Ch 4 Sensation And Perception Flashcards
What are psychophysics?
The study of how physical stimuli are translated into psychological experience
What is the difference between sensation and perception?
Sensation is the stimulation of sense organs
Perception is the selection, organization, and interpretation of sensory output
What is a threshold?
A dividing point between energy levels that do and do not have a detectable effect- difference threshold
Ie. Turning music up and down till you notice a difference
What is an absolute threshold?
The minimum amount of stimulation that an organism can detect 0—> something
True or false, for an absolute threshold to exist, it must occur 50% of the time
True
What is a just noticeable difference?
The smallest difference in the amount of stimulation that a specific sense can detect.
Eg. Smallest amount of salt you can add to notice difference
True or false, an absolute threshold is the just noticeable difference from nothing
True
Explain the signal detection theory
Proposes that he detection of stimuli involves decision processes as well as sensory processes influenced by a variety of factors
Explain sensory adaptation
A gradual decline in sensitivity due to prolonged stimulation
Eg. Smelly garbage
The smallest amount of tumult ion you can detect is (0—>something)
Absolute threshold
Light waves vary in amplitude, wavelength and purity. Explain what amplitude, wavelength, and purity are.
Amplitude– height
Wavelength– distance between peaks
Purity– how aired the mix of light is
True or false, humans can only perceive the wavelengths of light?
True
what are the two functions of the eye?
to channel light into the neural tissue, and to house that tissue
When referring to the eye, what is the lens?
Transparent eye structure that focuses the light rays falling on the retina
What is the difference between nearsightedness and farsightedness?
nearsightedness– close objects seen clear, far objects seem blurry
farsightedness– far objects seen clear, close objects are seen blurry
When does nearsightedness occur? When does farsightedness occur? What is “wrong” with the eye?
When the cornea bends the light too much (nearsightedness)
When the eyeball is too short
farsightedness
what are saccades?
When the eyes are scanning an environment and making brief fixations
What is the retina?
The neural tissue lining the inside back surface of the eye
What does the retina do?
absorbs light, processes images, and sends visual info to the brain
In the retina, what are the differences of the cones and the rods?
cones– specialized visual receptors that play key roles in daylight vision and colour vision.
Rods– specialized visual receptors that play a key role in night vision and peripheral vision
True or false, the rods and cones on the retina funnel signals to the receptive field
true
What is the receptive field?
he retinal area that when stimulated affects the firing of that cell (for example, the signal towards the brain and nearby cells)
What is lateral antagonism and when does it occur?
occurs when neural activity in a cell opposes activity in surrounding cells , when the excited neuron reduced activity of its neighbours
What is the fovea? (in the retina)
tiny spot in the center of the retina that contains only cones– visual acuity is best here
What is the optic chiasm?
the point at which the optic nerves from the inside of the eye cross over and project to the opposite half f the brain
from the optic chiasm, where do the visual signals travel?
thalamus– brains major relay centre or the
Superior colliculus
what are the main visual pathways that the main visual pathway splits into?
magonocellar and the parvocellar channels
where does most visual input arrive?
the primary visual cortex in the occipital lobe
What do feature detector neurons respond to?
very specific features of more complex stimuli ex. lines, edges, angle or movement
What is visual agnosia?
the inability to recognize objects
What is propagnosia?
the inability to recognize familiar faces
true of false, perceiving colour is a function of dominant wavelengths
true
What colour are the longest wavelengths and what colour are the shortest?
red and violet
What is subtractive colour mixing?
removing some wavelengths of light
leave less light than was originally there
happens when mixing paint (everything turns brown)
What is additive colour mixing?
superimposing light, putting more light in the mixture than exists
Explain the trichromatic theory of colour vision
the human eye has 3 types of receptors with differing sensitivity to different light weave lengths
red, green, and blue
plain the opponent process thoery
colour perception depends on receptors making antagonistic responses to 3 pairs of colours
think= negative colours then looking at a wall and seeing regular colours
what is a perceptual set?
readiness to perceive stimulus in a particular way.. expectations
What is feature analysis?
the process of detecting specific elements and assembling them into more complex ideas or shapes
ex. lines–> 2D shape–> 3D shape
explain the Phi phenonomenon
the illusion of movement created by presenting visual stimulus in rapid succession
ex. movies and tv
what are the two perceiving forms?
bottom up processing ( indiv. to the whole)
top down processing (progression from whole to the elements, ex. big to small.)
