midterm 2 Flashcards
similar in concept to place cells but have multiple place fields that are systematically distributed (and therefore follow a sort of spatial regularity)
Grid cells:
grid cells: similar in concept to place cells but have multiple _ _ that are systematically distributed (and therefore follow a sort of _ _ )
place fields; spatial regularity
grid cells
similar in concept to place cells but have multiple place fields that are systematically distributed (and therefore follow a sort of spatial regularity)
neurons that fire when in particular locations (their ‘place field’)
Place cells:
Place cells:
neurons that fire when in particular locations (their ‘place field’)
grid cells In theory, provides a way to code _
direction
neurological contributions from the parahippocampal gyrus indicates
(landmarks)
Head direction cells:
fire depending on direction animal is facing (recall Gibson’s complaint about pilots not being able to turn their heads in lab-based experiments!)
fire depending on direction animal if facing (recall Gibson’s complaint about pilots not being able to turn their heads in lab-based experiments!)
Head direction cells:
Border cells:
fire when an animal is near the edge of an environment
fire when an animal is near the edge of an environment
Border cells:
Maguire et al. (2006) studied the role of experience and neural plasticity in wayfinding
Compared to London bus drivers (who have more/less variability in their routes, and thus less demand on their _ navigation skills), London taxi drivers:
Performed better on a _ test of pictures of places in London
Had more anterior/posterior (and less anterior/posterior) hippocampal volume
less, spatial
recognition, posterior, anterior
reaching - Dorsal and ventral pathways
Identifying the object (dorsal/ventral)
Positioning hand and fingers to grasp (dorsal/ventral)
_ _region: Contains neurons that become active while reaching/grasping
ventral, dorsal
Parietal reach
grasping
Monkey is briefly shown object with lights on, then lights turn off and a cue prompts the money to reach for object (Fattori et al., 2010)
Requires money to not only remember _ of object but also it’s _ (to accommodate a hand grip)
Specific neurons found that respond to trials requiring specific _
location, form
grips
_ _ cells become active when simply _ at objects
Visuomotor grip, looking
proprioception
the ability to sense body position and movement
_ receptors in the elbow joint, muscle spindle, and tendon help guide reaching/grasping behaviour
proprioception
Proprioception receptors in the _, _, _ help guide reaching/grasping behaviour
elbow joint, muscle spindle, and tendon
Signals related to eye movements (aka _ _ _) get sent to regions involved with _ actions to help with motor planning
corollary discharge signals, motor
there is a close connection between eye movements and actions: we tend to make eye movements to objects we are
about to interact with
Using _ to create a ‘temporary lesion’ (i.e. increase/reduce neuronal excitability) in the _ disrupts discharge signals, disrupting reach trajectory
TMS (transcranial magnetic stimulation)
reduce
cerebellum
We also need to adjust the amount of _ we are applying while lifting objects to take into account differences in weight
force
Size-weight illusion: Erroneously predicting weight when observing two differently sized objects that have the same weight. The error occurs when
the perceiver predicts that larger object will be heavier, and therefore uses more force to lift it, causing it to be lifted higher and to feel lighter.
The amount of _ one is applying while gripping an object doesn’t change/changes as needed based on various inputs (e.g. while hitting the bottom of a ketchup bottle to coax some of it out)
force, changes,
If hitting the bottom of a bottle we are holding ourselves, the force applied to our grip is _ and temporary decreased/increased for exactly the point of impact
If someone else hits the bottle (that we are holding), there is a _ in the increase in force applied because we are adjusting our grip ‘after the fact’ (after the impact) –> t/f: not proactively
proactively, increased
lag, t
Mirror neurons in the _ of monkeys respond when a monkey _ an object, as well as when an _ grasps an object
cortex, grasps, experimenter
_ _ in the cortex of monkeys respond when a monkey grasps an object, as well as when an experimenter grasps an object
Mirror neurons
Response to the observed action ‘ _ ’ the response of what happens when the monkey grasps something themselves
t/f: Diminished/little response if object grasped less directly, e.g. by pliers
mirrors, t
Mirror neurons associated with various motor functions have been found distributed throughout the human _:
cortex
mirror neurons in human cortex for: MRTU
Movements directed toward objects (turquoise)
Reaching movements (purple)
Tool use (orange)
Movements not directed toward objects (green)
Upper limb movements (blue)
Possible functions of mirror neurons?
To help understand another animal’s _ and react to them appropriately
To help _ the observed action (i.e. learning)
_ applications (e.g. empathy)
actions, imitate, Social
_ mirror neurons: responds to stimuli associated with both seeing and hearing action
May help link _ perceptions and _ actions
Audiovisual
sensory, motor
Audiovisual mirror neurons:
responds to stimuli associated with both seeing and hearing action
_ - _ accounts of _ : the purpose of perception is to create a representation in the mind of how one can interact with their environment
action-based accounts of perception,
action-based accounts of perception, the purpose of perception is to create a
representation in the mind of how one can interact with their environment
_ _ _ hypothesis states that one’s environment is perceived in terms of how they are able to act on it
action-specific perception
action-specific perception hypothesis states that
one’s environment is perceived in terms of how they are able to act on it
e.g of action-specific perception hypothesis: Witt and Proffitt (2005): batters with higher batting averages reported
perceiving the ball as larger
eg of Action-Specific Perception Hypothesis
Estimates of distance increase/decreased as more weight is being carried (backpack vs. no backpack conditions) (Proffitt et al., 2003)
People with chronic back and/or leg pain over/underestimate distances of objects in their environment (Witt et al., 2009)
Tennis players who have recently won estimate the net to be lower/higher (Witt & Surgovic, 2010)
Football players who have had more recent success at kicking field goals estimate the goal posts to be farther/closer apart (Witt & Dorsch, 2009)
increase
over
lower
farther
Motion assists with _ recognition (e.g. separating figure from ground, Gestalt common fate principle, etc.)
object
Predators use _ of prey as a primary means of location in hunting (motion attracts _; attentional capture)
movement, attention
Motion also draws our attention to other members of a _ (could represent possible _, _, _ etc.)
species
competition, cooperators, mates
Viewing things from different perspectives (i.e. _ _ motion) provides additional information
t/f: can change interpretations of what we think we’re seeing
self-produced motion
t
We expect motion to be produced by other living/dead things, predisposing us to perceive things that move as being _ (i.e. Heider & Simmel, 1944)
living, alive
Motion is also a cue that we rely on for distinguishing between _ _
e.g. changes in _ /acceleration of actor’s hands was a good predictor of subjective judgments about events (Zacks et al. 2009)
The value of motion perception becomes particularly apparent with _ (an inability to perceive motion)
event boundaries
speed
akinetopsia
_ _ occurs when an object is physically moving
_ _ (AKA apparent movement, phi phenomenon): stationary stimuli are presented in slightly different locations
Real motion
Illusory motion
Real motion occurs when an
Illusory motion (AKA apparent movement, phi phenomenon):
object is physically moving
stationary stimuli are presented in slightly different locations
Basis of movement in movies and TV
illusory motion
: movement of one object (usually a larger object, e.g. clouds) results in the perception of movement in another object (usually a smaller object, e.g. the moon)
Induced motion
Induced motion:
movement of one object (usually a larger object, e.g. clouds) results in the perception of movement in another object (usually a smaller object, e.g. the moon)
_ _: Observer looks at movement of object for 30 to 60 seconds, then a stationary object, and movement appears to occur in opposite direction from original movement
Relates to fatiguing ( _ ) neurons tuned to motion in one direction, which become more/less sensitive compared to neurons tuned to motion in other directions (a relative difference that your system interprets as motion)
Motion aftereffect
adapting, less
The perception of real and apparent motion were traditionally treated as involving rather similar/different neural mechanisms
different
Larsen et al. (2006) scanned participants using fMRI while viewing one of three displays:
Control condition: two squares in slightly different positions are briefly presented simultaneously
Real motion condition: a small square is moved back and forth
Apparent motion condition: two squares are quickly alternated on alternate sides of the display so as to create illusory motion
control condition, each dot activated a _ area of visual cortex
In the apparent and real motion conditions, activation of visual cortex was _ for both sets of stimuli
Suggests the perception of motion in both cases (apparent and real) involve _ neural mechanisms
separate
similar
similar
sit: look straight as object moves past
obj: move
eyes: stationery
image on retina: move
obj movement perceived????
