
hubel and wiesels experiment
looked at how stimuli is “written” into our brains
identifies cells that respond only to horizontal and vertical lines
feature detectors
simple cells that react to a specific stimulus
complex cells
coordinate info drawn from simple cells
gestalts psychologists
brain looks for patterns to form coherent perceptual experience
proximity
how close things are to each other
similarity, continuity, closure, connectedness
obsener characteristics: motivation and expectation
desires and needs shape perception
perceptions about what we are supposed to perceive.
