The Origin and Evolution of Religious Prosociality

6 Pages·00.306 MB·English

by  Ara Norenzayan, Azim F. Shariff

The Origin and Evolution of Religious Prosociality
Ara Norenzayan, et al.
Science 322, 58 (2008);
DOI: 10.1126/science.1158757
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supremeGod,butalsomanymorallyconcerned
deitiesfoundintraditionalsocieties,suchasthe
The Origin and Evolution adalo, ancestral spirits of the Kwaio Solomon
islanders (7). These beliefs are likely to spread
culturallytotheextentthattheyfacilitateingroup
of Religious Prosociality
cooperation.Thiscouldoccurbyconformingto
individual psychology that favors reputation-
sensitiveprosocialtendencies,astheby-product
Ara Norenzayan* and AzimF.Shariff
accountholds;bycompetitionamongsocialgroups,
astheculturalgroupselectionaccountwouldsug-
Weexamine empiricalevidence forreligiousprosociality, thehypothesisthatreligionsfacilitate
gest; or possibly by some combination of the
costly behaviorsthatbenefitotherpeople. Althoughsociological surveysreveal anassociation
two. Religious behaviors and rituals, if more
between self-reportsofreligiosity andprosociality,experiments measuringreligiosity and
costly to cooperating group members than to
actualprosocial behaviorsuggest thatthisassociationemerges primarilyincontextswhere
freeloaders,mayhavereliablysignaledthepres-
reputational concernsare heightened. Experimentallyinducedreligiousthoughtsreduce rates
enceofdevotionand,therefore,cooperativeinten-
ofcheating andincreasealtruisticbehavioramonganonymousstrangers. Experiments
tiontowardingroupmembers,inturn,buffering
demonstrateanassociationbetween apparentprofessionofreligious devotionandgreater trust.
religious groups against defection from free-
Cross-culturalevidencesuggestsanassociationbetweentheculturalpresenceofmorallyconcerned
loadersandreinforcingcooperativenorms.Reli- 8
deities andlargegroup sizeinhumans.Wesynthesizeconvergingevidencefrom variousfields 0
gious prosociality, thus, may have softened the 0
forreligious prosociality,address itsspecificboundary conditions,andpointtounresolved 2
questions andnovelpredictions. limitations that kinship-based and (direct or 2,
indirect) reciprocity-based altruism place on r
groupsize.Inthisway,theculturalspreadofre- e
b
Religiousprosociality,ortheideathatre- One proposes that religious content itself is a ligiousprosocialitymayhavefacilitatedtherise o
ct
ligionsfacilitateactsthatbenefitothersat cultural by-product of a suite of psychological ofstable,large,cooperativecommunitiesofge- O
a personal cost, has many proponents. tendencies evolved in the Pleistocene for other neticallyunrelatedindividuals. n
o
Indeed, religious texts of all major religions purposes, such as detecting and inferring the Theacutehumansensitivitytoprosocialrep- g
explicitly encourage prosociality in their adher- content of other minds and sensitivity to one’s utation(12)isapsychologicalmechanism,orig- r
o
ents (1, 2). Social science theories have long prosocialreputationinthegroup(6,7).Religious inallyunrelatedtoreligion,thatevolvedtofacilitate g.
