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LONG ARTICLE

Imitation, Mind Reading, and Social Learning

Philip S. Gerrans

Received: 18 February 2013 / Accepted: 20 February 2013! Konrad Lorenz Institute for Evolution and Cognition Research 2013

Abstract Imitation has been understood in differentways: as a cognitive adaptation subtended by genetically

specified cognitive mechanisms; as an aspect of domain

general human cognition. The second option has beenadvanced by Cecilia Heyes who treats imitation as an

instance of associative learning. Her argument is part of a

deflationary treatment of the ‘‘mirror neuron’’ phenome-non. I agree with Heyes about mirror neurons but argue that

Kim Sterelny has provided the tools to provide a better

account of the nature and role of human imitation. What wecall imitative learning is an instance of social learning. It

has little to do with empathy, emotional contagion, or mind

reading.

Keywords Emulation ! Imitation ! Mind reading ! Mirror

neurons ! Modularity ! Social learning ! Tool use

Famously, John Stuart Mill did not think imitation a

sophisticated cognitive capacity. He gives a brief account of

what he takes to be characteristically human cognitive fac-ulties only to contrast them with the ‘‘ape-like one of imi-

tation (Mill 1989, p. 65).’’ His list of human capacities is onethat any cognitive scientist might endorse: ‘‘use observation

to see, reasoning and judgment to foresee, activity to gather

materials for decision, discrimination to decide, and when hehas decided, firmness and self-control to hold to his

deliberate decision.’’ We might characterize this suite asattentive observation, planning, inference, and executive

function involving the ability to represent, more or less

abstractly, a distant goal and use that representation to reg-ulate goal-directed behavior (Zelazo and Muller 2002).

Mill was wrong to contrast these executive capacities

with a less cognitively demanding capacity for imitation.Imitation is itself a cognitively demanding capacity, one of

those which in fact distinguishes Homo sapiens from the

great apes, and which most likely played a role in thedevelopment of the modern Homo phenotype.

The uniqueness of human imitation has been explained

in different ways. For some theorists it is an innatelyspecified cognitive module. In the rest of this article I offer

an alternative account building on the account of inheri-

tance of cognitive traits provided by Kim Sterelny in TheEvolved Apprentice (2012; hereafter, EA). Ultimately I will

argue that imitation, of the type that matters for the

transmission of cultural knowledge, is a sophisticatedcognitive ability that involves the suite of domain-general

abilities described by Mill.1

The presence in the human phenotype of sophisticated

but domain-specific cognitive capacities such as language

leads to hypotheses about innateness and modularity. Themain argument for innate modularity in the case of lan-

guage is that the primary linguistic data (PLD) underde-

termines hypotheses about syntactic structure (Garfield1987; Van der Lely 1997; Carruthers and Chamberlain

2000; Gerrans 2003). A domain-general learning process

such as inductive inference could not solve the frameColloquium on Kim Sterelny’s The Evolved Apprentice: HowEvolution Made Humans Unique.

P. S. Gerrans (&)Philosophy Department, University of Adelaide, Adelaide, SA,Australiae-mail: philip.gerrans@adelaide.edu.au

1 This article is one of four in Biological Theory’s Colloquium onKim Sterelny’s The Evolved Apprentice: How Evolution MadeHumans Unique (2012). See also Downes (2013, this issue); Sterelny(2013, this issue); and Sutton (2013, this issue).

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DOI 10.1007/s13752-013-0112-4

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problem without prior restriction of the domain of possible

solutions. Yet children automatically and effortlesslyacquire the correct syntactic structure of their native lan-

guage without explicit instruction and without being able to

explicitly represent that structure. This is the poverty ofstimulus (POS) argument. It is used to argue that language

acquisition depends on a genetically specified, specialized

computational system whose canalized maturation explainsthe development of linguistic competence (Segal 2008;

Chomsky 2010).

Even though some non-modularists resist the idea thatlanguage is modular, the structure of the POS argument for

innate modularity is not generally contested; so despite

controversies over the nature and extent of modularity theway to contest modularity hypotheses is relatively clear.