Explain distal stimuli
stimuli that lie in the distance outside the body
Explain proximal stimuli
stimulus energies impinge directly on sensory receptors
how do people bridge the gap between distal and proximal stimuli?
by making a perceptual hypothesis
what is a binocular depth?
differing views based on two eyes
What is retinal disparity?
objects projected slightly differently on the retina
what is monocular depth?
distance clues based on image in either eye alone
The Gestalt principles are used to help us…?
organize elements in a scene
true or false, sound waves are measured in amplitude, wavelength and purity
true
what does the external ear depend on to hear things?
vibration of air molecules and the pinna (a sound collecting cone)
What does the middle ear have to depend on to hear things?
the vibration of moveable bones called the ossicles
What are ossicles?
tiny bones in the middle ear (hammer, stirrup, and anvil)
what does the inner ear depend on to hear things?
waves in a fluid and the cochlea
Where is the coclea located?
inner ear
what is the basilar membrane,and what is it’s function?
membrane that runs down the cochlea and has auditory receptors that converts stimulation into neural impulses
what is the place theory of hearing?
the pitch perception is based off of where the vibrations occur along different parts of the basilar membrane
what is the frequency theory of hearing?
the pitch perception that is baed on the rate that the basilar membrane vibrates (as a whole)
Between the place theory and the frequency theory, which is based on vibration as a whole, and which is based on vibration of the hair-like receptors?
place theory– vibration of certain receptors
frequency theory- vibration of the whole basilar membrane
what is auditory localization?
locating the source of the sound in space
What are the 2 cues of auditory localization?
intensity and timing
When referring too the gustatory system (taste) what are papillae?
knoblike elevations on the tongue containing taste buds
What do gustatory receptors do?
absorb the dissolved chemicals and trigger neural impulses to the thalamus then insular cortex
what are the 4 primary tastes?
sour, sweet, salty, and bitter the fifth taste is umami (MSG)
What is the pathway of a physical stimuli travelling through the nasal passage? (hint: 3 steps)
1) travels through nasal passage
2) stimulates the olfactory cilia
3) olfactory nerves transmit neural impulses through the bulb to the brain
How many olfactory receptors do humans have?
350
True or false, smell is the only sensory system in which incoming info is not routed through the thalamus before it projects to the cortex
true
What is a physical stimulus hen referring to our sense of touch?
mechanical, thermal, and chemical energy that impinge on the skin
what is psychological perception?
warm/cold, pressure, pain, position, movement
when you feel pressure, how does it happen? 4 steps
Nerve fibres carry info about stimulation
routed through spinal cord to the brainstem
then thalamus
then somatosensory cortex
what are the two types of pathways to the brain?
1) fast pathways –> A-Delta fibres register localized pain and relays it quickly (paper cut)
20 slow pathways –> C-Fibres less localized and longer lasting aching pain)
Explain the gate control theory
incoming pain sensations must pass through a gate in the spinal cord that can be closed, thus blocking ascending pain signals
True or false, glial cells contribute to moderating chronic pain?
true
What does the kinestethic system do?
monitors the position of various body parts; receptors are located in joints and muscles
what does the vestibular system do?
sense of balance and equilibrium whole moving your body. depends on the semi-circular canals in the inner ear
Explain the door int he face technique
making a large request first that is likely to be turned down to increase the chance that people will agree to a smaller request
What does webers law state?
that the size of a just noticeable difference is a constant proportion of the size of the initial stimulus
What is Freshner known for?