YES
sit: follow moving obj w/ eyes
obj: move
eyes: move
image on retina: stationery
obj movement perceived????
yes
sit: look around room
obj: stationery
eyes: move
image on retina: move
obj movement perceived????
no
Recall the ecological approach (Gibson) focusses on what/how information directly available in the _ is useful to guide _ / _
environment
perception/action
The term optic array refers to the _ created by surfaces, textures, and contours in the environment, which _ as the observer moves through space
Gibson thought the optic array can be used to explain when motion is and isn’t perceived, with reference to two basic kinds of changes:
structure, change
Local disturbances in the optic array
Global optic flow
_ _ in the optic array: Objects moving relative to background (e.g. such that portions of stimuli are periodically covered and uncovered, e.g. the background and objects)
_ optic flow: Overall movement of the entire optic array (as a complete whole, i.e. without any local disturbances)
Local disturbances
Global
Local disturbances in the optic array: Objects moving _ to background
Global optic flow: _ movement of the entire optic array
relative
Overall
Prediction: if some aspects of the optic array change, and those changes are not _ (e.g. some objects are covered/uncovered, other are not), then motion will/will not be perceived
can be explained via _ _
uniform, will
Local disturbance
eg of local disturbance affecting optical array
(2)
- eyes stay stationery while something movies
- eyes move along with something that moves
if the optic array changes in a uniform way (e.g. the entirety of the optic array all moves in exactly the same way), then motion will/will not not be perceived
can be explained via _ _ _
will not
Global optic flow
Gibson’s take essentially comes down to:
Perceiving motion when one/entire part of the visual scene moves relative to the rest of the scene
Not perceiving motion when part of/the entire field moves, or remains stationary
one
the entire
Reichardt detectors only work for movement across the _
retina
_ detectors only work for movement across the retina
Reichardt
Corollary discharge theory hypothesizes that movement perception depends on three signals:
Image displacement signal (IDS)
Motor signal (MS)
Corollary discharge signal (CDS)
Image displacement signal (IDS): movement of _ stimulating receptors across the _
image, retina
Motor signal (MS): signal sent to _ to move _ muscles
eyes, eye
Corollary discharge signal (CDS): derived from the _ signal (essentially a ‘carbon copy’ of whatever the motor signal is doing, though it gets sent to a same/different part of the brain for another purpose)
motor, different
Movement is perceived when comparator receives input from either (but not both):
Corollary discharge signal OR
Image displacement signal
Movement is not perceived when comparator receives input, at the same time, from both:
Corollary discharge signal AND
Image displacement signals
scanning static scenes doesn’t result in perceived motion because
both signals are received (and effectively ‘cancel each other out’)
Starring at a large red dot can create an afterimage, which then appears to move as you shift your gaze (due to the presence of _ but no _)
Similarly, gently pressing on your eyeball (without shifting your point of focus) can create perceived motion because of a _ that occurs without an _
CDS, ids
CDS, ids
Damage to the _ _ temporal area in humans leads to perception of movement of stationary environment with movement of eyes
medial superior temporal area (MST)
Damage to the medial superior temporal area in humans leads to perception of movement of _ environment with movement of eyes
stationary
Real-movement neurons found in monkeys in _ cortex:
Respond when a _ moves
Do not respond when _ move
extra striate, stimulus, eyes
A Reichardt detectors is a model of a simple neural circuit that could fire in response to _ in one direction
movement
Reichardt detectors:
Neuron A and neuron B each send signals to the _ unit, which ‘compares’ the signals it receives from those two neurons to determine whether they are _
The signal that is sent from neuron A to the output unit goes through the _ unit, which slows down/speeds up the speed of transmission of the signal (to the _ unit)
If the timing is just right, the output units receives a signal from both neuron A and B at _ _, and motion is perceived
output, synchronized
delay, slows down, output, exactly the same time
What is the output unit ‘comparing’? It multiplies the signal it receives from neurons A and B at any one discreet point in time to ‘decide’ whether or not to fire
If those signals reach the output unit together = motion IS/IS NOT detected
Because a number > 0, when multiplied by another number that is also > 0, results in a value > 0 (and the neuron fires if the value it calculates is > or < 0)
If those signals do not reach the output unit at the same time, then motion/no motion is detected
Because 0, when multiplied by any number > 0, still results in a value = 0 (and the neuron does not fire if the value it calculates = 0)
is
>
no motion
If the timing is just right, and the _ unit ‘holds onto’ the signal from neuron A until the signal from neuron B naturally arrives at the output unit, that output unit will fire and (rightward) motion will be perceived
delay
Reichardt detectors are _, meaning that each one can only detect motion in one direction
t/f: need one configuration to register leftward motion, and a slightly different one to register rightward motion)
directional
t
Perception of motion begins in _ _ (V1), the region of the _ lobe where information from the _ first reach the cortex
_ _ cells (in V1) respond to movement of the _ of objects
_ _ area (MT) implicated in other aspects of motion perception
striate cortex, occipital, retinas
Complex cortical, ends
Middle temporal
Firing and coherence experiment by Newsome et al. (1995):
Coherence of movement of dot patterns varied
Monkeys taught to judge direction of dot movement
_ neurons recorded using electrodes
Results showed that as coherence of dot movement increased, firing of the MT neurons increased/decreased and the judgment of movement _
MT
increased, accuracy
Lesioning experiment by Newsome and Paré (1988):
Normal monkeys can detect motion with coherence of _ or _%
Monkeys with lesions in _ _ cannot detect motion until the coherence is _ to 20%
1 or 2%
MT cortex, 10 to 20%
TMS applied to _ in humans disrupts ability to perceive direction in a random pattern of moving dots
MT
Microstimulation experiment Britten et al. (1992):
Monkey trained to indicate direction of fields of moving dots
Neurons in _ cortex that respond to specific direction were activated using microstimulation, which shifted their judgment to the _ stimulated direction
MT
artificially
what relationship is this: flashing 2 dots with right timing can result in apparent motiion
stimulus affects perception
what relationship is this: moving bar activates cortical neurons
stim affects physl
what relationship is this: newsome - firing of MT cortex neuron and perception of movings dots are related
physl affects perc
_ _ constraint: apparent movement tends to occur along the shortest path between two stimuli
Shortest path
Shiffrar and Freyd (1990): Participants saw two images alternating rapidly or slowly:
Rapid alternations tend to result in perceiving arm _ _ head (impossible movement), slower alterations resulted in perceiving arm going _ head (possible)
Suggested the visual system sometimes needs more/less time to make sense of what it’s seeing and that the _ of the stimulus may influence how _ is perceived
going through head; around
more, meaning, motion
Stevens et al. (2000) showed with fMRI that _ cortex is activated for perception of _ movement only
motor, possible
Biological motion: self-produced motion of a _ or _
Can help with _ organization
person or other living organism
perceptual
Point-light walker stimulus: created by placing lights on the _ of a living organism, which convey their pattern of movement (and thus, conveys _ motion)
Think of ‘_ _ technology used in films and gaming
joints, biological
motion capture’
Grossman and Blake (2001): participants determined whether motion was biological or scrambled while being scanned (fMRI)
Used point-light walker stimuli with noise added to dots to reduce performance to _% accuracy
_ _ _(STS) more active for biological motion
Other studies show activation in response to biological motion in _ and _ that contain _ neurons
71
Superior temporal sulcus
FFA, PFC, mirror
Grossman et al. (2005) found TMS applied to _ decreased the participants’ ability to detect biological motion
superior temporal sulcus (STS)
Grossman et al. (2005) found TMS applied to STS increased/decreased the participants’ ability to detect biological motion
decreased
Implied motion is conveyed by still pictures that depict an action which involves motion
_ momentum: implied motion depicted in a photo can be ‘carried out’, or continue, in the observer’s mind
Representational
Freyd (1983) showed pictures during the learning phase then, during testing, asked participants to identify which pictures they had already seen
In addition to showing completely new pictures, manipulated whether the ‘familiar’ (previously seen) pictures were…
Exactly the same (control), image that happened slightly later than one seen (time _), happened slightly earlier (time- _ condition)
forward, backward
Freyd time forward/backward:
Participants were found to take longer to respond to time- _
This was interpreted to mean they resulted in more _ , because the downward motion would have been anticipated (and in some sense, represented in memory) based on the initial picture implying motion
Thus, although they didn’t actually see the time-forward picture, _
forward pictures (as compared to time-backward); interference
they may have imagined it, which can cause interference when trying to determine whether it had actually been viewed before (and thus account for the increased RT)
Kourtzi and Kanwisher (2000)
fMRI response was measured in _ and _ in four conditions:
Implied motion, No-implied motion, At rest, Houses
Areas of brain responsible for motion fire in response to pictures of _ motion
middle temporal area (MT) , medial superior temporal area (MST)
implied
Winawer et al. (2008):
Showed participants a series of photos with implied motion to one side (either the right or left) for 60 seconds, then asked them to identify the direction of movement in an array of moving dots
Before being ‘adapted’ to the pictures implying motion, participants were _ likely to perceive dots with zero coherence as moving to the right or left
After being ‘adapted’ to photos with implied motion to one side, participants were now more likely to indicate an array of dots with zero coherence was moving in the direction _ to which they had been adapted
e.g. adapt to pictures with leftward motion, report seeing dots moving to the _
equally, opposite, right
Perception of biological motion may not depend on visual experience - Vallortigara et al. (2005); (Simion et al., 2008) newly hatched chicks and infants prefer representations of _ motion
biological
Colour helps us _ and _ objects
Facilitates perceptual organization of elements into _
May provide an _ advantage (e.g. for foraging)
classify, identify
objects
evolutionary
Tanaka and Presnell (1999): participants identified foods presented in _ colours more rapidly
natural
Newton was interested in colour and light, experimented using two prisms, concluded:
White light is a mixture of _ _
Other colours on the spectrum are/are not mixtures but rather represent ‘ _’ colours (cannot be broken down any further)
the degree to which beams from each part of the spectrum were ‘bent’ by the second prism differed was indicative of a difference in some _ property
all colours
are not, pure
physical
Chromatic colours (e.g. _, _, _) are perceived when certain wavelengths are reflected by objects more/less than others (i.e. _ reflection)
e.g. red paper reflecting _ wavelengths (and absorbing _ / _)
blue, green, red
more, selective
long, short/medium
Achromatic colours (_, _, _) are perceived when light is reflected unequally/equally across the spectrum
e.g. white paper reflecting _ wavelengths equally
gray, black, white
equally; all
t/f: Objects typically reflect more than just a single wavelength
Reflectance curves plot percentage of light transmitted at _ _
t
each wavelength
The colour of objects that are transparent are created by _ transmission
occurs when only certain wavelengths pass through objects (e.g. cranberry juice selectively transmitting _ wavelengths results in a reddish appearance)
Can be plotted with _ _
selective
long
transmission curves
Subtractive colour mixing occurs when mixing together _ that have different pigments
Adding more pigments to a mixture results in more/fewer wavelengths being reflected (and more being _)
paints
fewer
absorbed
_ colour mixing occurs when mixing together paints that have different pigments
subtractive
e.g. why does a mixture of blue and yellow appear green?