One can provide a ‘‘wealth of stimulus’’ (WOS) argument

and show that the information necessary to determinecognitive architecture is present in the child’s environment,

either implicitly in the social interchanges in which it is

embedded or explicitly through direct instruction or dem-onstration (Pullum and Scholz 2002; Cowie 2003). A

corollary of the WOS is that domain-general cognitive

systems (operating on input provided by specialized per-ceptual and quasi-perceptual systems) must be able to

construct the necessary cognitive architecture scaffolded

by the wealthy environment. The result is the emergence ofdomain specificity in the cognitive phenotype without

innate modularity (Karmiloff-Smith 1992). The interactionof general-purpose learning mechanisms and specialized

input systems kept on track by supervision and teaching is

sufficient to account for the acquisition of a specificdomain of information.

Sterelny has given a version of the WOS argument in

arguing that there is no unique cognitive adaptation thatexplains human cognitive modernity. Important adapta-

tions for humanity are quite basic ones such as tolerance

for juveniles, (relative) lack of aggression, and prosociality,which jointly enable intensive social learning. Together

with the suite of (relatively) domain-general capacities

provided by the large prefrontal cortex in humans, theseadaptations make us learning machines. Crucial to the

argument is the idea that the necessary WOS is provided by

cognitive niche construction. The interaction betweenindividual human minds and the social milieu of peers and

caregivers provides a wealth of information and intensive

teaching. As a consequence there is no need to postulatethe presence of innate modularity to explain the develop-

ment of sophisticated, domain-specific cognitive traits.

An example of this approach is the explanation of mindreading, understood as the ability to meta-represent the

mental states of others (Currie and Sterelny 2003). The

theory of mind (TOM) explanation of mind reading arguesthat such meta-representational abilities are necessary for

mind reading. The innatist version of TOM argues that

unless the architecture necessary for TOM is geneticallyspecified, the reliable intergenerational transmission of

mind reading cannot be accounted for. Sterelny and others

have pointed out that an analogy between language andmind reading is imperfect: the child develops in an inten-

sively engineered cognitive niche in which not only the

behavior of others but the decoupled mental states under-lying that behavior are the most emotionally and conver-

sationally salient items. There is, in fact, a wealth of

information, both tacitly and explicitly conveyed, aboutothers’ mental states in the child’s environment (Gerrans

2002, 2003; Stone and Gerrans 2006; Gerrans and Stone

2008).Sterelny additionally points out that the early emergence

of TOM is not really consistent with the Machiavellian

intelligence hypothesis of TOM often used to support theinnatist hypothesis. Preschoolers do not use their meta-

representational capacities for competitive ends or for

collaborative enterprises that depend on the detection ofdefectors. ‘‘But they do face a pressing problem: social

learning’’ (EA, p. 146). Thus the rapidly developing

executive capacities, interacting with quasi perceptualprecursors (like joint attention and social referencing) in a

cognitive niche designed to enable transmission of social

knowledge explain the ubiquitous appearance of mindreading. It is an adaption for social learning, not co-oper-

ation or competition. But its reliable transmission is pro-duced, not by maturation of an innate module for TOM but

by learning within a niche constructed by humans for the

transmission of social knowledge.In the rest of this article I will argue that the human

capacity for imagination should be explained the same

way.Imitation is one of the cognitive traits, such as language

and mind reading, displayed by humans to a unique extent.

And, like language and mind reading, it has been proposedas a cognitive adaptation that drove the transition to human

modernity. Almost uniquely, humans can transmit complex

cultural artifacts, both concrete and abstract, with a veryhigh degree of fidelity across generations. Such transmis-

sion reproduces the human cognitive niche and enables

cultural inheritance. Imitation might well be a key to suchsocial learning: after all, a reliable way to learn how to use

tools, make fishing nets, hunt, play music, pronounce

words, or reproduce stories is to imitate an expert. Giventhat humans teach and demonstrate to a unique extent in

order to transmit expertise, imitation becomes a crucial part

of the cognitive repertoire.It also seems to constitute a specific domain of human

cognition, to develop early and reliably, buffered against

interference. Thus it is a candidate for innate modularityhypotheses. Indeed, since Meltzoff and Moore published a

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paper two decades ago claiming that neonates imitate

automatically, the innatist hypothesis of human imitationhas been a default hypothesis for some developmental

cognitive scientists (Gopnik and Meltzoff 1994; Meltzoff

and Moore 1977; Meltzoff 2002). The (comparative)inability of great apes and monkeys to imitate also lends

weight to the idea that imitation is uniquely human

(Tomasello 1996; Horowitz 2003; Whiten, Horner et al.2004; de Waal and Ferrari 2010).

