Chapter 4 Flashcards
Lens
a transparent eye structure that focuses the light rays falling on the retina.
Pupil
The opening in the center of the iris that helps regulate the amount of light passing into the rear chamber of the eye
Retina
the neural tissue lining the inside back surface of the eye; it absorbs light, processes images, and sends visual information to the brain
Optic disc
A hole in the retina where the axons from the eye converge and go to the brain
Also known as the blind spot because it is a hole where light cannot be processed
Cones
Specialized visual receptors that play a key role in daylight vision and color vision
About 6 million in human eyes
Rods
Specialized visual receptors that play a key role in night vision and peripheral vision
About 100 million in human eyes
Fovea
a tiny spot in the center of the retina that contains only cones; visual acuity is greatest at this spot
Dark adaptation
the process in which the eyes become more sensitive to light in low illumination
Light adaptation
the process in which the eyes become less sensitive to light in high illumination
Receptive field of a visual cell
the retinal area that, when stimulated, affects the firing of that cell
Optic chiasm
the point at which the axons from the inside half of each eye cross over and then project to the opposite half of the brain
Feature detectors
neurons that respond selectively to very specific features of more complex stimuli
What are the “what and where” pathways for visual processing
Ventral stream (what)
Dorsal stream (where)
What is processed in the ventral stream?
processes the details of what objects are out there
the perception of form and color
What is processed in the dorsal stream?
processes where the objects are located
the perception of motion and depth
What is subtractive color mixing
works by removing some wavelengths of light, leaving less light than was originally there
What is additive color mixing?
works by superimposing lights, putting more light in the mixture than exists in any one light by itself
What is trichromatic theory?
Holds that the human eye has three types of receptors with differing sensitivities to different light wavelengths
believed that the eye contains specialized receptors sensitive to the wavelengths associated with red, green, or blue
What us color blindness
a variety of deficiencies in the ability to distinguish among colors
Color blindness occurs in roughly 8% of males but in less than 1% of females
What are complementary colors
pairs of colors that produce gray tones when mixed together
What is afterimage?
a visual image that persists after a stimulus is removed
The color of the afterimage will be the complement of the color you originally stared at
What is opponent process theory?
holds that color perception depends on receptors that make antagonistic responses to three pairs of colors
The three pairs of opponent colors hypothesized are red versus green, yellow versus blue, and black versus white
The antagonistic processes in this theory provide plausible explanations for complementary afterimages and the need for four names (red, green, blue, and yellow) to describe colors
What is a reversible figure?
A drawing that is compatible with two different interpretations that can shift back and forth
What is a perceptual set?
a readiness to perceive a stimulus in a particular way
A perceptual set creates a certain bias in how someone interprets sensory input
What is inattentional blindeness?
The failure to see fully visible objects or events in a visual display because one’s attention is focused elsewhere
What is feature analysis?
the process of detecting specific elements in visual input and assembling them into a more complex form
Feature analysis assumes that form perception involves bottom-up processing
What is bottom-up prcessing?
a progression of processing from individual elements to the whole
What is top-down processing?
a progression of processing from the whole to the elements
What is the phi phenomenon?
The perception of movement from a series of still images (like animations)
In an image, what is the figure and the background?
The figure is the thing being looked at, and the ground is the background against which it stands
What is perceptual hypothesis?
An inference about what form could be responsible for a pattern of sensory stimulation.
What are binocular depth cues?
clues about distance based on the differing views of the two eyes.
What is retinal disparity?
refers to the fact that objects within 25 feet project images to slightly different locations on the right and left retinas, so the right and left eyes see slightly different views of the object
What are monocular depth cues?
clues about distance based on the image in either eye alone
What are pictorial depth cues?
cues about distance that can be given in a flat picture
What are the 6 pictorial depth cues?
□ linear perspective
□ Texture gradients
□ Interposition
□ Relative size
□ Height in plane
□ Light and Shadow
What is perceptual constancy?
a tendency to experience a stable perception in the face of continually changing sensory input
Ex. Someone’s face gets bigger as they get closer, but we understand their face isn’t actually growing, just coming towards us
What are the Gestalt principles?
Gestalt = form or shape
I\This states that the whole can be greater than it’s parts
What does the external ear consist of?
The pinna: the cone of the ear that we see
What does the middle ear consist of?
Eardrum
Ossicles
What are the ossicles and what is their function?
The hammer, anvil, and stirrup.
They transmit air vibrations from the outer ear into the inner ear
What does the inner-ear consist of?
Cochlea
Basilar membrane
What is the cochlea and where is it located?
A fluid-filled, coiled tunnel that contains the receptors for hearing. It is in the inner-ear.
What is the basilar membrane and where is it located?
Membrane in the cochlea that holds the auditory receptors, called hair cells. Waves in the fluid of the inner ear stimulate the hair cells which transmit neural impulses.
What are the two theories of hearing?
Place theory
Frequency theory
What does place theory state?
A pitch is heard because it vibrates a hair cell on the basilar membrane that corresponds to that pitch, sending a neural impulse to the brain
What does frequency theory state?
A pitch is heard because it vibrates the whole basilar membrane and all hair cells. The cells register the frequency of the pitch and send a neural signal
What is auditory localization?
locating the source of a sound in space
What is the gustatory system?
The sensory system for taste
What are gustatory receptors?
clusters of taste cells found in the taste buds that line the trenches around tiny bumps on the tongue
What are the four primary tastes?
sweet, sour, bitter, and salty
What is sensory adaptation?
a gradual decline in sensitivity to prolonged stimulation
What is the olfactory system?
Sensory system of smell
What are the cell receptors for smells and where are they located?
olfactory cilia
hairlike structures located in the upper portion of the nasal passages
What are pain receptors and where are they located?
mostly free nerve endings in the skin
What does the fast pathway for pain relay to the thalamus?
Registers localized pain and relays it to the cortex in a fraction of a second
This is the system that hits you with sharp pain when you first cut your finger
What does the slow pathway for pain relay to the thalamus?
This pathway (which also carries information about temperature) conveys the less localized, longer-lasting aching or burning pain that comes after the initial injury.
Lags a second or two behind the fast system
What does gate-control theory state?
Holds that incoming pain sensations must pass through a “gate” in the spinal cord that can be closed, thus blocking ascending pain signals.
What is the fifth taste detectable by our tongue?
Umami, the savory taste of glutamate found in foods such as meats and cheeses
How many taste buds do non-tasters have when compared to supertasters?
One-fourth
What are the four sensations of touch?
Pressure, warmth, cold, pain
What are the two regions of processing for touch?
Thalamus and the somatosensory cortex in the parietal lobes
What the natural painkillers produced by the body?
Endorphins
