Our Brains are Wired for Morality: Evolution, Development ...

Psychological and neuroscience research both tell us that morality, our mental ability to tell right from wrong in our behaviors and the ... ShareonFacebook ShareonTwitter DownloadPDF CoreConcept NeuroscienceandPsychology Published:March9,2016 OurBrainsareWiredforMorality:Evolution,Development,andNeuroscience Authorsandreviewers Authors JeanDecety JeanDecety ProfessorofPsychologyandPsychiatryattheUniversityofChicago,andDirectoroftheChildNeurosuite.Myresearchfocusesonthedevelopmentofmoralcognitionandbehaviorinyoungchildren,aswellasinindividualswithpsychopathy,aconditionassociatedwithpovertyinemotionalreactions,lackofattachmenttoothers,andacallousdisregardforthefeelings,rights,andwelfareofothers.Iemployamulti-levelperspective,includingbehavioraleconomics,genetics,affectiveneuroscience,developmentalscienceandclinicalneuroscience.*[email protected] JasonM.Cowell JasonM.Cowell AssistantProfessorofPsychologyandNeuroscienceatRiponCollege(Ripon,WI,USA).Iamtrainedasadevelopmentalneuroscientistandstudythedevelopmentofmorality,executivefunction,andsocialcognitionininfants,toddlers,andchildrenusingmultiplelevels(behavioral,neural,andenvironmental)acrossseveralcultures. YoungReviewers Bea Bea Age:12 MynameisBeaandIam12yearsold.Ilikewearingvintageclothes,readingbooks,andplayingwithmycats. Sadie Sadie Age:13 MynameisSadie.Iam13yearsoldandaminseventhgrade.Iloveschool,andthetopicsthatIreallyenjoyareScience,Math,English,Latin,Arabic,andHistory.Ialsoenjoysportsandhaveparticipatedinsoccerandtrackandfield.Outsideofschoolsomeofmyhobbiesincludecompetitive/noncompetitivesailing,swimming,windsurfing,reading,hangingoutwithmyfriends,andart. Thaddeus Thaddeus Age:13 HimynameisThaddeus;IamastudentwhoenjoysMath,Science,andLatin.Isailandplaysquash,aswellaspracticearchery.IlikevideogamesandYouTube.MyfavoritefoodisanythingthatisAsian.IplaychessandIhavearating.Ilikeschool,butnothomework.IfIcouldmakeonechangeinschoolitwouldbetomakeschoollongerbuthavenohomework.MostofwhatIdoafterschoolisSciencerelated. Abstract Psychologicalandneuroscienceresearchbothtellusthatmorality,ourmentalabilitytotellrightfromwronginourbehaviorsandthebehaviorsofothers,isaproductofevolution.Moralityhasbeenpassedonthroughthecourseofevolutionbecauseithelpsustoliveinlargesocialgroupsbyenhancingourabilitytogetalongandinteractwithothers.“Buildingblocks”ofmorality,suchassensingfairness,experiencingempathy,andjudgingothers’harmfulandhelpfulactions,canbeobservedininfancy,beforeachild’ssocialenvironmentwouldbeabletohaveastronginfluence.Specificpartsofthehumanbrainareinvolvedinmoralreasoning–boththekindthathappensveryquicklyandthekindthatisthoughtout.Damagetocertainpartsofthebraincandramaticallyaltermoraljudgmentandbehavior.Althoughhumanmoralityhasbeenpasseddownthroughevolution,itisalsodependentonthecultureinwhichwegrowup.Whathumansconsidertobemoralbehaviorvariesfromculturetocultureandalsovariesacrosstime. Introduction