Of course uniqueness does not show that the trait in

question is a cognitive adaptation with a geneticallyspecified neurocomputational architecture. However,

Meltzoff and Decety (2003), for example, have made that

claim. They argue that (1) imitation is innate in humans;(2) imitation precedes mentalizing and TOM (in develop-

ment and evolution); and (3) behavioral imitation and its

neural substrate provide the mechanism by which TOMand empathy develop in humans.

They go on ‘‘to suggest that infant imitation provides an

innate foundation for social cognition’’ (p. 497). This set ofclaims is anchored within an approach to social cognition,

the simulation theory, opposed to the TOM hypothesis.

They do not directly address conceptual arguments forinnateness, resting their claim largely on the interpretation

of evidence from developmental and cognitive neurosci-

ence about the neural mechanisms underpinning imitation.However, these conceptual issues are relevant. For

example, one could argue against their hypothesis on thegrounds that that the abilities involved are not really imi-

tative, or can be explained as learnt behaviors not depen-

dent on a genetically-specified neural system specializedfor imitation. While the first approach is a possibility for

some aspects of human learning (perhaps what we interpret

as imitation is actually emulation; see below for the dif-ference between imitation and emulation) it does not

generalize. There are many clear cases of imitation central

to social learning. So the second strategy is a better option,viz., to show that the imitative behavior can be explained,

not as the product of a modularized capacity, but as the

outcome of the deployment of one or more of the domain-general capacities available to humans as they develop.

While Sterelny does not discuss the nature of imitation,

he has provided a crucial resource for this second strategyin his general account of cognitive apprenticeship. Formal

results in learning theory and empirical studies of concept

and skill acquisition show that the domain of possiblesolutions to a problem must be appropriately restricted if

domain-general learning strategies are to succeed. If,

however, infants are apprentices whose development isscaffolded by intensive teaching, this constraint is met. We

would not need to evolve a modular capacity for imitation

in order to reproduce observed actions if the process ofmotor learning is supervised and corrected.

Cecilia Heyes gives an instructive domain-general

account of imitation congenial to Sterelny’s approach(Brass and Heyes 2005). She identifies two explananda for

any theory of imitation that might lead to the modularity

hypotheses, before rejecting it. The first is what she callsthe ‘‘correspondence problem.’’ The observer needs to map

a representation of the observed movement onto a corre-

sponding motor plan. This is a complex unconstrainedcomputational problem. It is difficult to see how it could be

solved as instantaneously as humans do unless the domain

of possible motor encodings was restricted.The second is the need to avoid ‘‘abstraction,’’ a term I

will use for the process of categorizing a movement or

movement sequence in terms of a potential hierarchy ofgoals. For example, pushing a piece of food towards a

conspecific might be coded as a motor sequence. More

abstractly, the same movement is a push, feeding, or astrategic move in alliance building. Abstraction is often of

vital importance. Does the trajectory of the arm of some-

one gesturing back to the shore from the ocean represent acry for help, an invitation to come for a swim or simple joiede vivre? Only in the last case is imitation the right

response. These are cases where an identical (or verysimilar) movement sequence can realize multiple goals.

Emulation is the converse case in which the same goal can

be realized by different means. For example, one can opena door by hand or foot. Adam Smith had the concept of

emulation in mind when he noted the exemplary role ofwealth in capitalist societies. He was not suggesting that

we are all inspired to become rich by manufacturing and

marketing the same products in the same way, rather thatacquiring wealth was a goal to be emulated in diverse

ways.

In the developmental and primate literature, the differ-ence between imitation and emulation becomes extremely

significant as a way to decompose cognitive capacities. For

example, a monkey that observes an experimenter grasp anobject by hand will grasp the object by mouth if its hands

are secured. Or if it sees an experimenter turn off a switch

by butting it with her head, the monkey will turn it off byhand. Similarly, a child who sees the experimenter hop a

toy kangaroo across a table and into a house will reproduce

that action, but if the route is blocked will pick the toy upand place it in the right location (Jackson et al. 2006). In

these cases the action is being emulated, not imitated. Mill

should have said: ‘‘the ape-like faculty of emulation.’’These cases tell us that (1) emulation is a more basic

capacity than imitation; (2) the representation of goals is

independent of the representation of means to attain thosegoals; (3) ‘‘true’’ imitation involves reproducing a move-

ment sequence in order to realize a goal. Another way to

put this is to say that specific actions rather than meremovement sequences are the object of imitation.

