Perception and Cognition Flashcards
1
Q
what is the visual pathway
primary visual cortex in one hemisphere receives…
A
eye - LGN - primary visual cortex primary visual cortex in one hemisphere receives only 1/2 visual field from contra-lateral (opposite) side from both eyes
2
Q
explain the receptive field of the ganglion cells
A
has two components
excitatory centre
inhibitory surround
3
Q
V1 primary visual cortex - how is it arranged
A
circular receptive fields from LGN combined into an elongated V1 still with an excitatory centre and inhibitory surround
4
Q
simple cells - Hubel and Wiesel
A
primary visual cortex V1 cells
selective for position on t=retina
orientation of edge / bar
size or width or bar
5
Q
hierarchical processing in V1
A
simple cells combine to form the complex cell again with excitatory centre and inhibitory surround
6
Q
complex cells are selective for
A
rough position on the retina
orientation of edge / bar
size or width of bar
movement within receptive field
7
Q
hypercomplex cells
how formed and additionally what are they selective for
A
complex cells combining and again same structure
length of edge or bar
needs to sop at one or both ends
8
Q
what does different types of receptive fields in V1 lead to
A
different orientation and spatial scale
leads to edges
the receptors are all orientated differently across the visual field so can do edges
9
Q
organization of the primary visual cortex
A
cortex mapped
one are processes contours on one region of retina
cells analysing one orientation lie in same column
damage to V1 leads to blindness (local field defect)
10
Q
what is Gestalt psychology about
A
the whole is more than the sum of the parts
grouping principles of perceptual organization: similarity - in luminance, shape, colour
11
Q
grouping principles in gestalt psychology
A
similarity proximity closure good continuation common fate law of closure maximum likelihodd principle parts of the image are seen as belonging together. these parts are likely to arise from the same object
12
Q
secondary visual cortex
A
V2
von der heydt, peterhans
v2 cells are selective for edges defined by good continuity and closure
v2 damge impairs grouping by some principles
good continuity, closure, similarity (colour
13
Q
gestalt principles - figure-ground
A
area bounded by contour is seen as separate object
contours seen as belonging to one object at a time
14
Q
problems in recognition
A
an p=object changes with distance position perspective view orientation lighting occlusion of parts
15
Q
object agnosia
A
failure to recognise objects
no loss of intelligence
no simple visual impairment
may draw object ok but not recognize drawing if later presented back to him
can see edges but cannot put them together
at first was thought to be a case of dementia coupled with poor vision - clearly fine vision and patient did not have dementia
brain scan found two localised lesions
16
Q
two types of edge/bar detectors (types of edges they detect)
A
fine and coarse
17
Q
Marr’s model of recognition
A
analyse image with range of edge filters
use gestalt grouping principles - eg continuity finds outline
segment outline at nearest concavities
define arrangement of part (cylinders)
- start with biggest cylinder (principle axis)
-work though progressively smaller cylinders
match descriptions f parts to 3D models in memory
18
Q
mar’s model of recognition, model predicts..
problem…
A
visibility of principle axis important
different orientations equally easy to recognise
problem - many objects gard to recognise if upside down or rotated
19
Q
Biederman ‘recognition by components’
A
detect arrangement of edges parallel co-linear co-terminating such arrangements do not alter with view determine geon type determine arrangement of geons match geon description to memory
20
Q
geons
A
part of biederman’s recognition by components
36
axis straight or curved?
cross section type (symmetric, smooth, angular)?
when arranged size, orientation to each other?
21
Q
problem with biederman
A
does not differentiate objects within class does not use surface pattern
22
Q
processing of form - where in the brain
A
pattern processing in temporal cortex cell selectivity code shape and colour and texture respond to all objects with these properties generalise across position orientation and size specific organised in columns =
23
Q
summary of how we perceive what we see
A
v1 edges - v2 contours - v4 simple features - elaborate features in the temporal cortex
24
Q
object coding
A
one cell not coding object concept (eg isn’t a cell for a pineapple)
object identity coded by large arrays of cells
vocabulary of around 500 properties to code many objects
25
what does a lesion to the temporal cortex do
disrupts pattern discrimination and object recognition
| produces object agnosia
26
prosopagnosia
symptoms
interpretation
failure to recognise individual faces
may recognise individuals bu theor clothes, voice
may recognise other objevt
faces processed by a specialised brain system?
