Shaping and reshaping the aesthetic brain: Emerging perspectives on the neurobiology of embodied aesthetics

(1)

NeuroscienceandBiobehavioralReviews62(2016)56–68

ContentslistsavailableatScienceDirect

Neuroscience

and

Biobehavioral

Reviews

j o u r n a l ho me p ag e :w w w . e l s e v i e r . c o m / l o c a t e / n e u b i o r e v

Review

Shaping

and

reshaping

the

aesthetic

brain:

Emerging

perspectives

on

the

neurobiology

of

embodied

aesthetics

Louise

P. Kirsch

a,b

_,

_Cosimo

_Urgesi

a,c,d

_,

_Emily

_S.

_Cross

a,e,∗

a_Wales_Institute_for_Cognitive_{Neuroscience,}_School_of_Psychology,_Bangor_University,_Bangor,_Wales,_United_Kingdom

b_Research_Department_of_Clinical,_Educational,_and_Health_Psychology,_Division_of_Psychology_and_Language_Sciences,_Faculty_of_Brain_Sciences,_University CollegeLondon,London,England,UnitedKingdom

c_Department_of_Human_Sciences,_University_of_Udine,_Udine,_Italy

d_Scientiﬁc_Institute_(IRCCS)_Eugenio_Medea,_Polo_Friuli_Venezia_Giulia,_San_Vito_al_Tagliamento,_Pordenone,_Italy

e_Department_of_Social_and_Cultural_Psychology,_Behavioural_Science_Institute,_Donders_Institute_for_Brain,_Cognition_and_Behaviour,_Radboud_University Nijmegen,TheNetherlands

a

r

t

i

c

l

e

i

n

f

o

Articlehistory: Received25July2015 Receivedinrevisedform 10November2015 Accepted10December2015 Availableonline15December2015 Keywords: Neuroaesthetics fMRI Brain Beauty Art Bodyperception Dance Embodiment

a

b

s

t

r

a

c

t

Lessthantwodecadesafteritsinception,theburgeoningfieldofneuroaestheticscontinuestogrowin interestandmomentum.Despitethebiologicalandsocialimportanceofthehumanbodyandthe atten-tionpeoplepaytoitsappearanceindailylife,onlyrecentlyhasneuroaestheticinquiryturneditsattention toquestionsconcerningtheaestheticappraisalofthehumanbody.Wereviewevidenceillustratingthat thecomplexityofaestheticexperienceisreflectedbydynamicinterplaybetweenbrainsystemsinvolved inreward,perceptualandmotorprocessing,withafocusonaestheticperceptioninvolvingthehuman body.Wethenevaluateworkdemonstratinghowthesesystemsaremodulatedbybeholders’ exper-tiseorfamiliarity.Finally,wediscussseminalstudiesrevealingtheplasticityofbehaviouralandneural responsestobeautyafterperceptualandmotortraining.Thisresearchhighlightstherichpotentialfor neuroaestheticinquirytoextendbeyonditstypicalrealmofthefineartstoaddressimportant ques-tionsregardingtherelationshipbetweenembodiment,aestheticsandperformingarts.Weconcludeby consideringsomeofthecriticismsandlimitationsofneuroaesthetics,andhighlightseveraloutstanding issuesforfutureinquiry.

Contents

1. Introduction...57

2. Embodiedaesthetics...57

2.1. Exploringaestheticswithinandbeyondtheﬁnearts...57

2.2. Reward,emotionandaestheticsofthehumanbody...58

2.3. Visualperceptionandaestheticsofthehumanbody...59

2.4. Theroleofthemotorsysteminaestheticexperience...60

3. Shapingandreshapingtheaestheticbrain...61

3.1. Familiarityandexpertise...61

3.2. Trainingtheaestheticbrain:visualexperience ... 64

3.3. Trainingtheaestheticbrain:motorexperience...64

4. Challengesandemergingprospectsforthefutureofneuroaesthetics...64

4.1. Maintainingintegrityasalineofinquiryinaneraofneuromania...65

4.2. Mappingtheneurobiologicalsubstratesofaesthetics:towhatend?...65

4.3. Disentanglingaestheticsfromemotion...65

∗ Correspondingauthorat:SchoolofPsychology,BangorUniversity,AdeiladBrigantia,FforddPenrallt,Bangor,GwyneddLL572AS,UnitedKingdom. E-mailaddress:[email protected](E.S.Cross).

http://dx.doi.org/10.1016/j.neubiorev.2015.12.005

(2)

L.P.Kirschetal./NeuroscienceandBiobehavioralReviews62(2016)56–68 57

5. Summaryandconclusions...66 Acknowledgements ... 66 References...66

1. Introduction

Beautyandaestheticshavebeenthesubjectofcuriositysince

antiquity,provokingdiscourseanddebatewithinphilosophyby

manyofwesternsociety’smostesteemedthinkers,includingPlato,

Kant,andHume(Hume,1777;Kawabata and Zeki,2004; Rolls,

2014).TheOxforddictionarydeﬁnesaestheticsas“asetof

princi-plesconcernedwiththenatureandappreciationofbeauty”(Oxford

Dictionariesonline).Beautyfrequently(butcertainlynotalways)

formsthecoreofanaestheticexperience,whichisthoughtofas

onethatdeliversgratiﬁcationofthesensesorsensuousdelights

(Goldman,2001).Whileinterestinaestheticshasextendedbeyond

therealmofphilosophyforatleastthepastcentury,itnowattracts

seriousempiricalattentionfromcognitivepsychology(e.g.,Leder

etal.,2004)andneuroscience(e.g.,Chatterjee,2011,2013).Inan

attempttolendabiologicalperspectivetotheunderstandingof

aesthetics,ChatterjeeandVartanian(2014)suggestthataesthetic

experiencesemergefromtheinteractionbetweenneuralsystems

involvedwithsensory–motorprocesses(sensation,perceptionand

motor system),emotion–valuationprocesses (reward; emotion;

wantingandliking),andmeaning–knowledge processes

(exper-tise,contextandculture;seealsoDiDioandGallese,2009).Along

thesesamelines,Xenakisetal.(2012)proposedthatthebasic

emo-tionalstatesofpleasureandpainplayamajorroleintheformation

ofanindividual’saestheticjudgement,anideabackedupbyseveral

otherauthors(Cupchik,1995;Ginsborg,2003;Guyer,2003,2008;

Iseminger,2003;Kant,1914;Matravers,2003).Inthiscontext,the

scopeofneuroaestheticsextendswellbeyondvisualartstoinclude,

forexample,performancearts(e.g.,dance)andnaturalstimuli(e.g.,

humanbodies).Sinceneuroscientistsﬁrstproposedaplaceforthe

braininempiricalaesthetics(RamachandranandHirstein,1999;

Zeki,1999),ithastakenlessthantwodecadesforneuroaesthetics

toestablishitselfasaseriousdisciplinewithanaimtoscientiﬁcally

examineaestheticsfromaneurobiologicalperspective(Chatterjee

andVartanian,2014;LederandNadal,2014).

Research in neuroaesthetics has been driven in partby the

developmentandincreasingavailability ofhumanneuroscience

approaches that enable in-depth study of cognitive and

emo-tionalprocesses,suchasfunctionalmagneticresonanceimaging

(fMRI),electroencephalographic(EEG)recording,andtranscranial

magneticstimulation(TMS).Usingthesetools,cognitive

neurosci-entistsinterestedinabroadrangeoftopics,includingperception,

emotion,attention,andaction,arebeginningtoillustratehowthe

aestheticexperienceismanifestinthehumanbrain.The

develop-ment,testingandreﬁningoftheoreticalframeworkstocharacterize

theneurobiological underpinningsof aestheticexperiencehave

reinforcedthenotionthatartappreciationisacomplex,

multidi-mensionalprocess.Ratherthanrevealingastaticpictureofbrain

areasassociatedwithoneofthemany componentsof aesthetic

experience,neuroaestheticsisshowingthatthecomplexityof

aes-theticexperienceisreﬂectedbytheinterplaybetweendynamic

brainsystems,whoseneurofunctionalorganizationmaybe

mod-ulated by different factors associated to objects, subjects and

contextsoftheaestheticexperienceandcanundergorapid,

plas-ticchangeswhenthesefactorsaremanipulated.Thisopensnew

possibilities forexamining howneuroaesthetics researchmight

informapplieddisciplinesinterestedineducatingandcultivating

artappreciation,broadlyconstrued.Whileanumberofprevious

reviewshaveattemptedtoprovideadescriptiveand

interpreta-tivepictureoftheneuralunderpinningsofaestheticexperiences

(e.g.,Brownetal.,2011;ChatterjeeandVartanian,2014;DiDioand

Gallese,2009;Nadaletal.,2012),themainaimofthisreviewis

todelineatetheprimaryfactorsthatshapeandmodulatethe

aes-theticbrain,withaparticularfocusontheroleofthehumanbody

asthesubjectorobjectofaestheticperception.

Thisreviewisorganizedintothreeparts.First,afterpresenting

brieﬂythecoreneurobiologicalcomponentssupportingaesthetic

evaluationofvisualstimuli,weprovidea focusedreviewofthe

three coreneuralsystems implicatedin aestheticprocessingof

thehumanface,body,and movement: brainregionsassociated

with(1)rewardprocessing,(2)visualperception;and(3)motor

responses.1_The_next_part_of_the_review_explores_major_factors_that

modulateaperceiver’saestheticexperiencesuchasvisual

famil-iarityandmotorexpertiseandthenfocusesonstudiesthathave

implementedactivetraininginterventionstoexaminehow

experi-encechangesanobserver’saestheticevaluationofstaticormoving

humanbodies.Theﬁnalsectionturnsacriticaleyetowardsseveral

keylimitationsandchallengesforthenascentﬁeldof

neuroaes-thetics,andsetsoutlimitationsofthedisciplineaswellasseveral

outstandingquestionsforfuturework.Importantly,aoverarching

aimoftheentirereviewistohighlightcontributionsfromresearch

usingthehumanbody(whetherstillorinmotion)asanaesthetic

stimulus,anemerginglineofinquirythatholdsparticularlyrich

opportunitiesforadvancingourunderstandingoftherelationship

betweenart,aesthetics,andthebrain.