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And these ideas are part of the standard definition of

imitation proposed by primatologists and developmentalpsychologists. On that definition imitation involves:

Novelty. The mere triggering of an automaticmovement sequence does not count as imitation.

Patients with various frontal pathologies will spon-

taneously mimic observed movements, activating andbeing unable to inhibit, motor plans. But they cannot

imitate. (Meltzoff and Decety 2003; L’Hermitte et. al.

2004, p. 330)

Representation of Ends—Representation of Means

These apparently innocuous constraints allow us to dis-tinguish imitation from closely related phenomena of

affective and motor contagion, as when smiles, yawns, and

postures spread within a group. What we are really seeinghere is not imitation per se. That these are not imitative

behaviors is shown by the fact that not all classes of action

are contagious. An angry expression or vocal tone is notcontagious: it will typically produce a variety of responses

including defensive or conciliatory posture and vocal tone.

This is just a consequence of the fact that evaluation ofsocial stimuli and coordination of response are low-level

reflexive phenomena. The ‘‘imitative’’ aspect of social

contagion is an instance of affectively driven social coor-dination. Perhaps there is a default setting to mimic pos-

tures and expressions but the evidence is equivocal here.

These ideas also suggest an interpretation of a puzzle gen-erated by the phenomenon of mirror neurons. ‘‘Mirror neu-

rons’’ were discovered in the premotor cortices of macaque

monkeys in the 1990s. These cells fire both when an action isobserved and when the same action is performed by the

observer. Observation and execution of hand and mouth

grasping will produce firing of the same premotor neuronsinvolved in grasp. Other neurons in the posterior parietal cortex

(area PF) fire when the consequence of an action is perceived.

For example, when a monkey hears the experimenter tear opena bag containing peanuts, its ‘‘grasping’’ mirror neurons will

fire (Buccino et al. 2004; Rizzolatti 2005). These monkey

mirror neurons are all transitive: they fire only when the actionhas a target or object and not when objectless gestures are

perceived, although they will fire when observing the last

segment of reach to a previously seen but currently occludedtarget (Kohler et al. 2002; Iacoboni and Mazziotta 2007).

The mirror properties of the motor systems are phylo-

genetically preserved in humans. Interestingly, humanmirror neurons also have the property of firing for intran-

sitive as well as transitive movements.Mirror neuron activity intuitively seems to be what

might be called ‘‘covert’’ imitation. It looks as though the

observer is automatically imitating the observed action

while inhibiting the motor output. Thus, initially, the mir-ror neuron phenomenon was hypothesized to be an adap-

tation for imitation.

The puzzle is that macaque monkeys and indeed othermonkeys and great apes do not imitate. Or, more accu-

rately, their imitative capacities are far more circumscribed

than humans’ and are tied to a range of ecologically salientoverlearned actions. Thus the presence of a mirror system

cannot be a sufficient basis for imitation.In fact this is only a puzzle if the mirror system if

conceived of as the neural substrate of a modular cognitive

capacity like language. It would be surprising if a creaturehad the necessary neural architecture to support a cognitive

process but could not perform it when the appropriate

elicitors were perceived.Heyes has an elegant solution to this problem, which

depends on the idea that imitation is not a modular process.

On her view imitation is an instance of associative learningin which association between stimulus and a response that

are repeatedly and consistently paired becomes automated

(Heyes 2001, 2010; Brass and Heyes 2005; Heyes et al.2005; Catmur et al. 2007, 2009).

As in all cases of associative learning, the stimulus

(observed movement) and the response (observer’s repro-duction of the movement) are paired by relations of con-

tingency and contiguity. Contingency refers to the fact that

one element of the sequence reliably predicts the next.Contiguity refers to temporal proximity. On this view of

things, the relation between action observation and repro-

duction is like any stimulus–response relationship installedby conditioning.

In effect, Heyes is saying that imitation is not a discrete

cognitive phenomenon, but a sub-domain of a larger one:associative learning.

Heyes’ account is designed to solve the correspondence

problem and the problem of ‘‘abstraction.’’ Recall that thecorrespondence problem is the problem of mapping the

observed movement to the observer’s own motor instruc-

tion. There is nothing intrinsic (one might think) about aperceptual representation of an action that links it to a

motor representation of the movement sequence needed to

reproduce that action. So imitation presents the would-beimitator with a problem of activating the right movement

sequence in herself. Emulation does not present the same

problem because the action is goal-driven. The observerjust selects an action appropriate to the goal from its

repertoire.

