bhad069原版完整文件

CerebralCortex,2023,1–11

/10.1093/cercor/bhad069

OriginalArticle

Theimpactofsocialdistanceontheprocessingofsocialevaluation:evidencefrombrainpotentialsandneuraloscillations

XinmuHu1,YinlingZhang1,XiaoqinMai1,2,3,*

1DepartmentofPsychology,RenminUniversityofChina,Beijing100872,China,

2LaboratoryofDepartmentofPsychology,RenminUniversityofChina,Beijing100872,China,

3InterdisciplinaryPlatformofPhilosophyandCognitiveScience,RenminUniversityofChina,Beijing100872,China

*Correspondingauthor:DepartmentofPsychology,RenminUniversityofChina,Beijing100872,China.Email:

maixq@

Previousresearchindicatesthatsocialdistancecaninfluencepeople’ssocialevaluationsofothers.Individualstendtoevaluateintimateothersmorepositivelythandistantothers.Thepresentstudyinvestigatesthemodulatingeffectofsocialdistanceonthetimecourseunderlyingindividuals’evaluationprocessesofothersusingadequateelectroencephalographymethods.Theresultsrevealthatintheinitialprocessingstage,theP2componentislargerwhenfriendsarenegativelyevaluated,whereasthispatternistheoppositeforstrangers.Inthesecondstage,medialfrontalnegativityandearlymid-frontalthetabandactivityisenhancedfornegativeevaluationsoffriends,whereasthiseffectisabsentinsocialevaluationsofstrangers.Atthelatestage,theP3islargerforpositiveevaluationsoffriendsbutinsensitivetosocialevaluationsofstrangers,andthelatemid-frontalthetaisalsomodulatedbysocialdistance.Thesefindingsprovidedirectandpowerfulevidencethatsocialdistancemodulatesindividuals’evaluationsofotherswithdifferentlevelsofintimacythroughoutallprocessingstages.

Keywords:socialevaluation;socialdistance;electroencephalography(EEG);medialfrontalnegativity(MFN);mid-frontalthetaactivity.

Introduction

Inasocialworld,peopleinteractwithothersatvariouslevelsofintimacy.Socialdistancecaneffectivelyreflectpsychologicalintimacybetweenoneselfandothers(

Tesser1988

).Generally,associaldistancegetscloser,peoplebecomeincreasinglyintimate(

Liuetal.2021

).Construalleveltheorysuggeststhattheperceivedpsychologicalintimacybetweentheselfandotherscouldaffectsubsequentmotivations,judgments,anddecisions(

Tropeetal.

2007).Socialidentitytheoryindicatesthatpeopledefineandevaluateothersintermsofsocialdistanceandtendtobemoti-vatedtojudgethoseatacloserdistance,suchasfriends,morepositivelycomparedwithmoredistantothers,suchasstrangers,andfavortheformeroverthelatterwhendistributingmoneyorresources(

TajfelandTurner1979

;

CrandallandEshleman2003

;

Durrheimetal.2016

).However,wouldevaluatingintimateothers,asopposedtostrangers,involveoverlappingordistinctneuralcorrelates?Thepresentstudyaimedtoexplorethisquestionfromaneuroscientificperspective.

Severalstudieshavefocusedondownstreamprocessesinfluencedbysocialdistance.Thoseresultsfoundthatpeopleexpressgreaterempathyfor,behavemorecooperativelytoward,andmorepositivelyevaluatecloseothersthandistantones(

RatnerandAmodio2013

;

Ballietetal.2014

;

Ofanetal.2014

;

ScheepersandDerks2016

).Furthermore,behavioralevidencehasshownthatindividualsexhibitmoreprosocialbehaviortowardintimateratherthandistantothers(

Levineetal.2005

).Recentneuroscienceresearchhasexaminedtheneuralmechanisms

underlyingsocialdistanceprocessesandsearchedforlinksbetweentheseprocessesandhumanbehaviors.