2. Embodiedaesthetics

2.1. Exploringaestheticswithinandbeyondtheﬁnearts

Fromtheﬁrstinvestigationsintotheneurobiologicalresponse

whenbeholdingﬁneartworks,suchaspaintingsorsculptures,it

becameclearthatneuralengagementextendedwellbeyondthe

occipitallobeand regionsofthebrainassociated withcomplex

visualprocessingtoincludeareasgenerallyinvolvedinprocessing

thehedonicvalueofnaturalaswellartisticstimuli(Brownetal.,

2011).Forexample,KawabataandZeki(2004)askedparticipants

withnoparticularexperienceinarttomakeaestheticjudgements

of paintings by categorizing themas ugly,neutral or beautiful.

Regardlessofthecategoryofpaintingbeingviewed(e.g.,abstract,

landscape,portrait,stilllife),theauthorsfoundtheorbitofrontal

cortextobemoreengagedwhenparticipantsperceivedpaintings

ratedasbeautifulcomparedtougly.Inasimilarvein,Vartanian

andGoel(2004)foundthatwhileactivityinbilateraloccipitalgyri,

left cingulatesulcus, and bilateralfusiformgyri increased with

increasingsubjectivepreferenceattributedtoaseriesofpaintings,

theactivityinrightcaudatenucleus,abrainregionimplicatedin

reward processing,showeda similarpattern. Thus,brain

activ-ityappearedtobemodulatedbytheaffectivevalueeachviewer

associatedwithindividualpaintings,suggestinganeurobiological

responserelatedtothehedonicvalueofanartisticstimulus.This

(3)

58 L.P.Kirschetal./NeuroscienceandBiobehavioralReviews62(2016)56–68

explanationﬁtswellwithotherresearchinvestigatingthereward

valueattributedtoagivenstimulus.Forexample,Smalletal.(2001)

showedmodulationofthemedialorbitofrontalcortexthemorea

participantfoundchocolatepleasantandrewarding(seealsoRolls,

2000).

In a seminal meta-analysis of 93 neuroimaging studies of

positive-valenceaestheticappraisalspanningfourdifferent

sen-sorymodalities(vision,audition,olfactionandgustation),Brown

etal.(2011)attemptedtoestablishcoreneurobiologicalfeatures

commonacrossall aestheticcontexts(asopposed to theother

majorneuroaestheticsmeta-analysis,performedbyVartanianand

Skov(2014),whichfocusedonvisualstudiesonly).Theybeganby

broadeningthedeﬁnitionofwhatcountsasanaestheticstimulus.

Tothisend,theysuggestedthatanystimulusevoking

positively-valencedemotionsmadeforadeﬁnitionofanaestheticstimulus

thatwasmorebiologicallyadaptiveinscope.Inotherwords,they

suggestedthatexclusivelyfocusingonartworksmissesthepoint

thatbrain systems typically associatedwith aestheticappraisal

ofartworkslargelyoverlapwiththosethatassignvalencetoall

mannerofevolutionarily-salientstimuli,suchastheattractiveness

ofamateorthedesirabilityofafooditem.Itisalsolikelythatart

appraisalhasco-optedthesamebraincircuits usedthroughout

evolutionforbiologicallyadaptivedecision-making(Brownetal.,

2011).Analysesrevealedcommonareasofactivationwhen

par-ticipantsmakeapositively-valenceddecisionaboutastimulusin

theorbitofrontalcortex,theanteriorcingulate,theanteriorinsula

andaventralportionofthebasalganglia,withtheanteriorinsula

emergingasthemostconcordantareaofactivationacrossall93

studiesincludedinthemeta-analysis.Theauthorsweresomewhat

surprisedthatpartoftheinsula,morecommonlyassociatedwith

negatively-valencedemotionssuchasdisgust,sadness,andpain,

emerged most frequently in studies assessing positive valence

acrossfourdomains.However,it wastheanterior-dorsal insula

that emerged from the meta-analysis, which is a region most

stronglyimplicatedinfunctionalintegrationofsuchprocessesas

emotion,empathy,interoception,olfaction andgustation(Kurth

etal.,2010).Theﬁndingsfromthemeta-analysisledtheauthors

toproposeafunctionalconnectivitymodelofaestheticswhereby

appraisalofastimulusisachievedbycomparingsubjective

aware-nessofone’scurrenthomeostaticstate(achieved bytheinsula)

with exteroceptive perception of stimuli in the environment,

mediated by sensory pathways that lead to the orbitofrontal

cortex.Suchamodelﬁtswellwiththeauthors’proposalthatan

aestheticsystemﬁrstevolvedtoappraisethevalenceofobjectsof

biologicalimportance,andisnowalsousedforevaluatingartistic

works,fromsongstopaintings.

Inthiscontext,itissurprisingthatonlyafewneuroscientiﬁc

studieshaveinvestigatedtheneuralcorrelatesofaesthetic

appre-ciationof theformand motionof thehumanbody, a stimulus

categorythathasincomparablebiologicalrelevanceandhaswidely

beentheobjectandtheinstrumentofartcreation.Overthepast

decade,aricherliteraturehasdevelopedthatexplorestheroles

playedbyreward,visualperception,andthemotorsystemwhen

perceivingandappraisingthevalenceoftheappearanceand

move-mentofthehumanbody(Fig.1).Thesefactorsareconsideredin

turn,withaparticularfocusontheemergingtheoriesthatattempt

tolinktheempiricalﬁndingsintoabroaderframeworkof

neu-roaesthetics.

2.2. Reward,emotionandaestheticsofthehumanbody

Initialevidencesupportingtheactivationofrewardcircuitryin

theprocessingofpersonattractivenesscomesfromthestudyof

facialbeauty(HahnandPerrett,2014;Senior, 2003).Ina

semi-nalstudy,Aharonetal.(2001)weretheﬁrsttodocumentwith

behaviouralmeasuresadissociationbetweenfacialattractiveness

ratingsandtheirrewardvalue.Theauthorsfoundthatmale

par-ticipantsrated asmore attractivethose facesthat werejudged

asmorebeautifulinanindependentpilotstudy,bothwhenthey

depictedindividualsofthesamesexandoppositesex.However,

maleobserversonlymadeanefforttolengthentheexposureof

beautifulfemalefaces,butnotmalefaces,inadifferentbehavioural

taskinwhichtheycouldcontrolthedurationofstimulithrough

akeypress.Thisﬁndingsuggeststhatbeautifulmalefaceswere

judgedasaestheticallypleasant,butnotasrewarding,asfemale

faces.Observingbeautifulvs.average-lookingopposite-sexfaces,

whichwerebothattractiveandrewarding,activatedreward

cir-cuitryareas,includingthenucleusaccumbens,orbitofrontalcortex,

ventraltegmentumand sublenticularnucleus.Crucially,

observ-ingbeautifulvs.averagesame-sexfaces,whichwereattractivebut

notrewarding,alsoactivatedtheventraltegmentumbutinduced

anegativeresponseinthenucleusaccumbensandsublenticular

nucleus.Alltogether,whilethispatternofﬁndingspointstowards

apartialdissociationbetweenrewardprocessingand

attractive-nessratings,italsosuggeststhatattractivenessmayengagesome

rewardcircuitryareasindependentlyfromsexualdesire.

Asubsequentstudy(O’Dohertyetal.,2003)investigatedneural

responsestofaceattractivenessinheterosexualmaleandfemale

observers.Observingattractivecomparedtonon-attractivefaces,

independentlyfromtheobserver’ssex,inducedgreateractivation

ofthemedial orbitofrontal cortex,which wasfurtherincreased

whenthefacesdepictedapositiveratherthanneutralexpression.

O’Dohertyetal.(2003)concludedthattheproﬁleofactivityofthe

orbitofrontalcortexreﬂectstherewardingvalueoffacialstimuli.

(4)

Inbothofthesepreviousstudies(Aharonetal.,2001;O’Doherty

et al., 2003), participants passively observed pictures of faces.

In a later neuroimaging study (Cloutieret al., 2008), male and

femaleobserverswereexplicitlyaskedtoratetheattractiveness

ofopposite-sexfaceswhileundergoingfunctionalneuroimaging.

Theresultsshowedthatreward circuitryareas,namelytheleft

orbitofrontalandmedialprefrontalcortex,theanteriorcingulum

and bilateralnucleus accumbens, showeda response proﬁleof

increasing activitywith increasingattractiveness ratings, while

therightlateralorbitofrontalcortexandtheleftmedialprefrontal

cortexshowedtheoppositepattern,withincreasingactivityfor

decreasingattractivenessratings.Whiletheactivityofreward

cir-cuitryareasshowsalinearincreasewithincreasedattractiveness

ratingsoffaces,theactivityofotherareas,forexamplethe

amyg-dala,whichisinvolvedinprocessingthevalenceofdifferenttypes

ofemotions,seemstoshowanon-linearproﬁleofactivation,with

greaterresponsestohighlyattractiveandhighlyunattractivefaces

comparedtoaveragefaces(Winstonetal.,2007).