So one way to solve the problem might be to representthe goal, i.e., to represent the movement sequence quaaction. This reduces the range of possible motor instruc-

tions to a narrow repertoire. A monkey can only reach byhand or mouth, for example. Note that the more one

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abstracts the easier the problem becomes. If the observer

understands that the target wants the observer to perform aparticular action then it is easier for her to reproduce the

action. This level of understanding seems to be one of the

large barriers to ape imitation. For example, a dominantmale chimp was trained to pull one handle of a two-han-

dled barrow while an experimenter pulls the other in order

to earn food. An observing chimp introduced after theexperimenter left, however, could not pull the other handle

to obtain the reward, even when the dominant chimppicked up the other one and ‘‘demonstrated.’’

If abstraction plays a necessary role in reproducing

observed behavior then imitation becomes something morethan associate learning, which at its most basic is the

detection and reproduction of sequences of events which

are not intentional, in the philosopher’s sense of carryingmeaning. Pure associative learning allows a subject to

associate an observed movement with her own movement.

Neither need be intrinsically intentional.To characterize a movement as intentional, i.e., as an

action, is to abstract. Or as Heyes might put it, to engage in

some cognitive ascent: meta-representing an event andapplying a concept to it in order to interpret it. Meta-rep-

resentation is of course a matter of degree, and some meta-

representation may not be very conceptually sophisticated.A monkey might merely need to classify movements as

similar along some dimension rather than as implementing

a goal, for example. Humans might explicitly representsome words as lies or compliments in order to determine a

response. Whether and how to imitate might depend on

degrees of meta-representation. Presumably, learning howto play a riff on the piano can be approached in different

ways according to whether it is represented as ‘‘this

sequence of notes,’’ ‘‘a blues riff,’’ or ‘‘an homage toProfessor Longhair.’’ The first is purely associative; the

second and third seem to involve higher degrees of con-

ceptual sophistication and meta-representation. But there isno doubt that much human imitation involves meta-

representation.

Heyes might agree, but she is concerned to show thatpure imitation does not necessarily need this type of

abstraction to solve the correspondence problem. For her,

the association between observation and action needs to beinstalled without abstraction.

Equally she cannot appeal, as ‘‘innate modularists’’ do,

to an innate solution to the correspondence problem.This is why she disputes the innatist interpretation of the

mirror neuron phenomenon, which has it that the mapping

from observation to reproduction of movement is auto-mated, and depends on the maturation of a neural system

specialized by evolution for the task. She agrees that mirror

neurons solve the correspondence problem because theyautomate the link between observed and reproduced

movement. She also agrees with one stream of the mirror

neuron movement that mirror phenomena are a form of‘‘covert imitation.’’

According to Heyes, the correspondence problem is not

solved by evolution but in development. She points out thatthe movements and other stimuli to which mirror neurons

respond are overlearned. The monkeys in the lab responded

to familiar actions with anticipated rewards such asreaching for a peanut. Mirror phenomena are far more

elusive for novel stimuli and in fact are strengthened byrepeated association. The fact that these associations are

intensively ‘‘taught’’ means that the monkey does not need

to rely on trial and error to match a motor program to anobserved movement. In the highly structured environment

of the laboratory the correspondence problem is solved by

a wealth of stimulus, or at least sufficient repetition andreinforcement to constrain the domain of possible

associations.

Thus for Heyes the correspondence problem is solved byteaching of a movement sequence, which leaves imitation

as essentially a non-intentional phenomenon. The monkey

has no need to meta-represent the sequence, which can beconceived of in non-intentional terms as the matching of

observed movement trajectory to performed movement.

The price is to make imitation a non-intentionalphenomenon.

