Sensation and Perception

Question 1

What is the psychology definition of Sensation?

Answer 1

Transduction; conversion of physical, electromagnetic, auditory, and other information from our internal and external environment to electrical signals in the nervous system

Question 2

What is the psychology definition of Perception?

Answer 2

Processing the information to make sense of its significance

Question 3

What is the difference between Sensation and Perception?

Answer 3

Sensation is merely information as a electrical signal from both outside and inside; Perception is processing this information to understand what is going on.

Question 4

What are Sensory receptors?

Answer 4

Neurons that respond to stimuli and trigger electrical signals

Question 5

What is Psychophysics?

Answer 5

Relationship between nature with perception and Sensation

Question 6

What is Ganglia?

Answer 6

Collection of neuron cell bodies found outside of CNS; They receive signals from the nerve endings and transmit the information to CNS.

Question 7

What are the 7 common receptors?

Answer 7

Photoreceptors
Hair cells(hearing, rotational and linear acceleration)
Nociceptors
Thermoceptors
Osmoreceptors
Olfactory receptors
Taste receptors

Question 8

What is a threshold?

Answer 8

Minimum amount of stimulus that renders a difference in perception

Question 9

What is the difference between Absolute threshold and Threshold of conscious perception? What happens when the stimulus is below each threshold?

Answer 9

Absolute threshold is the minimum stimulus energy required to activate a sensory system; Threshold of conscious perception is the minimum energy required to catch one’s attention and consciousness

Absolute threshold: if below, the signal is not transduced, not reaching the CNS
Threshold of conscious perception: If below, the signal is still transduced and reaches the CNS but maybe to quick or subtle that it doesn’t catch one’s attention

Question 10

What is jnd and how is it related to Weber’s law? Give an example.

Answer 10

jnd: just noticeable difference(jnd) is the minimum difference in magnitude between two stimuli before one can perceive this difference. But Weber’s law states that instead of the mere difference between the two values, the ratio of: (diff b/w two values / original value) is more important.
ex. if jnd is 0.68% from the ratio, then we apply it to various values: 1000Hz and 1006.8Hz is the difference that one can distinguish, not 1000 and 1003Hz.

Question 11

What is signal detection theory and what type of bias does this bring?

Answer 11

Theory that states perception of stimuli can be affected by nonsensory factors such as experience, memory, motives, and expectation.
It brings out Response bias which states one’s tendency to systematically respond to a stimulus in a particular way due to nonsensory factors.

Question 12

A basic signal detection experiment may have catch trials, noise trials, hits, misses, false alarms, and correct negatives. What do these terms mean?

Answer 12

catch trials: signal presented
noise trials: signal not presented
hits: correctly perceives the signal
misses: fails to perceive the signal
false alarms: perceives a signal when none was given
correct negatives: doesn’t perceive the signal when none was given

Question 13

How does sensory adaptation affect a difference threshold?

Answer 13

adaptation -> increases threshold because we are now “used to it”

Question 14

List the function of each structure:

• Cornea
• Iris
• Lens
• Ciliary muscle
• Canal of Schlemm
• Pupil
• Sclera
• Vitreous

Answer 14

Cornea: gathers and focuses the incoming light

Iris: divides the front of the eye into anterior and posterior chamber; controls the size of the pupil

Lens: refracts the incoming light to focus it on the retina

Ciliary muscle: produces aqueous humor; accommodation of the lens

Canal of Schlemm: drains aqueous humor

Pupil: allows passage of light from anterior to posterior chamber

Sclera: provides structural support

Retina: Detects images with Cones and Rods

Vitreous: Transparent gel behind the lens that supports retina

Question 15

List the structures in the visual pathway, from where light enters the cornea to the visual projection areas in the brain

Answer 15

Cornea -> Pupil -> Lens -> Vitreous -> Retina(rods and cones -> bipolar cells -> ganglion cells) -> Optic nerve -> Optic chiasm -> Optic tract -> Lateral geniculate nucleus(LGN) of thalamus -> radiations through parietal and temporal lobes -> visual cortex(in occipital lobe)

Question 16

What is a characteristic of Optic chiasm?

