PSY2002 W5 Multisensory integration 1 (L) Flashcards
What is body schema ?
“a representation of the positions of body parts in space, which is updated during body movement”
Sensorimotor representation that guides action
Does not require awareness
What are disorders of body schema?
Alice in Wonderland syndrome, Autopagnosia, phantom limbs
What is reference frame?
Player perspective: Coordinates of snake in the world, e.g. upper left corner
Snake perspective: Sees world through its eyes, can turn left or right
Problem: Sensory input in player perspective and Controls in snake perspective
What is coordinate transformation?
Eye-to-head: need to know orientation of eyes.
Head-to-body: need to know orientation of head.
→ Converting between reference frames requires us to know the position and orientation of body parts. In other words, we need a body schema
What is eye-/head-centred reference frames?
Head-centred frame is where you head is directed towards ()–a
Eye-centred frame is where your eyes are looking no matter the head is (¤) –
What is body image?
how do you imagine your body
how do you feel about your body
conscious (mostly visual) representation
What is alice in wonerland syndrome?
Distortion in size perception. Body parts might appear smaller (microsomatognosia) or larger than their true size (macrosomatognosia). Can affect whole body. Associated with childhood and migraines.
What is Autotopagnosia?
Inability to locate body parts. Loss of spatial unity of body. Patients can name body parts but relative order lost. Finger agnosia: Fused percept of fingers
What is Phantom limbs?
After limb loss, presence of limb is still felt. Can include agency over limb (movement). Often associated with pain. Phantom limb can change size over time (e.g. shrink: telescoping)
What is temporal-order judgements?
Heed & Azañón, Front Psychol, 2014
Does body posture affect perception?
Setup: stimulate both hands in random order
Task: Indicate which hand was stimulated first
Conditions: Arms uncrossed/crossed
Participants mix up which hand was stimulated when arms are crossed. Solving the task does not need input from body schema
-> Body schema affecting basic perception
What is peripersonal space?
The space immediately surrounding our bodies. Objects within peripersonal space can be grasped and manipulated immediately. Extent not fixed: can contract and expand.
What is the moravec’s paradox?
“It is comparatively easy to make computers exhibit adult level performance on intelligence tests or playing checkers, and difficult or impossible to give them the skills of a one-year-old when it comes to perception and mobility.” - Moravec, 1998
What are computers good at?
Computers are good at “hard” task – like playing chess, but are bad at seemingly “easy” tasks such as walking
Reasoning (high-level cognitive) ==> relatively easy to reproduce into a machine
Perception, Action (low-level) ==> surprisingly hard to reproduce into a machine
Does blocking the sensations from the fingers affect motor control?
Johansson, 2005
Blocked sensations from the fingers: anesthetize the fingers. Block all touch sensation from the fingers, does not affect motor control. After doing so the participant had to pick a match up and light it, in a normal condition it only takes a few seconds but after losing sensation in fingers it took around 25 seconds.
What is multisensory perception?
“I see and feel that I am touching this object.” – coordination of vision and touch. What robots have a difficulty integrating is the multisensory integration.