Another view is that Heyes is right and mirror neurons

are not intrinsically sensitive to the goal of a movement:they mirror movements, not actions. If they ‘‘mirror’’

actions they do so in virtue of upstream computations of

the intentional nature of the observed movement. That is tosay, when they play a role in imitation, as they do, it is

because the problem of abstraction has been solved

already. There are neural structures that are sensitive,indeed oversensitive, to goal-directed bodily movements

and these form part of the system activated when humans

engage in imitation. This view of the matter has been wellput by Jeannerod and Jacob as part of an argument that

mirror neurons are not part of a system for intention

detecting or the attribution of intentional content tomovements (Jacob 2008). A series of experiments have

shown that superior temporal sulcus (STS) neurons, which

have no motor properties, respond to goal-directed move-ment such as reaching when the actor is looking at the

target. That the STS seems to play a crucial role in the

detection of purposeful bodily movement is also shown inexperiments involving point light displays of human

movement and Heider- and Simmel-type experiments in

which subjects over-attribute intentions to moving geo-metric shapes. These cases are particularly interesting since

no motor or mirror activity is evoked by perception of

geometric shapes (the human motor system is indifferent tothe trajectories of geometric shapes), and yet the subjects

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still attribute goals to the triangles, squares, and circles

purely by virtue of their trajectories.Thus, provided that the STS is active, the observer has

information that what she is looking at is a targeted action,

which removes the need for abstraction.However, one might still wonder whether the joint

action of the mirror system and the STS, no doubt installed

by teaching, is sufficient to account for human imitation. Isuspect not, and we can see why when we turn from

monkeys grasping for peanuts and infants waving back attheir parents to the kinds of imitation that might be

involved in the transition to human modernity. The making

of tools such as adzes and arrowheads is an example. In thiscase a stone is transformed into a sharpened tool adapted

very precisely to a particular task, such as stabbing, cutting,

or skinning.Typically such skills are acquired in an intensively

supervised environment. There is demonstration and cor-

rection as well as trial and error.Moreover, the process is not merely one of process

imitation, or the reproduction of a sequence of movements,

but product imitation. The aim of teaching is not for thestudent to reproduce the teacher’s movements, but to

reproduce the final product, a suitably sharp tool.

In fact it is difficult to see how flints could be turned intoadzes by ‘‘pure’’ process imitation. If the student’s flint is

harder or has different planes of cleavage, then the iden-

tical movement sequence will produce a differently shapedflint than the target. More importantly the flint may be too

blunt or misshapen to be any use. Similarly the student may

encounter problems, which require her to depart from thedemonstrated movement sequence to produce an adequate

flint. She may need to turn it upside down to reshape an

obstinate surface or even start from a different surface.This problem is amplified when we consider other skills

such as making fishing nets or arrowheads, which have a

complex structure. Often it may be necessary to stop onepart of the task and jump ahead to the finish, or to go back

to the beginning to refine one component. For example, one

might need to unravel part of a fish net to fix a mistake,which only becomes apparent when the components are

assembled, or to undo the binding on an arrowhead, and

recarve it to make it fit better onto the shaft.Furthermore, even more abstract considerations may be

extremely relevant. For example, one might need to recall

the size of the fish one is catching when making a net orcarving bone into a fishhook. Similarly, one might need to

bear in mind whether the flint is being used for stabbing,

skinning, or cutting. And in fact one can imagine adaptingthe final goal according to the results of the initial pro-

cessing. A flint initially intended to be used for butchering

might be adapted for skinning if its planes of cleavage giveit a suitable shape.

These cases suggest that a mere capacity for motor

mimicry—the reproduction of movement sequences—isinadequate for the acquisition of worthwhile social

knowledge. Heyes notes that in this respect imitation of

movement sequences, while it may be useful in some kindsof synchronized activity useful for attachment and social

bonding (infants preferentially attend to people who imitate

them and engage in games of imitation, and in adulthood inmany societies synchronized movement such as dancing

combined with chanting in unison or singing are essentialmechanisms of social attachment) is unlikely to be the

basis for social learning.

Consequently, as she says:

my money is on sequence emulation coming out on

top. The cultural wisdom lies in the object transfor-

mations rather than the body movements…it won’tmatter, from the perspective of cultural evolution,

how the object movements are effected by the actor’s

body. (Heyes in press)

By sequence emulation Heyes means those movements that

effect the necessary final object transformations, forexample, the final carving necessary to produce the fishing

hook.

An interesting question here is whether the capacity forsequence emulation alone can suffice for social learning.

Heyes implies that it can (at least for things like flints and

arrowheads). If this is correct, then imitation need notinvolve much in the way of abstraction. It will consist in

fine-tuning the reproduction of a motor sequence with

reference to the represented object end state. Since emu-lation for perceptually represented goals is part of the great

ape (and old world monkey for that matter) repertoire this

raises the question, ‘‘Why can’t apes imitate?’’ Apes arecapable of associative learning and emulation.

