Transcript Biological Imitation

Biological Imitation
What is NOT imitation
o Not the passive and faithful echoing of an arbitrary
demonstration achieved in a single, immediate attempt.
o Mimicking – copying the form of acts without any
representation of their goal. (birds, rats)
o Pavlovian Conditioning
o Matched Dependant Behavior – use of demonstrator’s
behavior as a discriminative stimulus for the same or
similar behavior, without knowing that their behavior was
similar to that of the demonstrator.
More of Not Imitation
o Stimulus Enhancement – observing an action can
influence the degree to which the observer attends to
certain physical components of the problem situation,
facilitating independent acquisition by the observer of a
successful technique.
o Emulation Learning – Observer duplicates the results of
other individual’s behavior, but not the specific way to
achieve them.
o Response Facilitation – selective enhancement of motor
responses: watching a conspecific performing an act
increases the probability of an animal doing the same.
Only for actions already in repertoire.
True Imitation
o Generates new behavior on the basis of
observation rather than experience
o Active process of abstraction and reconstruction.
o Attempt to learn is purposeful, goal-directed
o Learns Form as well as Goal
True Imitation (2)
o May be most powerful and efficient of the
social learning processes
o Has special status because it is viewed as
involving symbolic mental processes
Metarepresentations
• Theory of Mind
• Mindreading
• Pretense
Theory of Mind
o To have a ToM: to believe that mental states play a causal
role in generating behavior and infer the presence of mental
states in others by observing their appearance and behavior.
• Theory of Mind = mentally represent the mental
representations of others
o Concerns Content of representations: Think about self and
others in terms of Mental States
Theory of Mind (2)
o Have mental state concepts such as
• Believe
Know
• Want
See
– and use these concepts to predict and explain behavior.
• Relevant because imitation is thought to involve the
ascription of purposes or goals by the imitator to the
model.
• However, it is possible that imitation occurs without a
Theory of Mind on the part of the imitator (eg mimicry,
associative learning).
Mindreading
o Basis: animal communication signals may be designed to
fundamentally manipulate others to the signal-sender’s
ultimate genetic advantage,
o which in turn leads to selection pressures for
protagonists to become more skilled at discerning the
true state of mind of the signalers: mindread!
o “Ability to recognize states of mind (mental states) in
oneself and/or others.”
o Ability to translate between one’s own and another
individual’s intentional or representational state –
“cognitive empathy.”
Pretense
o Imitators copy the actions in demonstrations, but
not the results.
• Pretend play in children points to the origins of the
child’s developing of a Theory of Mind;
– psychological operation of Metarepresentation
= Theory of Mind.
Metarepresentation
2 representations
– First order: program / action-plan, drives the
actions of the model
– Second order: in imitator, replicates the model’s
1st order representation.
o Can say that secondary representations are intrinsic
to imitation: that the basis of secondary
representation is the ability to coordinate multiple
models, which represent different situations.
Metarepresentation (2)
o BUT in human children, the ability to imitate
develops much earlier than either pretense or
mindreading!
• So maybe imitation is cognitively linked to
mindreading and pretense,
• on the principle that each incorporates a facility in
self-other representation, but imitation is a simpler
and developmentally prior achievement.
Infant Imitation
o Must consider both the Cognitive and Social domains
o There are questions of perception and control.
o Robust across contextual changes – learn here, do there;
imitative learning is flexible.
o Goal-directed: infants gradually correct their imitative
attempts.
– Creative error example: adult protrudes tongue to one
side, infant protrudes tongue and turns head!
Neonatal Imitation Debate:
Meltzoff & Moore
• Organ identification: during initial phase of imitation,
before actual movement, babies may quiet the rest of their
body and just wiggle the tongue.
• Body parts and movement patterns are recognized and
imitated: tongue for tongue, lip for lip.
• The later observed decline in facial movement is a result of
motivational change: babies become too distracted to Just
protrude their tongues anymore.
Neonatal Imitation Debate:
Susan Jones
Tongue Protrusion in neonates is motivated by interest in
visual display and exploration, Not imitation!
• Infants produce tongue protrusion when their interest is
aroused by any visual display
• Most infants find tongue protrusion more interesting and
arousing to watch than mouth openings.
• Infants move their tongues when they are interested because
interesting sights motivate exploratory behavior, and the
only exploratory behavior infants are capable of is tongue
movement. TP ceases once infants can reach for objects.
Why Infant Imitation is Important
o Imitation is one of the most sensitive tools available for
investigating the foundations of infants’ understanding of
people.
o Tells us about perception, and links between perception and
action.
o Provides information about infants’ notion of self, other,
and the mappings between the two.
o Provides first opportunity for infants to make the
connection between the visible world of others and the
infants’ own internal states.