Theresponseoffrontalareasduringexplicitattractiveness

rat-ings may not only reﬂect the intrinsic aesthetic property of a

stimulus,butalsotheirgeneralinvolvementinaffective

evalua-tivejudgements.Inparticular,thedorsolateralprefrontalcortex

hasbeenshowntobemoreengagedwhenpeopleratethe

attrac-tivenessoffacescomparedtootherjudgementsoffaces,suchas

theiremotionorcolour(Nakamuraetal.,1998),identity(Chatterjee

etal.,2009), orage(Winstonetal.,2007).Together,these

find-ingsreflectthespecificrequirementofanattractivenessjudgement

ascomparedtoperceptualprocessingoffacialfeatures.In

addi-tion, the activity of the anterior dorsolateral prefrontal cortex

parametricallyincreaseswithincreasingattractivenessratingsof

faces(Cloutieretal.,2008;Vartanianetal.,2013).Thecausative

involvementofprefrontalareasintheaestheticevaluationoffaces

hasbeendocumentedusingtranscranialdirect current

stimula-tion(tDCS),abrainstimulationtechniquethatcanalter cortical

excitabilitybyapplyingweakelectriccurrenttothescalp(Ferrari

etal.,2015).Inthisstudy,Ferrarietal.(2015)foundthatincreasing

corticalexcitabilityoftheright,butnotleft,dorsolateralprefrontal

cortexincreasedtheperceived attractivenessof faces,

indepen-dentlyoftheiraestheticandrewardingvaluesbeforestimulation,

butdidnotalterageestimation.

Theimpactofattractivenessonbrainactivityhasbeen

docu-mentednotonlyforfaces,butalsoforwholebodies.Platekand

Singh(2010)askedmaleobserverstoratetheattractivenessof

pre-andpost-operativepicturesoffemalepatientsundergoingplastic

surgerytoadjustwaist-to-hipratio,whichis widelyconsidered

anindex ofwomen’sbeauty.Results showedgreateractivation

inbilateralorbitofrontalcortexforpost-surgical pictures,which

werealsoratedasmoreattractive,ascompared topre-surgical

ones.Furthermore,theactivityoftheseareas,inadditionto

sub-corticalstructuressuchasthenucleusaccumbens, caudateand

putamen,increasedwithincreasingattractivenessratings.Similar

resultswereobtainedinarecentfMRIstudyinwhichfacesand

bod-ieswerepresentedtofemaleandmaleobserversandneuralactivity

wascomparedwhenparticipantsviewedstimuliratedasbeautiful

oruglywiththoseratedasneutral(Martín-Loechesetal.,2014).In

keepingwithpreviousstudies,activityinthenucleusaccumbens

andanteriorcingulatecortexincreasedwithincreased

attractive-nessratings,withhighestresponsetobeautifulpicturesandlowest

touglyones.Otherareas,however,inparticulartheprecuneus,

posteriorandmiddlecingulatecortexandthemedialorbitofrontal

cortex,showedanon-linearproﬁle,withhigherresponsetoboth

beautifulanduglypicturescomparedtoneutralones.Thus,inline

withneuroimagingstudiesofperceivingartworks(seeSection2.1),

theaestheticexperienceofperceivingpeople’sfacesandbodies

relatesnot onlytoprocessing thereward valueof theirbeauty,

butisalsoshowntobeamorecomplexphenomenoninvolving

emotionalresponsestothesalienceofextremeugliness.

Accord-ingly, a recent electrophysiological study (Mu ˜noz and

Martín-Loeches, 2015) has shown that a P300 event related potential

response,withamostlyfrontaldistribution,increaseswhen

par-ticipantsviewbeautifulcomparedtoneutralanduglybodiesand

faces,whichtheauthorsinterpretasreﬂectingcategorizationof

stimulusvalence.However,thelatepositivecomplex,withamostly

parietaldistribution,waslargerforbothbeautifulanduglystimuli,

comparedtoneutralstimuli.Theauthorsinterpretthisﬁndingas

reﬂectingincreasedtaskdemandsforjudgingemotionallysalient

stimuli,regardlessofvalence.

Inadditiontotheinherentpropertiesofafaceorabodythat

might bedeemed aesthetically pleasingor not, evidenceexists

tosuggestthatotherfactorscanalsoshape theneurobiological

foundationssupportingaestheticexperience,suchaswhetheran

observeris activelyengagedin anexplicitaestheticrating task

ratherthan passivelyobserving thestimuli. DiDioetal.(2007)

performedastudythatdirectlycomparedthesetwosituationsby

examiningbrainactivityduringpassiveobservationoraesthetic

ratingofClassicalandRenaissancesculpturesofthehumanform

that eitherrespectedordisregardedthegoldensectionin their

composition.Thegoldensectionis anindexofbodyproportion

thatisacceptedasanormativeWesternrepresentationofbeauty.

Results showedthat passive observationof theversions of the

sculpturesthatrespectedvs.thosethatdisregardedthegolden

sec-tioninducedactivationoftherightinsulaandmiddleprefrontal

areas,in additiontobilateraloccipitaland premotor areas(see

below).Conversely,duringtheexplicitaestheticratingcondition,

thesculpturesjudgedasbeautifulinducedastrongeractivation

of the right amygdala compared to those judged as ugly. The

authorsconcludedthatthesetwopatternsofactivationreﬂected,

respectively,theprocessingofthehedonicvalueoftheintrinsic

parametersofthestimuliandthesubjectiveemotionalreactionto

them.Allinall,thestudiesinthissectionsuggestthattheactivation

oftherewardsystemandprefrontalareasduringaesthetic

experi-encesofhumanbodiesandfacesdependsontheintrinsicbeauty

(orugliness)ofagivenstimulus,aswellastheobserver’smindset

ortaskwhenviewingthebodyorfaceinquestion.

2.3. Visualperceptionandaestheticsofthehumanbody

Earlyneuroaestheticaccountsemphasizedastrongconnection

betweenthepropertiesofthehumanvisualsystemandart

cre-ation(Zeki,1999).Indeed,theorganizationofartworksmaymeet

thebasicfunctionofthevisualsysteminthesearchforconstant

featuresofobjects,scenesandpeople.Thisviewwassupportedby

neuroimagingstudiesofartappreciationthatshowedmodulation

ofvisualareasduringobservationofpaintingsdepictingabstract

forms,landscapes,portraitsorstilllife(KawabataandZeki,2004;

VartanianandGoel,2004).

In additiontoviewingpaintings,it wasalsoshownthat the

preferenceattributedtonaturalstimuli,suchasfacesandbodies,

modulatedtheactivationofcategoryselectiveareasinthemedial

andlateraloccipitotemporalcortex(Yueetal.,2007;Chatterjee

etal.,2009;Kediaetal.,2014;Lutzetal.,2013;MarziandViggiano, 2010;OrtigueandBianchi-Demicheli,2008;Pizzagallietal.,2002; Trujilloetal.,2013).Forexample,viewingmoreattractivefaces

hasbeenassociated withgreateractivationofthefusiformface

areacomparedtolessattractiveones(Chatterjeeetal.,2009),thus

suggestingthatneuralactivityinthesecategory-selective

percep-tualareasisinﬂuencedbystimuluspleasantness.Crucially,while

aestheticmodulationofparietal,prefrontal,insularandcingulate

cortices(seeSection2.2)wasfoundonlyduringanexplicitaesthetic

ratingtask,modulationofoccipitotemporalareasaccordingtothe

attractivenessoffaceswaspresentalsoduringapurely-perceptual

(5)

implicitlycodetheaestheticvaluesofperceivedstimuli(Chatterjee

etal.,2009).Similaraestheticmodulationhasalsobeenreported

in the extrastriate body area (EBA), a lateral occipitotemporal

areathatresponds selectivelyto humanbodies and body parts

(Downingetal.,2001).Inataskwhereparticipantsobservedand

ratedtheirenjoymentofprofessionaldancersperformingballet

andcontemporarydancemovements,themoreparticipantsliked

anobservedmovement,themoreEBAwasengaged(Crossetal.,

2011).

However, modulation of neural activity in perceptual areas

accordingto theaesthetic valueof a stimulusdoesnot tellus

whethertheseactivationsarenecessaryforarewardingaesthetic

experienceoraresimplyepiphenomenaltoanobserver’saesthetic

experience.Forexample,activityinperceptualareasmaybegreater

formorelikedstimulibecauseparticipantstendtopaymore

atten-tiontothem(DowningandPeelen,2011).Testingattractiveness

judgementsinbrainlesionpatientsandapplyingtrainsof

repet-itiveTMS(rTMS)pulsesinhealthyindividualstodisruptneural

processingintheareasbeneaththecoilaretwoapproachesthat

holdpotentialtorevealcausalinvolvement ofperceptual areas

in aesthetic experience. In one such study, it was shown that

prosopagnosicpatientswithlesionsofthefusiformfaceareanot

onlywereimpairedinthediscriminationoffacialidentity,as

com-paredtohealthyindividuals,buttheyalsoshoweddeﬁcitsinrating

face attractiveness and in attractiveness-motivated behaviour

(measuredintermsofviewingtime;Iariaetal.,2008).UsingrTMS

inhealthysubjects,Calvo-Merinoetal.(2010)presentedaseriesof

staticimagesofdanceposturesandaskedparticipantstoratewhich

oneoftwodanceposturestheylikedmore.Resultsdemonstrated

thatrTMSoverEBAbluntedaestheticjudgementsaboutbody

pos-turesrelativetorTMSovertheventralpremotorcortex.Thispattern

ofﬁndingswasrelativetoaestheticpreferencesobservedforeach

participantina ratingsession withoutstimulation.No effectof

rTMSoverEBAwasobtainedfortheaestheticjudgementsof

scram-bledversionsofthesamebodypostures,whichsharedthesame

visualfeatures(e.g.,colourandcontrast)oftheoriginals,butlacked

informationaboutthehumanform.

