W4 notes

Question 1

sensation

Answer 1

Sensation is the process of detecting environmental stimuli arising from the body

Question 2

perception

Answer 2

Perception is the process of interpreting sensory info

Question 3

synesthesia

Answer 3

a condition where the stimulation of one sensory pathway leads to the simultaneous and automatic stimulation of another sensory pathway, the same sensory input can lead to dramatic differences in perception

Question 4

stimulus

Answer 4

A stimulus is anything that elicits a rxn from our sensory systems

Question 5

transduction

Answer 5

This process of translation from stimulus to neural signal is known as transduction

Question 6

sensory adaptation

Answer 6

Sensory adaptation is the tendency to pay less attention to a non changing source of stimulation

Question 7

bottom-up processing

Answer 7

We refer to the brain’s use of incoming signals to construct perceptions as bottom-up processing
For example, we construct our visual reality from information about light that is sent from the eye to the brain

Question 8

top-down processing

Answer 8

In top-down processing, we use knowledge gained from prior experience with stimuli to perceive them
For example, a skilled reader has no trouble reading sentences, even the words are jumbled

Question 9

gustav fechner

Answer 9

Gustav Fechner developed methods, which he called psychophysics, for studying the relationships between stimuli (the physics part) and perception of those stimuli (the psyche or mind part)

Question 10

absolute threshold

Answer 10

Absolute threshold is the smallest amount of stimulus that can be detected

Question 11

difference threshold

Answer 11

Difference threshold is the smallest detectable difference between 2 stimuli

Question 12

weber-fechner law

Answer 12

The amount of difference that can be detected depends on the size of stimuli being compared
As stimuli get larger, differences must also become larger to be detected by an observer, a phenomenon known as Weber-Fechner Law

Question 13

signal detection

Answer 13

Signal detection is a 2 step process involving the actual intensity of the stimulus, which influences the observer’s belief that the stimulus did occur and; the individual observer’s criteria for deciding whether the stimulus occurred

Question 14

vision

Answer 14

Vision, the processing of light reflected from objects, is one of the most important sensory systems in humans

Question 15

visible light

Answer 15

Visible light, or the energy within the electromagnetic spectrum to which our visual systems respond, is a type of radiation emitted by the sun, other stars and artificial sources such as a light bulb

Question 16

wavelength

Answer 16

Wavelength, or the distance between successive peaks of waves, is decoded by our visual system as colour or shades of grey

Question 17

height or amplitude

Answer 17

The height or amplitude, of the waves is translated by the visual system into brightness
Large amplitude waves appear bright, and low-amplitude waves appear dim

Question 18

cornea

Answer 18

Cornea is the clear surface at the front of the eye that begins the process of directing light to the retina

Question 19

pupil

Answer 19

Travelling light next enters the pupil, which’s actually an opening formed by the muscles of the iris

Question 20

iris

Answer 20

The iris adjusts the opening of the pupil in response to the amount of light present in the environment and to signals from the autonomic nervous system

Question 21

lens

Answer 21

Directly behind the pupil and iris is the main optical instrument of the eye, the lens
Muscles attached to the lens can change its shape, allowing us to accommodate, or adjust our focus to see near or distant object
The muscles relax and the lens flattens in order to focus on distant objects, and the muscles contract and the lens becomes more spherical to focus on near objects

Question 22

retina

Answer 22

Behind the lens is the main chamber of the eye, and located on the rear surface of this chamber is the retina, a thin but complex network of neurons specialized for the processing of light
In the deepest layer of the retina are specialized receptors, the rods and cones, that transduce the light information

Question 23

why does each eye have a blind spot

Answer 23

The blood vessels serving the eye and the axons that leave the retina to form the optic nerve exit at the optic disk
Because there are no rods and cones in the optic disk, each eye has a blind spot

Question 24

fovea

Answer 24

Toward the middle of the retina is the fovea, which’s specialized for seeing fine detail
Responsible for central vision

Question 25

optic nerve

Answer 25

The rods and cones are the only true receptors of the visual system Axons from the final layer of cells, the ganglion cells, leave the back of the eye to form the optic nerve The optic nerves cross the midline at the optic chiasm There, the axons closest to the nose cross over to the other hemisphere, while the axons to the outside proceed to the same hemisphere This is when if you focus straight ahead, everything to the left of centre in the visual field is processed by the right hemisphere, while everything to the right is processed by left hemisphere