Infant Imitation (2)
o Recognization of Being Imitated
o Infant plays more, looks more at person imitating him/her.
– Will test an adult by changing the ‘game,’ throwing a curve ball once
in a while to see if the adult is paying attention (9+ months).
o Identifying People
o Infants use Functional Criteria – gestural signatures
o Ex: 1st adult plays A with infant, then goes away, and then
2nd adult comes and tries to play B
• If infant has kept visual track and therefore Knows
that 2nd adult is not 1st adult, infant will switch
immediately to game B.
• If infant did lose visual contact with 1st adult, infant
will try to play A, to ascertain if adult is still 1st adult.
Developmental Consequences of Reciprocal
Imitation Games
o Infants gain a sense of what his or her felt
acts look like.
• Imitation games provide an opportunity to
the infant to see both self and other as
producers of intended acts instead of merely
of equivalent surface behaviors.
Autism
o Autistics perform significantly poorer than controls on
imitation of both body movements and actions involving
objects.
• “Early capacities involving imitation, emotion-sharing,
and theory of mind are primarily and specifically deficient
in autism. Further, these three capacities involve forming
and coordinating social representations of self and other at
increasingly complex levels via representational processes
that extract patterns of similarity between self and other.”
– imitation plays a primary constructive role in the generation of
theory of mind, pretence, and other capacities. (Rogers &
Penrose, 1991)
Primates
• Chimpanzees and Orangutans demonstrate imitative
capabilities
• Monkeys are Not good at imitation.
• Apes are thought to be true imitators, but we don’t have
much data on them.
– Learning may be importantly handled by apprenticeship,
– While Imitation serves self-teaching functions.
• Most of the work done in non-human primates can be
explained by non-True types of Imitation.
Deception
• Most deception, especially in non-human primates, can be
explained by
– associative learning
– chance
– inference about observable features rather than mental
states.
• Examples
– Female carnivorous baboon
– Chimpanzee-trainer interaction
– Vervet monkeys’ false leopard call
Mirror Neurons
• 2nd category of F5 visuomotor neurons
• Visually activated when a monkey observes a goaldirected action with either hand or mouth
o Tools and emotional gestures do not activate mirror
neurons.
o Majority only become active during the observation of a
single type of action
o Ex: Grasping, placing, manipulating.
o Precision grip
o Finger prehension,
o Whole-hand prehension
Resonance Mechanisms
o Motor neurons of higher centers always discharge in
association with a particular movement, but will also
discharge in the absence of overt motor behavior.
o It is not a command, but an internal representation of
the motor behavior they code.
• Resonance: internal motor representation of the observed
event which, subsequently, may be used for different
functions, among which is imitation.
Low Level Mechanisms
and Response Facilitation
o Mostly in the superior parietal lobule.
o 2 fundamental types of releasing signals
– Objects of certain size, shape, color
– Movements by conspecifics
• Is a fundamental way in which the behavior of groups of
animals acquires coherence. (Birds flocking)
o Infant imitation differs from Response Facilitation in that
infants do perform deferred imitation – the behavior does not
disappear with disappearance of the releasing signal.
• It is very difficult to refrain from imitating observed
movements. Ex: boxing match.
Evidence for Low Level Mechanisms
and Response Facilitation
o Motor Evoked Potentials recorded from arm and hand
muscles when observing meaningless intransitive arm
movements and grasping movements: increased upon
observation of arm and hand movements – no goal needed.
o Cortical 15-25 Hz rhythmic activity: usually suppressed
during movement execution, also significantly diminished
during movement observation.
o EEG: observation of human movements, but NOT objects or
animals, desynchronizes EEG patterns of precentral cortex.
– Desynch of primary motor cortex more likely due to arrival of action
potentials originating from premotor areas than from a direct visual
input to the primary motor cortex.
o Echopraxia: impulsive tendency to imitate other’s gestures.
Reflexive.
High-Level Resonance Mechanism,
Emulation, and True Imitation
o Left inferior frontal gyrus (Broca’s Region)
• Firing of F5 codes the motor representation of
the action, not the movements forming it.
Hypothesis: activity of F5 mirror neurons
mediates action understanding.
• Purpose of F5 is to generate a representation of
what another individual is doing.
• Meaning of an observed action can be recognized
because of similarity between observed and acted
representation.
• Emulation: allows observer to retrieve most
relevant information, the action goal.
• Mirror neurons constitute first step: action-goal
understanding.
True Imitation
results from interplay of the
two levels of resonance.
o High-level resonance describes the Goal
o Low-level resonance describes the Form