While the studyby Calvo-Merino et al. (2010) showed

evi-denceforcausalinvolvementofEBAinaestheticappreciationofthe

humanbody,itdidnotallowtheauthorstotestwhetheraesthetic

ratingsofbodieschangedinaspeciﬁcdirectionafterinterference

withEBA.Toaddressthisquestion,arecentstudybyCazzatoand

colleagues(2014)appliedrTMSoverEBAduringjudgementofthe

aestheticvalue(“liking”)ofmaleandfemalebodystimuli.

Impor-tantly,Cazzato etal.(2014)variedthesizeandimpliedmotion

ofthebodiesinordertomodulatetheiraestheticvalueina

pre-dictabledirection,withhigheraestheticratingofmoredynamic

andthinnerstimuli(Cazzatoetal.,2012).Resultsshowedthat,in

bothmaleandfemaleobservers,rTMSoverEBAaffectedaesthetic

ratingsonlyofoppositesexmodels.However,thedirectionofthe

aestheticratingchangeswasdifferentaccordingtothesexofthe

observerandthestimulatedhemisphere.Indeed,while

stimula-tionofbothleftandrightEBAdecreasedtheaestheticratingsof

femalemodelsinmen,inwomenonlyrTMSoverrightEBAaffected

aestheticratingsofmalemodels,withanoverallincreaseof

aes-theticratings.Theseresultsnotonlyshowthatneuralactivityof

EBAisnecessaryforprocessingthoseaestheticpropertiesthatare

usedtoappreciatethebodyofpotentialsexualmates,butalso

sug-gestthattheneuralorganizationunderpinningtheprocessingof

thesepropertiesdiffersbetweenmenandwomen.Thisresultis

inkeepingwithﬁndingsofdifferentlateralizationofvisualbody

processinginmenandwomen(AleongandPaus,2010)andwith

studiesshowingsex-relateddifferencesintheactivationoftheleft

andrighthemispheresduringaestheticratingsofpaintings and

photographs(Cela-Condeetal.,2009).Takentogether,thestudies

reviewedinthissectionshowthatmodulationofneuralactivity

invisualcorticalareasisacrucialcomponentoftheneural

archi-tecturesupportingaestheticexperience,and thatdifferences in

theneurocognitiveorganizationofperceptualprocessingmay

sub-serve,atleastpartially,individualdifferencesintheaestheticvalue

attributedtoenvironmentalstimuli.

2.4. Theroleofthemotorsysteminaestheticexperience

Sincetheseminalneuroimagingstudiesexploringbrainregions

implicated inaestheticappreciation (Kawabataand Zeki, 2004;

Vartanianand Goel, 2004), itwas apparentthat,in additionto

brainareasassociatedwithrewardandvisualprocessing,themotor

systemwasalsoinvolved. KawabataandZeki(2004),for

exam-ple,reportedthatwhiletheorbitofrontalcortexshowedincreased

activityfor paintings rated as more pleasant, themotor cortex

wasmoreactivewhen participantsviewedpaintings theyrated

asugly,comparedtopleasantorneutral.Asimilaractivationof

primarysensorimotorcortexwasobservedbyDiDioetal.(2007)

whenparticipantsviewedsculpturesofthehumanformratedas

uglyvs.pleasant.Activationofthemotorcortexduringaesthetic

judgementhasbeenspeculatedtorelatetopreparingtheobserver

foraction,eithertoavoidunpleasant(ugly)stimuliorapproacha

pleasant(beautiful)stimulus(ArmoryandDolan,2002;Kawabata

andZeki,2004).

Theroleplayedbythemotorcortexinaestheticexperiencehas

beenreconsidered,however,byatheoreticalframeworkproposed

by Freedberg and Gallese (2007).Accordingto this framework,

thesimulationofactions,emotionsandcorporealsensations

pro-vokedbyaparticularartformbringsaboutanaestheticexperience.

Thistheory,calledtheembodiedsimulationaccountofaesthetics,is

largelybasedonthenotionthatatightlinkexistsbetween

percep-tionandaction(Prinz,1997;Schütz-BosbachandPrinz,2007)and

onexperimentalﬁndingsinbothmonkeysandhumansthataction

perceptionengendersactivationoftheobserver’smotor system

(RizzolattiandCraighero,2004).Byallowingembodimentofthe

actionsdepictedonacanvasorperformedbyanactorordanceron

stage,orinanyotherwayelicitedbyanartistviaanartisticmedium,

sensorimotorbrainregionscontributetotheaestheticevaluation

ofagivenartworkandunderpinaspectator’sempathicresponse

towardstheart(Ticinietal.,2015).

Evidencesupportingtheroleofsensorimotorembodimentin

anindividual’saestheticexperienceofﬁneartworkscomesfrom

studiesshowing greateractivation ofmotor and premotor

cor-ticesduringobservationofsculpturesorpaintings ascompared

tomodiﬁed,non-artisticversionsofthesamestimuli.Forexample,

Battagliaetal.(2011)reportedthatcortico-spinalexcitability

mea-suredfromawristextensionmusclewasfacilitated,thusindexing

motor simulation, when participants viewed of Michelangelo’s

ExpulsionfromParadisepainting(showingahandextension

move-ment),comparedtoobservinga realhandphotographedinthe

sameposedepictedinthepainting,orofotherpaintings

show-ingrelaxedorﬂexedhands(e.g.,Michelangelo’sCreationofAdam

orBellini’sDeadChristwithAngels).Themovementspeciﬁcityof

theseﬁndings,whichwasindependentfromtheemotional

inten-sityofthepaintings, furtherpointstotherelationshipbetween

appreciationoftheaestheticqualityofaworkandmotor

map-pingof theimpliedmovementwithinit. Ina similarvein, Lutz

etal.(2013)usedfMRItocompareneuralactivityduringaesthetic

ratingsofhumanformsdepictedincanvasesorinphotographs.

Resultsshowedgreateractivationofnotonlyextrastriate,butalso

posteriorparietalcortextobodiesviewedwithinanartistic

con-textthaninnaturalphotographs.Similarly,anEEGexperimentby

Umiltaetal.(2012)foundsuppressionofthemurhythm

(index-ingmotoractivation)duringpassiveobservationofLucioFontana’s

slashedcanvases(wheretheactionoftheartistisnotseen,but

(6)

modiﬁedversionsofthem.Thus,evidencefromTMS,fMRI,andEEG

studiesconvergestosuggestthatmotorsimulationofmovements

impliedinartworksisrelevantfortheiraestheticappreciation.

Inareviewpaper,Nadaletal.(2012)addfurthersupportto

Freedberg and Gallese’sproposal (2007)by describing the

aes-theticexperienceasonethat isfullyembodied andenactive,in

which an observer’s prior experienceor expertise plays a role.

Theynotedifferentbrainprocessesinvolvedinpositiveaesthetic

experiences, including: (i) the enhancement of somatosensory

corticalprocessing(Calvo-Merinoetal.,2008,2010);(ii)

activa-tionof reward circuits (including corticaland subcorticalbrain

regions)involved ingeneratingpleasantemotionsandin

evalu-atingandanticipatinganartwork’s reward(KawabataandZeki,

2004;VartanianandGoel,2004);(iii)andattentionalmodulation

ofanumberofcorticalsensoryregionsthatenhanceperceptual

processingofdifferentfeaturesofaperceivedartwork(Cela-Conde

etal.,2004).

Whenconsideringtheroleofthemotorsysteminanobserver’s

aestheticexperience,researchinvestigatingdancehascontributed

a numberof importantinsights (Crossand Ticini,2012).Dance

is, at its core, a dynamic art form that is open to subjective

interpretation by the dancer and the spectator (Bläsing et al.,

2012;Orgsetal.,2016).Calvo-Merinoetal.(2008)weretheﬁrst

tousehumanneuroscience tools toinvestigatebrainprocesses

underlyinganobserver’saestheticexperienceofwatchingdance.

Theybuiltonpreviousworkusingstaticimagesorlimitedbody

movement by investigating the relationship between activity

withinsensorimotorcorticeswhenwatchingdanceandaesthetic

judgements.Functional MRI scans of non-dancers’ brainswere

recordedwhiletheyviewedballetandcapoeiramovementsthat

were later rated on a series of aesthetic dimensions (Berlyne,

1974).Calvo-Merino andcolleaguesreported greateractivityin

bilateraloccipitalcorticesandintherightpremotorcortexwhile

participantswatcheddancemovementstheylaterassignedhigh

liking ratingsto(asan averagegroupmean),in comparisonto

dancemovementsthatreceivedlow averagelikingratings.The

authorsconcludedthatvisualandsensorimotorareasplayarole

inanautomaticaestheticresponsetodance,intermsofhowmuch

spectatorsenjoywatchingamovement.

Inaninnovativestudy,Grosbrasetal.(2012)combinedfMRI

withTMStoidentifybrainareasimplicatedinemotionprocessing

duringdanceobservation(fMRI)andthentestchangestoemotional

responsesinducedbytemporaryreductionofneuralactivityinthe

sameareas (TMS).Theyﬁrstscanned onegroupof participants

whiletheywatcheda3-minmoderndancepiece,andlaterassessed

themeanvalenceoftheseparticipants’emotionalstatethroughout

thepieceusingacontinuousemotionalratingscale.This

proce-durerevealedasigniﬁcantnegativecorrelationbetweenactivity

intheposteriorparietalcortexandmeanemotionalvalence

dur-ingdanceobservation.Inanewgroupofparticipants,theyapplied

inhibitoryrTMSoverthisareaofparietalcortexfor15min,and

thenaskedtheseparticipantstowatchthesamedancepiecewhile

makingcontinuousratingsoftheiremotionalvalence.Theyfound

thatrTMSoverrightposteriorparietalcortexledtoenhanced

emo-tionalresponses(i.e.,morepositiveresponses)todancesegments

thatelicitedpositiveemotionsamongthepreviousgroupof

par-ticipants(Grosbrasetal.,2012).Theseresultsweretheﬁrsttotest

alinkbetweenposteriorparietalcorticalactivityandemotional

responsestodance,andraiseanumberofchallengingquestions

concerningtheroleofembodimentindanceenjoymentthatare

addressedinthenextsection.

