Chapter 4: Sensation and Perception Flashcards
transduction
transformation of sensory stimuli into neural impulses
sensory adaptation
decreased responsiveness to stimuli due to constant stimulation
sensory habituation
our perception of sensations is partially due to how focused we are on them
cocktail-party phenomenon
suddenly focusing on your name even if it’s said across the room at a cocktail party
rods
detect black and white
cones
detect color
fovea
center of retina, high density of cones;
optic chiasm
area where optic nerve joins the eye, blind spot
bipolar cells
layer under rods/cones that fires if provided enough stimulation
ganglion cells
cells that form the optic nerve, fire if the bipolar cells fire and lead straight to the lateral geniculate nucleus
lateral geniculate nucleus
area in the thalamus where optic signals are sent
optic chiasm
spot where optic nerves cross
feature detectors
different groups of neurons respond to different types of visual images, i.e. curves/lines/circles
David Hubel & Torsten Wiesel
discovered the presence of feature detectors
gate control theory
only one message can be sent at a time and higher priority messages (pain) can override lower priority ones (itchiness) and endorphins can ‘close’ the ‘gate’ too
olfactory receptor cells
receive particles of smell stuff and transmit it to the brain
olfactory bulb
receives messages from the olfactory receptor cells
vestibular sense
sense of balance of our whole body
kinesthetic sense
sense of where our individual body parts are oriented
difference threshold
just-noticeable difference; smallest amount a stimulus must change before the difference is noticeable
Weber-Fechner Law
Weber’s law; change needed to cross the difference threshold is proportionate to the intensity of the stimulus
Ernst Weber
Weber’s law; just-noticeable difference
Gustav Fechner
worked with WEber in creating Weber’s law
signal detection theory
tries to determine which stimulus we will pay attention to out of competing stimuli
response criteria
factors that will determine whether or not you detect a signla
false positive
when we think we see something that actually isn’t there
false negative
when we don’t see something that is actually there
top-down processing
using background knowledge to fill gaps in perception
bottom-up processing
relying on evidence to form an opinion
schemata
mental representations of how we perceive the world to be
perceptual set
perceiving something in a certain way
figure-ground relationship
distinction made between an object and its background
gestalt rules
proximity, continuity, similarity, closure
proximity
how close things are together; objects closer together are perceived to be grouped together
continuity
objects that form a continuous form are more likely to be perceived as belonging together
similarity
objects of similar size/shape/color appearance are seen as more similar
closure
objects that form an image are more likely to be grouped together
constancy
size, shape, brightness; ability to maintain a constant perception of an object despite changes in light/position
size constancy
objects close ot us look bigger but size constancy allows us to realize they are not actually bigger
brightness constancy
perceive objects as being a constant color even as reflecting light changes color
shape constancy
knowing that a coffee mug is circular even though it may appear elliptical from another perspective
stroboscopic effect
a series of pictures will appear to be moving if presented in a certain speed
phi phenomenon
series of lightbulbs turned on and off at a certain rate will appear to be a moving thing of light
autokinetic effect
if a light is steadily pointed at a blank wall/screen it will appear to move if you stare long enough
Eleanor Gibson
did the visual-cliff experiment with babies and concluded that we are able to perceive depth from a very young age
monocular cues
depth cues that do not rely on having binocular vision; linear perspective, relative size cues, interposition, texture gradient
binocular cues
depth cues that rely on having binocular vision; binocular disparity, convergence
linear perspective
parallel lines that extend to the edge of a page would appear to converge; railroad tracks
relative size cue
objects closer to the viewer appear larger than faraway objects
interposition cue
objects closer to us block out pieces of objects behind us
texture gradient
things are more detailed when they are close to us
shadowing
provides a cue to light source and shadow
retinal disparity
a faraway object causes the eyes to receive the same message/picture; a closeby object causes disparate images to appear
convergence
as an object moves closer to us, we become more crosseyed trying to look at it, and this gives a perception of near/far
Muller-Lyer illusion
a line with right angles looks longer than a line with arrowheads on the end; because of architecture with right angles
