Topic 6A

Question 1

Weber’s Law

Answer 1

states that the difference threshold is proportional to the magnitude of the stimulus, where ΔI is the difference in threshold and I represent the initial stimulus; suggests that the just noticeable difference is a constant proportion of the original stimulus

Question 2

signal detection theory

Answer 2

the detection of a stimulus depends on both the intensity of the stimulus and the physical/ psychological state of the individual. Basically, we notice things based on how strong they are and on how much we’re paying attention.

Question 3

presbyopia

Answer 3

image focuses behind the retina; similar in a sense to hyperopia which is caused by an eyeball that is too short

Question 4

Myopia

Answer 4

nearsightedness = eyeball is elongated and the image focus falls in front of the retina, so images in the distance are blurry but images nearby are clear

Question 5

Rods

Answer 5

are strongly photosensitive and are located in the outer edges of the retina. They detect dim light and are used primarily for peripheral and nighttime vision.

Question 6

Cones

Answer 6

weakly photosensitive and are located near the center of the retina. They respond to bright light, and their primary role is in daytime, color vision.

Question 7

fovea

Answer 7

region in the center back of the eye that is responsible for acute vision. It has a high density of cones.

Question 8

In humans, _____ far outnumber ____ in the fovea.

Answer 8

In humans, cones far outnumber rods in the fovea.

Question 9

magnocellular (big cell) pathway

Answer 9

carries information about form, movement, depth, and differences in brightness

Question 10

parvocellular (small cell) pathway

Answer 10

carries information on color and fine detail

Question 11

Parallel processing

Answer 11

the use of multiple pathways to convey information about the same stimulus.

Question 12

Feature detection

Answer 12

Once visual information reaches the visual cortex via parallel pathways, it is analyzed by feature detection. There are cells in the visual cortex of the brain that optimally respond to particular aspects of visual stimuli. These cells provide information concerning the most basic features of objects, which are integrated to produce a perception of the object as a whole.

Question 13

Hearing

Answer 13

transduction of sound waves into a neural signal that relies on the structures of the ear

Question 14

External ear

Answer 14

auricle/outer ear = visible structure of hearing The C-shaped curves of the auricle direct sound waves towards the ear canal, which enters into the skull through the external auditory meatus of the temporal bone. At the end of the auditory canal (external acoustic meatus) is the tympanic membrane (ear drum), which vibrates with the movement of air in sound waves.

Along the length of the auditory canal are ceruminous glands that contribute to the production of cerumen (earwax) which helps protect the tympanic membrane.

Question 15

Middle ear

Answer 15

ossicles
Malleus (hammer)

• Incus (anvil)
• Stapes (stirrup)

‣ The malleus is attached to the tympanic membrane and articulates with the incus, which articulates with the stapes. The stapes is then attached to the inner ear at the oval window where the sound waves will be transferred to the inner ear

Question 16

Internal ear

Answer 16

The inner ear is entirely enclosed within the temporal bone.

It has three separate regions:

• The cochlea: responsible for hearing
• The vestibule
• Semicircular canals: responsible for balance and equilibrium

Question 17

Oval window

Answer 17

the connection b/t the middle & inner ear; it’s a membranous area at the entrance of the snailshaped cochlea. The vibrations transmitted through the ossicles pass into the cochlea by way of the oval window.

Question 18

cochlea

Answer 18

composed of 3 chambers separated from one other by membranes.

◦ The scala vestibuli (upper chamber) and the scala tympani (lower chamber) extend the length of the cochlea and are continuous with a connection at the helicotrema

◦ The cochlear duct is the third, middle chamber positioned between the scala vestibuli and scala tympani.

◦ As the oval window is pushed in by sound waves vibrating from the ossicles, fluid within this tube is pushed along its length and the round window at its other end bulges out as a result of that movement.

Question 19

Organ of Corti

Answer 19

a spiral organ that is the organ for hearing and contains the sensory receptors. It’s located throughout the cochlear duct.

◦ It’s composed of a lower basilar membrane against the scala tympani and an upper tectorial membrane within the cochlear duct

Question 20

2 types of equilibrium:

Answer 20

Static (gravitational) equilibrium = involves the movement of the head w/ respect to gravity

◦ Dynamic (rotational) equilibrium = involves acceleration of the head in rotation, horizontal, and vertical movements

Question 21

interaural level differences

Answer 21

refers to the fact that a sound coming from the right side of your body is more intense at your right ear than at your left ear because of the attenuation of the sound wave as it passes through your head

Question 22

interaural timing differences

Answer 22

refers to the small difference in the time at which a given sound wave arrives at each ear. Certain brain areas monitor these differences to construct where along a horizontal axis a sound originates.

Question 23

Temporal theory of pitch perception

Answer 23

asserts that frequency is coded by the activity level of a sensory neuron. This would mean that a given hair cell would fire action potentials related to the frequency of the sound wave.