Functionalmagneticresonanceimaging(fMRI)studieshaverevealedthataffect-drivenevaluationsofintimatepersonsappeartobecharacterizedbyincreasedactivityintheventralmedialprefrontalcortex(vmPFC)andanteriorcingulatecortex(ACC),whichreflectsstrongempathy,mentalizing,andhuman-izationofcloseothers(

Beeretal.2003

;

Xuetal.2009

;

Cikaraand

VanBavel2014;

MolenberghsandMorrison2014

).Forexample,participantsinonefMRIstudywereexposedtoanimatedstimuliinpainfulandnon-painfulsituations.Theywereinstructedtoimaginethesescenariosfromthreedifferentperspectivesafterbeingprimedwiththeirrespectivephotographs:self,lovedone,andstranger.TheresultsshowedthatadoptingtheperspectiveofalovedoneincreasedactivityintheACCandinsula,whereasimaginingastrangerinducedasignalincreaseintherighttemporoparietaljunction(TPJ)andsuperiorfrontalgyrus.Theclosertherelationshipparticipantshadwiththeirpartners,thegreaterthedeactivationintherightTPJ.Theseresultsdemonstratethatsocialdistanceaffectsthebottom-upinformationprocessinginvolvedinempathy,asindicatedbythegreateroverlapbetweenneuralrepresentationsoftheselfandothers(

Chengetal.2010

).

Humansliveincomplexsocialenvironments,andmotiva-

tionsandbehaviorsinducedbysocialdistancehavebeeniden-tifiedasrapidprocesses(

Ashburn-Nardoetal.2001

;

Molenberghs

etal.2013).Therefore,exploringthetimecourseoftheneural

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Received:December22,2022.Revised:February14,2023.Accepted:February15,2023

©TheAuthor(s)2023.PublishedbyOxfordUniversityPress.Allrightsreserved.Forpermissions,pleasee-mail:

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processesinvolvedinbottom-upinformationprocessingaffectedbysocialdistanceisofgreatimportance.ComparedwiththefMRIapproach,thehightemporalresolutionofevent-relatedpotentials(ERPs)offersanappropriatemethodforexaminingthetimecourseofsocialevaluationinducedbysocialdistance.Inthepresentstudy,weexaminedtheeffectsofsocialdistanceonvariousprocessingstagesofsocialevaluationofotherswithdifferentlevelsofintimacy.

ThreeERPcomponents,theP2,medialfrontalnegativity(MFN),andP3,havebeenfoundtobeparticularlysensitivetoevalua-tiveprocessing.TheP2isapositivefrontalcomponentpeakingwithin150and250msfollowingstimulusonset,andplaysanimportantroleintheearlyprocessingofattentioncapture,vig-ilancetothreateningandnovelcues,andstimulusevaluation(

Nieuwenhuisetal.2004

;

Bar-Haimetal.2005

;

Correlletal.2006

;

DickterandBartholow2007

),reflectingautomatic,rapid,andlow-levelprocessingofstimuli(

Jerónimoetal.2017

).Generally,stim-uliconferredhighermotivationalrelevanceelicitedalargerP2(

SchindlerandKissler2016

).Giventhatsocialperceptiontendstobeautomaticallyaffectedbysocialdistance,theP2isconsideredagoodindicatoroftheautomaticprocessingofsocialdistanceinformation.

TheMFNisanegativedeflectionatfrontocentralscalpsitesthatpeaksapproximately200–350msafteroutcomeonset,pre-sumablygeneratedintheACC,abrainareareflectingsocialpainelicitedwhenapersonisnegativelyevaluatedorsociallyrejected(

Somervilleetal.2006

;

Krossetal.2011

;

Rotgeetal.2015

;

Dedovic

etal.2016).TheMFNalsodepictsrapidprocessingofthecurrentoutcomeona“good–bad”dimension(

Miltneretal.1997

;

Gehring

andWilloughby2002).SeveralstudieshaveindicatedthattheMFNismorepronouncedfornegativestimulithanforpositivestimuli(

GehringandWilloughby2002

;

Sidarusetal.2017

)andishighlysensitivetoexpectancyviolations(

Hajcaketal.2007

;

Marcianoetal.2018

).Inaddition,theMFNhasbeendemonstratedtobeaffectedbysomesocialfactorssuchassocialdistance,socialrejection,andempathy(

FukushimaandHiraki2006

;

Kujawaetal.

2014;

Liuetal.2021

).