Blue reflects mostly _ -wavelength (and some_), absorbs others
Yellow reflects mostly _ -wavelength (and some _), absorbs others
After being combined, both pigments in the paint mixture continue to reflect the same wavelengths they did on their own
the only wavelengths that are reflected from a mixture of blue and yellow are _ wavelengths (i.e. _!)
short-wavelength (and some medium),
long-wavelength (and some medium),
medium, green
Additive colour mixing occurs when mixing _ of different wavelengths
All of the light that is reflected from the surface by each light when alone is also reflected when the lights are _
lights
superimposed
_ colour mixing occurs when mixing lights of different wavelengths
additive
Pure blue light projected onto a white board looks blue because Similarly, pure yellow light projected onto that same white board looks yellow because
Superimposing blue and yellow lights onto that white board leads to the perception of white, because _, _, _ wavelengths are all reflected back to our eyes
wavelengths responsible for that colour perception (i.e. short wavelengths) are all reflected back to our eyes
the wavelengths responsible for that colour perception (i.e. short and medium wavelengths) are all reflected back to our eyes
short, medium, and long
Spectral colours are those that appear on the _
Many nonspectral colours exist, which can only be created by _ (e.g. magenta, which is a mixture of _ + _ )
_ is another term for a chromatic colour (blue, red, etc.), or what we might refer to as a ‘pure’ colour
spectrum
mixing spectral colours in various combinations; blue and red
Hue
Value refers to the _ - _ dimension
Saturation is determined by the amount of _ in a hue
More white = _
More dark = value increasing/decreasing
light-to-dark
white
desaturation, decreasing
HSV (hue/saturation/value) colour solids can be used to determine _ colour combinations
additive
The Trichromatic Theory was initially proposed by Young, and then was supported with experimental evidence by Maxwell and Helmholtz
States that all human colour vision is based on three principle colours: _, _, _
(red, green and blue)
3chromatic behavioural evidence:
_ - _ experiments provide one line of behavioural evidence, in which observers are shown a reference colour they must match by _
Colour-matching
mixing different amounts of various wavelengths of light in a ‘comparison field’ (see next slide)
Trichromatic theory:
t/f: > 3 were never needed and 2 was only sufficient to match some colours
Observers with colour deficiencies could match their perception of any colour with _ wavelengths
This was interpreted as meaning that ‘normal’ colour vision depends on _ receptor mechanisms (i.e. _ types of cones)
t
2
three, 3
Physiological evidence for the Trichromatic theory came from measuring the absorption spectra of visual pigments in receptors (1960s)
Pigments were found that respond maximally to:
Short wavelengths (_ nm)
Medium wavelengths ( nm)
Long wavelengths ( nm)
Later researchers found _ differences for coding proteins for the three pigments
419nm, 531, 558
genetic
Color perception is based on the combined responses of the three different types of _, which vary depending on the wavelengths available
cones,
cone size of short, med, long cone:
blue
green
red
yellow
white
big, m, s
m, b, m
s,m b
s, mb, b
b, b, b
Colour matching experiments show that colours that which are perceptually _ can be caused by _ combinations of various physical wavelengths (referred to as _)
This is because different combinations of wavelengths can create _ patterns of activity across the three cone types
similar, different, metamers
comparable
One receptor type cannot lead to colour vision because …
any two wavelengths can cause the same response in a monochromat (someone with only one cone type) simply by altering the intensity
1 receptor type related to principle of univariance:
Absorption of a photon causes the _ effect in all receptors, no matter what the stimulating _ is
Once a photon of light is absorbed by a visual pigment molecule, the identity of the light’s wavelength is lost
The only information the neural system encodes/retains is the _
same, wavelength
total amount of light absorbed
Imagine a hypothetical participant that only has a single cone type, who is exposed to two different test patches of light that can vary in both intensity and wavelength
Assume the absorption spectra (on the left) applies for their hypothetical singular cone pigment
Assume that 1000 photons reach the eye of our hypothetical monochromat from each light test patch
Their one pigment type absorbs 10% of the photons in 480 nm light (10% of 1000 = 100 photons)
Their one pigment type absorbs 5% of the photons in 600 nm light (5% of 1000 = 50 photons)
Thus, in this example, the 480 nm light would look brighter than the 600 nm light to them because this receptor would respond twice as strongly to it (would absorb 100 photons of the 480 nm light vs. 50 for the 600 nm)
This means that the receptor responds differently to the two stimuli in this first example, and thus our hypothetical monochrome can distinguish between them
However, if we now double the intensity of the 600 nm light to 2000 photons (and keep the 480 nm light the same, at 1000 photons), this receptor would now respond equally as strongly to both the 480 nm and 600 nm light (absorbing 1000 photons of light in both cases)
This means the pattern of activity in the receptor would be identical for both wavelengths in this second example
There would be no relative difference in the monochromat’s receptor response to these two different colours, which essentially means they cannot be distinguished
Having at least _ receptor types (i.e. dichromats or trichromats) solves the problem we see in the previous two examples (with monochromats) by allowing the system to distinguish between _ colours
This is accomplished by way of providing some kind of relative _ across receptor types to responses across wavelengths, independent of _
This amounts to a difference in the overall pattern of receptor activity generated by particular wavelengths
Having 3 receptor types (i.e. trichromats) affords the perception of even more colours than just 2 receptors
2, some
difference, intensity
The ratio of responses of two different pigments (associated with two different cone types) to two different wavelengths is always _, regardless of changes in _ / _
This relative difference in activity across receptor types helps us encode different _ as being distinct from each other
constant, intensity/brightness
wavelengths
Suggested to Hering that our colour vision is ‘built’ upon four primary chromatic colours (_, _, _, _), which are arranged in opposing pairs
evidence = _ wheel
red yellow green blue
color
Theory proposed by Hering (1800s) hypothesized that our colour vision arises from three primary mechanisms involving opponent-processes:
White/ _
Red/ _
Yellow/ _
Neural mechanisms respond to these three pairs of colours in an _ fashion
e.g. by increasing excitation (+) in response to red, and increasing _ in response to green
Black, green, blue
opposing; inhibition (-)
one line of supporting evidence of opponent processing: _
Fixate on the image for 30 seconds, then look at something white
In the afterimage that you should (briefly) see, the red and _ squares seem to ‘switch places’ (as do the blue and _ squares)
Complementary afterimages
green; yellow
Researchers performing single-cell recordings found _ neurons (1950s) which respond in an _ manner to one end of the spectrum and an _ manner to the other, located in the _ and _
Red: triggered by direct input from _ cones
Green: triggered by direct input from and _ cones
Blue: triggered by direct input from _ cones
Yellow: triggered by a combination of input from _ and _ cones
opponent, excitatory, inhibitory, retina, LGN
L; M;M S; M L
Each theory describes different _ mechanisms in the visual system which contribute to colour vision
Trichromatic theory explains the responses of the _ in the _
Opponent-process theory explains _ response for cells connected to the _ further in the brain
physiological
cones, retina
neural, cones
V4 was originally proposed as a sort of ‘_ _ ’
some areas show considerable overlap between neural mechanisms that seem to be processing _ and other _ properties (i.e. they aren’t ‘dedicated’ to colour perception)
_ (colour blindness) can cooccur with _, further suggesting such overlap
colour centre
colour, visual
Achromatopsia, prosopagnosia
V4: there are specific areas that respond just. to _, _, _ as well as a combination of all 3 features
colour, shape, or texture
Lafer-Sousa et al. (2016) showed participants video clips sometimes in colour and sometimes in black and white
Colour sensitive regions were found between the _ and _
Although colour and form are processed together/independently, the adjacent locations for processing these respective properties helps explain why so many people with achromatopsia (colour blindness) also have prosopagnosia (~72%)… because…
FFA, PPA
independently
damage to that general region can overlap with both ‘regions’
Monochromats have a very rare hereditary condition which could be considered to produce ‘true’ colour-blindness
Have no functioning _ (only _), leading them to only perceive the world in tones of
Can match any wavelength in the spectrum by simply adjusting the _
Poor visual _ (no cones!), Very sensitive to _ _ (all rods!)
