Visual Perception Flashcards
the set of processes by which we recognize, organize, and make sense of the sensations we receive from environmental stimuli
perception
the object in the external world
distal (far) object
__ could be sound waves, reflected light, tactile information
informational medium
when information comes into contact with the appropriate sensory receptors
proximal (near) object
perception occurs when a __ is created in you that reflects the properties of the external world
perceptual object
receptor cells adapt to constant stimulation by not firing until there is a change in stimulation
sensory adaptation
a uniform visual field where your eyes have adapted to the stimulus
ganzfeld
a mental representation of a stimulus that is perceived
percept
through the eyes electromagnetic light energy is converted
into
neural electrochemical impulses
a clear dome and protective covering of the eye
cornea
the opening in the middle of the iris
pupil
light continues through the __ and __
lenses and vitreous humor
gel-like substance that makes up majority of the eye
vitreous humor
converts electromagnetic light energy to neurochemical impulses
retina
vision is most acute in the __
fovea, a small and thin region in the retina
the very part of the retina that does the conversion of light to electrochemical energy
photoreceptors
two kinds of photoreceptors
rods and cones
is within the rods and cones (2 photoreceptors) which are chemical substances that reacts to light and transform physical electromagnetic energy into an electrochemical neural impulse that can be understood by the brain
photopigments
long and thin photoreceptors more highly concentrated in the retina’s periphery than in the foveal region
rods
the rods are responsible for __
night vision and are sensitive to light and dark stimuli
short and thick photoreceptors. more highly concentrated in the foveal region than in the periphery of the retina
cones
the cones are responsible for __
perception of color
the neurochemical messages processed by the rods and cones of the retina travel via the __ to the __
bipolar cells, ganglion cells
the axons of the ganglion cells in the eyes collectively form the __ of that eye
optic nerve
further path of sensory info from optic nerve
- optic nerve of the two eyes join at the base of the brain to form optic chiasma
- ganglion cells travel contralateral via optic chiasma and ipsalateral to the thalamus
- from thalamus, neurons carry info to primary visual cortex
from occipital lobe to the fasciculi (fiber bundles), info ascends to the parietal lobe
dorsal or where pathway
the dorsal/where pathway processes
location and motion info
from occipital lobe to the fasciculi (fiber bundles), info descends to the temporal lobe
ventral or what pathway
the ventral/what pathway processes
color, shape, identity of visual stimuli
temporal lobe lesions in monkeys
can indicate where but not what
parietal lobe lesions in monkeys
can indicate what but not where
the what-how hypothesis tells us that __
info about where something is is always present in visual info processing and how we can situate ourselves to grasp the object
describe approaches in which perception starts with the stimuli whose appearance you take in through your eye
bottom-up theories
perception is driven by high-level cognitive processes, existing knowledge, and the prior expectations that influence perception
top-down theories
bottom-up theories
- direct perception
- template theories
- feature-matching theories
- recognition-by-components theory
gibson’s theory of direct perception tells us that
info in sensory receptors and sensory context is all we need to perceive anything. no higher cognitive processing needed
according to gibson, we use texture gradients as cues for
depth and distance
mirror neurons start firing __ after a visual stimulus
30-100 ms
to recognize the incoming stimuli, you compare to templates in memory until a match is found
template theories
weakness of template theory
struggles to explain how we recognize variations of the same object
we attempt to match features of a pattern to features stored in memory
feature-matching theories
brain cells that respond to specific features such as lines and angles are referred to as __
feature detectors
4 kinds of demons in the pandemonium model
image demons, feature demons, cognitive demons, decision demons
we quickly recognized objects by observing the edges of them and then decomposing the objects into geometric shapes called geons
recognition-by-components theory
simply seeing a specific edge or geometric shape (geon) of an object allows us to recognize it, even if the full object is
not visible
the perceiver builds a cognitive understanding of a stimulus
constructive perception
influences of the surrounding environment on perception
context effects
objects presented in context are easier to recognize than objects presented alone
configural-superiority effect
the individual stores the way the object looks to him or her
viewer-centered representation
the individual stores a representation of the object, independent of its appearance to the viewer
object-centered representation
information is characterized by its relation to a well-known or prominent item
landmark-centered representation
the overarching law of the gestalt approach where individuals organize their experience in as simple, concise, symmetrical, and complete manner as possible
law of pragnanz
organize perceptions by distinguishing between a figure
and a background
figure-ground
elements tend to be grouped together according to their
nearness
proximity
items similar in some respect tend to be grouped together
similarity
perceive smoothly flowing or continuous forms rather than disrupted/continuous ones
continuity
perceptually close up, or complete objects that are not in fact complete
closure
prefer to perceive objects as mirror images
symmetry
