Chapter 4 - Sensation & Perception

Question 1

sensation

Answer 1

the process of detecting external events with sense organs and turning those stimuli into neural signals

receiving raw sensory input

Question 2

perception

Answer 2

involves attending to, organizing, and interpreting stimuli that we sense

e.g. organizing diff vibrations in eardrum -> recognition: human voice

Question 3

transduction

Answer 3

when specialized receptors transform the physical energy of the outside world into neural impulses

-> lead to our internal representation of the world

sensory receptors involved in this process differ for each sense

Question 4

from stimulus/sensation to perception

Answer 4

stimulus -> sensory receptors -> neural impulses -> perception

transduction occurs as a bridge btwn sensory receptors & neural impulses

Question 5

Doctrine of Specific Nerve Energies

Answer 5

1826, German physiologist Johannes Muller: States that the different senses are separated in the brain

Though, recent studies show that pathways are not immediately distinct:

perception is a skill that our brains learn through experience

Question 6

orienting response

Answer 6

elicited by changes in our sensory and perceptual worlds -> O.R. allows us to quickly shift our attention to new or altered stimuli

eg. stepping outside a building onto busy street (traffic, bright light)

Question 7

Sensory adaptation

Answer 7

the reduction of activity in sensory receptors with repeated exposure to a stimulus

Pro: allows us to adapt and focus on other more important events/stimuli

Con: not realizing that stimuli still affects, we are prone to eventual damage

Question 8

psychophysics

Answer 8

Gustav Fechner (1801-1887) German physicist. Helped create this field of study that explores how physical energy such as light & sound and their intensity relate to psychological experience

popular approach: measure min. amount of stimulus needed for detection degree to which stimulus must change in strength for change to be perceptible to people

Question 9

absolute threshold

Answer 9

minimum amount of energy or quantity of a stimulus required for it be be reliably detected at least 50% of the time it is presented

varies depending on subject (ie species) and current environment

Question 10

difference threshold

Answer 10

the smallest difference between stimuli that can be reliably detected at least 50% of the time

e.g. add salt to your food: to cross d.t. so taste buds can register

the more intense the original stimulus, the larger amount of it that must be added for the difference threshold to be reached

Question 11

Weber’s law

Answer 11

Ernst Weber (1795-1878) German physician: law states that the just noticeable difference between two stimuli changes as a proportion of these stimuli

Question 12

Signal Detection Theory

Answer 12

states that whether a stimulus is perceived depends on both the sensory experience and the judgement made by the *subject

examines both **sensory process ** and decision process

Question 13

subliminal perception

Answer 13

perception below the threshold of conscious awareness

(eg. “drink coke” on movie screen) -> can it control our behaviours?

supporting evidence prob due to participants’ expectations, though it is possible in under strict lab conditions

Question 14

priming

Answer 14

the activation of individual concepts in long-term memory

-> priming is unlikely to create motivations that hadn’t previously existed; instead, enhance the pre-existing

Question 15

figure-ground principle

Answer 15

Gestalt principle: objects or “figures” in our enviro tend to stand out against a background

Question 16

proximity principle

Answer 16

Gestalt principle: we tend to treat 2+ objects in close procimity to each other as a group

Question 17

proximity principle

Answer 17

Gestalt principle: we tend to group together individuals wearing the same uniform based on their visual similarity

Question 18

Continuity principle

Answer 18

Gestalt principle: perceptual rule that lines and other objects tend to be continuous, rather than abruptly changing direction

Question 19

closure principle

Answer 19

Gestalt principle: the tendency to fill in gaps to complete a whole object

Question 20

Main takeaway from Gestalt concepts

Answer 20

characteristic of perception: we create our own organized perceptions out of the different sensory inputs that we experience

Question 21

top-down processing

Answer 21

when our perceptions are influenced by our expectations or by our prior knowledge

reading 12 & 14 leads to expectation that ambiguous stimulus must be 13

Question 22

bottom-up processing

Answer 22

occurs when we perceive individuals bits of sensory information (eg. sounds) and use them to construct a more complex perception (eg. a message)

occurs when you encounter something unfamiliar/difficult to recognize

Question 23

perceptual set

Answer 23

a filer that influences what aspects of a scene we perceive or pay attention to

Question 24

divided attention

Answer 24

paying attention to more than one stimulus or task at the same tiem

Question 25

selective attention

Answer 25

focusing on one particular event or task

Question 26

inattentional blindness

Answer 26

a failure to notice clearly visible events or objects because attention is directed elsewhere

Question 27

wavelength

Answer 27

distance between peaks of a wave (re. colour perception: long wl correspond to perception of reddish colours, short wl w/ bluish colours) ## Footnote -> additionally, low-amplitude waves correspond with dim colours, and high-amplidude waves are seen as bright colours

Question 28

sclera

Answer 28

white, outer surface of the eye

Question 29

cornea

Answer 29

clear layer that covers the front portion of the eye and also contributes to the eye's ability to focus

Question 30

pupil

Answer 30

regulates the amount of light that enters by changing its size; it dilates to allow more light to enter and constricts to allow less light into the eye

Question 31

iris

Answer 31

a round muscle that adjusts the size of the pupil; it also gives the eyes their characteristic colour

Question 32

lens

Answer 32

a clear structure that focuses light onto the back of the eye

Question 33

accomodation

Answer 33

the lens can change its shape to ensure that light entering the eye is refracted in such a way that is focused when it reaches the back of the eye

Question 34

retina

Answer 34

lines the inner surfact of the back of the eye. consists of specialized receptors that absorb light & send **signals** related to the *properties of light* **to the brain