a
pointed to religion as a cultural facilitator of beliefs, to the extent that they were compatible strongreciprocalcooperativebondswithingroups m
social cohesion and ingroup solidarity (3, 4), withthesepsychologicaltendencies,couldthen (13). In an intensely social, gossiping species, e
c
often at the expense of rival groups. However, culturallyspreadthroughsociallearningmecha- reputational concerns likely contributed to the n
e
opinion, rather than careful observation, has nisms and could solve adaptive problems, par- evolutionary stability of strong cooperation be- ci
dominated the debate on religion’s role in ticularly the problem of cooperation in large tweenstrangers.Individualsknowntobeselfish w.s
prosocialbehavior.Recentyearshaveseennew groups.Athirdevolutionaryperspective,known could be detected, subsequently excluded from w
developments in evolutionary explanations of as cultural group selection (8), maintains that future interaction, and even actively punished w
religion, bolstered by a small but growing competitionamongsocialgroupsmayfavorthe (13,14).Thethreatofbeingfoundout,therefore, m
o
empirical base that unites several academic spread of fitness-enhancing cultural beliefs and became a potent motivator for good behavior. r
disciplines. Here, we critically examine and costly practices, such as religious prosociality Accordingly,studieshaverepeatedlyshownthat d f
synthesize evidence from anthropology, soci- (4,9,10).Thislast-mentionedviewtakesasits experimentallyreducingthedegreeofanonymity de
a
ology,experimentalpsychology,andexperimen- starting point that religious beliefs are cultural ineconomicgamesincreasestherateofprosocial o
taleconomicsforreligiousprosociality.Wealso by-products of evolved psychology, but argues behavior(15).Exposuretophotographicandeven nl
w
addressempiricalinconsistenciesfoundinstudies thatreputation-sensitivity,althoughimportant,is schematic representations of human eyes in- o
D
examining the association between religion and not sufficient to explain the features of strong creases prosocial behavior in economic games
prosociality,offerpossibleresolutions,andpoint prosocial tendencies such as the ones found in (16)anddecreasescheatinginnaturalisticsettings
toremainingissuesandfuturedirections. religiousbehavior. (17).Wearguethatreligion’seffectonprosocial
Various evolutionary theories of religion all Despite these important differences, large tendenciessimilarlydependsonsuchreputational
predictthatreligiousbeliefsandbehaviorshave agreement is emerging that selective pressures sensitivity. The cognitive awareness of gods is
facilitatedhumanprosocialtendencies,butthere overthecourseofhumanevolutioncanexplain likelytoheightenprosocialreputationalconcerns
isnoscientificconsensusyetastoexactlyhow the wide cross-cultural reoccurrence, historical amongbelievers,justasthecognitiveawareness
thismighthaveoccurred.Somearguethatatleast persistence,andpredictablecognitivestructureof ofhumanwatchersdoesamongbelieversandnon-
certainreligiousbeliefsandbehaviorsareevolu- religiousbeliefsandbehaviors.Thetendencyto believersalike(18).However,supernaturalmon-
tionaryadaptationsforgroup-livinginlargecom- detectagencyinnaturelikelysuppliedthecog- itoring,tothedegreethatitisgenuinelybelieved
munitiesthathavemaximizedgeneticfitness(5), nitivetemplatethatsupportsthepervasivebelief and cognitively salient, offers the powerful ad-
perhaps even by multilevel selection (4). How- insupernaturalagents(6,7,11).Theseagentsare vantagethatcooperativeinteractionscanbeob-
ever, these accounts have difficulty explaining widelybelievedtotranscendphysical,biological, servedevenintheabsenceofsocialmonitoring.
the differential cultural distribution and cultural and psychological limitations (6, 7). However, Thislineofreasoningaccountsforawiderange
changeovertimeofreligiousbeliefsandbehav- otherimportantdetailsaresubjecttoculturalvar- ofempiricalevidencelinkingreligiontoprosocial
iors.Twoadditionalevolutionaryaccounts,how- iation. Although in many societies supernatural tendenciesandpredictsthatthisassociationought
ever,arecompatiblewithsuchculturalvariability. agents are not directly concerned with human tobecontext-sensitive,withclearboundarycondi-
morality,inmanyothers,morallyconcernedagents tions.First,religiousdevotion,insofarasitinvolves
usetheirsupernaturalpowerstoobserveand,in habitualworshipofmorallyvigilantdeities,isex-
Department of Psychology, University of British Columbia,
2136WestMall,Vancouver,BCV6T1Z4,Canada. somecases,topunishandrewardhumansocial pectedtobeassociatedwithgreaterprosocialrepu-
interactions. Examples include the God of tationalconcern.Second,religioussituations,such
*To whom correspondence should be addressed. E-mail:
[email protected] Abrahamic religions and Viracocha, the Incan asreligiousritualperformanceorbeinginreligious
58 3OCTOBER 2008 VOL322 SCIENCE www.sciencemag.org