within object class discrimination defective? - patient may not recognize different cars, birds
27
patient WJ
WJ could remember sheep but not human faces
28
object agnosia patient
patient CK could see faces but not vegetables
| double dissociation - separate impairments in recognition of faces and objects
29
fusiform face area
right fusiform area - faces > objects
| faces but not other objects of expertise (eg cars) activate area
30
extrastriate body area
right occipitotemporal area: bodies > objects
31
where is the extrastriate body area
mid temporal
32
where is the fusiform face area
parahuppocampal place area
33
hierarchical models of processing
1. hubel and wiessel's findings in the visual cortex
- simple-> complex-> hypercomplex
2. selfridge's pandemonium model. feature demons -> cognitive demons - > deciiosn demon
3. grandmother cells
34
hierarchical processing what are grandmother cells
| problems?
specificity - respond to one object only
generalisation - respond to many instances
problems
not enough cells in the brain
but eery 1mm3 contains 1 million cells and most people recognise 20,000 words
unlikely to ever find them
35
monkey fMRI patch responsive to faces
test single cells in fMRI patch
16 faces, fruits, bodies, gadget, hands, scrambles
99% of cells selective for faces
36
summary of face processing in temporal cortex
V1 and V2 features -> temporal cortex elaborate feature -> STS faces
37
what face processing happens in the temporal cortex
cell populations selective for sight of face
generalize over size, position, orientation, lighting
most selective for view: so Marrs' model wrong
some 5% of cells show sensitivyt to identity
other cells selective for familir objects
38
visual cues for facial recognition
features
internal (eyes, mouth, nose)
external - hair
configuration - features have to be in the right place
face familiarity
external features more important for unfamiliar faces
internal faces more important for famous faces
39
thatcher illusion
features analysed independently
each feature coded relative to gravity
you don't notice if individual features flipped to right way round when face upside down
40
facial averageness
faces added together and warped to make a single average face - tends to be smooth and a little blurry\
we find average faces most attractive - probably an evolutionary explanation
41
effects of caricatures on face naming (famous faces, exaggerate features, can you name them?)
50% caricature can recognise the face almost twice as quickly compared to the original
caricatures exaggerate deviation from average
caricature familiar faces can improve recognition
implies faces coded by differences from average
42
brain asymmetry in face perception
face split vertically and mirror images formed left and mirror left look more like the target than mirror right
also if shown half male, half female face, the half of the face on the left dictates the answer
face perception is biased so left eye information favoured onto right hemisphrere
43
what is the perceptual bias in face processing and what is the explanation
judgements of face identity, sex, age, attractiveness are biased to left side of face
explanation
left 1/2 face projects to observers right hemisphere
right hemisphere is specialised for face processing
44
real life tests in IDs
supermarket check-out workers told to expect fraudulent credit cards and to check photo IDs
despite warnings 50% of false ID cards accepted
eyewitnesses inaccurate in identifying a face
30% errors identifying unfamiliar faces (live or video)
experience/training dos not improve accuracy
police officers = students matching photos to CCTV images
45
conclusions to draw from face identification
recognition of familiar faces is excellent
yet recognition of unfamiliar faces is very poor
beware eye witness claims
46
facial expression of emotion - production
cross cultural similarity of expressions and causes
dear and blind children's expression are normal therefore production of expressions is innate (Darwin)
cultural similarities - Ekman imagine your child died all came up with same facial expression
cultural differences - Asian faster changes in eye region, Jack et al
less negative expression in Japan compared to USA, matsumoto et al
47
comprehension of facial expression of emotion
universal interpretation of 6 basic emotions (Ekman) - happy, sad, angry, fear, surprise, disgust
does this mean comprehension is innate? or is there a potential role for learning
48
fear
facial expression similar across species
lab-reared monkeys show no fear of snakes
learn if another monkey seen fearing snakes (mieka and cook)
fear learning is stronger for snakes than flowers
adaptive if there are few or no poisonous snakes
vicarious (social learning) of what fear is
49
fear expression activate ... compared to happiness
activates the amygdala (more scared the face, more amygdala activation)
happy expression inhibit the amygdala
50
brain imaging for facial expressions of emotion and brain damage
different emotions activate different brain systems fear in amygdala