3. Shapingandreshapingtheaestheticbrain

Whilemoststudiesofaestheticprocessing(includingthose

dis-cussedinthisreviewsofar)focusontheperceptualfeaturesofa

stimulusoronthetaskperformedbyanobserver,itisimportantto

notethat,toalargeextent,aestheticprocessingisalsoinﬂuenced

byanobserver’spreviousexperienceandknowledge(Kirketal.,

2009;Bohrnetal.,2013).Moreover,thesefactorscanbeentirely

orthogonaltotheperceptualfeaturesofastimulusorthecognitive

demandsofthetask.Inthissectionofourreview,wefocusonhow

theaestheticexperienceofthehumanbodyisshapedbythe

exper-tiseoftheindividualexperiencingthestimulus,andhowitcanbe

modiﬁedorchanged(bytraining,forinstance).Table1

summa-rizestheprincipalaimandresultsofthemainstudiesinvestigating

themodulationofbehaviouralandcognitivecorrelatesofaesthetic

experiences accordingtothebeholders’expertise orfamiliarity

(Section3.1)aswellastheirplasticityafterperceptual(Section3.2)

andmotor(Section3.3)training,focusingonaestheticexperience

involvingthehumanbody.

3.1. Familiarityandexpertise

Thenotionthatfamiliarstimuliareratedasmorepleasanthas

beenwidelyinvestigatedintheﬁeldoffaceand,morerecently,

body attractiveness.Indeed, it hasbeen proposedthatthe

per-ceptionofstimulifromhomogenousclassesthatsharecommon

conﬁgurations,suchasfacesandbodies,isbasedonthefeaturesofa

templaterepresentationthatisusedasareferencepointtoperceive

otherexemplars,andthatthoseexemplarsthataremoresimilar

tothetemplaterepresentationreceivehigheraestheticappraisals

(Valentineetal.,2004).Thisseemstooccurbecausestimulithat

aremore similartoaface template,as comparedtodistinctive

faces,areprocessedmoreefﬁciently,asshownbothintermsof

faster discriminationperformance andreducedearlyperceptual

EEGresponses(Trujilloetal.,2013).

Therelationshipbetweenmotorexpertiseandaesthetic

expe-riencehasbeeninvestigatedinparticulardetailwithinthedomain

ofdance.Crossetal.(2011)soughttoquantifytherelationship

betweenobservers’abilitytophysicallyperformadancemovement

andhowmuchtheylikedwatchingthatmovement.Participants

ratedtheirperceivedabilitytophysicallyreproducedance

move-mentsperformedbyprofessionalballetdancers(afterCrossetal.,

2006),andassignedeachmovementanaestheticratingonthe

like-dislikedimensionofBerlyne(1974).Theyfoundthatparticipants

tendedtolikemostthosemovementstheyperceivedasdifﬁcult

toperformthemselves.Furthermore,thisinteractionbetween

lik-ing andphysical ability wasrepresentedby strongeractivation

withinoccipitalandparietalcortices.Theseresultswere

intrigu-ing,astheysuggestedthatthelessanobserverisabletoperform

a perceivedaction, themore heorsheenjoys watching it(and

viceversa).Theauthorshavedescribedthisasa‘CirqueduSoleil

effect’,meaningthatwelikewatchingspectacularorimpressive

movementsmostofuscouldneverreproducebecauseofthe

dis-crepancy betweenourbodies/physical repertoires and those of

talenteddancers,acrobats,orprofessionalathletes(seeCross,2015,

for furtherdiscussionofthis idea).Returning toFreedberg and

Gallese’sembodiedsimulationaccountofaesthetics,itcouldbe

thatengagementofsensorimotorareaswhenobserving

spectac-ularor sublimemovementsthatare wellbeyondanobserver’s

abilitiesreﬂectsanattemptbythesensorimotorsystemtoembody

theseimpressivemovements,orperhapstoassimilatetheunusual

orcomplexmovementsintoexistingmotorcodes(c.f.Crossetal.,

2012).

RecentworkbyLederetal.(2012)addsfurthersupporttothis

viewpoint.Theseauthorsdemonstratedthatparticipants’aesthetic

enjoymentofpaintingswasenhancedbyaskingthemtoperform

actionsthatmatchedanartist’spaintingstyle(forexample,

per-formingpointillist-styledabbingofpaintincreasedparticipants’

likingofpointillistpaintings).Notonlyexecutingtheactions,but

(7)

62 L.P. Kirsch et al. / Neuroscience and Biobehavioral Reviews 62 (2016) 56–68 Table1

Studiesexploringtheplasticityoftheneurocognitivebasesofaestheticappreciationinlong-termexpertsorafterlaboratory-inducedtrainingexperience–withafocusonhumanbodyperception.

Authors Date Methodology Stimuli Population Primaryresearchquestion Majorﬁnding

Familiarityandexpertise

Valentineetal. 2004 Behaviour Photographsoffemale

faces,infull-faceand proﬁleview

Non-experts Perceptualfamiliarity

Examinetheeffectofmanipulating theaveragenessoffemalefacesin proﬁleandfull-faceviewsonthe perceptionofattractiveness

Facesmorphedtowardsthe averagewereperceivedas moreattractiveinbothviews, buttheeffectwassigniﬁcantly strongerforfull-faceviews.

Trujilloetal. 2013 EEGand

behaviour

Attractive, unattractive,and averagedHumanand Chimpanzeefaces (categorizationtask)

Non-experts Perceptualfamiliarity

Testoftheaveragenesstheoryof facialattractivenessbycomparing behaviouralandERPresponsesto high-attractive,averaged,and low-attractivefacespresentedin thecontextofasimplespeciesface categorizationtask.

Behaviour:Attractiveand averagedfacesaremore prototypicalthanunattractive faces.

Averagedfacesratedasbeing moreattractive

EEG:High-attractiveand mathematicallyaveragedfaces bothengageﬂuentfacial processingatearlystagesof visualperception. Lederetal. 2012 Behaviour/Priming Paintings(pointillistvs.

Strokestyle)

Nonexperts Motorfamiliarity

Examinehowperceivingapainting styleelicitscovertsimulationsof concordanthandmovementsin theviewer,withandwithout motorpriming.

Participants’aesthetic enjoymentofpaintingswas enhancedbyaskingthemto performactionsthatmatched anartist’spaintingstyle.

Ticinietal. 2014 Behaviour/Priming Paintings

(pointillist-style)

Non-experts Motorfamiliarity

Towhatextentisartappreciation dissociablefrommotoractivityand towhatextentisitlinkedtoit? Primingwithimagesdepictinga motoracteithercompatibleor incompatiblewiththesimulation oftheartist’smovements (precisionvs.powergrip)

Actionpriming,whenthe actioniscongruentwiththe artist’spaintingstyle, enhancedaestheticpreference.

Crossetal. 2011 fMRIand

behaviour (ratings)

Classical

ballet/contemporary dance

Non-dancers Motorfamiliarity

Howisanobserver’saesthetic evaluationofdancerelatedtohis orherperceivedphysicalabilityto reproducethewatched

movements?

(8)

L.P. Kirsch et al. / Neuroscience and Biobehavioral Reviews 62 (2016) 56–68 63 Table1(Continued)

Authors Date Methodology Stimuli Population Primaryresearchquestion Majorﬁnding

Trainingtheaestheticbrain:visualexperience

Hayn-Leichsenring 2013 Perceptual expo-sure/Behaviour Humanface photographsandart portraits

Non-experts Investigateeffectsofadaptationto attractiveandunattractivehuman facesontheperceived

attractivenessofhumanfacesin photographsandartportraits

Adaptationtofacial attractivenesselicits after-effectsintheperception ofsubsequentlypresented facesforbothfacephotographs andartportraits.Theseeffects didnotcrossimagedomains (i.e.,betweenphotographsand portraits).

Rhodesetal. 2003 Perceptual

expo-sure/Behaviour

Facesimages Non-experts Examinetheeffectofbrief exposuretoconsistentfacial distortionsonwhatlooksnormal (average)andwhatlooksattractive

Perceptualadaptationcan rapidlyrecalibratepeople’s preferencestoﬁtthefacesthey see.

Meleetal. 2013 Perceptual

expo-sure/Behaviour

Bodyimages Non-experts Investigatehowperceptual

experiencemodulatesbody aestheticappreciation.

Foundatendencyfor participantstoconsidermore attractivethosebodieswhose weightissimilartothatof previouslyencounteredbodies. Winklerand

Rhodes

2005 Perceptual

expo-sure/Behaviour

Bodyimages Non-experts Investigatewhethershort

durations(5min)ofexposureto distortedbodiescanchange subsequentperceptionsof attractivenessandnormality.

Perceptionofbody attractivenesscanbe inﬂuencedbyexperience,but thereisanasymmetrybetween theeffectsofexposureto narrowandwidebodies. Themostattractivebodyshape wasconsistentlynarrower thanthemostnormallooking bodyshape.

Orgsetal. 2013 Sequence

expo-sure/Behaviour

Apparentmotionwith staticbodypostures

Non-dancers Investigatetheaestheticeffectsof threelevelsofmovement representation:bodypostures, movementtransitionsand choreographicstructure;with differentkindsofpriming.