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surroundings,would,insocietieswithmorallycon- ing, a common human tendency to project an Otherbehavioralstudies,however,havefound
cerneddeities,activatethoughtsofthesedeitiesand overlypositiveimageofoneselfinevaluativecon- reliableassociationsbetweenreligiosityandpro-
habitually facilitate prosocial behavior. Therefore, texts(21).Thisassociationraisesquestionsabout sociality, but under limited conditions. In one
experimentallyinducingreligiousthoughtswould thevalidityofself-reportmeasuresofprosocial study (23), researchers compared levels of co-
alsoincreaseprosocialityevenwhenthesituation behavior.Toaddressthesemethodologicallimi- operationandcoordinationbetweensecularand
isobjectivelyanonymous.Butthisshouldbethe tations, experiments with behavioral outcomes religious kibbutzim in Israel. In this economic
case only when thoughts of morally concerned mustbeconsulted. game, two members of the same kibbutz who
supernaturalagentsarecognitivelyaccessiblein remained anonymous to each other were given
themomentwhenprosocialdecisionsarecalled BehavioralEvidence:InSearchofthe accesstoanenvelopewithacertainamountof
for.Third,religiousbehaviorthatsignalsgenuine GoodSamaritans money.Eachparticipantsimultaneouslydecided
devotionwouldbeexpectedtomobilizegreater Inseveralbehavioralstudies,researchersfailedto howmuchmoneytowithdrawfromtheenvelope
cooperation and trust, and when internal and findanyreliableassociationbetweenreligiosity andkeep.Playersonlykeptthemoneytheyre-
external threats to group survival are high, re- and prosocial tendencies. In the classic “Good questedifthesumoftherequestsdidnotexceed
ligiousgroupswouldbeexpectedtooutlastsec- Samaritan” experiment (22), for example, re- the total amount in the envelope. If it did, the
ular ones. Fourth, large societies that have searchersstagedananonymoussituationmodeled players received nothing. The results showed
successfully stabilized high levels that,controllingforrelevantpredic-
of cooperative norms would be tors,systematicallylessmoneywas
more likely than smaller ones to withdrawninthereligiouskibbutzim
espousebeliefinmorallyconcerned thaninthesecularones(23). 8
0
godswhoactivelymonitorhuman Thus,unlikestudiessuchasthe 0
2
interactions. In the remainder of GoodSamaritan,thereweregreater 2,
this paper, we critically examine levels of prosociality among the r
theavailableempiricalevidencein religiousinthisstudy.Onekeydif- e
b
lightofthesefourpredictions. ferenceisthatremindersofGodare o
ct
likely to be chronically present in O
Self-Reports:Religiosity religious kibbutz, where religious n
andCharitability prayer and attendance are a daily og
If religions centered around mor- part of life. Another, is that proso- r
o
alizing gods promoteprosociality, ciality in the religious kibbutz was g.
a
itwouldbeexpectedthatindivid- clearly confined to the ingroup. In m
uals who report stronger belief in thekibbutzimstudy,highlyreligious e
c
suchgodswouldhavestrongeral- men, who engaged in daily and n
e
truistictendencies.Sociologicalsur- communal prayer, took the least ci
veys suggest that this is the case. money,therebyshowingthegreatest w.s
Those who frequently pray and amount of coordination and/or co- w
attend religious services reliably operationwithingroupmembers.It w
report more prosocial behavior, isalsopossiblethatregular,commu- m
o
such as charitable donations and nal prayer involves public ritual r
volunteerism(1,19).This“charity participation,which,independentof d f
gap”isconsistentacrosssurveysand religious devotion, might also en- de
a
remainsaftercontrollingforincome couragemoreprosociality. o
disparities,politicalorientation,mar- Another approach to clarifying nl
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italstatus,educationlevel,age,and thenatureandboundaryconditions o
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gender. These findings have been ofreligiousprosocialityistoinves-
much publicized as evidence that tigatethealtruisticoregoisticmoti-
religiouspeoplearemoreprosocial vation underlying the prosocial act.
than the nonreligious (19). How- Onepossibilityholdsthatthegreater
ever,itremainsunresolvedwhether prosocialityofthereligiousisdriven
Fig.1.IntheparableofTheGoodSamaritan[paintingbyJacopoBassano,d.
thischaritygappersistsbeyondthe byanempathicmotivetoameliorate
1592, copyright 2006, The National Gallery, London], Christ preaches
ingroupboundariesofthereligious theconditionofothers.Alternatively,
universalcompassionandprosocialbehavior.Asimilarmessageisfoundin
groups(1).Moreimportantly,these prosocial behavior could be driven
many religions. Modern research from social psychology, experimental
surveysareentirelybasedonself- byegoisticmotives,suchasproject-
economics, and anthropology suggests, however, that religious prosociality
reports of prosocial behavior. Psy- ing a prosocial image or avoiding
isextendeddiscriminatelyandonlyunderspecificconditions.