FollowingtheMFN,theP3isacentroparietalpositivecompo-nentthatpeakswithin300–600msfollowingstimulusonsetandplaysavitalroleinevaluativeprocessing(

HolroydandColes2002

;

YeungandSanfey2004

;

Nieuwenhuisetal.2005

).TheP3islargerforpositivestimulithanfornegativestimuli,andforlargerewardsthanforsmallrewards(

Holroydetal.2006

;

Guetal.2010

;

Hewig

etal.2011),andissensitivetosocialfactorssuchasinterpersonalrelationships(

Maetal.2011

;

LengandZhou2014

;

Zhangetal.

2021)andempathy(

Ikezawaetal.

2014).ResearchersbelievethatP3isrelatedtotheallocationofattentionalresourcesandhigh-levelaffectiveevaluationsofoutcomes(

Nieuwenhuisetal.

2005;

Polich2007

;

HuandMai2021

;

Liuetal.2021

).EvaluativeprocessingstudieshaveshownthattheP3islargerforwordsrelatedtoemotionalsocialevaluationthanforneutralwords(

SchindlerandKissler2016

).

InadditiontoERPanalysis,time-frequencyanalysishasrecentlybeenusedtoexaminetheneuralbasisofevaluativeprocessing.Thetaoscillationsspatiallyandtemporallyorganizeneuralprocessingthroughoutthehumancortex(

Zhangetal.

2018).Themid-frontaltheta,whichistypicallycapturedusingfrontocentralelectrodes,isinvolvedinsaliencedetectionandcog-nitivecontrol,suchasperformancemonitoringandinformationintegration(

CavanaghandFrank2014

;

DarribaandWaszak2018

).Recentstudiesfoundthat,duringtheperceptionofevaluativefeedback,earlyoscillationofthefrontalthetawithpowerpeaksof50–250mswassensitivetothefeedbacksourceandvalence,and

wasespeciallygreaterfornegativesocialfeedback(

Pfabiganand

Han2019;

Zhangetal.2022

).Furthermore,

VanderMolenetal.

(2016)foundthatlatethetaactivityincreasedforunexpectednegativefeedbackcomparedtounexpectedpositivefeedback.

Althoughextensiveresearchhasinvestigatedtherelationshipbetweensocialdistanceandsocialevaluationinanexplicitway,littleisknownabouthowweevaluateothersinanimplicitway.Electroencephalography(EEG)isanexcellenttechniqueforassessingspontaneoussocialevaluationofothersduetoitshightemporalresolution.Furthermore,itallowsformeasurementofthevariationsintheextenttowhichpeople’sbrainsprocessevaluativeinformationimplicitlyandrapidly.Withthisapproach,wesoughttoexplorehowthetimecourseofthebrainactivityunderlyingsocialevaluationprocessesofsocialagentsvarieswithdifferentlevelsofintimacy.Weexpectthatourfindingscouldextendtheknowledgeoftheneuralunderpinningofsocialdistancemodulatingsocialevaluationprocessingbyprovidingatemporaldescriptionofthemodulation.Moreover,thepresentstudycanalsoprovidemoredirectevidenceforalinkbetweensocialevaluationandneuralmarkersoftheself.Electrophysio-logicalresultscouldfurtherprovidenewevidencessupportingthesocialidentitytheory,whichsuggeststhatpeopletendtoshowfavoritismtowardtheircloseonesandevaluatethemmorepositivelyrelativetostrangers(

Brewer2007

;

ScheepersandDerks

2016).Therefore,weemployedanimplicitsocialevaluationtaskmodifiedfromthesocialevaluationparadigmusedby

Somerville

etal.(

2006)and

Yangetal.(2016)

toinvestigatethetemporalpro-cessingoftheeffectofsocialdistanceonindividuals’socialeval-

uationsfromtw

operspectives:intimatefriendsandstrangers.Wehypothesizedthatsocialdistancecouldmodulateindividuals’evaluativeprocessingfromtheautomatictoconsciousprocessingstage.Consideringpreviousresearchonpeople’spreferenceforlovedones,wefurtherpredictedthatnegativeevaluationsoffriendsandpositiveevaluationsofstrangerswouldinducealargerP2becausesuchassociationsmaybenovelcuestopar-ticipants.Furthermore,theMFNandmid-frontalthetaactivityfollowingnegativeevaluationwereexpectedtobemorenega-tivegoingthanforpositiveevaluationsinthefriendcondition,becauseindividualswouldhaveastrongmotivationandtendencytopositivelyevaluatetheirfriends.Inthestrangercondition,weexpectedtheMFNandthetaresponsemuchweaker(orevennonexistent)becausepeopleoftencarelessaboutdistantothers

compar

edwithfriends.Similarly,theP3shouldbelargerforpositivethannegativeevaluationsoffriendsandinsensitivetostrangersbecausepeoplegenerallyprefertheirownlovedones.