Howdowedistinguishgoodfromevil,rightfromwrong,justfromunjust,andvicefromvirtue?Anobviousansweristhatwehavelearnedtodosothroughsocialization,thatis,ourbehaviorswereshapedfrombirthonwardbyourfamilies,ourpreschools,andalmosteverythingwecontactedinourenvironments.Moralityisaninnersenseofrightnessaboutourbehaviorandthebehaviorofothers.Howwefeel,think,andactabouttheconceptsof“good”and“bad”areallpartsofourmorality.Forexample,hittinganotherpersonforanyreasonisseenasbad,whilesharingsomethingwelikewithanotherchildwhoissadisconsideredgood.Moralityissodeeplyrootedinthefabricofoureverydaylivesthatitseemshardtoimagineasocietywithoutanymoralrules.Indeed,observationsmadebyscientistswhostudydifferentsocietiesaroundtheworldhaveshownthat,despiteculturalandindividualdifferences,allhumanbeingshavesomesenseofrightandwrong. Whenweusetheword“morality”wearegenerallytalkingaboutideasofjustice,fairnessandrights,andtheruleswehaveabouthowpeopleshouldtreatoneanother.Considerthefollowing:asarewardforfinishingyourhomework,youhavebeengiven10marblesthatyoureallylike.Youarethentoldaboutapoorchildwhowouldnotbeabletogetanymarbles,eventhoughhedidhishomeworktoo.However,youhavetheoptiontogivesomeofyourmarblestothepoorchild.Whatwouldyouchoosetodo?Mostchildrenwouldnaturallysharesomeoftheirmarbleswithapoorchildandwouldalsobesurprisedifanotherchildreceivedmorethan10marblesafterdoingthesameamountofhomework!Thisshowsthatchildrenunderstandbothfairnessandjustice.Ashumans,whenweconsiderhowweorothersshouldsharesomethingwehavebeengiven,wetendtotakeintoaccountbothhowmuchofarewardsomeonedeservesforthe“work”theydidandwhetherrewardsareevenlysplitbetweenindividuals. Humansareanextremelysocialspecies.Wearedependentoneachotherandcannotsurviveandflourishwithoutinteractingwithothers.Newbornsonlysurvivetoadulthoodifgivenenoughcare,andsocietiessucceedthroughcooperation.Almostallofouractionsandthoughtsareaboutothersorareinresponsetoothers.Wecooperatewithandhelppeoplewhoarenotrelatedtousatalevelthatisunmatchedintheanimalkingdom[1].Sincehumansare,bynature,bothhelpfulandselfish,wethinkthatmoralityevolvedtosupportourhelpfulsocialinteractionswithothersandcontroloursomewhatselfishtendencies. However,itwouldbemisleadingtoseemoralityasonlyaresultofevolution.Althoughsomehumantraits,likeskincolor,aredeterminedbyourgenesalone,moralityisquitedifferentinthatitisalsodeterminedbothbyournatureandthesocietyinwhichwelive.Manymoralrulesandvaluesvarybetweendifferentculturesandalsochangeovertime.Forinstance,bullfightingisseenascruelformofentertainmentorevenasanimaltortureinNorthAmericaandmostEuropeancountries,butitisstillverypopularinSpainandColombiawhereitisconsideredaformofexpression,despitetheobvioussufferingoftheanimals.Anexampleofashiftinmoralityovertimeisourattitudetowardslavery.Mostpeopleintheworldtodaythinkthatitisimmoraltoownslavesbutthatwasnotthecaseacenturyago. Thus,ourmoralityhasbeenformedoverthousandsofyearsfromthecombinationofbothourgenesandourculture,ratherthanjustoneortheother.Thisgeneticandculturalevolutionhasshapedourbrainstocareforothers,reacttothosewhotrytoharmus,andtocreatemoralrulesthathelpustolivetogethersuccessfully[2]. Therearethreemainlinesofevidencethatsupporttheviewthatourbrainsarewiredformorality.