cones, rods, white, grey, and black
brightness
acuity, bright light
Dichromats are missing _ of the three types of cones
There are three types of dichromats (
Unilateral dichromats has _ vision in one eye and _ in the other
Provides a unique opportunity to understand how dichromats ‘see’ colour (because…
one
protanopia, deuteranopia, and tritanopia)
trichromatic, dichromatic
the same brain can interpret/describe perception of colour from both perspectives)
Protanopia affects
Missing the _ -wavelength pigment
AKA a form of _ colourblindness: red looks more _ and more/less bright
See short-wavelengths as blue
Neutral point occurs at 492nm
Above neutral point, they see _
long, red-green
green, less
yellow
Deuteranopia affects
Missing the _ -wavelength pigment
AKA a form of _ colourblindness: green look more _
See short-wavelengths as blue
Neutral point occurs at 498nm
Above neutral point, they see _
medium, red-green, red, yellow
Tritanopia
Missing the _ -wavelength pigment
AKA a form of _ colourblindness: difficulty separating blue and _, red and _
See short-wavelengths as blue
Neutral point occurs at 570nm
Above neutral point, they see _
short, blue-yellow, green, yellow
red
colour boosting glasses
t/f: evidence they help a large proportion of colour deficient individuals is mixed, make a difference for some people
In theory, they typically work by _ out certain wavelengths (e.g. that might produce an overlapping response across cone types), allowing for more _ in the range of colours perceived
t
filtering, contrast
Colour constancy: perception of colours as relatively _ in spite of changing _ sources
Sunlight has approximately _ amounts of energy at all visible _
Tungsten lighting (as is used in some bulbs) has more energy in the _ -wavelengths
Objects reflect different/similar wavelengths from these two sources
constant, light
equal, wavelengths
long,
different
Figure 9.32 Determining what wavelengths are reflected from the green sweater under different illuminations. Light reflected from the sweater is determined by multiplying (a) the illumination of sunlight, incandescent, and LED lightbulbs times (b) the sweater’s reflectance. The result is (c) the light reflected from the sweater. The maximum of each of the curves in (c) has been set at the same level to make the wavelength distributions easier to compare
Chromatic adaptation occurs with _ exposure to chromatic colours
When the stimulus colour selectively bleaches a specific cone pigment over an extended period of time, this results in a increase/decrease in sensitivity to the associated colour
This can occur in response to light sources, which contributes to colour constancy under different illuminations
prolonged, decrease
Color constancy experiment by Uchikawa et al. (1989): Observers shown sheets of coloured paper under three lighting conditions:
Baseline (control): paper and observer in white light
Observer not (chromatically) adapted: paper illuminated by red light; observer by white
Observer (chromatically) adapted: paper and observer both exposed to red light
Baseline: green paper is seen as _
Observer not adapted: perception of green paper is shifted toward _
Observer adapted: perception of green paper is only _ shifted toward red (demonstrating partial colour constancy)
green
red
slightly
The dominant colour of the lush scene in (a) is green. Looking at this scene causes adaptation to _ and increases/decreases the perception of green in the scene, as shown in (c).
The dominant colour of the arid scene in (b) is _. Adapting to this scene causes a increrased/decreased perception of yellow in the scene, as shown in (d).
green, decreases
yellow, decreased
Colour constancy works best when an object is surrounded by few/many colours
Showing participants scenes with masked surroundings reduces ‘accuracy’ of colour perception reports
This is not fully understand but probably relates to the perceptual system having more information (data) available to make calculations and inferences about the environment (e.g. illumination conditions, etc.) that allow it to make relevant corrections when making judgments
many
Hansen et al. (2006) showed participants photographs of fruits with characteristic colours against a grey background
When shown a spot of light which physically matched the grey background, participants accurately perceived the spot as being grey
However, when the fruits were adjusted to be grey, they were still perceived as being slightly coloured in a characteristic way (i.e. participants reported seeing a grey lemon as being slightly yellowish)
Interpreted as meaning _ _ of an object’s colour impacts _ perception
past knowledge, colour
Achromatic colours are perceived as remaining relatively _ across different lighting conditions (_ _)
Lightness: the perception of the _ of achromatic colour (white, grey, black)
Part of the explanation for this is because perception of lightness is not related to the _ _of light reflected by an object, but rather the _
constant, lightness constancy
shade
total amount, percentage
The intensity of light reaching the eye from an object depends on: (2)
The intensity of illumination (total amount of light hitting the object)
The object’s reflectance (the proportion of light reflected back by the object)
The intensity of illumination _ _ of light hitting the object)
The object’s reflectance (the _ of light _ back by the object)
total amount
proportion, reflected
light constancy is determined by _, not _
reflectance, intensity
Figure 9.36: A black-and-white checkerboard illuminated by (a) tungsten light and (b) sunlight
Assume the white squares reflect back 90% of the light, the black squares 9%, The white squares always look white and the black always look black, regardless of how much total light there is in the environment… what matters is the proportion of light reflected by the squares
The _ _ states that two areas reflecting different amounts of light look the same if the ratios of their intensities are the same (at least when evenly illuminated…)
ratio principle
The ratio principle states that two areas reflecting _ amounts of light look the same if the ratios of their intensities are the _ (at least when evenly illuminated…)
different, same
When perceiving lightness under uneven illumination, the perceptual system must distinguish between: (2)
reflectance edge, illumination edge
_ edges: edges where the amount of light reflected changes between two surfaces (between a/c in picture), i.e. changes in material
_ edges: edges where lighting of two surfaces changes (between a/b in picture), i.e. changes in lighting
Reflectance, Illumination
But how do we distinguish reflectance edges from illumination edges:
The _ of objects (e.g. palm tree shape is obvious in shadow in picture at left), _ of shadows
etc.
meaningfulness, Penumbra
Physical energy in the environment does not have _ qualities (light waves are not “coloured”)
Different _ systems have different experiences with perception
_ perceive colours outside that of human perception
t/f: and we therefore cannot ever truly understand what colours they “see”
perceptual
nervous
Honeybees, t
t/f: hard to know what an infant really ‘sees’
Perception of light stimulus can vary on at least two dimensions: _, _ (CB)
t/f: you don’t need to perceive colours to differentiate colour stimuli
t
Chromatic colours, Brightness
t
Bornstein et al. (1976): Looking time technique provided evidence that young infants have _ vision
Based on the pattern of _ and _ to _ wavelengths
colour
habituation, dishabituation, 3
A cue approach to depth perception focuses on information in the _ image that is correlated with _ in the scene
We learn the connection between cue and depth (e.g. _)
Association becomes _through repeated exposure
retinal, depth
occlusion, automatic
Oculomotor cues are based on sensing the _ of the eyes and _ tension
Convergence: _ movement of the eyes when we focus on far/nearby objects
Accommodation: the shape of the _ changes when we focus on objects at different distances
position, muscle
inward, nearby
lens
_ cues: based on sensing the _ of the eyes and muscle tension
_ : inward movement of the eyes when we focus on nearby objects
_ : the shape of the lens changes when we focus on objects at different distances
Oculomotor
Convergence
Accommodation
Monocular cues: information that can be based on the image from a _ eye
Pictorial Cues: sources of _ information that come from 2/3-D images, such as pictures
Occlusion: when one object partially _ another
single
depth, 2
covers
_ cues: information that can be based on the image from a single eye
_ Cues: sources of depth information that come from 2-D images, such as pictures
_ : when one object partially covers another
Monocular
Pictorial
Occlusion
monocular cues
Relative height:
Objects below the horizon that are higher in the field of vision are more _
Objects above the horizon that are _ in the visual field are more distant
distant
lower
Determining the location of the horizon line is both important for understanding what is happening in a scene
This poses a challenge for _ -based object/scene recognition programs (e.g. the inverse projection problem)
computer
Relative size: when objects are equal size, the closer one will take up more/less of your visual field
more
Perspective convergence: parallel lines appear to come _ in the distance
together
Atmospheric perspective: distance objects appear more ‘ _ ’
Occurs because the farther away something is, the more _ we have to look through to see it
Farther objects also tend to appear more ‘ _ ’ (for the same reason the sky looks blue, i.e. our atmosphere preferentially scatters short/long wavelengths and looking ‘through’ more of increases the ‘blueness’ this imparts on our perpeption)
fuzzy
air/particles
blue
short
Texture gradient: equally spaced elements are more/less closely packed as distance increases
Shadows: helps enhance depth by indicating where _ are located
more
objects/features
In contrast to the oculomotor and monocular cues just discussed, some monocular cues result from _
motion
Motion parallax: close objects in direction of movement glide rapidly/slowly past but objects in the distance appear to move rapidly/slowly
Relates to the larger distance the image of something closer to us ‘travels’ across the retina, as compared to something farther away, in an equivalent amount of time
rapidly, slowly
Motion parallax is relied heavily upon by some animals to judge _ (e.g. locusts quickly move their head back and forth before pouncing on prey to help them judge how far to jump, similar to some of Gibson’s ideas about self-produced information!)
