PSY2002 SEMESTER 1 - WEEK 5 Flashcards
what is Moravec paradox
reasoning (high-level cognitive tasks) relatively easy to be implemented in a machine compared to other task like perception, action (low-level cognitive tasks) that are surprisingly hard to be implemented in machines
summarise Moravec’s paradox
computer good at “hard task” (chess)
bad at “easy task” (walking)
what does blocking all touch sensations from fingers do
doesn’t affect motor control but make movement difficult/clumbsy
multisensory integration of touch and vision for feedback to know that we have grasped match and where our matchbox is
we can replicate tactile/visual sensor in robut, but where do issues lie
how to replicate multisensory integration = how to integrate info from visual and tactile systems
name 2 challenges for multisensory integration
- how to transform representations from different senses into common representation
- how to integrate info from different senses in coherent percepts
what is the visual reference frame
eye-centred/retinal (location of visual stimulus on retina)
what is the audition reference frame
head-centred (location of sound source with respect to ears)
what is the touch reference frameq
body-centred (location of tactile stimulus on skin)
do reference frames move independently or in sync
move independetly, meaning info they gather can be v. different
and body needs to convert between reference frames to external space (coordinate)
when converting from eye-centred reference frame to head-centred reference frame what do we need to know
orientation of eyes
when converting from head-centred reference frame to body-centred reference frame what do we need to know
orientation of head
what does converting btw/ reference frame in general require us to do
know position and orientation of body part = body schema
input coming in from 2 different sense (hear and see dog, if dog moves, representation moves in both frame). if dog is central, what is position of visual/auditory reference frame
visual (eye-centred) = dog in middle
audition (head-centred) = dog in middle
input coming in from 2 different sense (hear and see dog, if dog moves, representation moves in both frame). if dog moves, what is position of visual/auditory reference frame
visual (eye-centred) still straight as head hasn’t moved only eye has
audition - head hasn’t moved meaning dog no longer in centre of head-reference frame
input coming in from 2 different sense (hear and see dog, if dog moves, representation moves in both frame). if dog is central, but head moves what is position of visual and auditory reference frame
visual frame moves (looks away) = dog is no longer central
but still central for auditory
define body schema
internal representation of positions of body parts in space, which is updated during body movement
includes posture, spatial extensions
(at any given moment knows where all limbs are so doesn’t need visual input)
explain how body schema is spatially coded
position of each body part in external space
explain how body schema is modular
different body parts processed separately
explain how body schema is updated with movement
automated and “always on”
explain how body schema is adaptable
changes when body changes
explain how body schema is supramodel
combines input from multiple senses eg, proprioception, touch, vision, audition
explain how body schema is coherent
spatial continuity when resolving perceptual conflicts (everything that is part of body is always attached to body, never have feeling of arm not attached)
explain how body schema is interpersonal
observed actions are represented within same body schema = viewing someone elses actions, automatically represent this within own body schema to copy if we need
compare body schema with body image
schema= sensorimotor representation guiding action and doesn’t require awareness
image= how you imagine your body, feel about it and consciously represent it
name two bodily illusions
pinocchio illusion
rubber hand illusion
what is pinocchio illusion
- vibrating bicep activates same receptor, make arms feel extended
- point to nose
- if arm extended then nose feels super long
what is rubber hand illusion
ppt real hand hidden, stroke real and rubber simulataneously
ppt see and feel rubber hand = vision and touch undergo multisensory integration, showing us body schema can be modifiable
outline crossmodel congruency in rubber hand experiment
larger in rubber hand than non, and virtual body effects suggest visual info about apparent hand position has objective and subjective cross-modal influence on tactile judgement even if vision conflicts with proprioception, but no effect if put in anatomically implausible posture
meaning visual info can dominate slightly wrong proprioception (but proprioception reduces impact of vision when visual info inconsistent with proprioception)
what is location for neurons responding to visual and tactile stimulation (cortical)
ventral premotor cortex
parietal, ventral intraparietal
superior temporal sulcus
what is location for neurons responding to visual and tactile stimulation (subcortical)
putamen, superior colliculus
how can the impact of body posture on perception be studied
