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 3 rd person as experienced in 1 st 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