Perception Flashcards
another word for perception
consciousness
define perception
integration of sensory information to form “percept”. Must involve memory.
define top-down and bottom-up processing.
yeah, define it
Define visual capture
the ability of the the visual senses to override the other senses.
Define the McGurk effect
the ability of the visual senses to override the auditory senses, where a girl may be lipping “bar” but the soundtrack is actually “far”. We will here “bar”
Figure-ground defintion
in order to perceive, we need to perceive a figure as being distinct from its surroundings
how many dimmensions does our retina have?
2
what is cool about depth perception of the eye?
We only have a two dimension retina, yet we are partially born with the ability to perceive three dimensions
Define binocular cues.
The two eyes do not see the same thing. Therefore, the two images are patched together to give an example of depth perception
what is a stereogram?
contain two different views of the same image
Define monocular cues
Things such as relative size, height, and linear perspective that allow us to get a sense of three dimensions.
Define relative size
Near objects are larger that far objects
Define relative height
far objects are higher on the visual field
Deifne linear perspective
Linear lines merge as they go off into the distance
Define interpositin
the near object will block a far object
Define relative brightness
near objects reflect more light than far objects. shading provides an illusion for depth
How is shading used in technology
placement of shading allows for differences in depth perception
How do we perceive motion?
light sequentially stimulating one retinal cell after another
what part of the eye is very good at detecting movement?
rods
Define stroboscopic motion
Still pictures vary slightly in position.
Define apparent (illusional) movement
When an image chagnes position on the retina, it is pervceived to move, except for when you move your eyes and the image doesnt movve
Define apparent motion
Based on your visual cortex making an error. It misinterprets eye movement for the image movement
Define perceptual constancies
allows us to perceive an object as unchagning even though the stimuli that fall on our recptors have changed
shape constancy
a person may walk away, but we know he stays the same size
Define perceptual context
Identical colours are not perceived the same when placed on different backgrounds. Context changes the perception.
with people who receive sight late in life, they cannot…
- recognize objects
- cant recognize faces
- lack of perceptual constancy ( if someone gets further away)
Perceptual adaptation: what happens to non-mammals when they have their retina rotated?
They cannot learn to re-see right-side-up
what is important for learning perception?
It must occur within a critical period. If they mess with what a person sees in a critical period of development, they can be permanently damaged and can never perceive properly
What is gestalt psychology?
given a cluster of sensations, the perceiver organizes them into a “whole” of a “gestalt”
Define Figure-ground perception?
The process by which we perceive, where we need an object to be disticnt from its surroundings
Grouping defintion
The process of grouping stimuli together.
What is Weber’s law?
Delta I/I = k
What is adaptation?
if a stimulus intensity remains constant, our sensory receptors adapt to it, and we dont hear it as much
What are the three parts of the retina?
- Cones and rods
- Fovea
- Blind spot
What are the four major components of the eye?
Cornea
Lens
Iris/pupil
Retina
When light strikes the eye, what is the first thing that happens?
The rods and cones have a chemical reaction to it
What occurs after the rods and cones have a chemical reaction to light?
First of all, the reaction must be strong enough. Given that it is strong enough, the bipolar cells are activated
What do the bipolar cells activate?
The ganglion cells
Where do the axons of the ganglion converge, and what is it called?
They converge at the blind spot to form the optic nerve
What are the three types of cones?
red, green and blue
Define cones? (5)
- packed in the center of retina, near the fovea (where vision is most acute)
- can project to single or several bipolar cells
- The output of the cone must be very high to be activated
- Output is dependent on the intensity of light
- Need a great deal of light to see in colour
Define the rods (6)
- In the perphery
- There are many more rods than cones
- Spaced far apart
- Excellent for detecting movement
- Not sensitive to colour
- several rods project to a single bipolar cell, so sensitive to low levels of light
Define the Young-Helmholtz 3 colour theory
States that we see colour by the cones of our eyes mixing the three basic colours
What is the problem with the Young-Helmholtz laws?
We never see a redish-green or a blueish yellow colour.
What is the the Hering 2-colour theory?
The red and green cones project to common bipolar cell.
Red-green bipolar cell increases firing when red is presented but decreases firing when green is presented
What is the crossing point optic nerves called?
optic chiasm
What is the Gate control theory (Melzack and Wall)
- Bottom-up processing, where pain receptor and other sensation received simultaneously, and attention is given to other sensation, so we do not feel the pain
- Top-down processing, consciously will to ignore pain and attend to something else