brain damage - damage can selectively impair emotion recognition, amygdala -> no recognition of fear
51
amygdala damage
reduced sensitivity to facial expression of fearreduced sensitivity to sound of fear
reduced experience of fear
patients lacking amygdala look less at the eyes. therefore do not notice the open eyes of fear expressions
52
disgust
what induces it
what is the utility of disgust
contamination from food etc
moral transgression
helps us avoid illness
closes off senses and stops ingestion
53
what are of the brain does disgust activate
insular cortex
54
understanding emotions and empathy
can map brain for pleasure / disgust sight and experience of
emotion perception - see reactions to an odour
emotion experience - smell odours
sight in the insula scanned, see disgust > see neutral
55
brain regions for odours
anterior insula activated only by unpleasant odors
is the same brain region activated by smell and sight
-> insula stimulation evokes taste and odour experiences
56
empathy
where in the brain
what
why
insula cortex
processes sight of others disgust expressions
processes unpleasant tastes, smells
- we understand others emotions by matching to our own emotions
witnessing others disgust activates our on insulas as if we are disgusted
contagious emotion response aids social learning, eg fear of snakes
57
disgust expression
brain imaging
brain damage
disgust emotion activates insula cortex
brain damage
damage to the insula cortex or basal ganglia in huntigtons disease impairs disgust recognition
huntingtons disease relatives without clinical symptoms show impairment in recognising disgust expressions
58
classification of expressions
categorizing mixed emotions is hard
expressions are often ambiguous
depends on the context
59
disorders with biased emotion processing
negativity bias in depression
hostile attribution bias in conduct disorder
assuming hostility is rational in adverse environment, but may be self reinforcing
60
vicious cycle in aggression
biased negative interpretation of another's expression leads to an aggressive reaction which is reciprocated
61
establishing a virtuous cycle
shifting the interpretation bias set up a virtuous cycle in which positive reactions are reinforced
62
modifying emotion perception experiment
trained participants (adolescent males)
shift emotion attribution - see less anger and more happiness
report lower levels of anger
staff report less aggressive behaviour in adolescents with criminal records in 2 weeks after training
63
conclusions in the perception of emotional expressions
bias in the perception of emotional expressions has a causal role in subjective anger and aggressive behaviour
biased emotion perception may contribute to mood disorders
64
social signals for interaction - gaze, where in the brain
ventral thalamus
| activity modulated by attractiveness and gaze direction
65
attraction and eye contact
brain reward system activated by attractive faces looking at you (unattractive faces looking away)
66
2 social signals for interaction
gaze - kampe
| expression - O'Doherty
67
attraction and interaction
attractiveness is abstract
attraction to you is important
looking and smiling indicates attraction to you
faces attracted to you activate reward systems
68
emotion recognition
brain systems - specific emotions
empathy - analysis of own and others emotions
social learning - contagion of fear or disgust
biased interpretation - psychopathology
regulates - aggression
69
how we see in 3D (cues available to painters)
height in the field of view - further away an object, the higher in the visual field, the lower it projects on the retina
geometric perspective - parallel lines appear to converge with distance
texture gradient - finer (denser) texture is seen as further away
size of familiar objects - object size decreases with increasing distance, if size know distance can be gauged
occlusion or overlap - close objects overlap far objects
blurring and increase of blueness - distant objects = hazy or blurred, dust particles scatter light (depending on wavelength of light) so distant objects appear more blue as will have a different wavelength when they reach your eye
shadow - more ambiguous as we must assume light direction to see cue
pictorial cues - again ambiguous, many 3D situations produce the same 2D image
70
the hollow mask
light direction interpreted so that hollow mask appears as a solid face
71
seeing depth and distance - unambiguous cues
```
dynamic cues
- motion parallax
accommodation
-focus of the eye
binocular sues
-binocular convergence
stereopsis
accommodation and binocular cues only work for close distances
```
72
relative motion or motion parallax
when we travel in one direction, stationary objects move opposite to our direction of travel
the speed of relative motion is related to distance
close objects appear to move fast, far objects slow
73
what are binocular cues
cues of convergence of eyes having to converge more for close objects to bring them into focus
74
what is stereopsis
left and right eye differ
they don't have the same view
discovered by the victorian stereogram (red and green glasses that makes it seem 3D
75