Participantsexposedto asymmetricalsequences showedincreasedlikingof asymmetricalsequences. Moreover,participants preferredmovementsthathad beenfrequentlyobservedto movementsthatwereseenless frequently.

Trainingtheaestheticbrain:motorexperience

Kirschetal. 2013 Training/Behaviour Streetdancesequences Non-dancers Clarifytherelationshipbetween physicalexperienceandaffective evaluationofdancemovements. Inabetween-subjectsdesign, participantsreceivedeither physical,audiovisualorauditory onlytraining.

Participantsfromthephysical traininggroupnotonly improvedtheirphysical performanceofthedance sequences,butalsoreported higherenjoymentandinterest inthedancesequencesafter training.

Kirschetal. 2015 fMRIpre-and

post-training

Streetdancesequences Non-dancers Investigatehowlearningto performanactionimpactsthe neuralresponsewhenwatching andaestheticallyevaluatingthe sameaction.

Inawithin-subjectsdesign, participantsreceivedphysical, audiovisualandaudioonlytraining ondifferentdancesequences.

(9)

increasedtheparticipants’aestheticenjoymentofpaintings,after

theparticipantsreceivedavisuo-motortrainingtoassociateeach

speciﬁcactiontothecorrespondingpaintingstyle (Ticinietal.,

2014). These ﬁndings ﬁt nicely with Freedberg and Gallese’s

embodiedsimulationaccountofaesthetics(2007),showingthat

themoreanobservercan simulatethepainter’smovementsin

producingart,themoreheorshereportslikingtheartwork.

3.2. Trainingtheaestheticbrain:visualexperience

Asexploredintheprevioussection,anobserver’sfamiliarityor

expertisewithastimuluscanprofoundlyshapehowitthe

stimu-lusinquestionisperceivedandevaluated.Herewereviewstudies

thathave activelymanipulatedthesefactorsand documentthe

plasticityofthevisual,motorandrewardsystemsduringaesthetic

appreciation.

Consideringperceptualfamiliarity,itisknownthatthe

norm-based representations used to perceive face and body stimuli

maybeshapedbyexperience,sincethetemplatecorrespondsto

theaverageofallexemplarsthathavebeenpreviously

encoun-teredbyagivenindividual.Importantly,pre-exposingobservers

withrepeatedpresentationsofphotographsorportraitsoffaces

increasesaestheticratingscomparedtonovelfacestimuli(

Hayn-Leichsenringetal.,2013;Rhodesetal.,2003).Similarresultshave

beenobtainedfortheaestheticappreciationofbodyshape,witha

tendencytoconsidermoreattractivethosebodieswhoseweightis

similartothatofpreviouslyencounteredbodies(Meleetal.,2013;

Winklerand Rhodes,2005).Ofnote,theeffectsof bodyweight

familiarizationcorrelatewiththedegreeofbodydissatisfactionand

internalizationofWesternidealsreportedbyparticipants(Glauert

etal.,2009).Thissuggeststhatperceptualfamiliaritywiththetype

ofextremelythinmodelsfeaturedbythemediamayexplainthe

tendencytoidealizeleanbodyshapes,whichisparticularlystrong

inWesternsocieties.

Perceptualfamiliaritymayaffectnotonlytheaestheticvalue

attributed to the form of bodies, but also how we appreciate

theirmovements.FindingsbyOrgsetal.(2013)furthersupport

therelationshipbetweenfamiliarityandliking.Inthisstudy,the

authorsfound that participants preferred movementsthat had

beenfrequentlyobservedtomovementsthatwereseenless

fre-quently(Orgs etal.,2013).Byusingapparentbiologicalmotion

wherestillphotographsofadancerindifferentposeswere

pre-sentedinrapidsuccession,andpre-exposingparticipantstoeither

symmetricalorasymmetricalmovementsequences,Orgsand

col-leaguesfoundthatparticipantsexposedtoasymmetricalsequences

showedincreasedlikingofasymmetricalsequences.Itisofnote,

however,thatpre-exposingparticipantstosymmetricalsequences

didnotaffectlaterratings.Theauthorstakethisasevidenceof

a “baseline” preference for sequential symmetry that does not

dependonfamiliarizationintheexposurephase.

Whilethestudiesdiscussedinthis sectiondemonstratethat

acquiringperceptualfamiliarityaffectsaestheticappreciationof

faceandbodystimuli,toourbestknowledge,littleisknownon

theneuralunderpinning ofthesemodiﬁcations.Incontrast,the

followingsectionfocusesmoreontheeffectsofacquiringdirect

motorexperiencewithperformingarts,andexplorestheeffectsof

thistrainingonbothbehaviouralandneuralindexesofaesthetic

appreciation.

3.3. Trainingtheaestheticbrain:motorexperience

Inadditiontoacquiringvisualfamiliarity,acquiringdirectmotor

experiencewithperformingorcreatingartcan alsochangethe

aestheticappreciationofothers’performances.Inthedomainof

theneuroaesthetics of dance, Kirsch et al. (2013) conducted a

between-groups training study withnon-dancers toclarify the

relationshipbetweenphysicalexperienceandaffectiveevaluation

ofdancemovements.Onegroupofparticipantsreceived

physi-caldancetrainingusinganimmersivevideogamesystem,another

groupreceivedvisualandauditoryexperiencewiththesamedance

sequences,andathirdgroupreceivedauditoryexperienceonly(i.e.,

simplylistenedtothesoundtracksthataccompaniedthedance

movementsexperienced bytheothergroups).Participants’

aes-theticpreferencesfordancestimuliweremeasuredbeforeandafter

thetraining sessions.Resultsshowedthatparticipantsfromthe

physicaltraininggroupnotonlyimprovedtheirphysical

perfor-manceofthedancesequences,butalsoreportedhigherenjoyment

andinterestinthedancesequencesaftertraining.Thesedatathus

suggestthatmasteringphysicalperformanceofmovementsleads

togreaterenjoymentwhileobservingthem.Aswellasproviding

supportforFreedbergandGallese’sembodiedtheoryofaesthetics

(2007),thisﬁndingalsoresonateswithMontero’s(2012)

sugges-tionthatdancetrainingcanfacilitateakinestheticexperiencewhen

watchingdance,withoutwhichsomeaestheticaspectsofdance

performance,suchasgrace,power,orprecision,maygounnoticed

amongnoviceobservers.Assuch,Monterosuggeststhat(dance)

expertisecanfacilitatea moredifferentiated andinformed

aes-theticexperienceofadanceperformance.

Intermsofhowtheseﬁndingscomparetothepreviousstudy

byCrossandcolleagues(2011),whichfoundgreaterenjoyment

for movements participants rated as difﬁcult or impossible to

reproduce,itappearsthatwhenphysicalexperienceis

experimen-tallymanipulated,andembodimentdirectlymeasured(intermsof

actualmotorperformance),thedataprovideclearsupportforan

embodiedsimulationaccountofaesthetics(FreedbergandGallese,

2007).Inafollow-upstudyaimingtocharacterizetheneural

archi-tecturesupportingtherelationshipbetweentrainingexperience

and liking,Kirsch etal. (2015)directlycompared how learning

toperformanactionimpactstheneuralresponsewhenwatching

andaestheticallyevaluatingthesameaction.FunctionalMRIwas

obtainedpriortoandimmediatelyfollowingthetrainingperiod,

aswereaffectiveandphysicalabilityratingsforeachdance

stimu-lus.Theauthorsfoundthat,aftertraining,brainregionsinvolvedin

mediatingtheaestheticresponseshiftedfromsubcorticalregions

associatedwithdopaminergicrewardprocessingtoposterior

tem-poralregionsimplicatedinmultisensoryintegration,emotionand

biologicalmotion.Whilethisstudyprovidesamorein-depthlook

intothecomplexanddynamicrelationshipbetweenexperience,

aesthetics, reward, and emotion, it also raises many questions

regarding themalleabilityof a perceiver’saestheticexperience,

whichwillrequirecarefulfurtherinvestigation.Moreover,

char-acterizingthe shiftin processing frombrain regions mediating

rewardtothoseinvolvedinhigher-levelperceptualandemotion

processingremainsanopenchallengeforfutureresearch,indance

andotherdomainsofneuroaesthetics.

4. Challengesandemergingprospectsforthefutureof neuroaesthetics

Ouraimforthisreviewhasbeentocontributeanew

perspec-tivetotherichbodyofneuroaestheticsliteraturebyfocusingon

factorsthatmodulateandshapeanindividual’saestheticappraisal

ofbody-relatedstimuliatbrainandbehaviourallevels.Aswithany

emergingﬁeldthatcombineselementsfromdistinctandarguably

distantdisciplines(suchasneuroscienceandart,inthiscase),itis

importanttonotonlyevaluateandsynthesizetheextantresearch,

butalsotocriticallyexaminethelimitationsandshortcomingsof

theﬁeldasawhole.Inthisﬁnalsection,weattempttoarticulate

someof theselimitations,areas ofcaution, andpitfalls for this

ﬁeldasevermoreresearchersundertakeempiricalinvestigation

oftheneurobiologicalantecedentsandconsequencesofaesthetic

(10)

4.1. Maintainingintegrityasalineofinquiryinaneraof

neuromania

While enthusiasmforneuroscience-basedapproaches tothe

studyofaestheticscontinuestogrow, thenascent ﬁeldof

neu-roaesthetics is also experiencing its share of growing pains.

Perhapsunsurprisingly, concomitantwithanincreasinginterest

inneuroaestheticshasbeenamounting“counter-neuroaesthetics”

movementcriticizingtheuseofbrain-basedapproachestoaddress

aestheticquestions(e.g.,Ball,2013;ConwayandRehding,2013).

