Chapter 4: Sensation And Perception (Lecture Notes)

Front 1

Sensation is

Back 1

the stimulus detection process carried out by sensory organs - takes place without our awareness

Front 2

Perception is

Back 2

our brains attempts to make sense of the signals generated by sensory organs

- we ARE aware of the end product of the perceptual process

Front 3

Basic structure of the eye: it consists of

Back 3

1. sclera: white of the eye

2. iris: coloured part of the eye (controls how much light enters the eye)

3. pupil: circular hole through which light enters the eye - also controls how much light enters eye

4. pulpillary reflex: dilation and constriction of the pupil

5. cornea: the transparent layer in front of the pupil and iris

6. lens: bends light by changing its curvature so light bends on the FOVEA for clear visions (accommodation)

Front 4

1. retina location

2. consists of

Back 4

1. back of the eye

2. consists of different types of neurons and 2 which are cones and rods (called photoreceptors)

Front 5

Rods and cones fire when

Back 5

Stimulated by light energy of different wavelengths

Front 6

Cones (3)

Back 6

1. about 6 million in each eys

2. function best under bright light - don't work in the dark

3. play central role in colour vision

Front 7

What are the 3 types of cones? Describe each

Back 7

1. red: activated by long light waves and give rise to perception of red color

2. green: are activated by medium length light waves - gives rise to perception of green color

3. blue: activated by short light waves - give rise to perception of blue color

Front 8

Hermann von Helmholtz is responsible for what?

Back 8

- scientist who first discovered relationship b/w cone cells and color visions

- theory: trichromatic theory of color vision

Front 9

Are cones cells alone enough for color vision?

Back 9

No. another type of cells that are found in the primary visual cortex called opponent process cells (blue-yellow, red-green, black-white) are also require in order for us to become aware of color

Front 10

What theory describes how these cells work?

Back 10

Opponent process theory

Front 11

Cones location in the retina?

Back 11

densely packed in small area of retina called fovea

Front 12

Blurred and unclear images

Back 12

fall far away from fovea

Front 13

Rods (3)

Back 13

1. about 120 million rods in each eye

2. function best under dim light - used for night visions

3. distributed relatively evenly throughout the retina - give us peripheral vision and sensitivity to subtle movement of objects (can differentiate slight changes in brightness)

Front 14

The eye: optic nerve (2)

Back 14

1. consists of about 1 million ganglion cells (type of neuron)

2. optic nerve leaves eye at optic disk (blind spot) and travels to thalamus and primary visual cortex of occipital lobe

Front 15

Feature detectors in the visual cortex: (3)

Back 15

1. consists of 3 types: simple, complex and hyper-complex cells

2. together, feature detectors process information about lines and group lines into simple shapes based on their length, width, movement, position, orientation

3. grouped info is then sent to other feature detectors that detect more complex shapes - such as neurons that recognize facial features, color, shapes, etc. (all of them rely on info derived from 3 fundamental feature detectors discovered by hubel and wiesel)

Front 16

The principles of visual perception (2)

Back 16

1. simultaneous bottom-up and top-down processing (parallel processing)

2. depth perception

Front 17

Bottom-up processing

Back 17

we see small and familiar units first - then build these units up into a complete perception

Front 18

Top-down processing

Back 18

we use knowledge to rapidly organize those small units into meaningful "wholes"

Front 19

How do we perceive depth/2D space?

Back 19

Usig 2 sets of cues:

1. monocular cues

2. binocular cues

Front 20

What are monocular cues?

Back 20

also called pictorial cues, require use of only one eye

Front 21

Monocular cues (5)

Back 21

1. interposition

2. linear perspective

3. relative size

4. height in plane

5. light and shadow

Front 22

What is interposition?

Back 22

A monocular cue

- an object that interrupts the natural flow of another object or hidws a portion of another, will likely be presumes to be in front of theo therobject

Front 23

What is linear perspective?

Back 23

a monocular cue

- lines that converge toward the top of the visual field will be perceived as moving away

- ponzo illusion: converging lines give such powerful sense of depth, ponzo illusion can be created even when the lines converging sideways

Front 24

What is relative size?

Back 24

a monocular cue

- all thing being equal, object occupying a smaller area in the visual field will be perceived as being further away

Front 25

Ames Room Illusion shows that

Back 25

the use of relative size to judge distance can be overidden by other factors easily

Front 26

What is height in plane?