definition of a visual illusion
| why do we study them
illusions occur when what we seen does not correspond to what is physically present in the world
we study them as they tell us things about normal vision
76
what do brightness after effect and colour after effect tell us about vision
pigment bleaching / neuronal fatigue and opponent processing of colour
77
reconcile
| ng colour theories
three colour receptors feed to ganglion cells
| lots of green light, receptors adapt, post adaption see too much green
78
motion after effect
waterfall illusion, spiral after effect
| explanation - neuronal fatigue and opponent processing of motion direction
79
illusions over time
| examples and perceptual principles
```
brightness after effect
colour after effect
motion after effect
orientation after effect
perceptual principle
adapt to a steady state
code (overemphasise) change in values across time
```
80
illusions over space examples
| conc
brightness contrast
object brightness coded relative to the surround brightness - so square appears darker on a lighter background
colour contrast
object colour coded relative to surround colour
motion contrast
orientation contrast (Zolner illusion
visual qualities are coded relative to the surround
81
what is the Zollner illusion
orientation contrast
| lines appear orientated differently when covered in lots of parallel hashes
82
illusions of size
geometrical illusion
ponzo
muller-lyer
ames room
83
size distance relationship
object size is inferred from perceived distance and image size
for 2 objects with the same image size, the object appearing further away is seen as larger
84
the ponzo illusion and gregorys theory
two parallel lines same size but one higher up page made to look further away so perceived as bigger
gregorys theory - the visual system makes hypothese about distance to objects based ont he evidence in the image. interpretation of size follows
85
Muller-lyer illusion
objectively equal in separation, percpetuaqlly different. way two lines split, made to look different in size when actually the same
perceptive cues set up false interpretations of distance
86
ames room
room set up to screw with size and distances for the observer
room has false distance cues. left and right corners appear equally far but are not
objects at different distance appear equally far (retinal size differences are seen as real size differences)
87
Richard Gregory carpentered theory
population from more carentered environemtns see more right angles so fall for the illusion more?
in reality noce idea but not true in practice
illusions occur in populations across the world
88
impossible figures
penrose triangle
escher's prints
brain cannot compute 3D structure from all parts at once, each part looks plausible in isolation
89
ambiguous figures
necker cube - 2d images have one or more 3d interpretation
| entertain each interpretation, but only one at a time
90
conditions for motion perception in apparent or phi motion
lights flashing with close separation and short time interval = motion
wide separation or long time interval = no motion
91
utility of motion
```
rigid structure
articulating structure
heading direction
maintain posture
interpreting causality
attributing goals
```
92
what are the mechanisms for detecting motion direction
local inhibition in one direction
| detects real or apparent motion in direction, opposite to inhibition
93
cartoon motion explained
again apparent or phi motion
relies on apparent motion
brain interpolates smooth change in shape
94
controlling posture
| experiment
postural stability - posture is less stable with closed eyes
lee's swinging room - when te room moves, visual motion is attributed to body motion which causes inappropriate posture compensation
95
optic flow
j. Gibson
focus of expansion = heading direction
landing a plane on an aircraft crrier
96
estimating time to contact
lee
| rate of expansion predicts when to react
97
kinetic depth use
circling ballet dancer, can detect shape from changing silhouette
98
detecting form from motion
rigid motion - kinetic depth, shape from changing silhouette
| biological motion - form moving body from lights on joints, biological motion
99
perception of causality in collisions (michotte)
impression of causality - one object bumps into a second objects stops, then second object moves off
reduced impression of causality
second object moves off before the collision
second object moves off after a long delay
100
attribution of pupose Heider and simmel
cartoon moves in which actos are arbitray shapes with trajectories appropriate for meaningful actions
subjects attribute actions and intentions to the moveing shapes (eg big triangle chased the little triangle)
101
habituation paradigm
repeat film until infant observer is bored
change film
measure renewed interest
violation of expectations - surprise and long looks
102
motion defining goals
behavioural sensitivity
1 year olds infer unseen goals ie are sensitive to the likely goals of an action
increased attention if agents action is inconsistent with earlier goal - catching a small ball
does not take shortest path to small ball
