The visual world Week 8 Flashcards
electromagnetic energy
Pulses of energy waves that can carry information from place to place
wavelength
The distance between one wave peak and the next wave peak
visible spectrum
The part of the electromagnetic spectrum that our eyes detect (only the range from about 400 to 700 billionths of a meter)
cornea
A clear covering that protects the eye and begins to focus the incoming light
pupil
A small opening in the centre of the eye
iris
The coloured part of the eye that controls the size of the pupil by constricting or dilating in response to light intensity
lens
A structure that focuses the incoming light on the retina
retina
Cell layer in the back of the eye containing photoreceptors.
visual accomodation
The process of changing the curvature of the lens to keep the light entering the eye focused on the retina
nearsighted
When the focus is in front of the retina
farsighted
When the focus is behind the retina
optic nerve
A collection of millions of ganglion neurons that sends vast amounts of visual information, via the thalamus, to the brain
rods
Photoreceptors of the retina sensitive to low levels of light. Located around the fovea.
- 120 million in each eye
cones
Photoreceptors of the retina sensitive to color. Located primarily in the fovea.
fovea
The central point of the retina
Margaret Livingstone (2000) on Mona Lisa
She smiles until you look at her mouth, and then it fades
blind spot
A hole in our vision that is created because there are no photoreceptor cells at the place where the optic nerve leaves the retina
feature detector neurons
Specialized neurons, located in the visual cortex, that respond to the strength, angles, shapes, edges, and movements of a visual stimulus
hue
The shade of a colour
trichromatic colour theory
The colour we see depends on the mix of the signals from the three types of cones
color blindness
The inability to detect green and/or red colours
opponent process theory
Proposes that we analyze sensory information not in terms of three colours but rather in three sets of “opponent colours”: red-green, yellow-blue, and white-black
gestalt
A meaningfully organized whole
- whole is more than the sum of its parts
Depth perception
ability to perceive three-dimensional space and to accurately judge distance.
Psychologists Eleanor Gibson and Richard Walk (1960)
14-month-old infants by placing them on a visual cliff
visual cliff
A mechanism that gives the perception of a dangerous drop-off, in which infants can be safely tested for their perception of depth
depth cues
Messages from our bodies and the external environment that supply us with information about space and distance
binocular depth cues
Depth cues that are created by retinal image disparity — that is, the space between our eyes — and which thus require the coordination of both eyes
convergence
The inward turning of our eyes that is required to focus on objects that are less than about 50 feet away from us
accomodation
Helps determine depth
monocular depth cues
Depth cues that help us perceive depth using only one eye
beta effect
The perception of motion that occurs when different images are presented next to each other in succession
phi phenomenon
We perceive a sensation of motion caused by the appearance and disappearance of objects that are near each other
Describe the transduction of somatosensory signals: The properties of the receptor types as well as the difference in the properties of C-afferents and A-afferents and what functions these are thought to have.
Describe the social touch hypothesis and the role of affective touch in development and bonding.
Identify the key structures of the eye and the role they play in vision.
Summarize how the eye and the visual cortex work together to sense and perceive the visual stimuli in the environment, including processing colours, shape, depth, and motion