PSY2001 Flashcards
What happens when you see an object?
Light reflected from the object strikes your eyes
The optic nerve comes from what type or types of cells?
Ganglion cells
Where do the rods and cones of the retina send their input?
To bipolar cells within the eyeball
Where do the bipolar cells of the retina send their input?
To ganglion cells
Where does light from the right side of the world go?
To the left half of each retina
What causes the blind spot of the retina?
The optic nerve exits the eye at that point
What is one reason why you don’t notice the blind spot of the eye in everyday life?
Anything in the blind spot of one eye is visible to the other eye
What is the fovea?
The center of the retina
In which of these ways is a hawk’s eye specialized?
It has more receptors on the top half of the retina than the bottom
Why is vision less detailed in the periphery?
In the periphery, many receptors converge onto each bipolar cell
Why does vision in the periphery have high sensitivity to faint light?
Toward the periphery, the retina has more convergence of input
What are the effects from having so many receptors converge their inputs onto the bipolar cells in the periphery of the eye?
Good perception of faint lights, but poor perception of detail
In which of these ways does foveal vision differ from peripheral vision?
Foveal vision has better acuity but less sensitivity to dim light
According to the trichromatic theory, or Young-Helmholtz theory, how do we perceive color?
Each wavelength elicits a unique ratio of responses by three kinds of cones
What is color constancy?
The ability to recognize an object’s color after a change in lighting
In humans, what crosses to the contralateral hemisphere at the optic chiasm?
Half of each optic nerve, the part representing the nasal half of the retina
What function does lateral inhibition serve in the visual system?
It sharpens contrast at borders
Why do ganglion cells have larger receptive fields than bipolar cells do?
Ganglion cells receive input from several bipolar cells
Where is the primary visual cortex?
Occipital cortex
What do people lose after damage to area V1?
All conscious vision
When you close your eyes and imagine a visual scene, where does the activity start?
In the memory and language areas of the cortex
Which of these is another term for the ventral stream in the visual system?
The “what” pathway
The inferior temporal cortex is especially important for which of the following?
Recognizing familiar objects
What might cause someone to be unable to perceive visual motion?
Damage to brain area MT
The fusiform gyrus responds most strongly to which of the following?
Faces
The ganglion cells in the human fovea, each connected to just one cone, are called _____ ganglion cells.
midget
The type of visual receptor found in the fovea is a _____.
cone
The Young-Helmholtz theory of color vision is also known as the _____ theory.
trichromatic
The theory devised to explain color constancy is the _____ theory.
retinex
The type of neuron that inhibits bipolar cells to produce lateral inhibition is a _____ cell.
horizontal
The “what” pathway and the “where” or “how” pathways for vision are called the _____ stream and the _____ stream.
ventral; dorsal
Damage to area MT (also called V5) causes _____ blindness.
motion
Explain how we see images from the external world.
When we see a tree, for example, our perception is not in the tree. It is in our brain. We see something only when light from it alters our brain activity. Even if we did send out rays from our eyes—and we don’t—when they struck some object, we wouldn’t know about it, unless they bounced back and returned to our eyes.
You sometimes find that you can see a faint star on a dark night better if you look slightly to the side of the star. Why?
When you look slightly to the side, the light falls on an area of the retina with more rods and more convergence of inputs. The result is greater sensitivity to faint light.
Describe the route for visual information, from the retinal receptors to the cortex.
Receptors connect to bipolar cells, which connect to ganglion cells, whose axons form the optic nerve. The optic nerves from the two eyes cross at the optic chiasm. Most of each optic nerve goes to the thalamus, which sends information to the visual cortex.
According to the trichromatic theory, how do we perceive color?
The retina has three types of cones, sensitive to short-, medium-, and long-wavelength light. The relative rate of response by the three types determines the color.
Explain lateral inhibition.
When light shines on a group of receptors, they excite bipolar cells, but they also excite horizontal cells. Horizontal cells inhibit all the bipolar cells around them, regardless of whether those cells had been excited or not. A bipolar cell that is stimulated by light but surrounded by other stimulated cells will have its response somewhat reduced. A bipolar cell that is next to stimulated cells on only one side will be inhibited less. A bipolar cell that is not stimulated, but is next to stimulated cells, is inhibited without being excited. The result is to enhance the contrast at edges.
What is blindsight, and what is a probable explanation?
Some people with damage to area V1 can respond to visual stimuli that they do not perceive consciously, by moving their eyes toward something, reaching for it, imitating an expression, or indicating an object’s shape, color, or direction of movement, while insisting that they are just guessing. In many if not all cases, connections are intact between visual areas of the thalamus and cortical areas outside V1.
