CHAPTER 4 Flashcards
Define sensation
how the senses detect visual, auditory and other sensory stimuli and encode them as neural signals
define Perception
how sensory information is selected, organized and interpreted
What are the 2 types of perception?
1) Bottom-up processing
2) top-down processing
Describe Botton-up processing
constructing an image from its parts. Ex: perceiving an object on the basis of its edges
describe top-down processing
constructing perceptions based on our experience and expectations
What is the McGurk effect?
The illusion occurs when the auditory component of one sound is paired with the visual component of another sound, leading to the perception of a third sound
define absolute threshold
minimum of a stimulus needed for the nervous system to detect a change 50% of the time.
Define Eagleman’s experiment
Time delay when making a decision based on previous attempts. Basically, we compare out current choices with previous ones so is there really a difference? basically he explored the idea of free will
define inattention blindness. state the example the textbook used
Failure to detect stimuli that are in plain sight when our attention is focused elsewhere.
Ex: individuals were asked to count how many times 2 people in the white shirts were tossing the football around. well at the end of the experiment when they were told to report the number they were also told that in the video there was a man with a gorilla suit facing around. More than 50% of people failed to see the gorilla because they were so focused on counting the number of times the football was thrown.
define change blindness and where is it mostly found?
failure to detect obvious changes in one’s environment
Mostly found in pilots
define subliminal perception
below absolute threshold for conscious awareness
define accommodation
Changing the shape of the lens to focus on objects near or far
define presbyopia
loss of lens flexibility
define colour blindness
decrease in number of cones in the eye
define visual agnosia
deficit in perceiving objects. A person with this condition can tell the shape and colour BUT not recognize/name the object
Are there more rods or cones?
rods
Which ones help you see during daytime and nightime
daytime -> cones
night time -> rods
which area of the eye has no rods?
fovea
What photopigment is located in rods?
rhodopsin
Trichromatic theory
Idea that colour vision is based on our sensitivity to 3 primary colours. —> red, green, blue
Opponent-process theory, name an example
Theory that we perceive colour in terms of 3 pairs of opponent colours: either red & green, blue & yellow, or black & white.
Example in textbook used was the Canadian flag experiment
Nearsightness vs farsightedness
Nearsightness –> light focused in the front
farsightedness –> light focused in the back
define feature detectors
each detector is tuned to a particular aspect of the stimulus information
define the Gestalt principles
our perceptual world is organized in ways that the stimulus is not. the the organization must be contributed by the perceiver. Example: kanizsa squares
” your perception goes beyond the info given”
explain perception and the visual cortex
visual inför from the retina travels to the superior colliculus as well as the lateral geniculate nucleus (LGN) and then to the secondary cortex(V2) and then along 2 visual pathways.
1) “where” pathway, going to the partial lobe, which processes visual form, position, and motion
2) “ what” pathway, to the temporal lobe which processes visual form and colour
define interposition
Object partly blocks your view of another. You perceive the partially blocked object as farther away.
define linear perspective
Parallel lines known to be the same distance apart
appear to grow closer together, or converge as they recede into the distance.
define relative size
Larger objects are perceived as being closer to the viewer, and smaller objects as being farther away.
define texture gradient
the texture of objects become less apparent as objects move further away
Müller-Lyer Illusion
A line of identical length appears longer when it ends in a set of arrowheads pointing inward than in a set of arrowheads pointing outward.
A)
B) >-<
B appears longer but they’re the same size
which people are not susceptible to the muller-layer illusion?
the Zulu people
Define ponzo illusion
objects closer to the converging line as larger than those far away when they’re all the same size.
Example: Train tracks. the closest rail looks larger than the ones far away
define carpentered world
describes how those who live in cities are exposed to a higher percentage of straight lines, right angles and square corners
define Akinetopsia aka Motion blindness
difficulty of perceiving objects in motion
Which part of the brain is affected by motion blindness?
occipital lobe (damage to this causes motion blindness)
define blinding problem
we don’t really know how - our brains manage to combine or “bind” these pieces of information of the real world into a unified whole(colour, depth, movement, form etc)
cornea
bends lights and protect ye
iris
how much light enters
lens
focus and accommodation
retina
light sensitive surface
pupil
dilation, excitement
rods
respond to low light
cones
respond to high light, colour
fovea
highest concentration of cones
blind spot
no rods or sense receptors