chologists have long known that guilt(failingtoliveuptoone’spro-
self-reportsofsociallydesirablebehaviors(such aftertheBiblicalparable—amanwaslyingona social self-image). The preponderance of the
as charitability) may not be accurate, reflecting sidewalkappearingtobesickandinneedofas- evidence supports the latter explanation. Studies
instead impression management or self-deception sistance(Fig.1).Participantsvaryinginreligious- repeatedly indicate that the association between
(20).If,aswehypothesize,religiousindividuals ness were led to pass by this victim (actually a conventional religiosity and prosociality occurs
aremoremotivatedtomaintainaprosocialrepu- research confederate) on their way to complete primarilywhenareputation-relatedegoisticmoti-
tationthanthenonreligious,thentheformermay their participation in a study. Unobtrusively vationhasbeenactivated(2).Inoneexperiment,
bemorelikelytoengageinprosocialreputation recordedoffersofhelpshowednorelationwith forexample,participantsweregiventheoptionof
management.Supportingthishypothesis,psycho- religiosityinthisanonymouscontext(22).Only volunteeringtoraisemoneyforasickchildwho
logical research summarizing many studies has asituationalvariable—whetherparticipantswere couldnotpayhismedicalbills(24).Participantsin
found that measures of religiosity are positively toldtorushortaketheirtime—produceddifferences oneconditionwereledtobelievethattheywould
associatedwithtestsofsociallydesirablerespond- inhelpingrates. certainly be called upon if they volunteered. In
www.sciencemag.org SCIENCE VOL322 3OCTOBER2008 59
REVIEW
another, participants could volunteer although ThoughtsofGod,activatedwithoutconscious recognizedthatevolutionarypressuresmusthave
toldthattheywereunlikelytobecalledupon.In awareness (28), thus caused greater generosity favoredcostlyreligiouscommitment,suchasritual
the latter condition, participants could reap the between anonymous strangers. One explanation participationandvariousrestrictionsonbehavior,
social benefits of feeling (or appearing) helpful forthisfindingisthattheimaginedpresenceofa diet,andlife-style,thatvalidatesthesincerityof
withoutthecostoftheactualaltruisticact.Only morally concerned supernatural watcher reduced otherwise unobservable religious belief (5, 29).
in the latter situation was a link between the anonymity of the situation and heightened However,forcostlysignalstoevolveasastable
religiosity and volunteering evident. Many prosocialreputationalconcerns,therebyincreasing strategy, religious behaviors ought to be more
studieshavecorroboratedthatreligiositypredicts prosocialbehavior.Alternatively,itispossiblethat costly for cooperators than for freeloaders, and
prosocialbehaviorprimarilywhentheprosocial thoughts of God and thoughts of charity or variation in costliness should predict degree of
act could promote a positive image for the benevolencearecognitivelyassociated;thus,prim- intragroup trust and cooperation. Mathematical
participant, either in his or her own eyes or in ing the former concept increased behavioral modelsquestionthepossibilitythatcostlysignal-
theeyesofobservers(2). tendencies consistent with the latter (27). This ing as an individual fitness-maximizing strategy
Asinsightfulasthesebehavioralstudiesare, explanation,however,begsthequestionastowhy extendstonondyadiccollectivecooperationasin
however, causal inference has been limited by Godconceptsarementallyassociatedwithcharity thecaseofreligion(9,10),andmodelsofcostly
theirrelianceoncorrelationaldesigns.Ifreligios- in the first place. These alternative explanations signaling applied to religious behavior, with or
ity is related to prosocial behavior under some awaitfurtherexperimentalinvestigation.Ineither withoutculturalgroupselection,arecurrentlyin
contexts, it is possible that having a prosocial case, the effect occurred only to the extent that their infancy (30). Nevertheless, qualitative and
disposition causes one to be religious or that a thoughts of a morally concerned divine agent quantitativeevidenceisemerging,that,although
thirdvariable(suchasdispositionalempathyor wereactivatedinthemomentofdecision-making. not yet definitive, addresses parts of these 8
0
being prone to guilt) causes both prosocial and Self-reported belief in God or self-reported predictions. 0
2
religious tendencies. Recent con- Attitudinalsurveysshowthatre- 2,
trolledexperimentshaveaddressed ligiousindividualsareperceivedto r
this limitation by experimentally be more trustworthy and more co- e
10 b
inducing thoughts of supernatural operative(31).Frombehavioralevi- o
agents and then measuring pro- 9 dence,ethnographicexamplessuch Oct