What are the specializations of the ventral and dorsal visual streams?
The ventral stream responds to the shape of an object, identifying faces, objects, scenes, and movement. The dorsal stream attends primarily to the location of an object, guiding movement on the basis of visual information.
Under what condition do normal people become briefly motion blind, and what causes this?
While making a voluntary eye movement (a saccade), people become briefly motion-blind because area MT and part of the parietal cortex decrease their activity and receive less than usual blood flow.
The frequency of a sound corresponds to which aspect of perception?
Pitch
Why do different musical instruments sound different when they play the same note?
They differ in timbre
What is the function of the pinna?
It helps us locate the source of a sound
What is the function of the three tiny bones of the inner ear?
They amplify vibrations onto the oval window
What stimulates the auditory receptors (hair cells)?
Vibrations in the fluid in the cochlea
Which of the following limits the applicability of the frequency theory of pitch perception?
The refractory period of axons
According to the place theory, how do you identify the pitch of a sound?
By a traveling wave that peaks at one point on the basilar membrane
The traveling wave that peaks at a particular point along the basilar membrane enables us to perceive which aspect of a sound?
Pitch
What is one way in which areas A1 and V1 differ?
V1 damage causes blindness, but A1 damage doesn’t produce deafness
Legion has experienced damage to area A1, which of the following could Legion still do?
Localize a sound
Most neurons in the primary auditory cortex (A1) respond best to what?
A dominant tone and its harmonics
Most neurons in the secondary auditory cortex respond best to what?
Meaningful sounds, such as music or speech
A difference between your ears in time of arrival of a sound helps you identify what type of sound?
A sound with a sudden onset
A difference between your ears in loudness of a sound helps you identify what type of sound?
A high-frequency sound
A phase difference of a sound between your ears helps you identify what type of sound?
A low-frequency sound
What structure enables us to localize sounds in the up–down axis?
The pinna
What causes conductive deafness?
Impairment of the bones of the middle ear
Which of the following could cause nerve deafness?
Damage to the hair cells
Hearing improves if the listener watches the:
speaker’s face
What does the vestibular system enable you to do?
Read while jiggling your head
Which of the following does your vestibular system tell your brain?
Which direction you are moving
To what extent does the nervous system maintain separate representations of touch, heat, pain, and other aspects of somatic sensation?
Different types remain separate even in the cortex
The anterior cingulate cortex and the insular cortex respond to what aspect of skin sensations?
Pleasantness or unpleasantness
Where are the taste buds in adult humans?
Along the edge of the tongue
The saccule, utricle, and the three semicircular canals produce _____ sensation.
Vestibular
Someone who perceives each letter and number as having a particular color has the condition known as _____.
Synesthesia
What is the frequency theory of pitch perception, and why does it apply to lower frequencies and not to higher frequencies?
According to the frequency theory, the basilar membrane vibrates in synchrony with sound waves, causing the auditory nerve to produce action potentials at that frequency. This theory works for lower frequencies, but people can hear up to 20,000 Hz, and the refractory period of the axon prevents action potentials from approaching that level.
What is a major way in which the primary visual cortex differs from the primary auditory cortex?
After damage to the primary visual cortex, people become blind. Damage to the primary auditory cortex impairs perception of speech, music, and other meaningful sounds, but it does not make one totally deaf.
Why is it harder to read while jiggling a page than while jiggling your head?
When you move your head, the vestibular system monitors the head movements and makes compensatory movements of your eyes. It can’t help when you jiggle the page.
If you had a cut through the left or right half of your spinal cord, why would it affect touch sensations and pain differently?
The axons conveying pain cross immediately to the opposite side of the spinal cord, whereas the axons conveying touch travel up the ipsilateral side of the cord until they reach the medulla. Therefore, a cut through half of the spinal cord would destroy touch information from that side of the body, and pain information from the opposite side.
What factors contribute to individual differences in olfactory sensitivity?
People differ in olfactory sensitivity because of genetics, age, illness, and gender.
For a small animal, seeing a predator can activate mainly the sympathetic or parasympathetic nervous system, depending on what?
Distance to the predator
Other things being equal, which of the following would increase your probability of feeling angry?
Standing instead of lying down
Which of the following increases (slightly) your rating of a cartoon as being funny?
Holding a pen with your teeth
Which of the following would be a test of the facial-feedback hypothesis?
Does holding a pen with your teeth make you feel happier?
Can you identify someone’s emotion by measuring autonomic activities? If so, how?
No, you cannot.
Which of the following is part of the limbic system?
Amygdala
When researchers recorded brain activity during emotions, what conclusion resulted?
The activity evoked by any emotion varies among studies