continues on non-intercept trajectory
103
brain processing of motion and form
v1 and v2 features outputs on motion and IT colour and form to STS
104
what does biological motion do
activates specific brain regions
105
motion processing in the brain (cells)
V5 cells are motion sensitive
v5 damage causes motion blindness
inability to track fast movement
see a series of frozen snapshots
106
evidence for top-down processing
```
anatomy
context
imagination
observer bias
priming expectations
```
107
bottom up processing
high level object detections
mide level pattern detectors
low level feature detectors
108
top down influence
memorized concepts
high level object detectors
mid level pattern detectors
109
bidirectional processing models
information flow is bottom up and top down
| expectations lower threshold for likely items
110
anatomy to determine whether top down or bottom up
eye -> lgn < v1 < v2 < v4 < temporal cortex
more connections descend than ascend
only 3% of v1 input layer synapses are from lgn
vision = 97% reconstruction or halucination
111
context of an object
within a scene it is easier in a context to find an image where it belongs in an image than in an obscure place
within an object - word context biases interpretations, jumbled letter judged based in context of word
word superiority effect
detecting a ltter in is easier when in a word
112
can visual areas be activated without visual input
brain areas processing sight of faces and places fusiform face area, parahippocampal face area
imagine doing thigs - can detect awareness
113
expectations - object permanence
we expect an object moved behind a screen to reappear with the same form when screen removed
under 8 months abort search if object is hidden
114
object permanence food location
tinklepaugh - monkeys
clayton - scrub jays
remember the reward value of hidden objects
115
perceptual priming
conscious and subliminal
rapid cereal presentation
brief images are seen but memory is fleeting
they may not achieve full awareness but can affect recognition and bias behaviour
the rord alzeihmers can impair memor performance
the word fast speeds up reading and walking
116
signal detection
hits and misses
reward for hits and no penality fro false alarns - encourages target present bias
no reward for hits and severe penalty for false alarms encourages target absence bias
bas affected by
subject confidence
% trials target present
payoff detecting / missing targets
payoff matric
consider benefits from hits and correct rejections
117
types of eye movements
fixations (pauses) when the eyes are still 3-4 per second
saccades (jumps) between fixations
slow tracking following a moving object
118
functions of eye movements
to direct fovea to features of interest
119
why does the world appear static when our eyes move
vision turned off during eye movement
we cannot see our own saccades in a irror
relative conditioning of motion
inhibition between similar motion detectors
compare movement predicted and occuring
120
stability of the visual world
feed-back from stretch receptors in the eye muscles
feed-forward from planed movements (von Holst)
efference copy of commands to move eyes cancels incoming image movement
121
evidence for feed-forward
passive eye movement - press eye gently, scene moves
| paralysis of eye muscles, try to move paralysed eye, scene jumps
122
general principles behind stability of the sensory world
attend to unpredictable events
| ignore predictable consequences of own actions
123
unstable sensory world
schizophrenic hallucinations?
sub-vocal speech not recognised as self-generated
own actions and thoughts controlled by others
124
factors affecting face attractiveness
```
face owner
averageness
symmetry
sexual dimorphism - masculinity in men, femininity in women
health
face admirer
hormone levels
own status
imprinting
theory - immune competence handicap hypothesis
```
125
composite faces
averageness
blending a group of faces shows consisitent traits and looks the most attractive
skin texture gets smoother
face becomes more symmetric
evolutionary explanation
avoid extreme mutant genotypes
psychological explanations - we like what we see often
126
is averageness as attractive as it gets
no
| attractive faces are systematically different from average faces
127
evolutionary theory of attractiveness
```
female investment
eggs (bigger than sperm)
gestation
incubation
lactation
nursing
so females choosier than males, exception sea-horses and stickleback
```
128
symmetry in attractiveness - animal world
```
left = right for population
low fluctuating asymmetry
shows coped with challenges during growth
indicates health ad immunity
tail symmetry is preffered in swallows
is symmetry attractive in humans
```
129
symmetry in humans attractiveness
more symmetric face shape preffered
130
evolutionary theory - what do females
low fluctuating asymmetry, ability to grow / plan
hnest signals of a costly handicap
immune competence - testosterone surpresses immunity; only fit males can afford testosterone cost
predicts sexually dimorphic male traits
131
male masculinity shows.....