socialbehavior. 8 as the spread of Islam in Africa, n
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Ivnerosinteyssutcuhdeenxtpserwimheontw(2e5re),ruanni-- offer 5 Mcheadnitesv(a3l3)JeawreischonMsisategnhtrewbiithmtheirs- ema
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domly assigned to a condition in s $2.56 idea.Costlycommitmenttothesame n
a e
whichtheywerecasuallytoldthat C 3 supernaturaldeitymayhavelowered ci
the ghost of a dead student had 2 monitoring costs and fostered co- w.s
been spotted in the experimental operation in communities spread w
room,cheatedlessonariggedcom- 1 across geographic and even ethnic w
puter task. A different study con- 0 boundaries.However,itisdisputable m
cteemptpuoarlalyry,reupnlcicoantsecdiouthsisacetfifveactti—on Nperuimtreal Replrigimioeus Spercimulear wlighieotuhsergmroeumpsberwshaispcionsttlhieersethraen- d fro
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of God concepts lowered rates of commitment to local deities or d
cheating (26). Moreover, among Fig. 2. Implicit activation of God concepts, relative to a neutral prime, whethercostlinesswasdirectlyasso- oa
thoseinthecontrolcondition,reli- increasedoffersintheone-shot,anonymousDictatorGame,t(48)=2.47,P= ciated with greater intragroup trust; wnl
giosity as an individual difference 0.02,SE= 0.81,d = 0.71.(27).Priming secular concepts indicatingmoral therefore, the ethnographic data are o
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measure did not predict levels of authorityhadasimilareffect,t(48)=2.29,P=0.03,SE=0.82,d=0.67.The open to other interpretations, for
cheating. In another experiment, results showed not only a quantitative increase in generosity, but also a example, that religious conversions
children were explicitly instructed qualitativeshiftinsocialnorms.Inthecontrolgroup,themodalresponsewas led to greater access to preestab-
nottolookinsideabox,andthen selfishness,apluralityofplayerspocketedall$10.IntheGodgroup,themode lished trade networks along these
leftaloneintheroomwithit(25). shiftedtofairness,apluralityofplayerssplitthemoneyevenly(N=75).It religiouslines.
Those who were previously told remainstobeseen,however,whethertheseeffectswouldoccuriftherecipient To address these limitations,
thatafictionalsupernaturalagent— wasclearlymarkedasanoutgroupmember. quantitative analyses are needed.
PrincessAlice—waswatchingwere Sociologicalanalysesareconsistent
significantly less likely to peek inside the for- religiousdevotionwas,ashasbeenfoundbefore, withtheideathatreligiousgroupsimposingmore
biddenbox. not a reliable predictor of generous behavior in costlyrequirementshavememberswhoaremore
Wehaveproposedthattheculturalspreadof anonymoussettings. committed.Controllingforrelevantsociodemo-
religiousprosocialitymayhavepromotedstable graphicvariables,“strict”Protestant(e.g.,Mormon)
levels of cooperation in large groups, where Religious Prosociality,Costly Signaling, and Jewish denominations (Orthodox) show
reputationalandreciprocityincentivesareinsuf- and Trust higherlevelsofchurchandsynagogueattendance
ficient.Ifso,thenremindersofGodmaynotonly Intheabsenceofreputationalinformationabouta andmoremonetarycontributionstotheirreligious
reducecheating,butmayalsoincreasegenerosity stranger’sprosocialinclinations,outwardevidence communities (despite lower average income
towardstrangersasmuchasremindersofsecular ofsincerebeliefinthesameor similar morally levels)thanlessstrictones(MethodistandReform,
institutions promoting prosocial behavior. These concernedgodsmayserveasareliablecooper- respectively)(30).However,thesefindingsdonot
hypotheses were supported in two anonymous ativesignal. But asignal is onlyreliabletothe demonstrate that strictness predicts community
economicgameexperiments,onewithasample extentthatitisdifficulttofakebypotentialfree- survivalandgrowth.Onesystematicattemptto
of university students and another with non- loaders. Because professions of religious belief dosoexaminedreligiousandsecularcommunes
studentadults(27)(Fig.2). can be easily faked, theorists of religion have in 19th-century America, whose survival de-
60 3OCTOBER 2008 VOL322 SCIENCE www.sciencemag.org
REVIEW
pendeduponsolving the collective thereachofsuchnorms,facilitating
actionproblem.Religiouscommunes the emergence of larger cooperative
1.0
were found to outlast those moti- communitieswhichotherwisewould
vatedbysecularideologies,suchas bevulnerabletocollapse.Weexam-
socialism (Fig. 3) (29). A further 0.8 Religious ine this hypothesized association
quantitative analysis of 83 of these Secular between moralizing gods and large
g
religiousandsecularcommunes(34) n groupsizenext.