Methods

Participants

Twenty-ninehealthycollegestudentsparticipatedinthisstudyaspaidvolunteers.Allparticipantswereright-handed,hadnormalorcorrected-to-normalvision,andreportednohistoryofneuro-logicalorpsychiatricdisorders,headinjury,significantphysicalillness,oralcoholordruguse.Allparticipantsprovidedwritteninformedconsent.ThestudywasapprovedbytheInstitutionalReviewBoardoftheDepartmentofPsychologyatRenminUniver-sityofChina.Twoparticipantswereremovedfromdataanalysisbecauseofuncorrectableartifactsduringelectroencephalography(EEG)recording,resultinginafinalsampleof27participants(14women,meanage±SD=20.8±1.7years).AnapriorisamplesizeestimationwasconductedusingG∗Powerv.3.1(

Fauletal.2009

).Accordingtotheanalysis[d=0.3,α=0.05,β=0.8,analysisofvariance(ANOVA):repeatedmeasures,withininteraction],atotal

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samplesizeof24participantswasrequiredtodetectareliableeffect.

Stimuli

Theimplicitsocialevaluationtaskinthisstudywasamodifiedversionofthesocialevaluationparadigmpreviouslyusedby

Somervilleetal.(2006)

and

Yangetal.(2016)

.DuringtheERPexperiment,eachparticipantwaspresentedwithtwophotosoffaces,oneofapersonalfriendandoneofastranger,alongwithwordsassociatedwithpersonalitytraitsandspecificobjects.

Facialphotos

Oneweekpriortotheexperiment,eachparticipantwasaskedtosendtheresearchersaportraitphotographofaclosesame-genderfriendwithaneutralexpression.Weadditionallycollected

16photosfromstudentsintheDepartmentofPsychologyatRenminUniversityofChina.Twentystudents(10females,meanage±SD=22.54±2.17years)fromRenminUniversityofChinaratedallphotosona5-pointscaleforemotionvalenceandfacialattractiveness.Theemotionvalencescore(M=3.08,

SD=0.29)wasnotsignificantlydifferentfromtheneutralscore

(3)forallphotos,t(41)=1.66,P=0.105.Wethendividedthephotosintofourgroupsbasedonfacialattractivenessscores:female-high(M=4.47,n=11),female-low(M=3.35,n=11),male-high(M=4.38,n=10),andmale-low(M=3.32,n=10).Independent-samplest-testrevealedthatthefemale-highgroup

hadsignificantlyhigherattractivenessscoresthanthefemale-lowgroup[t(20)=8.20,P<0.001],whilethemale-highgroupalsohadsignificantlyhigherattractivenessscoresthanthemale-lowgroup[t(18)=7.95,P<0.001].Inthepresentstudy,ifafemaleparticipant’sfriend’sfacebelongedtothefemale-highgroup,then

thestranger’sfacewasselectedfromthesamegroup(possiblyafriendofanotherparticipantsoravolunteerfromtheDepartmentofPsychology).Therefore,duringtheformaltask,bothphotospresentedtoeachparticipantshowedthefacesofpeersofthesamegenderwithneutralfacialexpressionsandwereconsistentintermsofhairstyle(e.g.lengthandcolor),accessories(e.g.glasses),andfacialattractiveness.Allphotographswerecoloredandofsimilarquality.

Words

Tocreateacontextforsocialevaluationintheexperiment,80personalitytraitadjectives(40positivevs.40negative;e.g.honestvs.shameless)wereselectedfromapersonalitytraitadjectivepoolestablishedby

HuangandZhang(1992)

.Intheirstudy,thevalencesofadjectiveswereratedby565collegestudentsfrom1(extremelynegative)to7(extremelypositive),familiaritywasmeasuredby470collegestudentsfrom0(completelyunfamiliar)to4(stronglyfamiliar),andunderstandingofthemeaningofeachadjectivewasassessedby500collegestudentsfrom

1(totallyunknown)to4(understandverywell).Forvalencescores,thepositiveadjectivesselectedinthisstudywereratedsignificantlyhigherthanthenegativeones(5.75±0.40vs.