(1)The“buildingblocks”ofmoralityhavebeenobservedinnon-humananimals,(2)evenveryyoungbabiesappeartoexhibitsomebasicmoralevaluations,and(3)thepartsofthebraininvolvedinmoraljudgmentsarebeginningtobeidentified. BuildingBlocksofMoralityinNon-HumanSpecies Naturalobservationsofanimalsinthewildandresearchinlaboratoriesshowusthatanumberof“buildingblocks”ofmoralbehaviorcanbefoundinanimals.Forinstance,manyanimalsexhibitbehaviorsthatbenefitothermembersoftheirspecies.Suchprosocialbehaviors(meaningbehaviorsthataregoodforothers),likehelpingeachotherandcaringforoffspring,havebeenseeninrodentsandprimates.Ratswillhelpotherdistressedratsthathavebeensoakedwithwater,anditwillalsochoosetohelpacagematethatisindistressbeforeobtainingafoodreward.Chimpanzeeswillhelpeachotherandsharewitheachother,butonlywhentheybenefitfromthesharing,aslongasthecostsareminimalandtheneedsoftheotherchimpanzeesareclear.Chimpanzeesalsocollaborateandformalliancesinfightsorwhenhunting.Capuchinmonkeyshaveevenbeenshowntoreactinanegativewaywhentheyseeothermonkeysbeingtreatedunfairly. Humansoftentrytocomfortorconsoleotherhumanswhohavebeenhurtorareafraid.Chimpanzeeswillalsotrytoconsolethe“victim”ofafightbygrooming,hugging,andkissing.Thisbehaviordecreasesthelevelofstressthatthevictimfeels.Helpingbehaviorshavealsobeendemonstratedinmiceandrats.Importantly,withbothhumansandanimals,theseprosocialbehaviorsaremorelikelytobeshowntowardkin(thoserelatedtotheanimal)andmembersofthesamesocialgroups.Theseexamplesillustratethatempathy,whichistheabilityto“feel”another’semotionalstate,oftenleadstoprosocialbehaviorsandispresentinmanymammals.Empathydoesnotrequireconsciousthinkingorlanguage.Empathyoriginallyevolvedtopromoteparentalcarefortheiroffspring,butitisnowexpressedbyhumansinmanydifferentwaysandisnotrestrictedtokin. Ofcourse,justbecausewecanobservesomebuildingsblocksofmoralityinnon-humananimalsdoesnotmeanthatthoseanimalshavethesamesenseofmoralitythathumansdo.But,itstronglysuggeststhatmoralityisaproductofevolution.Whenbehaviorsseenintheanimalkingdomaresimilartobehaviorsfoundinhumans,itsuggeststhatthesebehaviorshavebeenselected,becausetheyincreasetheabilityofhumanstoprosperbothasindividualsandinthegroupsinwhichtheylive. EvidenceforMoralBehaviorinBabies Whenweseeearlysignsofmoralityinyoungbabies,thisprovidesstrongevidencefortheevolutionaryrootsofmorality,becausebabieshavenotyethadmuchtimetobeinfluencedbytheirenvironment.Psychologistswhostudyhumandevelopmenthaveshownthathumanbabiesentertheworldreadytopayattentionandrespondtosocialstimuli,suchasvoicesandfaces,andthatbabiesbeginformingsocialrelationshipsduringthefirstyearoflife.Youngchildrenprovidecomfortandassistancetobothotherchildrenandadultsinemotionaldistress.Forinstance,whentheyseetheirmothersinpain,18-month-oldtoddlersshowcomfortingbehaviors(suchashugging,patting,andsharingtoys).Asinfantsdevelopandbecomemoreabletoanalyzewhatisgoingonaroundthem,theyevenhavetheabilitytorecognizewhenapersonintheirenvironmentistreatinganotherpersonbadly.Atayoungage,infantsarequicklyabletofigureoutwhethertheconsequenceofabehaviorisgoodorbad,suggestingthattheirgenesareinvolvedandthatexperienceandlearningarenottheonlycausesofmoraldevelopment.Atjust3monthsofage,infantsspendmoretimelookingatapuppetcharacterthathaspreviouslyactedinanicewaythanatonethatactedinanegativeway,suggestingthatinfantspreferthosewho“dogoodthings.”By6monthsofage,thispreferenceisstronger,withchildrennotonlylookingmoreathelpfulandnicepuppetcharactersbutalsoactuallyreachingforthem[3].By12monthsofage,infantsbegintounderstandtheconceptoffairness.Whentheseinfantswitnesscookiesbeingshared,theyexpectanequalnumberofcookiestobegiventoallofthepeopleinvolved. Takentogether,evidencefromtheselaboratorystudiestellsusthatchildrenundertheageof2haveaverygoodunderstandingofwhichactionswillbenefitothers.However,aschildrengetolder,theexpressionoftheirmoralitychanges.Forexample,whileinfantsseemtoseefairnessasequality(everyoneshouldgetthesamenumberofcookies,forexample),teenagerstendtoprefergivingmoreresourcestothosewhodonothaveanyalreadyortothosewhoworkedharder.Thus,theseearlytendencies(ininfancy)areconsideredtobethefoundationfor,butnottheexactsameas,adultmorality.Ourconceptsofmoralityarebuiltfromthecombinationofemotions,motivations,andourincreasinglevelofmentalunderstandingaswedevelop. TheRoleofTheBraininMorality Ourunderstandingoftheroleofthebraininmoralityislargelybasedonthethreedifferentmethods.Thefirstisthestudyofpeoplewithbrainlesions,meaningindividualswhohavehadanareaofthebrainremovedinsurgeryorhaveexperiencedaninjurytoacertainareainanaccident[4].Neuroscientists(scientistswhostudythebrainandnervoussystem)examinehowmoralbehaviorschangeinthesepeople.AnotherwaytounderstandtherolethebrainplaysinmoralityistouseMRIscannersorelectrophysiology(EEG)toimagethebrainasitfunctions.Intheseexperiments,neuroscientistspresentedchildrenandadultswithmoraltasksoractivitiesandlookedatwhichregionsofthebrainwereactivatedwhiletheparticipantsperformedtheseactivities.Finally,chemicalsinthebraincanalsobeexploredtoseeiftheymightplayaroleinmoralbehaviors(seeBox1). Box1-BrainChemicalsandMorality. Severalchemicalsproducedinthebrain,calledneuromodulators,influencemorality.Thehormone,oxytocin,thoughwronglycalledthemoralmolecule,hasreceivedalotofattentionandhype.Inhumans,oxytocindoesincreasetrustandgenerosityinsomesituationsbutcanincreaseenvyandbiasinothers.Whatisreallyinterestingfromanevolutionaryperspectiveisthatthisisaveryancientmoleculethat,acrossmammalianspecies,playsacriticalroleinthemother–childrelationshipbyincreasingbondingandreducingfearandanxiety.Anotherneuromodulator,serotonin,isinvolvedinsocialbehaviors,particularlyaggression,andismanufacturedinthebrainandtheintestines.Serotoninhasbeenshowntoinfluencemoraljudgmentbyenhancingthenegativefeelingswehaveinresponsetoseeothersexperienceharm. Todeterminewhichpartsofthebrainareinvolvedinmoraldecisions,neuroscientistsdesignedanexperimentinwhichpeoplehavetheirbrainsimagedastheyareperformingtasksrelatedtomorality.Forexample,theywereshownpicturesoraskedtoreadstoriesaboutsituationsthatwouldusuallybeconsideredrightorwrong,suchasastoryinwhichsomeoneishurtfornoreason,ortheywereaskedtomakeadifficultdecision,suchaswhethertheywouldstealadrugatapharmacytosavethelifeofasickchild.Thesestudiesshowthatspecificregionsofthebrainareresponsibleformoralityandmoraldecision-making(Figure1;Box2).Otherstudieswithchildrenhavealsotaughtusaboutthepartsofthebrainthatplayaroleinmorality.Thesechildrenwereshownvideosofcartooncharacterseitherpushingandshovingothers(bad)orcomfortingandsharingwithothers(good).Infantsasyoungas12monthsofageshoweddifferencesinthewaytheirbrainsreactedtothegoodandbadactions,andthesedifferenceswereseen<500ms(lesstimethanasnapofyourfingers)aftertheysawtheseactions[5]!However,mostmoraljudgmentsrequirebotharapid,automaticreactionguidedbyanemotionalresponse,andamoreslowerreasoningcapacity. Figure1-Moralityrequiresaninteractionamongseveralseparatebutconnectedbrainregions,inparticulartheposteriorsuperiortemporalsulcus(pSTS),theinsula,theamygdala,themedialprefrontalcortex(mPFC),thedorsolateralprefrontalcortex(dlPFC),andtheventromedialprefrontalcortex(vmPFC). Moralitythusinvolvesseveraldifferentprocesses,whicharenecessarytounderstandwhyotherpeoplebehavethewaytheydoandtohelpusfeeltheemotionsnecessaryformakingmoraldecisions. Box2-TheHumanBrainDoesNotHaveOneMoralCenterorOneSystemthatisDevotedSolelytoMakeMoralDecisions. Instead,variousregionsandcircuitsofthebrainthatareassociatedwithemotion,planning,problemsolving,understandingothers,andsocialbehaviorarerecruitedwhenmakingmoraljudgments.Thesepartsofthebraininclude –Medialprefrontalcortexplaysanimportantroleininterpretingandunderstandingthethoughtsandmentalstatesofourselvesandothers. –Amygdalaisimportantforemotional(positiveandnegative)reactions. –Ventromedialprefrontalcortex:acriticalhubforcaregivingbehaviors,morality,anddecision-making,bycombiningcognitiveandemotionalprocessesnecessarytoguidesocialbehavior. –Dorsolateralprefrontalcortexplaysanimportantroleinself-controlandintelligence. –Insulaprovidesthefoundationforbeingawareofourbodyfeels. –Posteriorsuperiortemporalsulcusisakeyregiontounderstandtheintentionsofothers. Anareaofthebraincalledtheventromedialprefrontalcortexhasbeenfoundtobeimportantforcertainaspectsofhumanmorality.Ifthisbrainregionisdamagedearlyinlife(before5yearsofage),thepersonismorelikelytobreakmoralrulesorinflictharmonothers,suggestingthattheventromedialprefrontalcortexhelpsustounderstandwhatisandisnotmoral.Patientswhohavedamagetothisbrainregionorwhohavehaditremovedalsotendtoexperiencelessempathy,embarrassment,andguiltthanpeoplewithoutdamagetothisregion. Conclusion Usingevidencefromevolutionarybiology,developmentalpsychology,andneuroscience,wehavecometorealizethatmoralityisnotmerelytheresultofculturallearning,handedtousfromourfamilies,peers,andenvironment.Moralitywasselectedbyevolutioninourhumanancestorsinordertopromotecooperationandsmoothsocialinteractions.Developmentalpsychologistshavedemonstratedthatsomebuildingblocksofmoralityareinplaceveryearlyindevelopment[3].Additionally,thepartsofthebrainandthebrainchemicalsinvolvedinmoralityanddecision-makingarebeginningtobeidentified. Moralityisaproductofevolutionbutthatdoesnotmeanthatitissetinstoneandtotallyunchangeable.Thecultureinwhichweliveinfluenceswhatwethinkisrightandwrong.Forinstance,second-handsmokingwastotallyignoredsomedecadesago,whileinWesternEuropeandNorthAmerica,itisnowconsideredmorally(aswellasmedically)wrong.Inanutshell,wecreateourowndefinitionofmoralitythroughourinteractionsthepeoplearoundus.Ideasaboutwhatisandwhatisnotmoralareguidedbyouruniquehumanreasoningandintelligence,andnotjustbyourfeelingsorgutreactions.Itisreason,andnotemotion,thatprovidesthepushtowidenthecircleofempathyandconcernforothersbeyondthoserelatedtousandourcommunity. Neuroscience,psychology,andevolutionarybiologywillcontinuetohelpusgainabetterunderstandingofhowwethinkandmakemoraldecisions[2].Futureresearchinneurosciencewillhelpustoexplainhowwemakedecisions,weighouroptions,reflectonourdesires,andmodifyourbehaviorsonthebasisoftheirmoralconsequences.Hopefully,Sciencewillalsohelpustounderstandwhysomepeople,likepsychopaths,arenotabletoactmorally,anddiscoverwaystohelpthem. Glossary SociomoralEvaluation:↑Isconsideredtobeaprecursortomaturemoralityinbabiesandinvolvesbasicappraisalsofthesocialinteractionsofothers. ProsocialBehavior:↑Referstoanybehaviorintendedtobenefitanotherindividual. Empathy:↑Istheabilityto“feel”theemotionsthatanotherpersonisexperiencing,oftenleadingtothemotivationtocareforsomeoneindistressorneed. Kin:↑Referstoone’srelativesorfamilywithwhomgenesareshared. References [1]↑Tomasello,M.,andVaish,A.2013.Originsofhumancooperationandmorality.Annu.Rev.Psychol.64:231–55.doi:10.1146/annurev-psych-113011-143812 [2]↑Decety,J.,andWheatley,T.2015.TheMoralBrain:AMultidisciplinaryPerspective.Cambridge:MITPress. [3]↑Hamlin,J.K.2014.Theoriginsofhumanmorality:complexsocio-moralevaluationsbypreverbalinfants.InNewFrontiersinSocialNeuroscience,ed.J.DecetyandY.Christen,165–88.NewYork:Springer. [4]↑Moll,J.,deOliveira-Souza,R.,andEslinger,P.J.2003.Moralsandthehumanbrain:aworkingmodel.Neuroreport14:299–305.doi:10.1097/00001756-200303030-00001 [5]↑Cowell,J.,andDecety,J.2015.Precursorstomoralityindevelopmentasacomplexinterplaybetweenneural,socio-environmental,andbehavioralfacets.Proc.Natl.Acad.Sci.U.S.A.112(41):12657–62.doi:10.1073/pnas.1508832112 Articleinformation Citation DecetyJandCowellJ(2016)OurBrainsareWiredforMorality:Evolution,Development,andNeuroscience.Front.YoungMinds.4:3.doi:10.3389/frym.2016.00003 Editor PaulGlimcher ScienceMentors J.PenneyPeterson Publishingdates Submitted:August21,2015;Accepted:February25,2016; Publishedonline:March9,2016. Copyright©2016DecetyandCowell Thisisanopen-accessarticledistributedunderthetermsoftheCreativeCommonsAttributionLicense(CCBY).Theuse,distributionorreproductioninotherforumsispermitted,providedtheoriginalauthor(s)andthecopyrightowner(s)arecreditedandthattheoriginalpublicationinthisjournaliscited,inaccordancewithacceptedacademicpractice.Nouse,distributionorreproductionispermittedwhichdoesnotcomplywiththeseterms. RelatedArticles NewDiscovery May23,2022 HowDoBacteria“See”MoleculesInsideThemselves? RNA,likeitsclosecousinDNA,isusedtostoreinformationinthecell.UnlikeDNA,RNAisreallygoodatfoldingup... Authors AndrewJ.Knappenberger,DavidA.Hiller YoungReviewers Blythe Age:14 JuanDiego Age:15 CoreConcept April7,2022 TheAmazingDiversityofCichlidFishes Imagineswimmingthroughwarm,clear-bluewaterwhere,allaroundyou,youseebrightlycoloredfishesofallshapes... 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