Question 35

optic nerve

Answer 35

a dense bundle of **fibres** that *connect to the brain

Question 36

optic disc

Answer 36

area of the retina with no photo receptors (due to placement of the optic nerve) -> results in a *blind spot*

Question 37

rods

Answer 37

*photoreceptors* that occupy peripheral regions of the retina; they are highly sensitive under **low light levels**

Question 38

cones

Answer 38

*photoreceptors* that are sensitive to the different **wavelengths of light that we perceive as colour**

Question 39

fovea

Answer 39

central region of the retina

Question 40

dark adaptation

Answer 40

the process by which the rods and cones become increasingly sensitive to light under lower levels of illumination

Question 42

trichromatic theory (/Young-Helmholtz theory)

Answer 42

maintains that colour vision is determined by three different cone types that are sensitive to short, medium, and long wavelengths of light

Question 43

opponent-process theory (of colour perception)

Answer 43

states that we perceive colour in terms of opposing pairs | -> red to green, yellow to blue, and white to black ## Footnote explains tendency of *negative afterimage * complementary of trichromatic theory bc/ both are required to explain how we see colour --> trichromatic: expl colour vision in terms of the **activity of cones** --> opponent-process: expl what happens when ganglion cells process signals from a # of diff cones at the same time

Question 44

optic chiasm | 1st stop of info from the optic nerve

Answer 44

point at wh/ the optic nerves cross at the midline of the brain

Question 45

feature detection cells | cells of the visual cortex

Answer 45

respond selectively to simple and specific aspects of a stimulus, such as angles and edges | -> principle location that visual imput is organized for perception

Question 46

ventral stream

Answer 46

extends from the visual cortex to the lower part of the temporal lobe main function: **object recognition** | "what" pathway

Question 47

dorsal stream

Answer 47

extends from the visual cortex to the parietal lobe main function: **locating objects in space & allowing you to interact with them** | "where" pathway

Question 48

perceptual constancy

Answer 48

the ability to perceive objects as having constant shape, size, and colour despite changes in perspective | -> applies to *shape, size, colour*

Question 49

# t propagnosia

Answer 49

'*face blindndess'* an inability to recognize faces

Question 50

binocular depth cues

Answer 50

distances cues that are based on the differing perspectives of both eyes

Question 51

convergence

Answer 51

a type of **binocular depth cue** that occurs when the eye muscles contract so that both eyes focus on a single object

Question 52

retinal disparirty

Answer 52

the difference in **relative position of an object** as seen by both eyes -> provides info to the brain about *depth* | possible bc/ *stereoscopic vision:* result of overlapping visual fields

Question 53

monocular cues

Answer 53

depth cues that we can perceive with only one eye | cues include *accomodation, motion parallax*

Question 54

pitch

Answer 54

the perceptual experience of sound wave frequencies | -> loudness (function of sound wave amplitude)expressed in decibels (dB)

Question 55

cochlea

Answer 55

a fluid-filled membrane that is coiled in a snail-like shape and contains the structures that **convert sound into neural impulses**

Question 56

sound localization

Answer 56

process of ID'ing where sound comes from (handled by brainstem & midbrain structure called *inferior colluiculus*) | -> involves which ear the sound hits first, intensity & sound shadow

Question 57

place theory of hearing

Answer 57

how we perceive pitch is based on the** location along the basilar membrane** that sound stimulates | high-freq sounds stimulate **hair cells @ base of cochlea** low-freq **@

Question 58

frequency theory

Answer 58

the perception of pitch is related to the frequency at which the basilar membrane vibrates | eg, 70 -Hz sound stimular hair cells 70x/second ## Footnote volley principle: groups of neurons fire in alternating fashion for sounds that exceed the # of times a neuron can fire/second (1000Hz)

Question 59

primary auditory cortex

Answer 59

major perceptual centre of the brain involved in perceiving what we hear

Question 60

vestibular system

Answer 60

a sensory system in the ear that provides information about spatial orientation of the head as well as head motion | contains 2 groups of structures (vestibular sacs & semicircular canals)

Question 61

vestibular sacs

Answer 61

structures that influence your ability to detect when your head is no longer in an upright position (made up of *utricle* and* saccule)*

Question 62

semicircular canals

Answer 62

3 fluid-filled canals found in the inner ear that respond when your head moves in diff directions

Question 63

somatosensory cortex

Answer 63

located in the parietal lobes of the brain (neural region associated w/ sense of touch) -> responsible for *sensual* experiences

Question 64

haptics

Answer 64

the active, exploratory aspect of touch sensation and perception

Question 65

kinesthesis

Answer 65

the sense of bodily motion and position

Question 66

nociception

Answer 66

the activity of nerve pathways that respond to uncomfortable stimulation | **fast fibres** register sharp, immediate pain **slow ** 4 chronic, dull

Question 67

gate-control theory

Answer 67

explains our experience of pain as an interaction between *nerves that transmit* pain messages and those that *inhibit* these messages

Question 68

phantom limb sensations

Answer 68

frequently experienced by amputees, who report pain & other sensations coming from the absent limb

Question 69

gustatory system

Answer 69

functions in the sensation and perception of taste

Question 70

oflactory system

Answer 70

involved in smell - the detection of airborne particles with specialized receptors located in the nose

Question 71

oflactory epithelium

Answer 71

a thin layer of cells that are lined by sensory receptors called *cilia* | ->cilia transmit messages directly to neurons that converge on ol. bulb

Question 72

olfactory bulb

Answer 72

which serves as the brain's central region for processing smells | on the bottom surface of the frontal lobes

Question 73

multimodal integration

Answer 73

the ability to combine sensation from **different modalities** such as vision and hearing into a **single integrated perception**