depth
Deletion and accretion: objects are _ or _ as we move relative to them
_ refers to covering an object
_ refers to uncovering an object
covered or uncovered
Deletion, Accretion
We rely on lots of different depth cues, each of which have particular _ / _
we _ all of the available information to make the ‘best guess’
limitations/strengths
integrate
Stereoscopic depth perception is constructed based on input provided to _ eyes
both
Stereoscopic depth perception is the basis for how 2/3D glasses typically work
This has been accomplished by presenting same/different images to each eye using various techniques (e.g. shutters, red/blue filters, polarized lenses, etc.)
3D, different
Corresponding retinal points are points on the retina that would _ if the eyes were superimposed on each other
overlap
Binocular disparity refers to the _ in images from _ eyes
This difference can be described by examining corresponding _ _ on the two retinas
The _ is an imaginary sphere that passes through the point of focus
difference, 2
retinal points
horopter
Objects on the horopter fall on _ _ on the retinas
e.g. both Julie and the tree fall on the horopter, therefore we know that they each fall on corresponding points on the retinas
This also tells us that they are both approximately the same _ away from the observer
corresponding points
distance
Objects that are not on the horopter fall on _ points
These points make _ images
The degree to which these images deviate from corresponding points is the _ disparity (and can be represented by a calculation referred to as the _ _ _)
non-corresponding
disparate
absolute
angle of disparity
Crossed disparity occurs whenever an object is _ to the observer than where they are looking (_ _ of the horopter)
Uncrossed disparity occurs whenever an object is _ away from the observer than where they are looking ( _ the horopter)
closer, in front
farther, behind
An example of crossed disparity
The observer is looking directly at Julie
Bill is in front of Julie
The image of Bill is on the ‘_’ side of Julia’s image, in each eye of the observer
inside
An example of uncrossed disparity
The observer is looking directly at Julie
Bill is behind Julie
The image of Bill is on the ‘_’ side of Julia’s image, in each eye of the observer
outside
Determining whether disparity is crossed or uncrossed tells us whether something is behind or in front of our point of focus (i.e. the _ )
objects that are farther away from the horopter create smaller/larger angles of disparity, this information tells us how far away something is from the horopter
horopter
larger
Stereopsis refers to _ information provided by _ disparity
Stereoscopes are viewers which use two pictures from slightly _ viewpoints
Random-dot stereograms have two identical patterns of ‘noise’ with one ‘piece of information’ _ in position
depth, binocular
different
shifted
Random-dot stereograms allow researchers to isolate contributions to _ perception attributable to _ from those associated with other kinds of depth cues (e.g. monocular cues, etc,)
Julesz (1971) used this kind of stimuli to demonstrate experimentally that, even though participants find it very difficult, they can still extract _ information from these kinds of stimuli
depth, stereopsis
depth
Neurons have been found that respond best to binocular disparity, referred to as binocular depth cells or _ _ cells
Are found in _, as well as along the _ and _ streams
Respond best to a specific degree of _ _between images on right and left ,
Disparity tuning curves: plot neural response as a function of _
disparity selective cells
V1, dorsal, ventral
absolute disparity, retinas
disparity
DeAngelis et al. (1998) trained a monkey to indicate depth from disparate images
Disparity- _ neurons were activated by this process
Used microstimulation to activate different disparity-selective neurons
Monkey shifted judgment to _ stimulated disparity
selective
artificially
Selective rearing experiment by Blake and Hirsch (1975): Cats reared by alternating vision between two eyes had few binocular neurons and were unable to use _ disparity to perceive _
binocular, depth
what relationship is this: binocular disparity causes perception of depth (stereopsis)
stim -> perc
what relationship is this: binocular disparity causes firing of disparity-selective cells
stim -> physl
what relationship is this: elimination of disparity-selective neurons by selective rearing eliminates binocular depth perception
microstimulation of disparity-selective neurons changes depth perception
physl -> perc
Visual angle refers to the _ of an object relative to the observer’s eye
There are 360 degrees around the circumference of the eye
1 degree = 1/360 of this circumference
That equates to an image of about 0.3 mm
As things get closer, the visual angle increases/decreases
As things get farther away, the visual angle increases/decreases
angle,
increases, decreases
Figure 10.31: The “thumb” method of determining the visual angle: When the thumb is at _ length, whatever its width covers has a visual angle of about _ degrees.
t/f: the visual angle will change if the distance between the woman and the iPhone changes.
arm’s, 2
t
t/f: Figure 10.34: The moon’s disk almost exactly covers the sun during an eclipse because the sun and the moon have the same visual angles.
t
Holway and Boring (1941):
Comparison circle was always 10 feet away, Test circles ranged from 10-120 feet, Participants were asked to adjust the diameter of the comparison circle to match the test circle
P1: participants able to adjust the comparison circle to accurately match the test circle by relying on various _ cues (binocular disparity, shading, etc.), in addition to _ _
P2: the various depth cues were systematically eliminated;
responses produced by participants suggested they began relying on _ _ alone to judge size
Because this is/is not an accurate way to judge distance (because stimuli have smaller/larger visual angles as they get farther away/closer), accuracy in the second phase was very good/poor
depth, visual angle
visual angle
is notpoor
Figure 10.33: Results of Holway and Boring’s experiment.
size of comparison circle based off of visual angle is much bigger/smaller compared to actual physical size
smaller
size-distance scaling formula
S = __
S = perceived size, K = a scaling constant, R = retinal size
D = perceived distance
As an object moves farther away, we perceive it to remain a constant size because as the retinal size get smaller our perception of the distance increases
Note that because K is a constant, we can leave that out of our future discussion of this formula
K (R x D)
If you create an afterimage (by starring at a large red dot in the textbook), it’s visual angle will remain _ as you move your eyes across the room
However, if you look at something distant (and therefore cause the afterimage to appear to fall on a distant object), you tend to perceive it as smaller/larger than if it falls on something close
In effect, you’re holding the retinal size constant but varying the perceived distance, which conforms to predictions based on this simple formula: S = R x D
constant
larger
t/f: other contributions beyond size of retinal image and perceived distance influence size judgments
e.g. texture gradients (pictures on the left), relative size (pictures on the right)
t
The Müller-Lyer illusion: Straight lines with inward fins appear shorter/longer than straight lines with outward fins
Lines are actually the same length
explanation: illusion involves misapplied _ - _ scaling (of a form that works in _ -D but is misapplied for _ -D objects)
shorter
size-constancy, 3, 2
If equivalently sized images are formed on the retina, and one is judged to be farther away, it will be perceived as larger/smaller (thus, the ‘inside corner’ is judged as larger because it is perceived as being an equivalent size but farther away)
larger
One problem with the size-constancy scaling explanation of the Müller-Lyer Illusion is that similar illusions can be produced which don’t convey any sense of _
e.g. the ‘dumbbell’ version of this illusion below, and another version using books
depth
Another explanation of muller-lyer: conflicting cues theory, which states that our perception of line length depends on two factors:
The conflicting cues are integrated into a compromised perception of the length
The actual length of the vertical lines
The overall length of the figure
The Ponzo illusion: Horizontal rectangular objects are placed over railroad tracks in a picture
The far rectangle appears smaller/larger than the closer rectangle but both are the same size
Misapplied size-constancy scaling may offer an explanation (same retinal image formed, yet perceived to be at different _, will be perceived as being different actual sizes)
larger
distances
Two people of equal size appear very different in size in an _ room
The room is constructed so that the shape looks like a normal room when viewed with one eye
The actual shape has the left corner twice as far away as the right corner
Ames
Size-distance scaling = plausible explanation for ames room,S = R x D
Observer thinks the room is rectangular, which would mean the Women would be the _ distances away
Woman on the right has smaller visual angle (R)
The perceived distances (D) of the two women are the same
Therefore, the perceived size (S) of the women on the right is smaller/larger
same
smaller
ames room possible factor: relative size
Perception of size depends on size relative to _ _
One woman fills the distance between the top and bottom of the room
The other woman only fills part of the distance
Thus, the woman on the right appears taller/shorter
other objects
taller
The moon illusion refers to the fact that it appears larger/smaller on the horizon than when it is higher in the sky (despite having the same visual angle)
One possible factor: apparent-distance theory: horizon moon surrounded by depth cues, moon higher in the sky _
While the visual angle of the moon is the same, the perceived distance is different (horizon is perceived as farther away/closer than the sky), resulting in a difference in perceived size (S = R x D)
larger
has none
farther away
Animals with frontal eyes that have fields which significantly overlap afford good _ depth perception
