Chapter 5

Question 1

What is synesthesia

Answer 1

“mixing of the senses”

ex. sounds as coulors, tastes as touch

Question 2

What is the process of Transduction?

Answer 2

Your sensory receptors must translate into the only language your nervous system understands: nerve impulses

Question 3

What is the role of feature detectors?

Answer 3

break down the analyze the specific features of stimuli

Question 4

Describe Perception

Answer 4

organizing and giving meaning to input

Question 5

Define sensation

Answer 5

the stimulus-detection process by which our sense organs respond to and translate environmental stimuli into nerve impulse that are sent to the brain

Question 6

Define perception

Answer 6

making “sense” of what are senses tell us – is the active process of organizing this stimulus input and giving it meaning

Question 7

Pschophysics

Answer 7

studies relations between the physical characteristics of stimuli and sensory capabilities, is concerned with two kinds of sensitivity

1) limits of sensitivity
2) difference between sensitivity

Question 8

absolute threshold

Answer 8

the lowest intensity at which a stimulus can be detected correctly 50% of the time
thus…
the lower the absolute threshold the higher the sensitivity

Question 9

define decision criterion

Answer 9

a standard of how certain a person must be that a stimulus is present before they say they detect it

Question 10

Signal Detection Theory

Answer 10

is concerned with the factors that influence sensory judgement

Question 11

Differentiate between a miss, hit, false alarm and correct regection

Answer 11

stimulus there:
yes- hit no- miss

stimulus not there
yes- false alarm
no- correct regection

Question 12

Difference Threshold

Answer 12

is defined as the smallest difference between 2 stimuli that people can perceive 50% of the time, sometimes called the Just Noticeable Difference

Question 13

What does JND stand for??

Answer 13

Just noticeable difference

Question 14

Weber’s Law

Answer 14

states that the difference threshold, or JND is directly proportional to the magnitude of the stimulus with which the comparison is being made, and can be expressed as a Weber fraction

it is a proportion not a constant number. music that is very quiet and then slightly turned up we notice right away in contrast to LOUD music that is turned up and we don’t seem to notice

• humans are most sensitive to sight and tonal pitch

Question 15

Sensory Adaptation (habituation)

Answer 15

sensory neurons are engineered to respond to a constant stimulus by decreasing their activity, and the diminishing sensitivity to an unchanging stimulus is called sensory adaptation

ex. when you put on clothes you notice right away but soon after you get used to wearing them

occurs in all sensory modalities

Question 16

adaptive value

Answer 16

frees sense to be more sensitive to changes in environment

Question 17

Order of the Spectrum?

Answer 17

ROY G. BIV

Question 18

cornea

Answer 18

Transparent protective structure at the front of the eye

Question 19

pupil

Answer 19

adjustable opening that controls amount of light

Question 20

lens

Answer 20

elastic structure for focusing
thinner to focus on distant objects
thicker to focus on nearby objects

Question 21

retina

Answer 21

photoreceptors transduce light energy into electrical impulses

Question 22

describe myopia

Answer 22

nearsightedness (difficulty seeing far away objects)
eyeball is longer back to front
lens focuses light in front of retina

Question 23

Describe Hyperopia

Answer 23

Farsightedness (difficulty seeing things close up)
eyeball is short
lens focuses light behind retina

Question 24

What are the 2 light sensitive receptor cells and where are they located

Answer 24

cones and rods located in retina

Question 25

Cones

Answer 25

``` (chipmunks only have cones) for coulor and detail function best in high illumination concentrated in centre of retina favea (in centre of retina) contains only cones ```

Question 26

Rods

Answer 26

(most species only have rods) function best in low illumination 500 times more sensitive to light then cones found mostly in periphery of retina--- although found everywhere in retina except favea

Question 27

Bipolar cells

Answer 27

have synaptic connections with rods and cones. The bipolar cells, in turn, synapse with a layer of about one million ganglion cells, whose axons are connected into a bundle to form the optic nerve

Question 28

visual acuity

Answer 28

ability to see fine detail

Question 29

cone connections vs. rod connections

Answer 29

cones have "single line" connections (one to one) fine detail connections with bipolar cells where as, many rods connect to single bipolar cell

Question 30

"blind spot"

Answer 30

Where the optic nerve exits from eye

Question 31

photopigments

Answer 31

rods and cones translate light waves into nerve impulses through the action of protein molecules called photopigments

Question 32

Visual transduction

Answer 32

Action of photopigments Absorption of light changes rate of neurotransmitter release Greater rate of release = stronger the signal passed on (protein pigments split when hit by light)

Question 33

dark adaptation

Answer 33

the progressive improvement in brightness sensitivity that occurs over time under conditions of low illumination (going from bright sunlight into a movie theator you need to give it time before you can see)-- rely on rods in dark

Question 34

How long does it take rods and cones to adapt to dark conditions

Answer 34

it takes the cones about 10 minutues and it is at its maximum and it takes about 30 mins for rods to be at their maximum however, rods can detect light intensities 1/10000 as great as those before dark adaption

Question 35

What coulor are rods not affected by?

Answer 35

red

Question 36

Trichromatic Theory (young- Helmholtz)

Answer 36

- - Three types of color receptors in retina - - Cones most sensitive to blue, green, red wavelengths - -Visual system combines activity from these cells - -Colours are perceived by additive mixture of impulses - -If all are equally activated - white colour is produced

Question 37

problems with Trichomatic theory?

Answer 37

Red-green colour blind individuals should not be able to perceive yellow (red + green = yellow) Afterimages Stare at red - look away you’ll see green (same for blue and yellow)

Question 38

Opponent--- process theory (Hering 1870)

Answer 38