Question 26

optic tracts

Answer 26

Beyond the optic chiasm, the visual pathways are known as optic tracts

Question 27

amygdala

Answer 27

The amygdala uses visual information to make quick emotional judgments, especially about potentially harmful stimuli

Question 28

primary visual cortex

Answer 28

The primary visual cortex begins the processing of visual input

Question 29

dorsal stream

Answer 29

The dorsal stream extends upward from V1 in the occipital into the parietal lobe This is the “where” pathway that helps us process movement and localize objects in space

Question 30

ventral stream

Answer 30

The ventral stream extends downward from V1 in the occipital lobe to the temporal lobe This is the “what” pathway that responds to shape and colour and contributes to our ability to recognize objects and faces

Question 31

trichromatic theory

Answer 31

Trichromatic theory is a theory of colour vision based on the existence of different types of cones for the detection of short, medium and long wavelengths Consistent with the existence of 3 types of cones in the retina that respond best to short (blue), medium (green) or long (red) wavelengths

Question 32

when does colour blindness occur

Answer 32

Colour blindness occurs when a person has fewer than the typical 3 types of cones

Question 33

opponent process theory

Answer 33

An opponent process theory is a theory of colour vision that suggests we have a red-green colour channel and a blue-yellow colour channel in which activation of one colour in each pair inhibits the other colour

Question 34

Which of these two theories of colour vision, trichromatic theory or opponent process theory, is correct?

Answer 34

The trichromatic theory provides a helpful framework for the functioning of the three types of cones in the retina However, as we move from the retina to higher levels of visual analysis, the opponent process theory seems to fit observed phenomena neatly Both theories help us understand colour vision but at different levels of the visual system

Question 35

gratings

Answer 35

The simplest patterns of lines are gratings Gratings can vary along two dimensions: frequency and contrast. High-frequency gratings have many bars in a given distance and provide fine detail, while low-frequency gratings have relatively few bars High-contrast gratings have large differences in intensity between adjacent bars, like black next to white Low-contrast gratings have subtler differences in intensity between bars, such as dark gray next to black

Question 36

fusiform face area

Answer 36

The visual processing of faces activates a particular area of the brain known as the fusiform face area (FFA), part of the ventral pathway, located in the inferior temporal cortex

Question 37

proximity

Answer 37

A second Gestalt principle is proximity Objects that are close together tend to be grouped together The dots that make up our Dalmatian are close together, suggesting they belong to the same object

Question 38

principle of similarity

Answer 38

The principle of similarity states that similar stimuli are grouped together

Question 39

principle of continuity

Answer 39

The principle of continuity suggests that we assume that points that form smooth lines when connected probably belong together

Question 40

principle of simplicity

Answer 40

The principle of simplicity, which suggests that we will use the simplest solution to a perceptual problem

Question 41

depth perception

Answer 41

Depth perception is the ability to use the 2D image projected on the retina to perceive 3D

Question 42

monocular vs binocular cues

Answer 42

To construct a 3D image, we use both monocular cues (one eye) and binocular cues (two eyes)

Question 43

occlusion

Answer 43

Among the most powerful monocular depth cues is occlusion, or the blocking of images of distant objects by closer objects

Question 44

retinal disparity

Answer 44

Retinal disparity is the difference between the images projected onto each eye (requires the use of both eyes → binocular cue)

Question 45

astigmatism

Answer 45

Astigmatism is when the surface of the cornea is uneven

Question 46

audition

Answer 46

Audition, our sense of hearing, not only allows us to identify objects in the distance but also plays an important role in our ability to communicate with others through language

Question 47

pitch

Answer 47

In the case of sound, the height or amplitude of the wave is encoded as loudness or intensity and the frequency of the wave is encoded as pitch

Question 48

pinna

Answer 48

The outer ear consists of the structures that are visible outside the body The pinna, the outer visible structure of the ear, collects and focuses sounds, like a funnel In addition, the pinna helps us localize sounds as being above or below the head

Question 49

cochlea

Answer 49

The inner ear contains 2 sets of fluid-filled cavities embedded in the bone of the skull One set is the cochlea which contains specialized receptor cells that respond to vibrations transmitted to the inner ear May be divided into 3 parallel chambers divided from one another by membranes

Question 50

basilar membrane

Answer 50

The cochlear duct is separated from the tympanic canal by the basilar membrane