Sight Flashcards
Non-verbal communication
other ways of communicating like facial expressions and body language
Visual light spectrum
the part of the electromagnetic spectrum that humans can see
What is the stimuli for vision
electromagnetic radiation
What is light made of?
photons
Iris
adjusts the pupils to let more or less light in (there are muscle who also do this)
What is the process of seeing?
- the iris changes shape to allow the our pupils to let more or less light in.
- Muscles adjust the shape of the lens.
- The light gets focus on to the retina
- Photoreceptors on the retina stimulate the axons of ganglion cells
- signal travels along the optic nerve and leads to the brain
Transduction
the conversion of light into neural impulses
Photoreceptors
sensory receptor cells along the retina
Rods
a type of photoreceptor that detect light at night and have no colour receptors
Cones
A type of photoreceptor that detects light during the day and the night and work in colour.
Layers of the retina
Optic nerve axons > ganglion cells > bipolar cells > cones/rods
Optic nerve
axons that carry the visual information out of the eye to the brain
Optic disc
(blind spot) is the part of the retina without any cones or robs; where the optic nerve connects with the brain
Why do we not have a blind spot in our vision?
the brain fills in the gaps
Fovea
a region of the retina made up of cones that allows us to see more sharply
Sensory adaptation of sight
The dilation and constriction of the pupil changes the amount of light that you can see
What senses colour
cones
Hue
Colour bases on the wavelength of the light
Saturation
Purity/vividness of the colour
Brightness
How much light is being reflected (black and white scale)
Trichromatic theory
Specialized cones that each detect one of the three main colours and the rest are all mixtures
What are the three main colours?
Green, blue, red
What are the shortcomings of trichromatic theory
does not explain afterimage
Opponent process theory
colours work to inhibit eachother and display their colour.
Opponent process theory pairs
red and green, black and white, blue and yellow
Negative after-image effect
Seeing the image in its antagonistic colour after you have looked away
Two stage model
Stage one: cones respond to the three primary colours
Stage two: the signal is processed by the opponent process cells
Sight path in brain
superior colliculus > thalamus > contralateral primary visual cortex
What psychological group is used to explain vision groupings
gestalt psychology
Figure ground
determining what is in the foreground and the background when the image is ambiguous
Proximity
visual stimuli closer together must be in the same group
Continuity
stimuli along the same plane must be grouped together
Closure
tendency to fill in the gaps between lines to make an image
Similarity
stimuli that resembles one another are grouped together
Retinal disparity
viewing things slightly different out of each eye
binocular cues
requiring both eyes
monocular cues
requiring one eye
Convergence
the inward movement of eyes to look at something close
Interposition
when one object blocks part of another from our view, the blocked object looks farther way (monocular)
Relative height
seeing objects higher as farther away (monocular)
Texture gradient
Seeing details on the surface (monocular)
Linear perspective
converging parallel lines (monocular)
Light and shadow
Light as a cue to distance (monocular)
Clarity or aerial perspective
tendency to see closer objects with more clarity
Familiar size
the assumption that things stay the same size
Relative size
seeing smaller objects as farther away
Motion parallax
the relative movement of objects vs stationary objects
monocular goal
to determine distance and depth
Perceptual constancies
top-down processing that causes us to believe that things are unchanging despite environmental changes
What are the types of perceptual constancies
colour constancy, size constancy, shape constancy
What do infants rely on for sight
contrasts
when does sight fully develop
8 months
Strabismus
misalignment of the eyes and causes blindness in the weaker eye
Amblyopia
partial or complete loss of vision due to abnormal brain development.
