Modeling and Imagery: Intro
Wilson & Knoblich, 2005
Conspecifics?
• The case for motor involvement in perceiving
conspecifics

The idea that we use a part of motor cortex to
interpret the movements of others of our species
• Starts with the notion that other people are
special (perceptually), because they can be
directly compared with ourselves (& they’re
the only thing that can be)
Perceiving people
• Generates motor representation


But no movement
So why have a movement plan without movement?
• Purpose?

It’s proposed here it’s for an emulator
 This is something that in computer hardware/software terms
enables programs intended for one device to run on others
 Perhaps the motor plan enables us to predict other’s actions
Covert imitation of actions
• Chameleon effect
Facial expression (cinema, the nodder)
 Gestures & body sway (mothers/babies,
launderette, bar)
 Tone of voice, pronunciation (Janet & Corinne)

 Ever watched a sport you play and experienced that
you are “playing” yourself?
Covert imitation of actions
• Frontal lobe damage
Loss of inhibition
 Automatic tendency to imitate

 (evidence for covert but inhibited imitation in the rest
of us)
Covert imitation of actions
• Mirror Neurons



Previous examples: overt
imitation
This example: covert
imitation exists when overt
behavior is absent
These neurons (in premotor
cortex of monkey) fire both
when acting and when
watching action
Diagram shows activity in
both premotor and
parietal areas
Covert imitation of actions
• Mirror Neurons



Previous examples: overt imitation
This example: covert imitation exists when overt behavior
is absent
These neurons (in premotor cortex of monkey) fire both
when acting and when watching action
 Note: this is in monkeys, not humans, but the idea is that
perhaps we also have imitative circuitry in our brains
 Recent research confirms MN systems in humans –
throughout brain
Covert imitation of actions
• Activation of motor planning
areas in humans

Observation of other’s body
movement (finger, hand, arm,
mouth, foot) leads to activation
of motor cortex
 Only occurs for plausible
movements
 Also occurs for complex
movements…more so for those
who are expert in the activities
• Heard sounds in piano players
promotes activation of finger parts
of motor cortex
Covert imitation of actions
• Activation of motor planning
areas in humans

Observation of other’s body
movement (finger, hand, arm,
mouth, foot) leads to activation of
motor cortex
 Implies new mappings can be
learned
 Mappings can be from different
stimuli (don’t have to be matched,
e.g. hand for hand)
 Thus music can be “heard” as
movement, provided you are
familiar with the required
movement
• Piano players again
Covert imitation of actions
• Facilitated muscle activity

Trace EMG activity found in response to watching
same limbs of others move
Why do we covertly imitate?
• Might be due to the need for action understanding…



To assist in categorizing the action
To uncover the purpose behind the behavior
To understand the antecedents of the action (why do this? Affective
state)
 Makes sense if both sensory and motor consequences are initiated
• …or we might be trying to perceive what we are seeing

Serves as an “emulator”
 Can perhaps be used to fill in missing or scratchy information
 Can perhaps be used to project likely movements of other’s body even
when unsighted
 Info must permeate other systems beyond the motor system for this
to work
Why do we covertly imitate?
• Contrasts w/other (previous) proposals

Others “postdictive”, this is predictive
• This requires allocentric representation of body


Can map something watched in 3rd person as experienced in
1st person
Clear tie ins for modeling, no?
p. 464
Perception is predictive
• Your favorite CD/playlist
• Similar prediction has been shown in
movement perception
Suggests perceptual extrapolation
 “Filling in” – the x-y example
 Also found for human movement (point light)

Perceptual Prediction & Emulation
• How does it work?

Emulators (again)
 See definition on p. 466
 Model of external system run internally, in real time
• Implies information about external world can be had before it occurs
 Emulation easier for simple patterns, or for very familiar patterns
Motor involvement in perceptual
prediction
• There must be a match between what is seen
and what is experienced (what is experienced
is what builds the emulator)

In the case of watching human bodies, the match
is pretty good – we have one, so we “know” how
it behaves
• Does covert imitation get used for perceptual
prediction in human movement?
Motor involvement in perceptual
prediction
• Motor activation that precedes the related
perceptual event

Pianists generate motor imagery prior to the event
that relates to it
 Motor activation of a finger used to play a note occurs
prior to the note being heard in a familiar piece of
music
Motor involvement in perceptual
prediction
• Superior perceptual prediction by viewing
oneself

Idea here is that if the internal model is based on
an estimation of the external reality, then it
should be best when the external reality is one’s
own!
 And it is borne out
 People watching themselves perform better in point
light task identification then those watching others
So, um, what?
• Internal emulators imply perceptual
sophistication of unparalleled complexity
• That these are unconscious implies there is a lot
going on of which we are not aware
• That the events invoke motor imagery is really
important…see next week’s audio slides
• The point is that this process is going on all the
time…to help us understand the world around us.

Implies that this is a means of communication we can
use for movement teaching/learning