2.76±0.43,t[78]=−38.40,P<0.001).Furthermore,thefamiliarity

scoresforbothpositiveandnegativeadjectiveswereabove3andshowednodifferences(3.56±0.14vs.3.51±0.43,t[78]=1.75,P=0.23).Scoresonparticipants’understandingofpositiveandnegativeadjectivesalsoexceeded3andshowednodifferences(3.11±0.29vs.3.06±0.32,t[78]=0.78,P=0.64).Therefore,the

chosennegativeandpositiveadjectivesonlydifferedinvalence.EachtraitadjectiveconsistedoftwoChinesecharacters.Intheformalexperiment,48commonconcretenounsconsistingoftwoChinesecharacters(e.g.apple,coffee)wereusedasfilleritems.

Procedure:implicitsocialevaluationtask

Toconcealthetruepurposeofthisstudy,participantsweretoldthattheexperimentwasaconcretenounjudgmenttaskinwhichseveralwordsconsistingofpersonalitytraitadjectivesandconcretenounswouldbepresentedonacomputerscreen.Participantswererequiredtopressthespacebaronthekeyboardassoonastheyobservedaconcretenoun.Actually,wearereallyconcernedwiththeprocessingofevaluativewordsthatfollowthefacesoffriendsorstrangers.Whenfacesappear,participantsspontaneouslycategorizethemintocorrespondinggroups(e.g.ingroupvs.outgroup),andmentallyactivateandconveybeliefsaboutthem.Previousevidencesuggeststhatpeopleshowastrongfavoritismfortheirclosefriendsandincludetheintimateothersintotheirself-concept(

Aronetal.1991

;

Mattingly

andLewandowski,2013).Therefore,alinkisformedbetweenfriendsandpositiveevaluativewords.Incontrast,peopleareoftenprejudicedagainststrangersduetodistantsocialdistanceandlowfamiliarity(

MyersandHodges,2011

).Thus,alinkbetweenstrangersandnegativeevaluativewordsisformed.Thisparadigmmodelstheimplicitsocialevaluationprocessofindividualstowardsocialtargetsatdifferentsocialdistances.

Allparticipantswereseatedcomfortablyinasound-shielded

andelectricallyshieldedEEGchamberatadistanceofapproxi-mately80cmfroma22-inchcomputermonitor.

Figure1

showstheschematicoftheexperimentaldesign.Eachtrialbeganwithawhitefixationcrosspresentedagainstablackbackground.After500ms,thefaceofeitherafriendorastranger(width=3.5◦VA,height=4.5◦VA)wasrandomlypresentedatthecenterofthescreenfor1,000ms.Then,atraitadjectiveorconcretenoun(white,size30,fontCourier,bold)appearedrandomlyinthecenterofthescreenfor1,200msafterarandomintervalof600–1,000ms.Participantswereaskedtopressthespacebaronthekeyboardassoonasaconcretenounappearedonthescreen.Responseaccuracywasemphasizedintheinstructions.Eachinter-trialintervalwas500ms.

Webelievethatbecauseparticipantswererequiredtodistin-guishtypesofwordsandrespondasquicklyaspossible,theymustprocessthesewordsattentively.Therefore,the“target-evaluation”connectionswereimplicitlyformedintheirmindswhenthetraitadjectivesappearedafterthepresentationofthefacialphotos.Participantswouldreadeachwordfollowingaphotoandformsocialevaluativeconnectionswithtargetsofdifferentsocialdis-tanceswhenpersonalitytraitadjectiveswerepresented.FourtaskconditionswereconsideredduringtheEEGdataanalysis:friend-positive,friend-negative,stranger-positive,andstranger-negative.Erroneousresponsetrials(i.e.thoseinwhichparticipantspressedthespacebarwhenviewingatraitadjective)wereeliminatedfromthesubsequentEEGdataanalyses.

