week 5 perception Flashcards
perception
integration of stimulation from cells, active process involving top-down process
top-down process
using memory, expectations, mood, contexts and beliefs on interpretation of information from senses
perceptual constancy
even though the information our senses receive changes, our brain helps us see the world as stable and consistent.
size constancy
we know an objects size doesn’t change even if it looks smaller when its far away
shape constancy
we know an objects shape stays the same even if it looks different in different angles
color constancy
we see colors the same even if lighting changes eg a face in day/night
brightness constancy
we know an objects brightness doesn’t change even if light level around does eg a white wall still looks white at night
brightness contrast
our perception of brightness is not solely dependent on the
absolute amount of light reflected from surface of an object, but
also on the amount of light reflected from other objects in the
vicinity.
examples of top down processes in perception
1) Phonemic restoration
2) Illusory contours
3) Degraded figures
perceptual set
readiness to interpret stimuli in a certain way depending on
expectations, experience and psychological state.
phenomic restoration
brain fills in missing sounds to complete words or phrases
illusory contours
visual perceptions of edges or boundaries that do not physically exist in the stimulus but are inferred by the brain based on surrounding visual information. These “invisible” edges are created by the brain to make sense of the image, filling in gaps to form a coherent shape or figure.
convergence
eyes move together as object gets closer; muscle tension is a
cue to how far away object is
Binocular (retinal) disparity
slightly different views of world presented to
each eye are interpreted by brain to give depth information
the further an object is from the observer, the less
____ between images projected on the retinas of 2 eyes
disparity
motion parallax
depth perception cue that occurs when objects at different distances appear to move at different speeds. It’s a monocular cue, meaning it can be perceived with just one eye
objects closer to observer appear to move faster
relative size
size of an object relative to others around It
moon illusion
moon appear larger when it’s close to the horizon and smaller when it’s higher in the sky
linear perspective
apparent convergence of parallel lines on the horizon - converge at vanishing point
texture gradient
objects at a distance are denser, less detailed, and closer together
aerial perspective
distant objects are fuzzy due to moisture and particles in the air
occlusion
objects that block others are percieved to be closer
Muller-Lyer illusion
depth cues suggest the “long” line is closer, the principle of size constancy causes us to see same size retina image as larger (similar to moon illusion)
a line with arrowheads at the ends will appear shorter, while a line with arrowtails at the ends will appear longer.
Ponzo illusion
one of two parallel lines appear longer than the other. It’s often depicted as two horizontal lines of equal length with converging lines above them. The top line appears longer than the bottom line
linear perspective suggests that object is further away; perceptual system makes same size retinal image seem larger (size constancy).
The Ames room illusion
all depth cues suggest these people are the same
distance from the observer; however, they are not
what does the perceptual system compensate for
voluntary eye movements
phi-phenomenon
two or more stationary lights are turned on and off in quick succession, creating the illusion of motion.
apparent motion
perceptual system fills in the gaps on successive, motionless images
induced motion
if objects near a stationary one are moving, the stationary one also appears to move
motion after-effect
after moving forward for some time then stop, scenery outside seems like its moving backwards slightly
gestalt
perceiving the object as a whole first then analysing the parts
feature analysis
analyzing parts of objects first then object as a whole
what process does feature analysis use
bottom-up process
how do we recognize letters
activated feature detector cells in turn activate different stored representations of letters in memory, memory representation that is most activated wins
what cell layer in the eye does light hit first
ganglion cell layer
what cell layer does light travel to after ganglion cell layer
bipolar cell layer
what process does gestalt
top-down process
figure/Ground Distinction
Our brain automatically separates what we focus on (the figure) from everything else around it (the ground)
how are gestalts formed
organising principles then grouping them
give 3 grouping principles
proximity, good continuation and closure
how can proximity be applied to sound perception in a song
proximity of notes in a song allow you to hear successive notes as belonging to a melody
how can good continuation be applied to sound perception eg a song
allows you to pick out the melody in the presence of
other background harmonies
how can closure be applied to sound perception
allows you to fill in the gaps of a radio announcer who is
competing with a lot of static that cuts out several of his words
evidence for nature inborn
at 6 months, infants will not go to beckoning mother if there is a
visual cliff
shows that infants at 6 months respond to depth cues
ii] Newborns show preference for shapes that resemble human face
evidence for nurture
feature detector cells can be trained to be sensitive to particular orientation
what was blakemoor and Cooper kitten experiment findings
The kittens that had been raised in an environment with only vertical stripes had difficulty perceiving horizontal lines later on, and vice versa.
This suggests that the kittens’ brains had adapted to processing only the type of visual information (vertical or horizontal) they were exposed to during their early development. Their brains had become “tuned” to those specific orientations.
As you watch a door opening, the shape projected on your retinas changes drastically, yet you still perceive the door to have the same shape rather than its shape changing. This illustrates the principle of
perceptual constancy
A binocular depth cue can also be called
binocular aka retinal disparity
Using audition, a person can use ____ to infer the location of an object
intensity of sound at each ear
recognition of objects can be aided by
adding context cues
A perception based on information about the elements of a stimulus, beginning with the image that falls on the retina, is called __________ processing:
bottom up
When we focus on an object, the images of other objects in the environment, at different distances, will fall on different portions of the two retinas. The degree of difference produced by the images of an object on the two retinas is called binocular __________ and provides an important cue about its distance:
disparity
The Ponzo illusion relies on which depth cue to create the illusion:
linear perspective
ponzo illusion
two parallel lines of equal length appear to be different in length due to converging lines that surround them
Some computer animations and “moving” neon signs make use of the __________ to give the illusion of movement:
phi phenomenon
what is texture gradient an example of
monocular depth cue
A cue to depth that is based on muscle strain as your eyes move together as an object gets closer is
called
convergence
jack looks out on some mountains and sees that some seem fuzzy due to
moisture in the air. John determines that
the “fuzzier” mountains are far away. This
is called
aerial perspective
The Muller-Lyer illusion (when two
vertical lines are equal in length but
one appears longer due to other
attached lines) relies on
_______________ to fool us
depth cues
_________ is the readiness to interpret stimuli in a certain way depending on expectations, experience and psychological state.
perceptual set
____________ distance is the distance
between the observer and object,
whereas ____________ distance is the
distance between objects.
absolute, relative
Different ________ cells are activated when different stimulus features are presented.
ganglion