Answer 16

has fibers that cross from nasal side of the retina

Question 17

What is the difference between cones and rods?

Answer 17

cones: pick up colors(blue, green, red; short to long wavelengths)
rods: pick up black and white(light or dark)

Question 18

What is parallel processing?

Answer 18

ability to simultaneously analyze and combine information regarding color, shape, and motion

Question 19

In feature detection, what type of cells are responsible for color? Shape? Motion? what is the difference between the cells that are responsible for shape and motion?

Answer 19

Color: Cones
Shape: Parvocellular cells; high color and spatial resolution but low temporal resolution
Motion: Magnocellular cells; low spatial resolution but high temporal resolution

Question 20

What does outer ear consist of(3)?

Answer 20

Pinna(auricle), External auditory canal, Tympanic membrane

Question 21

What does middle ear consist of(2)?

Answer 21

Ossicles(malleus, incus, stapes)

Eustachian tube

Question 22

What does Inner ear consist of(2)? what is the difference between the two?

Answer 22

Bony labyrinth. filled with Perilymph

Membraneous labyrinth: filled with Endolymph

Question 23

What does Membraneous labyrinth consist of and what are their functions?

Answer 23

Cochlea: works with basilar membrane to distinguish sounds of low and high pitch

Vestibule(2): Utricle and Saccule, sensitive to linear acceleration

Semicircular canals(3): three of them with half circular loops, sensitive to rotational acceleration

Question 24

List the structures in Auditory pathway

Answer 24

Pinna -> external auditory canal -> tympanic membrane -> malleus -> incus -> stapes -> oval window -> perilymph in cochlea -> basilar membrane -> basilar membrane -> hair cells -> vestibulocochlear nerve -> brainstem -> medial geniculate nucleus(MGN) of thalamus -> auditory cortex(temporal lobe)

Question 25

How does the organization of the cochlea indicate the pitch of an incoming sound?

Answer 25

Basilar membrane is tonotopically organized: high-pitched sounds cause vibrations at the base of cochlea(outer), whereas low-pitched sounds cause vibrations at the apex of the cochlea(inner)

Question 26

List the structures in the olfactory pathway.

Answer 26

Nostrils -> nasal cavity -> olfactory nerve(chemoreceptors) -> olfactory bulb -> olfactory tract

Question 27

Both smell and taste are sensitive to chemicals what is different about the types of chemicals each one can sense?

Answer 27

Smell: volatile compounds, gaseous
Taste: dissolved compounds

Question 28

What are the four main modalities of somatosensation?

Answer 28

Pressure, Temperature, Vibration, Pain

Question 29

which lobe is responsible for somatosensory?

Answer 29

somatosensory cortext is in parietal lobe

Question 30

What is the difference between Bottom-up processing and Top-down processing?

Answer 30

Bottom-up(data-driven) processing gathers information using parallel processing and feature detection, then integrated into one cohesive whole. -> slower but less prone to mistakes

Top-down processing depends on experience and expectations to make conclusion and make one cohesive whole -> faster but prone to mistakes

Question 31

Describe each of the Gestalt principles:

• Proximity
• Similarity
• Good continuation
• Subjective contours
• Closure
• Pragnanz

Answer 31

Proximity: close to each other -> one unit
Similarity: similar -> grouped together
Good continuation: same pathway -> grouped together
Subjective contours: seeing invisible edges
Closure: space surrounded by lines -> enclosed
Pragnanz: Perceptual organization will always be as regular, simple, and symmetric as possible

Question 32

What is somatosensation?
Kinesthetic sense?
Vestibular sense?
Chemoreception?

Answer 32

• various modalities of touch
• ability to tell where one’s body is in space
• detection of linear and rotational acceleration in the middle ear
• sensing chemicals in the environment

Question 33

Difference between signal detection and Feature detection?

Answer 33

signal detection: when a stimulus is given, one tries to find/seek if it is what one expected it to be(stimulus -> investigate). Picks up a stimulus(signal) -> looks for it

Feature detection: Investigate -> finds. Detail gathering then finds.