Animals with lateral eyes have poor stereoscopic depth perception (but gain a more _ view)
stereoscopic
panoramic
Bats can rely on _ -like processes to perceive depth using sound waves
sonar
Granrud (1985): Showed infants objects A and B during the familiarization period, then objects C and D during the test period
Hypothesized that showing infants a larger version of the same toy they had previously seen (object C) would be perceived as being closer if they relied on familiar size to judge distance (and remembered object B)
_ behaviour supported their prediction
Reach
Granrud (1985): Tested 5 and 7 month olds using the stimuli
5-month olds showed _ _ for reaching towards either object (50/50)
7-month olds reached for the object that appears closer/farther 59% of trials
Suggests infants develop the ability to use shadows to guide depth perception at approximately _ months
no preference
closer
7
Two kinds of definitions for ‘sound’:
Physical definition: _ changes in the air or other medium
Perceptual definition: the experience we have when we _
pressure
hear
Loud speakers:
The diaphragm of the speaker moves in/out, pushing air molecules together called _ (compression)
The diaphragm also moves in/out, pulling the air molecules apart called _ (expansion)
The cycle of this process creates alternating _ and _ pressure regions that travel through the air
out, condensation
in, rarefaction
high and low
Pure tones are tones which create changes in _ pressure that can be described by a single _ wave
Basic building block of sounds, used extensively in research yet relatively _ in the natural environment
air, sine
rare
Frequency: number of _ within a given time period
Measured in _ : 1 Hz is one cycle/second
Perception of pitch is related to _
Tone height is the increase in _ that happens when _ is increased
cycles
Hertz (Hz)
frequency
pitch, frequency
_ : number of cycles within a given time period
Measured in hertz : 1 Hz is one cycle/ _
Perception of _ is related to frequency
_ height is the increase in pitch that happens when frequency is increased
Frequency
second
pitch
Tone
Amplitude: difference in _ between high and low peaks of wave
Perception of amplitude is known as _
The decibel (dB) scale is used as the measure of _
The decibel scale relates the _ of the stimulus with the psychological experience of _
pressure
loudness
loudness
amplitude, loudness
_ : difference in pressure between high and low peaks of wave
Perception of _ is known as loudness
The _ is used as the measure of loudness
Amplitude
amplitude
decibel (dB) scale
Both pure and some complex tones are _ tones (tones in which the waveform _)
Periodic complex tones consist of a number of pure tones called _
Fundamental frequency is the _ rate and is also referred to as the _ _
Additional harmonics are multiples of the _ _ (referred to as _ harmonics)
periodic, repeats
harmonics
repetition, first harmonic
fundamental frequency, higher harmonics
frequency spectras plot _ of complex sounds
harmonics
Human hearing range: _ - _ Hz
The audibility curve shows the threshold of hearing in relation to _
Changes on this curve show that humans are most sensitive to _ to _ Hz (important for understanding speech!)
20 to 20,000
frequency
2,000, 4,000
The auditory response area falls between the _ _ and the threshold for _ (point at which sounds we can ‘feel’ sounds, where they can cause _)
It shows the range of response for human _
audibility curve, feeling, pain
audition
Equal loudness curves can be determined by using a standard 1,000 Hz tone (using two dB levels: 40 and 80)
Participants match the perceived loudness of all other tones to the 1,000 Hz standard
Tones sound _ at 40 dB for high and low frequencies than the rest of the tones in the range
softer
Pitch – _ quality we describe as _ and _
perceptual, high and low
Timbre: all other perceptual aspects of a sound besides _ _ _ (LPD)
Effect of missing fundamental frequency: removal of the first harmonic results in a sound with the same perceived pitch, but with a different _
Timbre is closely related to the _ _ _ (HAD) of a tone
Attack of tones: _ of sound at the beginning of a tone
Decay of tones: _ in sound at end of tone
loudness, pitch, and duration
timbre
harmonics, attack, and decay
buildup
decrease
_ : all other perceptual aspects of a sound besides loudness, pitch, and duration
Effect of missing _ _: removal of the first harmonic results in a sound with the same perceived pitch, but with a different timbre
_ is closely related to the harmonics, attack, and decay of a tone
_ of tones: buildup of sound at the beginning of a tone
_ of tones: decrease in sound at end of tone
Timbre
fundamental frequency
Timbre
Attack
Decay
outer ear contains
pinna, auditory canal
The _ helps with sound location
The _ _ is a tube-like structure, Protects the _ membrane (the eardrum) at the end of the canal
Resonance occurs when sound waves that are reflected back from the _ membrane interact with sound waves _ the canal, which can reinforce (increase the intensity of) certain frequencies
The auditory canal amplifies frequencies between _ and _ Hz (which is the canal’s _ frequency, or the frequency that is most reinforced)
pinna, auditory canal, tympanic
tympanic, entering
1,000 and 5,000, resonant
3 ossicles
smallest. orlargest bones in body
malleus, incus, stapes
smallest
The middle ear is a two cubic centimetre cavity separating the _ from _ ear
Contains the three ossicles
Malleus (hammer): moves due to the vibration of the _ membrane
Incus (anvil):
Stapes (stirrup): transmits vibrations of the _ to the _ ear (via the _ window of the _)
inner, outer
tympanic
transmits vibrations of the malleus
incus, inner, oval, cochlea
While the outer and middle ear are filled with _, the inner ear is filled with _ that is more/less denser than air
Pressure changes in air transmit well/poorly into the denser medium (the liquid); Ossicles act to amplify the vibration for better _ to the fluid
The middle ear muscles also dampen the ossicles’ vibrations to protect the inner ear from potentially damaging stimuli when exposed to high _ sound waves
air, fluid, more
poorly
transmission
amplitude
Two properties of the middle ear assist with amplifying the sound:
By concentrating the vibrations of the small/large tympanic membrane onto the much larger/smaller stapes
By being _ and therefore creating ‘lever action’ which amplifies a _ force
large, smaller
hinged, small
The _ is the main main structure of the inner ear, and the location at which _ of pressure waves occurs
Divided by the cochlear partition into two sections: the upper half is referred to as the _ _ and the lower half the scala _
cochlea, transduction
scala vestibuli, tympani
The organ of Corti is located within the _ partition and contains inner and outer _ cells, which are the receptors for _
_ membrane vibrates in response to sound and supports the _ _ _
_ membrane extends over the hair cells
cochlear, hair, hearing
Basilar, organ of Corti
Tectorial
The ‘back and forth’ motion of the oval window transmits vibrations to the liquid inside the cochlea:
Puts the basilar membrane into an ‘_ _ ’ motion
Puts the tectorial membrane into a ‘ _ _’ motion
up-and-down
back and forth
The _ (parts of the outer hair cells) bend in response to movement of _ _ _ and the _ membrane
Movement in one direction opens _ channels in the _ links (parts of the stereocilla)
Movement in the other direction _ the ion channels
stereocilia, organ of Corti, tectorial
ion, tip
closes
Phase locking: nerve fibres firing at/near _ of sound wave, and are thus “locked in phase”
Groups of fibres fire with periods of _ _, creating a pattern of firing
overall pattern of activity (on average, across all nerve fibres) that is produced closely matches the _ properties of the pressure wave
peak
silent intervals
physical
Békésy’s Place Theory of Hearing: the frequency of sound is indicated by the place on the _ _ _ that has the highest/lowest firing rate
Békésy determined this through direct observation of the _ membrane in cadavers, and building a model of the _ using the physical properties of the basilar membrane
He noticed that the basilar membrane’s vibration was like a _ wave
organ of Corti, highest
basilar, cochlea
travelling
The functionality of the basilar membrane can be related to it’s _ properties, as the base of the membrane is:
Three to four times narrower/wider than at the apex
100 times _ than at the apex
While vibration occurs over a large portion of the membrane for most pressure waves, the place that vibrates the most depends on the _
physical
narrower, stiffer
frequency
Because the amount of _ on the basilar membrane is a function of _, we can think of the cochlea as effectively functioning like a _
Coffee bean filter analogy
displacement, frequency, filter
The cochlea shows an orderly map of frequencies along its length, which can be referred to as a tonotopic organization
Apex responds best to _ frequencies
Base responds best to _ frequencies
_
tonotopic
low
high
_ tones can be used to determine the threshold for specific frequencies measured at single neurons, which can then be used to produce neural frequency _ curves
Frequency to which the neuron is most sensitive is the _ frequency
Frequency tuning curves of cat auditory nerve fibres demonstrate the _
Pure, tuning curves
characteristic
selectivity/specificity
Békésy used basilar membranes isolated from cadavers and his results showed no difference in response for close frequencies that people can distinguish
New research with live membranes shows that the entire _ hair cells respond to sound by slight _ and a change in _
These cells are referred to as the _ _
outer, tilting, length
cochlear amplifier
Damage to the _ hair cells impacts the frequency tuning curve, demonstrating the role they play when intact
Higher threshold = lower sensitivity = worse hearing
outer
Place theory suggests that pitch perception is based on the relation between a sound’s _ and the place along the _ membrane that is activated
frequency, basilar
The ‘effect of the missing fundamental’: even if the fundamental is missing, we can generally still perceive it
How could we perceive a 200 Hz pitch if the fundamental was missing, and therefore that place on the membrane never vibrated?