thresholds
Explain the signal-detection theory
the detection of stimuli involves decision processes as well as sensory processes, which are both influenced by a variety of factors besides stimulus intensity
true or false, psychophysicists use a variety of methods to relate sensory inputs to subjective perception. Absolute threshold is not really that absolute
true.
true or false, absolute thresholds are not that absolute
true
true or false, fechners law states that you need a larger and larger increase in a stimulus o produce a just noticeable difference
true
does the signal detection theory replace Fechner’s threshold theory with he concept of detectability and emphasises that factors besides stimulus intensity influence detectability
true
Can perception happen without our awareness?
yes
What is the optic disk?
a hole in the retina where the optic nerve fibres exit the eye
the receptive field of a visual cell, is a retinal area that, when stimulated affects….?
affects the firing of that cell
What is an afterimage?
an image that persists after a stimulus is removed
the opponent process theory of colour vision holds that ?
colour perception depends on receptors that make antagonistic responses to thee pairs of colours
What are the 5 principles of the Gestalt theory of perceptual organization?
1) proximity
2) closure
3) similarity
4) simplicity
5) continuity
true or false, perceptions of colour are primarily a function of light wavelength
true
what theory do we use today: the trichromatic theory (3 types of receptors) or the pponent process theory (sensors depend on antagonistic responses)
both
What is the opponent process theory?
colour perception depends on receotirs that make antagonistic responses o red vs green, blue vs yellow, and black vs white
what does form perception depend on?
the selection and interpretation of sensory inputs
what is a motion parallax?
images of objects at different distances moving across the retina at different rates
true or false, the motion parallax was one of the earliest areas of study in depth perception
true
What are the two types of monocular cues?
deoth cues and motion parallax
what are pictorial depth cues?
clues about the distance that can be given in a flat picture
what is a perceptual constancy?
a tendency to experience a stable perception in the face of continually changing sensory input
What happens when the pupil constricts?
less light comes into the eye, sharpens the image
true or false, if saccades didn’t exist, you would have bad vision
true
Can studying saccades help us learn more about huntingtons disease?
yes
what is the retina, and what are it’s 3 duties?
lining inside the back of the eye, it absorbs light, processes images, and sends info to the brain
True or false, the retina is a part of the central nervous system located in the eye
true
what are the two types of receptors in the retina?
rods and cones
In our retinas, do we have more rods or cones?
Rods
do rods or cones provide better visual acuity?
cones
Are rods or cones concentrated most heavily in the centre of the retina?
cones
do either rods or cones handle the majority of peripheral vision?
rods
What happens to light going into the eye? (hint: 4 steps)
1) light strike retina’s receptors (rods and cones)
2) send impulses along the optic nerve
3) leave the eye through optic disk
4) goes to the brain
what is the lateral geniculate nucleus? (LGN)
where axons from the retina synapse , visual signals are processed here
what happens in the magnocelular and parvocelluar channels?
parallell processing (extracting different kinds of info from the same input)
What is Hubel known for?
identifying various types of specialized cells in the visual cortext that respond to different stimuli
What are the 5 principles of Gestalt perception?
proximity– objects close are group together
closure– viewers supply missing pieces
similarity– elements that are similar are grouped t
simplicity– organize things in the simplest way pos
continutity– see things that produce smooth continuation
What is convergence?
sensing the eyes converging toward eachother as they focus on closer objects
true or false, depth perception depends primarily on monocular cues
true
what have optical illusions proved about the perceptual hypothesis?
it is inaccurate
do vision for perception and vison for action travel a different pathway to the brain?
yes
What is the name for collection of rod and cone receptors that funnel signals to a particular visual cell in the retina?
receptive field
e visual pathway to the dorsal lobes is as the visual pathway to the temporal lobes is to…
a) the what pathway- the where pathway
b) the where pathway- the what pathway
b
an artist draws converging lines to that a set of train track appears to go off into the distance. What is the name for this monocular cue for depth perception?
linear perspective
what perceptual cue is manipulated in a 3D movie?
convergence