Question 24

place theory of pitch perception

Answer 24

suggests that different portions of the basilar membrane are sensitive to sounds of different frequencies. More specifically, the base of the basilar membrane responds best to high frequencies and the tip of the basilar membrane responds best to low frequencies. Therefore, hair cells that are in the base portion would be labeled as highpitch receptors, while those in the tip of basilar membrane would be labeled as low-pitch receptors.

Question 25

inner hair cells

Answer 25

the primary auditory receptors and exist in a single row, numbering approximately 3,500.

Question 26

stereocilia

Answer 26

from inner hair cells extend into small dimples on the tectorial membrane’s lower surface.

Question 27

outer hair cells

Answer 27

are arranged in three or four rows. They number approximately 12,000, and they function to fine tune incoming sound waves

Question 28

Merkel’s disks

Answer 28

ound in the upper layers of skin. They are densely distributed in the fingertips and lips. They are slowadapting, unencapsulated nerve endings, which respond to light touch

Question 29

Meissner’s corpuscles

Answer 29

found primarily in the glabrous skin on the fingertips and eyelids. They respond to fine touch and pressure, but they also respond to low-frequency vibration or flutter.

Question 30

Ruffini endings

Answer 30

aka bulbous corpuscles; they’re located deeper in the dermis, near the base. They are slow-adapting, encapsulated mechanoreceptors that detect skin stretch and deformations within joints.

Question 31

Pacinian corpuscle

Answer 31

they’re located deep in the dermis are rapidly-adapting mechanoreceptors that sense deep, transient (not prolonged) pressure, and high-frequency vibration. Pacinian receptors detect pressure and vibration by being compressed, which stimulates their internal dendrites.

Question 32

Proprioception

Answer 32

sense of the position of parts of our body and force being generated during movement.

Question 33

Golgi tendon organs

Answer 33

they are proprioceptive sensory receptor organs that are located at the insertion of skeletal muscle fibers into the tendons of skeletal muscle.

Question 34

Describe the tastants

Answer 34

A salty tastant (containing NaCl) provides the sodium ions (Na+) that enter the taste neurons, exciting them directly.

• Sour tastants are acids which belong to the thermoreceptor protein family. Binding of an acid or other sour-tasting molecule triggers a change in the ion channel which increases hydrogen ion (H+) concentrations in the taste neurons; thus, depolarizing them.
• Sweet, bitter, and umami tastants require a G-protein-coupled receptor.
• These tastants bind to their respective receptors, thereby exciting the specialized neurons associated with them.

Question 35

Olfactory transduction

Answer 35

a series of events in which odor molecules are detected by olfactory receptors. These chemical signals are transformed into electrical signals and sent to the brain, where they are perceived as smells.

Question 36

Kinesthesia

Answer 36

awareness of the position and movement of the parts of the body using sensory organs (proprioceptors), in joints and muscles. It is a critical component in muscle memory and hand-eye coordination.

Question 37

Bottom-up processing

Answer 37

perceptions are built from sensory input. In bottom-up processing, sensory receptors pick up signals for the brain to integrate and processs.

Ie- stubbing your toe on a chair, the pain receptors detect pain and send this information to the brain where it is processed.

Question 38

top-down processing

Answer 38

how we interpret those sensations is influenced by our available knowledge, our experiences, and our thoughts

An example of this is if you see the chair you have stubbed your toe on before and you avoid it to make sure it does not happen again.

◦ In top-down processing, there is always bias of environmental factors on a personal perception of the stimulus = context effect. Where cognitive psychology of a person’s environment affects their stimulus processing.

Question 39

Gestalt laws of grouping

Answer 39

set of principles in psychology first proposed by Gestalt psychologists to explain how humans naturally perceive stimuli as organized patterns and objects. Gestalt psychology says that our brain groups elements together whenever possible instead of keeping them as separate elements.

Question 40

law of proximity

Answer 40

posits that when we perceive a collection of objects, we will perceptually group objects that are physically close to each other. This allows for the grouping together of elements into larger sets and reduces the need to process a larger number of smaller stimuli. For this reason, people tend to see clusters of dots on a page instead of a large number of individual dots. The brain groups together the elements instead of processing a large number of smaller stimuli, allowing us to understand and conceptualize information more quickly.

Question 41

Law of Similarity

Answer 41

tates that people will perceive similar elements will be perceptually grouped. This allows us to distinguish between adjacent and overlapping objects based on their visual texture and resemblance.

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Question 42

Figure-Ground Law

Answer 42

posits that a visual field can be separated into two distinct regions: the figures (prominent objects) and the ground (the objects that recede into the background. Many optical illusions play on this perceptual tendency

Question 43

Law of Closure

Answer 43

explains that our perception will complete incomplete objects.

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Question 44

Law of Continuity

Answer 44

explains that lines are seen as following the smoothest path.