| attractiveness?
shows strength and immunity
should it be attractive
surprising aversion to masculinity (shown by women)
feminine warm and hinest whereas masculine is cold and dishonest
132
sexual selection for parental care
selection may show preference for facial features indicating paternal investment
high testosterone inked to marital problems (mazur and booth)
133
do mate preferences change over a woman's menstral cycle?
conception most likely in follicular phase
women select most attractive face and report cycle pahse
increased attraction to masculinity when fertile
134
preference for masculinity due to relationship desire
preferences for masculinity follows fertility for short bt not long term relationships
parallel effects for voice, dominant behaviour, body shape, pheromone odour
135
male choice of partner
selection occurs for both sexes
in several primate species females compete for males attention
high oestrogen is associated with health and fertility
feminized female features (face, voice, body shape) should be attractive to men
feminised features in female faces are attractive to men
136
if humans compete for partners how will partners pair up
own status and competition
women report own attractiveness and judge faces for
-long term relation
-short term relation
chose faces manipulated in masculinity or symmetry
137
more attractive women prefer what features
attractive women prefer more masculine men
| attractive women prefer more symmetric men
138
competition and mate preferences
for long term relationships, less attractive women prefer lower level of masculinity and focus less on symmetry
interpretation
attractive women may extract greater commitment from symmetric / masculine men
we learn attraction to individuals we can get / keep
139
imprinting on parent characteristics
imprinting - early exposure to parent traits affects later mate preferences in birds and mammals
Lorenz's birds
male lambs fostered by female goats prefer goats to sheep as sexual partners (Kendrick et al)
140
imprinting in humans?
does a human resemble a woman's father or mother
opposite sex parent and partner are similar
imprinting on opposite sex parent
141
odours found attractive
pheromones - airborne chemicals influencing physiology or behaviour
awareness not needed for effects
142
Gibson's theory of direct perception
visual information controls actions directly
visual properties of objects afford actions
we recognise which actions can be achieved
143
perception and action where in the brain
occipital lobe
direct control of actions - parietal lobe
recognition and memory - temporal lobe
where and what pathways
144
ventral pathway damage
cannot recognise objects, orientation, size
patient DF poor at matching handle to target orientation
but patient DF cam guide actions visually
145
action pathway
dorsal pathway v1 -> parietal lobe
| damage = ataxia; cannot guide actions but can recognise objects
146
perception pathway
ventral pathway v1 -> temporal lobe
| damage = agnosia: cannot recognise objects but can guide actions
147
visual illusions - does it effect motor
red circle surrounded by different shaped circles, makes the red circle appear bigger or smaller (visual illusion)
visual control of action does not suffer illusions
grip size during reaching under online visual guidance is accurate
148
are the motor and the perceptual systems integrated?
| motion primed by actions experiment
stimulus - rotation with ambiguous direction
response - turn hand, think
turn clockwise
percept - display moves with your action plan
interpretation - common code for perception and action control
see intended or associated effects of action
149
mirror neurone systems
premotor cortex
cells fire during performance of hand actions
cells fire when other seen or heard doing the same action
interpretation
seeing and doing use same brain systems
action recognition depends on production ability
150
understanding actions and mirror neurones
premotor cortex mirror neurons
discharge during the observation and execution of an action
discharge when the action goal hidden but can be deduced
discharge when an action can only be hear
could enable understanding actions of others by translating them into our own actions
support imitation or empathy?
151
seeing or doing
does our brain systems respond to the sight of actions because they are familiar or we know how to do the actions
how do we test this
what is the result
ballet dancers have visually familiar but not performed dance moves and otorically familiar dance moves due to different sexes having different moves
premotor and parietal cortex
active more to seeing own-sex than other-sex dance moves
same and opposite sex dance moves were equally visually familiar
mirror systems active when see actions with out motor repertoires
analyse their actions in terms of how we would perform them
152
does observing someone else being touched activate our own somatosensory cortex - experiment
movies of actors being touched on their legs
touch of the subjects legs
hypothesis - some brain areas activated by both sight and touch
primary somasensory cortex
sight of touch > non-touch
see touch, feel touch overlap
153
social perception summary
seeing or hearing others actions activates our premotor action plans as if we do the actions
witnessing touch activates our secondary somatosensory cortex as if we are touched
witnessing others disgust activates our insula cortex as if we experience disgust
witnessing others in pain activates similar brain regions to experiencing pain ourselves
154
action perception and production summary
TMS (trans-cranial magnetic stimulation) of motor cortex produces electrical potentials in muscles
seeing actions using the same muscles reduces the threshold for TMS produced muscle potentials
hearing speech and seeing lip movements increases tongue and vocal muscle excitability
155
what is motor theory of speech perception
we stimulate production of speech we hear
156
what is the benefits of attention
can benefit processing
attending on to one object types
-boosts sensitivity
-boosts activity in relevant brain system
157
what area of the brain attends to faces, houses?