Possibly the answer is the wealth of stimulus provided to

human infants in their enriched instructional environments.Apes are not tolerant of juveniles and do not teach skills.

This suggests that apes that are intensively taught could

learn to imitate, but even here they show limitations. Theexample of the chimpanzee that could not learn to pull the

barrow is an example.

And those limitations are in the kind of higher-ordercognitive capacities unique to humans: mind reading via

‘‘theory of mind’’ inferences, meta-representation, and

executive function causal and inductive reasoning. Thissuite of capacities harnessed in the service of social learning

allows a child who is intensively coached to reproduce

artifacts and actions. A child who can understand theintentions of her teacher, envision the end product of her

sequence copying, meta-represent elements of the sequence

in order to adjust, and fine-tune her actions and communicatein language is better placed to learn by imitation.

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Like Heyes, I do not think that imitation is a unique

cognitive module that provides a breakthrough to sophis-ticated social learning. And like her I suggest that we

decompose imitation into components that enable the child

to reproduce elements of a sequence using domain-generallearning strategies in an enriched environment.

However, those domain-general strategies also include

capacities for abstraction: meta-representation, theory ofmind, and causal inference. The development of these

capacities both depends on and enables the construction ofrich cognitive niches characterized by imitative learning.

At present it is very difficult to parse the mechanisms of

social learning. The functional and neural architectures arenot sufficiently well understood. One mechanism may be

the mirror system but it cannot be the case that the mirror

system evolved to enable imitation. Rather, if it plays anecessary role in imitation (perhaps by solving the corre-

spondence problem after suitable training), it does so as

part of a larger system. Where I differ from Heyes is insuggesting that those larger systems will include circuitry

necessary for abstraction because imitative learning is

actually a more complicated task than reproducing anobserved movement. To reproduce the movement will

typically require the representation of more information

than the motor encoding of the movement trajectory.In an interesting experiment, Higuchi et al. (2012,

p. 1668) asked participants to imitate pictures of hands

making chords on a guitar. The contrast with the ‘‘obser-vation’’ condition was in the ‘‘fronto-parietal mirror cir-

cuit’’ (FPMC). They concluded that ‘‘a mechanism of

automatic perception–action matching alone is insufficientto account for imitation learning. Rather, the motor rep-

resentation of an observed, complex action, as provided by

the FPMC, only serves as the ‘raw material’ for higher-order supervisory and monitoring operations associatedwith the prefrontal cortex’’ (emphasis added). This is what

we might expect if imitation requires higher-level super-vision. In particular, the dorsolateral prefrontal cortex

(DLPFC) is activated in paradigms requiring high-level

cognitive control.Interestingly, the DLPFC involvement receded as

expertise was acquired. This is part of a general feature of

skill acquisition. As expertise increases, the tasks becomesmore automated, and high-level systems are not recruited.

Thus early mirror neuron studies of motor contagion for

overlearned associations may have been slightly mislead-ing since, once the association is acquired, the phenomenon

is automatic. In the acquisition phase, however, as both

Heyes and Sterelny note, supervision and teaching areessential.

I close with a speculation. True imitation is a more

cognitively sophisticated phenomenon than motor mim-icry. One reason noted by Sterelny is that childhood is a

period of apprenticeship in which social supervised learn-

ing plays a crucial role. This is consistent with theories ofmiddle childhood that note a pronounced shift in abilities at

this age, evidenced by more abstract and decoupled forms

of understanding in many domains, of which mind readingis especially salient. Why? Konner in his epic The Evolu-tion of Childhood provides an answer: ‘‘the five to seven

shift is an ontogenetic evolutionary legacy that helps formthe basis of cultural transmission through intersubjectiveteaching and learning, one of the defining features of thehuman species’’ (Konner 2010, p. 288; emphasis added). In

particular, the cognitive advances of middle childhood are

adaptations for participation in family life. The child nowhas the ability to be taught how to look after younger

children, to help and participate.

True imitation is not a modularized capacity that enablesthis shift, but one of a suite of abilities which co-develop

rapidly after infancy as the child’s mind matures within an

intensively engineered ecological niche. Imitation is, asHeyes notes, evidence of successful teaching rather than

spontaneous unsupervised learning. In humans, teaching

and learning of most tasks requires both intensive super-vision and the ability to understand future states and

potential purposes of the objects being constructed and the

goals, intentions, and mental states of other people.

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