AsConwayand Redhing state,“itis anopenquestion whether

an analysis of artworks, no matter how celebrated, will yield

universalprinciplesofbeauty”(pp.3),andthat“rational

reduc-tionistapproachestotheneuralbasis forbeauty(...)maywell

distill out the very thing one wants to understand” (pp. 4,

Conway and Rehding, 2013). Theseauthors also criticizemany

researchersworkinginthedomainofneuroaestheticsfor

conﬂat-ingnotions of beauty,art and perception,and stronglycaution

against looking to any one region of the brain as a universal

“beautycentre”.Astheyrightlypointout,andasthemyriad

stud-iesdiscussed in this review illustrate, sucha complex reaction

(considering a percepttobebeautiful) engagesa complex

pat-tern of corticaland subcortical activity and can vary based on

a number of factors,includingmany of those discussed in this

review, such as the context, expectations and expertise of the

beholder.

WeagreewithConwayandRehding(2013)thatthe

“neuroma-nia”thatthreatenstodowngradethelegitimacyofneuroathestics

isaconcern,butalsoarguethatthediscipline,atitscore,

appreci-atestheintersubjectivityofindividuals’aestheticexperiences,and

isnotseekingtoestablishuniversalabsolutesaboutthe

neurobio-logyofbeauty.However,alongwiththeconcernsraisedbyConway

andRehding(2013),anumberofotherissuesrequirecareful

con-siderationasthisnascentdisciplinematures,whichweconsiderin

thefollowingsection.

4.2. Mappingtheneurobiologicalsubstratesofaesthetics:to

whatend?

Oneimportantchallengefor theﬁeld concernstheextentto

which universalneuralsubstratessupporting theexperienceof

beautyshouldevenbesought,wheninterindividual differences

might bemore interesting and illuminatingthan what is

com-monacrossindividuals.We presentedseveralstudiesthathave

begun to scratch the surface on the impact of task demands

(Di Dio et al., 2007; Chatterjee et al., 2009), expertise (Bohrn et al., 2013; Kirsch et al., 2013,2015; Orgs et al., 2013; Ticini

etal., 2014), visualfamiliarity(Mele etal.,2013; Rhodesetal.,

2003;WinklerandRhodes,2005),andtheobserver’ssex(Cazzato etal.,2014;Cela-Condeetal.,2009),butmyriadadditionalfactors

couldinﬂuenceanobserver’saestheticpreferenceandresponse,

including culture, age,and education level, toname a few. As

the ﬁeld is still so young, not enough data exist to create a

clearor complete pictureof what inﬂuencesor drives

percep-tionsofbeauty.We anticipatethatintheyearsahead,theﬁeld

ofneuroaestheticswillcontinuetogrow,andwillbeginto

pro-vide answers to someof thesequestions. As long as scientists

engaged in thepursuit of characterizingthe biological

founda-tions of aesthetics respect the limits of human neuroscientiﬁc

approaches,weforeseeabrightfutureinthestudyof

neuroaes-thetics.

4.3. Disentanglingaestheticsfromemotion

Anotherfrequentlymentionedcriticismofacommon

neuroaes-theticsapproachisthesubjectivityof likingratingsassignedto

stimuli(Helleretal.,2011;KahnemanandKlein,2009).Byrelying

onextremelysimplisticratingsofliking (oftenjust‘likevs.

dis-like’;c.f.Zekietal.,2014),itdoesnotseemfeasible(orsensible)to

attempttocharacterizeacommonneuralarchitecturesupporting

thehumanperceptionofabeautifuloraestheticallypleasing

stim-ulus.Onewaytoovercome,oratleastbegintoaddress,thisconcern

wouldbetoconsiderapositiveevaluationofastimulusmoreasa

feeling,suchasapositively-valencedemotion.Methodsusedfor

subtleemotiondetection,suchasfacialEMG(Dimbergetal.,2000)

andgalvanicskinresponsemeasures,areprovingusefulforgaining

insightsintomoredirectindicesofapositiveaffectiveexperience

when beholding a stimulusfor aestheticappraisal (Christensen

etal.,2014;Gergeretal.,2014;Lederetal.,2014).Wesuggest

thatfutureexperimentscouldattempttointegratesuchimplicit

measures of aesthetic appraisal with brain imaging measures,

suchasfMRI orEEG, togainclearer insightsinto subtle

differ-encesinaperceiver’saffectiveexperiencesandsupportingneural

processes.

This,however, raises animportant issue for future research

inneuroaesthetics:disentanglingaestheticexperiencefrom

emo-tion.AsdiscussedinSection2,manyoftheneuralunderpinnings

ofaestheticexperienceinperceptual,motorandrewardsystems

are involved to someextentin both aestheticexperiences and

favourableattitudestowardspositivelyvalencedstimuliin

gen-eral,evenwhentheyarevoidofanyovertaestheticvalue(such

asa chocolatebar).In asimilarvein, a complexofcorticaland

subcorticalstructureshasbeenassociatedwithprocessingbodily

expressionofemotions,whichpartiallyoverlapthoseinvolvedin

bodyaesthetics(CandidiandAglioti,2015;Candidietal.,2011;de

Gelder,2009;deGelderetal.,2011,2010).Furthermore,thedirect

relationshipbetweenemotionandaestheticshasbeendocumented

bytheﬁndingthatactivatingnegativecomparedtopositive

emo-tionsandneutralstateschangestheaestheticvalueattributedto

bothabstractformsandbody postures(Eraetal.,2015).Which

aspectsdistinguishthepatternsofactivationwithintheseareas

duringspeciﬁcallyaestheticexperiencesfrommoregeneral

pos-itiveaffectivereactions?Onepossibleworkinghypothesisrelies

onthesegregation,atleastin therodentbrain(Berridgeetal.,

2009),oftwo differentpathwaysintheventralstriatum,a

cru-cialcomponentoftherewardsystem.Onepathwayismediated

byopiateandcannabinoidsystemsand associatedwith“liking”

experiences,andtheotherismediatedbyadopamine

neurotrans-mitter system and associated with outcome-related “wanting”

experiences.ChatterjeeandVartanian(2014)haveproposedthat

aestheticexperiencesrely ontheﬁrstsystemintheabsenceof

activityinthesecond,thustriggeringappreciationofobject

prop-ertiesindependentlyfromadesiretopossessoractontheobject

itself (Ortony et al., 1990). In this view, modulation of neural

activityinreward, perceptualand motorareas duringaesthetic

experienceandpositiveattitudestostimulimaynotsomuchbe

segregated intheirneuroanatomical organization, butrather in

theirtemporaldynamicsandultimateoutcome.Forexample,while

theultimateconsequenceofanaffectiveappraisalofastimulus

maybetoapproachpositivestimuliandavoidnegativeones(as

reﬂectedbythegreateractivationofprimarymotorcortexduring

observationofuglythanneutralandpleasantstimuli;Kawabata

andZeki,2004;DiDioetal.,2007),theultimateproductof

aes-theticexperiencemaybestimulusperceptionitself,asreﬂected

by greater activation for pleasant than neutral and unpleasant

stimuli inareas involvedin perceptual processingand

embodi-ment (e.g.,Calvo-Merinoet al.,2008; Crosset al.,2011; DiDio

et al., 2007). This may explain why dysfunctions of

category-selective extrastriate areas after brain lesion or rTMS interfere

withbothperceptualandaestheticprocessing(Calvo-Merinoetal.,

2010;Iariaetal.,2008;Urgesietal.,2007),whileprocessingof

(11)

Althoughspeculative,thishypothesismaybetestedby

compar-ingthetemporaldynamicsandcausativeinvolvementofreward,

perceptual and motor areas in aesthetic and positive affective

experiences.

5. Summaryandconclusions

Inthisreview,wehaveexaminedtheprimaryfactorsthat

inﬂu-enceaestheticexperience in thehumanbrain, focusing onthe

humanbodyandtheroleplayedbyembodiment.Asanumberof

otherreviewsprovidedetaileddescriptionandinterpretationof

theneuralcorrelatesofaestheticexperiencesperse,herewehave

insteadfocused ontheplasticityandmalleabilityof an

individ-ual’saestheticexperience,withparticularemphasisonstudiesthat

haveexaminedperceptionofstimuliinvolvingthehumanbody.

Whilecontinuedin-depthinvestigationoftheneuralsubstrates

supportingpositiveaestheticexperiencesofclassicalpaintingsand

abstractart willundoubtedlyfurtheradvance understandingof

howthehumanbrainsupportsevaluationandappreciationofart,

awideningoffocustoincludeaestheticevaluationofstimulithat

comefromdomains beyondthevisualﬁnearts,suchasdance,

ormorebroadly,body perception,holdspromiseforgenerating

amoreholisticunderstandingofaesthetics.Ashighlightedinthis

review,researchinthedevelopingdomainofneuroaestheticsisstill

raisingmorequestionsthanitisanswering,andongoingandfuture

workwillhelptoconstructamoredetailedandnuancedpictureof

thefeaturesthatshapeaestheticpreferencesfroma

neurobiologi-calperspective.

Acknowledgements

TheauthorsthankEmily Butlerfor helpfulcomments onan

earlierversionofthismanuscript.E.S.C.gratefullyacknowledges

researchfundingfromaFutureResearchLeadersAwardfromthe

ESRC (ES/K001892/1), a VENI award by the Netherlands

Orga-nisationfor ScientiﬁcResearch (451-11-002)and a Marie Curie

CareerIntegrationgrant(CIG11-2012-322256).C.U.issupported

byfundingfromtheEuropeanUnion’sFrameworkProgram7under

theMarie Curie“Intra-Europeanfellowshipsforcareer

develop-ment”action(grantagreementNo.625488),fromtheMinistero

IstruzioneUniversita’eRicerca(FuturoInRicerca,FIR2012,Prot.N.