faces - fusiform face area
| houses - parahippocampal place area
158
gorilla experiment
85% miss the gorilla in an image when cancer screening
159
what is inattention blindness
subjects attending to one object or position can be blind to other objects or unexpected events (neisser)
subjects must attend to objects to notice them but attention may not be enough
changes (saccades and events) can distract us
160
change blindness
while a door is carried between people, one person changes identity 50% of observers don't notice the change
simons and Levin
161
flashing within a screen does what
decreases the chance of seeing other changes
162
change blindness - when do we miss change
if it happens slowly
if an irrelevant transient (flash, occlusion, saccade) occurs between the original and new forms
movement can itself prevent us noticing colour changes
163
hemi-spatial neglect explained
damage to right temporal / parietal cortex
inattention to left side of space and objects
cross items only on right of display
bisect right of lines
draw only right side of objects
164
evidence for coding of attention direction
2/3 cells code gaze and face view
2/3 cells code face and body view
gaze > face > body
wrong gaze inhibits correct face view
165
problems processing gaze
autism
| shyness
166
autism and gaze
spontaneous attention following deficit in autism
| but good at gaze geometry - can work out where picture was looking
167
how do we use attention direction
```
competition
get food out of dominants sight (chimps)
re-hide food if seen
define what others know or believe
knowledge used competing / cooperation
social learning
objects of fear
words for objects looked at
```
168
nature vs nurture, learning to see who and brief what they think
nativist - Descartes, percpetual abilities inborn
| empiricist - Berkeley, perception depends on experience
169
sources of evidence (just titles) in nature vs nurture debate on learning to see
infant abilities
restored vision
cultural differences
adaptation
170
infant abilities of vision - brief
Gibson - visual cliff, size constancy - bower
face perception
object perception
171
visual cliff
Gibson - visual cliff, (can only test once mobile but infants avoid the visual cliff, done on goats who are walking from day one and they avoid the cliff. rats don't)
suggest innate
172
infants object perception
bower - size constancy
| trained head turn response with peekaboo reward generalises to trained size at changed distance
173
face perception in infants
fantz, goren et al, h=Johnson et al
looking preferences for 2 min olds of facial configurations
and potentially imitate facial gestures
174
neonate imitation
meltzoff and moore
Ferrari et al
infants imitate tongue protrusions
but also will imitate if any object comes near so up for debate
175
recovery from blindness
```
abilities present
-figure ground degregation
cross modal matching touch to vision
problems in interpretation
-unknown experience before blindness
adult knowledge used in interpreting vision
degeneration of the visual system
```
176
experience and the nervous system
visual cortex
temporal cortex
orientation sensitive cells present at birth
visual environment influences the distribution of orientation sensitive cells
critical period of influences (3-7 weeks in cats)
temporal cortex
cells responsive to simple aspects faces may be inborn
but show effects of experience
177
effects of culture in experience and perception
effects of culture
recognition of letters and words
inuit perception and discrimination of snow
colour words blue and green
178
adaptation to prisms
chicks
motor system matures; consistency in aim increases
but ability to hit target does not
humans
prisms shift the visual world in one direction, adaptation in humans
visual - motor coordination compensates
adaptation leaves an after effect
behaviour biased in compensatory direction
179
adaptation to inverted vision
initially world looks upside down (and is sickening)
after weeks of adaptation world looks normal
motor skills return - cycling, skiing possible
180
adaptation to prisms
| why should the system adapt
limbs grow
eye changes shape
need to re-calibrate visuo-motor coordination