``` Three cone types Each responds to two different wavelengths Red or green Blue or yellow Black or white Explains Afterimages Stare at certain colour Neural processes become fatigued Have ‘rebound’ effect with receptor responding with its opponent opposite reaction ```

Question 39

Dual processes Theory

Answer 39

Combines trichromatic & opponent process theories 3 cone types sensitive to short (blue), medium (blue), and long (red) wavelengths stimulate opponent-process reactions Opponent processes occur in ganglion cells, neurons in relay stations & visual cortex

Question 40

Differentiate between trichromats, dichromats and monochromat

Answer 40

``` Trichromats Normal colour vision Dichromats Deficient in one system (red-green is most common) Monochromat Sensitive to black-white only ```

Question 41

Reconstruction of visual scenes

Answer 41

1 Impulses go from Thalamus to primary visual cortex (occipital lobe) Specific regions of retina processed in specific areas of cortex 2 Fovea has large representation in visual cortex Multiple ‘maps’ where stimuli are processed

Question 42

Feature detectors

Answer 42

fire selectively in response to stimuli that have specific characteristics such as bars, slits, orientation, coulor, depth ect

Question 43

How do we unify images

Answer 43

Parallel processing Modules which process colour, movement, shape, distance simultaneously Attaching meaning to what we see Information goes to visual association cortex Interpreted in terms of our memories & knowledge

Question 44

Differentiate between the two kinds of processing functions

Answer 44

Bottom up processing Analysis of individual stimulus elements Re-combines into unified whole Top-down processing: Existing knowledge, concepts, ideas, expectations example: learning to read at first it is hard (bottom up) but as you get better it isnt as difficult and you are even able to skim read (top-down)

Question 45

What are the roles of Attention

Answer 45

Involves 2 processes Focusing on certain stimuli Filtering out other information

Question 46

What is the experimental techinique shadowing?

Answer 46

participants wear headphones with 2 different messages playing

Question 47

differentiate between high track and low track

Answer 47

high track needs your full attention (talking) | low track you can do subconsciously (walk)

Question 48

describe unintentional blindness

Answer 48

the failure of unattended stimuli to register in consciousness looking without seeing (watch bballs being passed and miss gorilla) proves why we should text and drive

Question 49

define newbophobic

Answer 49

dont like new things in environment, cows dont like it when there is shovel in the way of walkig out of the parlor

Question 50

What is a illusion

Answer 50

an error in perception

Question 51

describe the Gestalt principles of perceptual organization

Answer 51

Gestalt = pattern, shape, form Wholes we perceive are more than sum of their parts Suggested perception was governed by laws that determined how things were grouped together Gestalt Laws of Perceptual Organization figure-ground relations - we tend to organize stimuli into a central or foreground figure and a background

Question 52

Descrive gestalt laws of organization including similarity, proximity, closure and continuity

Answer 52

Similarity - Similar items belong together Proximity - Elements that are close together belong together Closure - Close open edges; perceive boundaries Continuity - Elements linked to form continuous line

Question 53

perceptual schema

Answer 53

a mental representation to compare stimuli with Role of perceptual schema Mental representations Allows for classification of stimuli

Question 54

perceptual set

Answer 54

a readiness to perceive stimuli in a particular way. sometimes believing is seeing

Question 55

perceptual constancies

Answer 55

allow us to recognize familiar stimuli under varying conditions

Question 56

Understand shape constancies, size constancies and brightness constancies

Answer 56

Shape constancy friend’s face has a different shape when you look at their profile than face on – has friend’s face has changed? Size constancy walk to your car - image on your retina gets larger - do you perceive your car to be growing? Brightness constancy coulor of your shirt you know is the same under black light even though it seems different

Question 57

Depth Perception

Answer 57

Image on the retina is 2 dimensional | But we live in a 3 dimensional world

Question 58

Monocular cues vs Binocular cues?

Answer 58

Monocular cues Depth perceived with one eye Binocular cues Depth perceived with 2 eyes

Question 59

What are the monocular depth cues?

Answer 59

1) Light & shadow 2) Linear Perspective Parallel lines converge in distance 3) Interposition Closer objects are in ‘front’ of others 4) Height in horizontal plane Further objects are higher in the horizontal plane 5) Texture Objects farther away have finer texture (less detail) 6) Clarity Objects farther away are hazier 7) Relative size More distant objects are smaller 8) Motion parallax When we move - nearby objects move faster in opposite direction than more distant objects

Question 60

Binocular depth cues?

Answer 60

Have two eyes for a reason Gives exquisite depth perception 1) Based on binocular disparity Two eyes receive different visual images (hold a finger up in front of your face - look with one eye closed and then the other closed) 2) Feature detectors analyze differences 3) Convergence Feedback from ocular muscles when focusing on something distant and then close

Question 61

What is the Primary cue of movement?

Answer 61

Primary cue = image movement across retina ``` Also use: Movement against a background Apparent motion Illusion of motion Stroboscopic motion (phi phenomenon) - e.g., motion pictures (is a series of still pictures) ```

Question 62

Illusions- incorrect perceptions

Answer 62

Perceptual constancies show context can produce illusions | E.g., converging lines disrupt size constancy

Question 63

Restored Sensory Capacity?

Answer 63

Experience plays important role in visual development Can vision be restored? Usually not Individuals born with cataracts and then had vision restored Able to perceive figure-ground relationships Scan objects Not able to identify objects that were familiar through touch (e.g., eating utensils