Theentiretaskcontained368trialsdividedintoeightblocks,witheachsocialevaluationconditioncomprising80trials,exclud-ingthe48fillers.Eachpersonalitytraitadjectiveappearedtwicefollowingeachfacethroughoutthetask,whereasitappearedonlyonceperblock.Forfillertrials,eachconcretenounappearedonceduringthetask.Participantscompleted16practicetrials(12eval-uationtrialsand4fillers)beforetheformaltask.Beforetheformaltask,participantswereaskediftheyknewtheperson(stranger)onthescreentoensurethatthepicturedefinitelyshowedadistantperson.Inaddition,participantsweretoldthatthistaskwasatestoftheirquickreactioncapability.Uponfinishingtheexperiment,allparticipantswereaskedaboutthecredibilityofthecoverstory,andnooneraiseddoubtsaboutit.Theentiretasklastedapproximately25min.StimuluspresentationandbehavioraldataacquisitionwereconductedusingE-Prime2.0software(PST,Inc.,Pittsburgh,PA).

Fig.1.Illustrationofasingletrialofthesocialevaluationtask.Eachtrialbeganwithafixationcross.Participantsviewedthefaceofeitherapersonalfriendorastranger.Afteranintervalof600–1,000ms,thewordstimulus(i.e.personalitytraitadjectiveorconcretenoun)waspresentedfor1,200ms.Participantswererequiredtopressthespacebaronthekeyboardassoonastheysawtheconcretenoun.

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EEGrecordinganddataanalyses

EEGswererecordedusing64cap-mountedtinelectrodesarrangedaccordingtothe10/20internationalplacementsystem(Neu-roscanInc.,Herndon,VA,USA),withanonlinereferencetotheleftmastoidandanofflinere-referencetotheaverageoftheleftandrightmastoids.Horizontalelectrooculograms(EOGs)wererecordedusingelectrodesplaced1.5cmlateraltotheoutercanthiofbotheyes.VerticalEOGswererecordedusingelectrodesplacedaboveandbelowthelefteye.Allinter-electrodeimpedancewaskeptbelow5kΩduringrecording.Signalswereamplifiedusinga0.01–100Hzband-passfilterandcontinuouslysampledat1,000Hz/channel.

OfflineanalysesofEEGdatawereperformedusingScan4.5software.Ocularartifactswereremovedusingaregressionpro-cedureimplementedinNeuroscan(

Semlitschetal.

1986).AllEEGdatawerelow-passfilteredbelow30Hz(24dB/oct)andsegmentedintoepochsfrom200msbeforeto800msafterwordpresentationonset.Thedatawerebaseline-correctedaccordingtoa200-mspre-stimulusbaseline.Epochscontainingartifacts

exceeding±70μVwereexcludedfromfurtheranalyses.The

epochswerethenaveragedseparatelyforeachconditionandeachparticipant.

AnalyzedERPcomponentsincludedtheP2,MFN,andP3.MeanamplitudesofthethreeERPcomponentsweremeasuredwithintherespectivetimewindowsof200–250ms,250–350ms,and380–530msfollowingwordstimuluspresentation.TopographiesofthevoltagedifferencesbetweennegativeandpositiveevaluationsintheP2,MFN,andP3timewindowsindicatedthattheP2,MFN,andP3effectspeakedinthefrontal,frontocentral,andcentroparietalscalpareas,respectively(

Fig.2C

).Therefore,basedonscalptopographiesofeachcomponentandpreviousstudies(

GehringandWilloughby2002

;

YeungandSanfey2004

),theP2,MFN,andP3werecalculatedattheFz,FCz,andCPzelectrodesites,respectively.

TheEEGdatasegmentationandartifactcorrectionwereper-formedusingScan4.5softwareforthetraitadjectiveprocessingstage.Individualepochsweresegmentedinto1,800msepochsbeginningfrom600msbeforethewordonset.Time-frequencycharacteristicswereextractedfromtheEEGtimeseriesusingtheshort-timeFouriertransformmethod(1–30Hz,windowwidthof250ms)implementedinEEGLAB(version12.2.6b).Toavoid

boundaryeffects,atimeintervalof−350to−250mswasselectedasthebaselineforcorrection.Thetaoscillationswereextractedfromthebandof4–8Hz(

VanderMolenetal.2016

).Bycollaps-ingthefourconditions(friend-positive,friend-negative,stranger-positive,a