assuming the _ also vibrate the membrane, and that the spacing of the intervals is informative of the fundamental
i.e. a second and third harmonic at 400 and 600 Hz allows the system to ‘recognize’ the 200 Hz fundamental
harmonics
The frequency tuning curves of auditory nerve fibres tend to be more narrow at _ frequencies, and wider at _ frequencies
lower, higher
The lower harmonics produced by tones tend to create distinct neural responses, which are referred to as _ harmonics
In contrast, higher harmonics tend to create neural responses that are/are not clearly distinguishable, and are referred to as _ harmonics
In theory, this should mean that lower harmonics are more useful for perceiving _, as compared to higher harmonics
resolved, are not, unresolved, pitch
the _ spacing (or repetition rate) may carry useful information about pitch
Along similar lines, phase locking carries similar temporal information that may assist with _ perception
Pitch perception only occurs for sounds above ~ _ Hz, which…
…is also about the upper limit of _ locking (supporting the idea that the two are related)
…also reinforces the idea that the distinction between the _ and _ properties is an important one!
interval, pitch, 5000, phase
physical, perceptual
The auditory nerve sends signals generated in the cochlea to various subcortical structures while en route to primary auditory cortex, including:
Acronym: SONIC MG
Cochlear nucleus
Superior olivary nucleus (brain stem)
Inferior colliculus (midbrain)
Medial geniculate nucleus (thalamus)
Primary auditory cortex (auditory receiving area, or _ , in _ lobe) can be divided up into three general subregions:
_, _, _ area (CBP)
A1, temporal, Core area
Belt area
Parabelt area
Temporal coding with phase locking is effective up to _ Hz in auditory _ _, but only up to _ - _ Hz in auditory cortex
5,000, nerve fibres, 100-200
how is pitch represented in cortex:
Evidence for pitch neurons that respond to the same _ frequency, regardless of what _ is heard
Evidence for a greater responses to pitch information in _ auditory cortex
fundamental, harmonic, anterior
Noise-induced hearing loss: Acute exposure to very _ noises can severely damage the hair cells in the _ _ _
Various standards for noise levels at work can be set to protect workers
_ noise can also cause hearing loss
loud, organ of Corti
Leisure
Hidden hearing loss: individuals may have normal _ (e.g. thresholds) in a standard hearing test using _ tones played in isolation, yet have difficulty perceiving more _ ‘real-word’ sounds
Standard measurements of _ have more to do with the _ (hair cells) themselves, whereas functioning of the auditory nerve may be more important for processing more _ sound-based stimuli
If the hair cells are functioning normally yet the auditory nerve is not, this could produce _ hearing loss
exposing mice to 100 dB sound for two hours produced a relatively short-lived deficit in _ _ functioning, whereas auditory nerve function remained _ after the hair cells had already largely recovered
results, pure, complex
thresholds, receptors, complex
hidden
hair cell, compromised
_ : Results from the cumulative effects of exposure to noise over time
Greatest loss at high/low frequencies
Affects _ more severely
Can be caused by exposure to some _ (which damage the hair cells)
Presbycusis
high
males
drugs
Cochlear implants place electrodes in the cochlea to (directly) electrically stimulate _ nerve fibres
The device is made up of:
A _ worn behind the ear
A _ processor
A transmitter mounted on the _ bone
A receiver surgically mounted on the _ bone
auditory
microphone, sound, mastoid, mastoid
Olsho et al. (1988): produced infant audibility curves for three-month olds
Relied on observers to indicate whether or not infant heard each stimuli (based on behaviour, e.g. orienting towards stimuli, eye moments, facial expressions, etc.)
t/f: The infant audibility curve comes to more closely approximate the adult curve over time
DeCasper and Fifer (1980): found evidence that infants’ recognize their mother’s voice as early as _ days after birth
t
two
Unlike with the retina in vision, information about location is/is not contained in the receptor cells for hearing
On average, people can localize sounds most accurately directly in front/behind of them (and least accurately to their _ and _ their heads)
is not
front, sides, behind
Locating sounds in space is referred to as _ localization
Auditory space surrounds an observer and exists _ there is sound
_ coordinates: left to right position
_ coordinates: up and down position
_ coordinates: position relative to observer
auditory
wherever
Azimuth, Elevation, Distance
_ cues are created based on how sound waves interact with our head/ears
Similar to vision, we can distinguish between _ cues and _ cues
Binaural cues: location cues based on the comparison of the signals received by the left and right ears (interaural time and level differences) to determine the _ (i.e. left-right) position of sounds
Location, binaural, monaural
azimuth
Interaural level difference (ILD): _ cue related to differences in sound _ levels reaching each ear
Reduction in intensity occurs for _ frequency sounds for the far (relative to audio source) ear, due to the head casting an _ shadow
This effect does not occur for low frequency sounds because the distance, or spacing, between waves (i.e. frequency) for low frequency sounds is relatively _, in comparison to the object casting the acoustic shadow (i.e. your head)
binaural, pressure
high, acoustic
large
Interaural time difference (ITD): binaural cue related to differences in the _ of when a sound reaches each ear
When distance to each ear is the same, there is no difference in timing (ITD = _ )
When the source is to the side of the observer, the times will differ
Behavioural experiments show that _ is most effective for localizing low/high frequency sounds
timing, 0
low
ITD
ILD and ITD are useful binaural cues for judging azimuth and distance
t/f: because time and level differences can be the same at a number of different elevations, ILD and ITD cannot reliably indicate the elevation of a sound source
This phenomenon is referred to as the ‘ _ _ _’, in reference to the (many) conical space(s) around the ears for which various possible pairs of points on an ‘imaginary cone’ would produce the same ITD and ILD
t
cone of confusion
_ cues are location cues based on signals reaching a single ear
These are particularly important for judging _ , given that ILD and ITD are not effective for doing so since they may be zero in many different locations
The monaural cue we primarily rely on is referred to as a _ cue, because it involve using information related to the distribution of intensities of a particular spectrum of frequencies experienced
These occur because the _ and _ affect the intensity of sound waves entering the system
Monaural
elevation
spectral
pinna, head
Frequency spectra recorded by a microphone placed inside the ear for the same stimulus being played at different elevations
difference in intensities at different points in the frequency spectrum related to the difference in _
elevation
Experiments investigating spectral cues:
Gardner and Gardner (1973): found that changing the pinnae (by smoothing out nooks/crannies using a molding compound) resulted in participants producing worse localization judgments about _
elevation
Hofman et al. (1998): introduced a mold that participants wore for an extended period of time to determine initial changes in perception, as well as track how participants adapted to the change (see next slide)
Participants were measured for performance localizing sounds coming from different places, then were fitted with a mold that changed the shape of their pinnae
On day 0, performance was poor for elevation though unaffected for azimuth, By day 5, performance for elevation judgments began improving, By day 19, performance for elevation was close to original performance
Once the molds were removed, performance remained high
This suggests that there might have been two somewhat distinct neural ‘ _ ’ that were somehow created (possibly involving different neurons), one for each set of cues, which the participants seemed to be able to flexibly switch between
configurations
ILD and ITD work for judging _
ILD works best for _ frequency sounds
ITD works best for _ frequency sounds
_ cues help us judge elevation; Multi-modal cues are also relevant (i.e. vision)
Idea of self-produced information can also apply here, as we are constantly moving our heads (which can modify many of these parameters) and thus accumulating more ‘ _ ’
azimuth
high, low
Spectral
data
The Jeffress neural coincidence model proposes that some neurons receive input from _ ears and respond to _ (are essentially ITD detectors)
These are hypothesized to have a similar mechanism as _ detectors, which makes a judgment as to whether or not two incoming signals are received simultaneously
These _ _ only fire if they receive input from both axons _, or in other words only fire if they receive signals originating from each ear simultaneously
The specific coincidence detector (i.e. neuron) that fires codes _ (neuron 3 only fires when a particular ITD is present, e.g. 5 ms)
both, ITD
reichardt
coincidence detectors, simultaneously
ITD
eg. 1: sound originating directly in front of listener
both ears get stimulation at same time, signals start journey from ear to _ at same time and end at the _ spot at the _ time
cortex, same, same
Example 2: sound originating to the right of a listener
The signal from the _ ear gets a ‘head start’ (on beginning it’s journey to the cortex, because it is stimulated first), relative to the signal from the left ear
The point at which they ‘meet’ is therefore skewed to the left/right
right, left
_ tuning curves can be examined to see if they provide supporting evidence for the Jeffress neural coincidence model
Barn owls have neurons with narrow/wide tuning curves which respond best to specifics ITDs
t/f: consistent with what would be expected based on the idea of the Jeffress neural coincidence model
ITD
narrow
t
Compared to barn owls, ITD tuning curves are much _ for mammals (curves shown for neurons in superior olivary nucleus)
This is/is not consistent with what would be expected based on the Jeffress neural coincidence model (because there isn’t enough specificity for a single neuron to code for ITD)
wider
is not
It may be more likely that mammals use _ coding to encode ITD for the purpose of localizing sounds (whereas birds may use something more akin to _ coding)
Neurons in the left hemisphere respond best to sound from the right/left
t/f: Any single neuron would be insufficient to resolve location though the distributed activity of _ could provide enough data
Conceived of in this way, location of sound can be indicated by the ratio of responding for two types of neurons; consider how this is similar to how typical colour vision is encoded by the relative difference in response across three pigment types, or perceived direction of motion on the basis of pooled input from MT neurons
population, specificity
right
t, many
1) Sounds from the far left would activate right/left hemisphere sensitive neurons strongly and left hemisphere sensitive ones much less
2) Something from straight ahead would activate _ and _ neurons equally
right
both left and right sensitive neurons
Area A1 involved in _ sound
Neff (1956): Cats rewarded with food for approaching boxes emitting a sound, no longer able to localize sounds after bilateral lesions to A1 (even after 5 months of training!)