RBFR12F0BD),andfromIstitutodiRicoveroeCuraaCarattere

Sci-entiﬁco‘E.Medea’(RicercaCorrente2014,MinisteroItalianodella

Salute).

References

Aharon,I.,Etcoff,N.,Ariely,D.,Chabris,C.F.,O’Connor,E.,Breiter,H.C.,2001.Beautiful faceshavevariablerewardvalue:fMRIandbehavioralevidence.Neuron32, 537–551.

Aleong,R.,Paus,T.,2010.Neuralcorrelatesofhumanbodyperception.J.Cogn. Neurosci.,1–14.

Armory,J.L.,Dolan,R.J.,2002.Modulationofspatialattentionbyfear-conditioned stimuli:anevent-relatedfMRIstudy.Neuropsychologia40,817–826. Ball,P.,2013.Neuroaestheticsiskillingyoursoul.Nature,March22.

Battaglia,F.,Lisanby,S.H.,Freedberg,D.,2011.Corticomotorexcitabilityduring observationandimaginationofaworkofart.Front.Hum.Neurosci.5,79,http:// dx.doi.org/10.3389/fnhum.2011.00079.

Berridge,K.C.,Robinson,T.E.,Aldridge,J.W.,2009.Dissectingcomponentsofreward: “liking”“wanting”,andlearning.Curr.Opin.Pharmacol.9,65–73,http://dx.doi. org/10.1016/j.coph.2008.12.014.

Berlyne,D.E.,1974.StudiesintheNewExperimentalAesthetics:StepsTowardan ObjectivePsychologyofAestheticAppreciation.HemisphereCo.,Washington. Bläsing,B.,Calvo-Merino,B.,Cross,E.S.,Jola,C.,Honisch,J.,Stevens,C.J.,2012.

Neu-rocognitivecontrolindanceperceptionandperformance.ActaPsychol.(Amst.) 139(2),300–308.

Bohrn,I.C.,Altmann,U.,Lubrich,O.,Menninghaus,W.,Jacobs,A.M.,2013.Whenwe likewhatweknow–aparametricfMRIanalysisofbeautyandfamiliarity.Brain Lang.124(1),1–8.

Brown,S.,Gao,X.,Tisdelle,L.,Eickhoff,S.B.,Liotti,M.,2011.Naturalizingaesthetics: brainareasforaestheticappraisalacrosssensorymodalities.Neuroimage58, 250–258,http://dx.doi.org/10.1016/j.neuroimage.2011.06.012.

Calvo-Merino,B.,Jola,C.,Glaser,D.E.,Haggard,P.,2008.Towardsasensorimotor aestheticsofperformingart.Conscious.Cogn.17(3),911–922,http://dx.doi. org/10.1016/j.concog.2007.11.003.

Calvo-Merino,B.,Urgesi,C.,Orgs,G.,Aglioti,S.M.,Haggard,P.,2010.Extrastriate bodyareaunderliesaestheticevaluationofbodystimuli.Exp.BrainRes.204(3), 447–456,http://dx.doi.org/10.1007/s00221-010-2283-6.

Candidi,M.,Aglioti,S.M.,2015.Visualandsensorimotorcontributionstotheesthetic appraisalofbodyform,motion,andemotion.Eur.Psychol.20,16–26,http://dx. doi.org/10.1027/1016-9040/a000221.

Candidi,M.,Stienen,B.M.C.,Aglioti,S.M.,deGelder,B.,2011.Event-related repet-itivetranscranialmagneticstimulationofposteriorsuperiortemporalsulcus improvesthedetectionofthreateningposturalchangesinhumanbodies.J. Neu-rosci.31,17547–17554,http://dx.doi.org/10.1523/JNEUROSCI.0697-11.2011. Cazzato,V.,Mele,S.,Urgesi,C.,2014.Genderdifferencesintheneuralunderpinning

ofperceivingandappreciatingthebeautyofthebody.Behav.BrainRes.264, 188–196,http://dx.doi.org/10.1016/j.bbr.2014.02.001.

Cazzato,V.,Siega,S.,Urgesi,C.,2012.“Whatwomenlike”:inﬂuenceofmotionand formonaestheticbodyperception.Front.Psychol.3,235,http://dx.doi.org/10. 3389/fpsyg.2012.00235.

Cela-Conde,C.L.,Marty,G.,Maestu,F.,Munar,E.,Fernandez,A.,Roca,M.,Rossello,J., Quesney,F.,2004.Activationoftheprefrontalcortexinhumansvisualaesthetic perception.Proc.Natl.Acad.Sci.U.S.A.101,6321–6325,http://dx.doi.org/10. 1073/pnas.0900304106.

Cela-Conde,C.J.,Ayala,F.J.,Munar,E.,Maestú,F.,Nadal,M.,Capó,M.a.,delRío,D., López-Ibor,J.J.,Ortiz,T.,Mirasso,C.,Marty,G.,2009.Sex-relatedsimilaritiesand differencesintheneuralcorrelatesofbeauty.Proc.Natl.Acad.Sci.U.S.A.106, 3847–3852,http://dx.doi.org/10.1073/pnas.0900304106.

Chatterjee,A.,Thomas,A.,Smith,S.E.,Aguirre,G.K.,2009.Theneuralresponseto facialattractiveness.Neuropsychology23,135–143,http://dx.doi.org/10.1037/ a0014430.

Chatterjee,A.,2011.Neuroaesthetics:acomingofagestory.J.Cogn.Neurosci.23, 53–62.

Chatterjee,A.,2013.TheAestheticBrain:HowWeEvolvedtoDesireBeautyand EnjoyArt.OxfordUniversityPress,Oxford.

Chatterjee,A.,Vartanian,O.,2014.Neuroaesthetics.TrendsCogn.Sci.18,370–375, http://dx.doi.org/10.1016/j.tics.2014.03.003.

Christensen,J.F.,Gaigg,S.B.,Gomila,A.,Oke,P.,Calvo-merino,B.,2014.Enhancing emotionalexperiencestodancethroughmusic:theroleofvalenceandarousal inthecross-modalbias.Front.Hum.Neurosci.8,757,http://dx.doi.org/10.3389/ fnhum.2014.00757.

Cloutier,J.,Heatherton,T.F.,Whalen,P.J.,Kelley,W.M.,2008.Areattractivepeople rewarding?Sexdifferencesintheneuralsubstratesoffacialattractiveness.J. Cogn.Neurosci.20,941–951,http://dx.doi.org/10.1162/jocn.2008.20062. Conway,B.R.,Rehding,A.,2013.Neuroaestheticsandthetroublewithbeauty.PLoS

Biol.11(3),e1001504.

Cross,E.S.,Hamilton,A.F.D.C.,Grafton,S.T.,2006.Buildingamotorsimulationde novo:observationofdancebydancers.Neuroimage31,1257–1267. Cross,E.S.,Liepelt,R.,Hamilton,A.F.deC.,Parkinson,J.,Ramsey,R.,Stadler,W.,Prinz,

W.,2012.Roboticmovementpreferentiallyengagestheactionobservation net-work.Hum.BrainMapp.33(9),2238–2254.

Cross,E.S.,2015.Beautifulembodiment:theshapingofaestheticpreferenceby per-sonalexperience.In:Huston,J.P.,Nadal,M.,Mora,F.,Agnati,L.F.,Cela-Conde, C.J.(Eds.),Art,AestheticsandtheBrain.OxfordUniversityPress,Oxford,pp. 189–208.

Cross,E.S.,Kirsch,L.,Ticini,L.F.,Schütz-Bosbach,S.,2011.Theimpactofaesthetic evaluationandphysicalabilityondanceperception.Front.Hum.Neurosci.5, 102,http://dx.doi.org/10.3389/fnhum.2011.00102.

Cross,E.S.,Ticini,L.F.,2012.Neuroaestheticsandbeyond:newhorizonsinapplying thescienceofthebraintotheartofdance.Phenomenol.Cogn.Sci.11(1),5–16. Cupchik,G.C.,1995.Emotioninaesthetics:reactiveandreﬂectivemodels.Poetics

23(1–2),177–188.

deGelder,B.,2009.Whybodies?Twelvereasonsforincludingbodilyexpressionsin affectiveneuroscience.Philos.Trans.R.Soc.Lond.B:Biol.Sci.364,3475–3484, http://dx.doi.org/10.1098/rstb.2009.0190.

deGelder,B.,VandenStock,J.,Meeren,H.K.M.,Sinke,C.B.A.,Kret,M.E.,Tamietto, M.,2010.Standingupforthebody.Recentprogressinuncoveringthenetworks involvedintheperceptionofbodiesandbodilyexpressions.Neurosci.Biobehav. Rev.34,513–527,http://dx.doi.org/10.1016/j.neubiorev.2009.10.008. deGelder,B.,vanHonk,J.,Tamietto,M.,2011.Emotioninthebrain:oflowroads,

highroadsandroadslesstravelled.Nat.Rev.Neurosci.12,425,http://dx.doi. org/10.1038/nrn2920-c1,authorreply425.

DiDio,C.,Macaluso,E.,Rizzolatti,G.,2007.Thegoldenbeauty:brainresponseto classicalandrenaissancesculptures.PLoSONE2,e1201,http://dx.doi.org/10. 1371/journal.pone.0001201.

DiDio,C.,Gallese,V.,2009.Neuroaesthetics:areview.Curr.Opin.Neurobiol.19, 682–687.

Dimberg,U.,Thunberg,M.,Elmehed,K.,2000.Unconsciousfacialreactionsto emo-tionalfacialexpressions.Psychol.Sci.11,86–89.