vibration on both hands in random order, ppt indicates which hand stimulated first
condition: arm crossed/un
found ppt mixed up what hand was stimulated when arm crossed = solving task doesn’t need input from body schema but body schema is always on, never off (this can be counterproductive)
outline how cross-modal integration can be studied
ppt touch block with monitor on thumb/index, receive tactile stimulus, respond with location
visual distractor= light close to index/thumb buzz when happening but not always congruent
found quicker reaction in congruent>incongruent, suggesting congruency effect exist in both hands, cross modal integration and visual interference but greater effects for same hand
is greater interference based on hand location (body schema) or visual field? how is this tested
arm-crossing (change body schema), tactile stimuli on same body side, visual on different
as we move arms, effect of visual distractor moves with hand during arm crossing
found body schema >visual repres mediates integration between visual and tactile stimulation = means cross-modal interactions mediated by body schema
what occurs at 6 months for body schema development
body schema start intefere with tactile orientating
baby reach for foot if vibrated
cross/un feet, stimulate, see which baby thinks stimulated first
4 months can tell, but 6 month cannot
name 3 disorders of the body schema
Alice in Wonderland syndrome
autotopagnosia
phantom limbs
summarise alice in wonderland syndrome
distortion of size perception, microsomatognosia, macrosomatosognsia
affecting whole body
define microsomatognosia (alice in wonderland syndrome)
body parts appear smaller
define macrosomatognosia (alice in wonderland syndrome)
body part appear larger than its true size
what is alice in wonderland syndrome associated with?
childhood
migraines, head trauma, viral encephalitis
outline autotopagnosia
inability of locating body parts and loss of spatial unity of body
can name part but relative order lost
what is finger agnosia
fused perception of fingers
outline phantom limb
still feel limb, can include agency over limb (movement)
associate with pain
can change over size (shrink = telescoping)
define cross-modal congruency effect
performance difference between incongruent vs congruent trial
outline research into cross-modal congruency effect using visual lights near same/other hands
incongruent visual distractor delays tactile judgement, shows cross-modal congruency effect
is more pronounced for visual distractor near tactually stimulated hands and visual stimuli closest to current hand position produces largest effect on vibrotactile judgement = means combination of retinal visual stimulation and somatotopic vibrotactile stimulation produce largest remaps with postural changes
what is a critical factor for spatial precueig
proximity of tactile and visual stimulus in external space
outline visuotactile interactions in a patient with brain-damage, who can show spatial extinction
can detect single stimuli regardless if presented on same/different side of lesion
but if given 2 stimuli at same time then different side stimuli is extinguished, can also be observed crossmodally
whats peripersonal space, and what happens to objects wihtin the area
immediately surrounding body
objects within peripersonal space can be immediately grasped/manipulated
extent not fixed, can contract and expand (encodes space outside body, incorporates tools into body schema)
allows us to figure out what tools we can currently use/manipulate
outline tool use when extending our body
tool incorperated into our body schema, and neurons respond to stimuli at far end of tool
apply cross-modal congruency effect to tool use
no crossing of body parts, only tools crossed
same delay effects as seen during arm crossing
if tool held straight, what happen to cross-modal congruency effect
stronger
if in crossed position, larger
change in spatial nature of visuotactile interaction depend on experience in active use of tool
what does extension of visual reference frames of multisensory neurons in tool use suggest
body schema extends along tools, due to multisensory coding of space by intraparietal neurons
in research with right-hemisphere patients with cross-modal extinction of touch on left hand by concurrent visual event near right hand, what is found (regarding extintion)
extinction reduces with increased distance away from hand, and effect of using tool decreased with time
what can prolonged tool manipulations linking visual events on right to left hand do
have opposite effect of decreasing competitive exctinction between visual event on right and left hand touch after right-hemisphere damage
for mirror studies of tactile judgements, what cross-modal effects are found
larger cross-modal congruency effect from visual distractor found for mirror reflection of light near hand than further away but seen directly
applied even if light seen close to rubber hand or confed hand opposite mirror of ppt hand
suggest mirror reflection of lights near ppt hand recoded as originating from peripersonal space despite same optical properties as distant lights placed beyond mirro