Back 26

a monocular cues

- objects low in the visual field appear to be nearer than objects higher in the visual field

Front 27

What is light and shadow?

Back 27

a monocular cue

- patterns of light and dark give impression of 3D and distance

Front 28

Binocular cues require

Back 28

the use of both eyes

Front 29

Types of binocular cues (2)

Back 29

1. binocular disparity

2. binocular convergence

Front 30

What is binocular convergence?

Back 30

our eyes move toward e/o as they focus on nearby objects

- muscle tension created by such convergence provides us w/ info regarding the depth of diff. objects

Front 31

Sound is

Back 31

type of energy that travels through a medium and causes the molecules to vibrate in the process - creating energy waves

Front 32

Sound consists of 3 properties:

Back 32

1. pitch

2. loudness

3. timbre

Front 33

pitch is(3)

Back 33

- the rate (frequency) which molecules vibrate

- higher the rate of vibration -> the higher the pitch

- measured in Hertz (Hz)

Front 34

Humans can detect vibrations between

Back 34

20Hz-and 20 000 hz

Front 35

What is loudness? (3)

Back 35

- the amplitude of the waves or energy contained in the waves

- measured in descibels (dB)

- can detect waves at about 20dB

Front 36

At 125dB sound will cause

Back 36

humans to feel pain

Front 37

What is timbre?

Back 37

- quality or complexity of the sound in terms of the number of different pitch that are present in the sound

Front 38

The ________ directs sound waves to the ________ through the _________

Back 38

The pinna directs sound waves to the middle ear through the ear canal

Front 39

What sound waves enter the middle ear(3)

Back 39

- sound waves vibrate the eardrum

- are magnified by more than 30x by the ossicles

- vibration of stirrup cause hair cells in inner ear to fire

Front 40

Ossicles

Back 40

- hammer

- anvil

- stirrup

Front 41

Hair cells in the ear:

Back 41

- are neurons

- located on the basilar membrane that lines the chochlea of inner ear

- they transudce auditory energy into neural signals that travel to the temporal lobe for processing

Front 42

the semicicular canal is

Back 42

one of 3 fluid-filled structures that play a role in balance

Front 43

the ear canal

Back 43

conducts sound waves to the eardrum

Front 44

pinna is

Back 44

the flexible outer flap of the ear, which channels sound waves into the ear canal

Front 45

The eardrum is

Back 45

membrane that vibrates in response to soundwaves

Front 46

The chochlea converts

Back 46

converts vibration into neural activity

Front 47

Perception of pitch - theories (3)

Back 47

1. frequency theory

2. volley theory

3. place theory

Front 48

Frequency theory

Back 48

- perception of pitch corresponds to rate at which hair cells fire

- only true for low frequency pitch

- research shows very little difference in the rate of neural firing for sound > 100Hz

Front 49

Volley theory

Back 49

valid for sound b/w 100 Hz and 5000 Hz

- different clusters of hair cells, each firing at 100 Hz, but all at slightly diff. time to create higher combined rates of firing

- higher the frequency, the higher the number of clusters involved

Front 50

Place theory

Back 50

- sound of different frequencies excites diff. parts of the chochlea

- high pitch sound excites most strongly part of chochlea that is closer to the stirrups

-low pitch sound excites most strongly the tip of the chochlea

Front 51

Based on research, how do we process higher-pitch sounds?

Back 51

the place theory

Front 52

Types of deafness/hearing loss: (3)

Back 52

1. nerve deafness: damage to auditory nerve

2. conductive deafness: malfunctioning of the eardrum or the ossicles

3. noise-induced hearing loss: damage to hair cells due to chronic exposure to loud noise and to old age

Front 53

Causes of deafness and hearing loss (5)

Back 53

1. genetic

2. disease

3. injury, exposure to loud noise

4. normal aging

Front 54

Smell is caused by

- explain the neuron movement involved

Back 54

airborne chemicals that interact with olfactory neurons

- the neurons send signals to olfactory bulb, which then sends signals to limbic system and frontal lobe for olfactory processing

Front 55

Taste buds are found inside

Back 55

papillae (bumps on our tongue)

Front 56

How many types of taste buds are there? what are there?

Back 56

5:

- sweet

- salty

- sour

- bitter

- unami (savoury)

- may be a sixth (fat)

Front 57

The many different tastes we perceive is due to

Back 57

interaction between these taste buds and our sense of smell