Nodal et al. (2010): lesioning A1 in ferrets detrimentally impacted (but did/did not eliminate) their ability to localize sounds
Malhorta and Lomber (2007): deactivating (via cooling) A1 in cats impairs their sound localization
locating
did not
Posterior belt area also involved in _ sound
Recanzone (2000): single-cell recordings of monkeys revealed neurons that only respond to sounds coming from particular locations in space
Some neurons of this nature were also found in other parts of A1, though the neurons in the posterior belt area had more specificity (i.e. were contingent on more fine-grained divisions of space)
locating
Posterior belt area also involved in locating sound
Lomber and Malhotra (2008): temporarily disputing the posterior belt (again, via cooling) disrupts localization
This did/did not affect their ability to distinguish between differences in patterns of timing related to sound stimuli
did not
Anterior belt involved in perceiving more _ sound
Rauschecker and Tian (2000): while some neurons in A1 respond to pure tones, those in the anterior belt respond to more complex sounds (e.g. monkey vocalizations)
Lomber and Malhotra (2008): Cooling this area in cats disrupts their ability to discern differences in timing patterns related to sound (but not _ )
complex
localization
Where, or _ stream, extends from the _ belt to the _ lobe and _ cortex -> Used to _ sounds
What, or _ stream, extends from the _ belt to the _ lobe and _ cortex -> Used to _ sounds
dorsal, posterior, parietal, frontal, locate
ventral, anterior, temporal, frontal, identify
Can distinguish between two kinds of sound waves that reach your ears:
_ sound: sound that reaches the listener’s ears straight from the source
_ sound: sound that is reflected off of environmental surfaces and then to the listener
When a listener is outside, most sound is _
Inside a building, there is _ and _ sound
Direct, Indirect
direct, direct and indirect
Experiment by Litovsky (1997): listeners sat between two speakers, a lead speaker and a lag speaker
When sound comes from the lead speaker followed by the lag speaker with a long delay, listeners hear one/two sounds
When the delay is decreased to 5-20 msec, listeners hear the sound as only coming from the _ speaker
Referred to as the _ _
Reflects a sort of threshold for attributing differences in timing, which helps us understand why slight differences in direct and indirect sound waves reaching our ears doesn’t (always) lead to the perception of _ sounds
two
lead
precedence effect
distinct/separable
_ acoustics refers to the study of how sounds are reflected in _ (e.g. how the design of concert halls influence the perception of sound)
_ time: the time it takes sound to decrease to 1/1000th of its original pressure
If it is too long, sounds seem ‘ _ ’
If it is too short, sounds seem ‘ _ ’
Ideal times are around _ seconds
Architectural, rooms
Reverberation
muddled, dead, 2
_ time: time between when sound leaves its source and when the first reflection arrives
Best time is around 20 ms
Bass ratio: ratio of low to middle frequencies reflected from _
High/low bass ratios are best
Spaciousness factor: fraction of all the sound received by listener that is _
High spaciousness factors are typically perceived as most _
Intimacy
surfaces
High
indirect
pleasing
_ scene: the array of all sound sources in the environment
Auditory Scene Analysis: process by which sound sources in the auditory scene are separated into _ perceptions
Does not happen at the _ since simultaneous sounds are processed together in the pattern of vibration of the basilar membrane
Auditory
individual
cochlea
Heuristics help to perceptually organize stimuli (similar to idea of Gestalt principles for grouping objects based visual properties)
Onset time: sounds that start at different _ are likely to come from different _
Location: a single sound source tends to come from one _
Individual sources of sound also tend to move in a _ and _ way (e.g. a car driving by)
Similarity of timbre and pitch: similar sounds are grouped together (e.g. a flute will typically continue sounding like a flute throughout an entire piece of music)
times, sources
location
smooth, continuous
μs = microsecond
1 second = 1 000 000 μs
The absolute values on these tuning curves represent the magnitude of ITD
0 = signals that reach both ears at the _ time
Small values = signals that reach each ear with _ difference in timing
Large values = signals that reach each ear with _ difference in timing
The sign (+ or -) for the values on these tuning curves indicates which ear the signal reached first
same, less, more
The ITD values on these tuning curves are calculated by subtracting the time at which the signal reaches the ipsilateral ear from the time at which the signal reaches the contralateral ear
e.g. if the sound reaches the ipsilateral ear 2 μs after stimulus presentation, and the contralateral ear 1 μs after stimulus presentation, that would be: 2 - 1 = +1 μs
Positive values = neurons that respond best to sounds that reach the _ ear first
Negative values = neurons that respond best to sound that reach the _ ear first
contralateral
ipsilateral
When a single instrument alternates rapidly between streams of low and high notes, the listener perceives it as two separate melodies
This is referred to as implied polyphony or compound melodic lines by musicians, or _ _ segregation by psychologists
auditory stream
Experiment by Bregman and Campbell (1971): Alternated high/low tones at different speeds
When stimuli played slowly, listener perceives high and low tones alternating within a single stream
When played quickly, listener perceives two _ streams, one high and one low
Demonstrates grouping role of both similarity (based on pitch) and timing
separate
Another demonstration of grouping by pitch: the red dots represent the same note being played repeatedly, the blue dots an ascending series of notes
Two distinct streams of notes are perceived when pitches are relatively different, though the streams get ‘melded’ when the _ are similar (as they crossover), producing what some listeners describe as a ‘galloping’ effect
notes
Experiment by Deutsch (1975): demonstrates the scale illusion or melodic channeling
Stimuli were two sequences alternating between the right and left ears
Listeners perceive two smooth sequences by grouping the sounds by similarity in _
Because sounds with the same frequency usually come from the same _ in the natural environment, this heuristic often allows us to accurately separate sound sources
pitch
source
_ _ _: sounds that occur in rapid succession usually come from the same source
This principle was illustrated in auditory streaming
_ _: sounds that stay constant or change smoothly are usually from the same source
Proximity in time
Auditory continuity
Warren et al. (1972): Tones presented that were interrupted by either gaps of silence or noise
In the silence condition, listeners perceived that the sound _ during the gaps
In the noise condition, the perception was that the sound _ behind the noise
Similar to Gestalt principle of good continuation
stopped, continued
Deutsch (1999): Effect of past experience on melody perception
Melody is played with notes alternating between octaves (e.g. “Three Blind Mice”)
Listeners find it difficult to identify the song in a control condition in which that is all they hear
If they are first _ with hearing a more ‘typical’ (i.e. within the same octave) version of that melody, they can then hear it in the _ version
Demonstrates the role of experience and memory, and in particular melody schema, in interpreting melodies
primed, modified
_ capture (aka the ventriloquist effect) occurs when an observer incorrectly perceives a sound as coming from a location suggested by visual information
Represents an example of vision ‘superseding’ _
In the two-flash illusion, seeing a single dot flash on a screen is misinterpreted as two flashed dots if accompanied by two beeps
Represents an example of _ ‘superseding’ _ input
Visual, audition
audition, visual
Coordinated receptive fields refer to neurons which respond to _ stimuli (e.g. sound and vision) that originate in common regions of space
e.g. a neuron in _ lobe might respond to visual information in the lower left of your visual field, and sounds coming from that same point in space
Thaler et al. (2011): used expert blind echolocators to create clicking sounds
These stimuli activated _ cortex in the blind participants, but not the controls (with normal vision)
multimodal
parietal
visual
