Week 7 - Sensation, Perception

Question 1

Sensation

Answer 1

physical processing of environmental stimuli by the sense organs.
(sense organs engage in transduction to convert sensations into electrical stimulation to be understood by the brain)

Question 2

Perception

Answer 2

the psychological process that makes sense of the stimuli.

Question 3

differential threshold, “just noticeable difference” (JND)

Answer 3

the smallest difference needed in order to differentiate between two stimuli.

Question 4

Weber’s Law

Answer 4

the JND is proportional to the magnitude of the initial stimulus; larger stimuli require larger differences to be noticed (i.e. differentiating between a 1 and 2 lb weight vs. a 10 and 11 lb weight).

Question 5

bottom-up processing

Answer 5

build up to perceptual experience from the individual pieces.

Question 6

top-down processing

Answer 6

stimuli we’ve experienced in the past influence how we process new stimuli

Question 7

Vision

Answer 7

light bouncing off of an object and into our eye.
Light enters through the pupil, which regulates the amount of light by either contracting or dilating in bright or dim environments respectively.
It is then passed through the lens, which focuses an image on the retina.

Question 8

binocular disparity

Answer 8

result of our two eyes processing slightly different images provides us with the ability to perceive 3D space and depth through binocular vision.

Question 9

rods

Answer 9

sensitive to low levels of light (black, grey, white)

• found more in the periphery
• more rods than cones

Question 10

cones

Answer 10

sensitive to colour and allow us to see fine detail (concentrated in the fovea (the central region of focus))

Question 11

Dark adaptation

Answer 11

the adjustment of our eyes to low levels of light (night vision).
- takes about 10 minutes to occur, due to our rods becoming bleached in normal light conditions.

Question 12

light adaptation

Answer 12

adjustment of our eyes to high levels of light (entering the daylight after being in a dark room).
-occurs when a large number of rods and cones, which have been adjusted to the dark, become bleached at once, and can cause brief blindness.

Question 13

trichromatic theory

Answer 13

proposes that colour vision is influenced by three different cones that respond preferentially for red, green, and blue.

Question 14

opponent-process theory

Answer 14

proposes that our cones send information to retinal ganglion cells, which respond to pairs of colours. This is what causes after-images to occur when we shift our eyes away from something we have been staring at.

Question 15

hearing

Answer 15

Sound waves are funneled by the pinna into the auditory canal, where they reach the tympanic membrane (eardrum). The eardrum vibrates against the malleus (hammer), incus (anvil), and stapes (stirrup), collectively known as the ossicles.
The ossicles amplify the sound waves entering the cochlea by striking the oval window.

Question 16

sound waves

Answer 16

• The amplitude of a sound wave changes the volume of a stimulus.
• The frequency of a sound wave changes the pitch of a stimulus.
• The complexity of a sound wave changes the timbre of a stimulus.

Question 17

somatosensation

Answer 17

ability to sense touch, pain, and temperature. This process transduces physical stimuli into electrical potentials to be processed by the brain.

Question 18

cutaneous

Answer 18

senses of the skin

Question 19

kinesthesis

Answer 19

sense of bodily movement

Question 20

proprioception

Answer 20

sense of the position of our body

Question 21

nociception

Answer 21

ability to sense pain and discomfort

Question 22

mechanoreceptors

Answer 22

tranduce tactile stimuli in skin

• merkel’s disks
• meissner’s corpuscles
• ruffini corpuscles
• pacinian corpuscles

Question 23

Olfaction (Smell)

Answer 23

Odorants in our environment bind with olfactory receptors in the olfactory epithelium.

Question 24

gustation (taste)

Answer 24

Taste receptor cells, found in the taste buds of the tongue, respond to chemicals known as tastants.

Question 25

Interaural time differences (ITDs)

Answer 25

differences in the time at which a sound is received between the two ears. A sound originating from your left will reach the left ear first. We are most sensitive to ITDs at low frequencies.

Question 26

Interaural level differences (ILDs)

Answer 26

differences in the intensity of a sound received between the two ears. A sound originating from the left will sound louder to the left ear than to the right. ILDs are most useful at high frequencies.

Question 27

A-fibers

Answer 27

highly myelinated (fast-conducting) sensory nerves, project to the somatosensory cortex to locate the source of the pain and propel you to remove the source.

Question 28

C-pain fibers

Answer 28

convey information to the insular cortex, which processes emotion. This causes a longer, aching pain that conditions us to avoid the source in the future.

Question 29

C-tactile fibers

Answer 29

respond to gentle touch, with their firing rate correlating with how pleasant the touch feels.

Question 30

analgesia

Answer 30

loss of sensation of pain (expecting pain relief from a medical treatment contributes to the placebo effect)

Question 31

allodynia

Answer 31

pain occurs as a result of a stimulus that does not normally provoke it.