forwhichmoredetailedrecordsare vivi 0.6
availablefoundthatreligiouscom- ur BigGroups,BigGods:
s
munesimposedmorethantwiceas n Cross-CulturalEvidence
o 0.4
manycostlyrequirements(including cti Fromlargevillagesettlementsatthe
foodtaboosandfasts,constraintson a dawn of agriculture to modern
r
F
material possessions, marriage, sex, metropolises today, human beings
0.2
and communication with the out- arecapableoflivinginextraordinar-
sideworld)thansecularones.This ilylargecooperativegroups.Howev-
differenceemergedforeachofthe 0.0 er, extrapolating from cross-species
22categoriesofcostlyrequirements 0 20 40 60 80 100 120 comparisonsofneocortexsize,ithas
examined. Importantly for costly Duration (years) been estimated that human group
religious signaling, the number of sizescannotexceed150individuals 8
costly requirements predicted reli- beforegroupsdivideorcollapse(37). 00
0g.i3o8u)sacftoemrmthuensetudloyngcoevnittryoll(eRd2fo=r yF2e0iga0r.ro3efl.itghLieiofieursleifxaepnecdoctsuaerncsuecy,laroreflciogremioliumgsiuocunosemsvmeinrus1un9sestshew-cceuerlenatraubcroyomuAtmmfoueurnirectasi.m(A2en9s)aa,nsfoalilrkyeeslivyseotroyf Abelethnoudgihsputhtiesdsp(3e8ci)f,icanndumwbehrerheaass r 2, 2
populationsizeandincomeandthe survivethantheirsecularcounterparts,logrankTstatistic=40.14,df=1,P< some Pleistocene foragers possibly be
yearthecommunewasfounded,al- livedinlargevillages,itisapparent o
0.00001. This difference remained after statistically controlling for type of ct
though the number of costly re- communemovement,yearfounded,andyearatriskofdissolution(thelast that the size of human settlements O
quirementsdidnotpredictlongevity control assesses major historical trends that may independently impact since the end of the Pleistocene far n
o
forsecularcommunes.Finally,reli- communedissolution).[Copyright2003,reprintedfrom(29)withpermission exceedthelimitationsthatkin-based g
giousideologywasnolongerapre- ofWiley-Liss,Inc.,asubsidiaryofJohnWiley&Sons,Inc.] andreciprocity-basedaltruism place or
dictorofcommunelongevity,once ongroupsize. g.
a
thenumberofcostlyrequirementswasstatistical- responder in an anonymous context. Results Culturalevolution,drivenbybetween-group m
ly controlled, which suggests that the survival indicated that more money was forwarded to competition for resources and habitats, has fa- e
c
advantageofreligiouscommuneswasduetothe respondersperceivedtobereligious,andthiswas voredlargegroups.However,largegroups,which n
e
greater costly commitment of their members, particularlytrueforreligiousproposers.Further- until recently lacked institutionalized social- ci
rather than other aspects of religious ideology. more, religious responders were more likely to monitoring mechanisms, are vulnerable to col- w.s
However,thesefindingsarecorrelational,making reciprocate the proposer’s offer than less reli- lapsebecauseofhighratesoffreeloading(13).If w
causal conclusions premature. They collectively giousresponders.Thesefindingsareconsistent unwavering and pervasive belief in moralizing w
imply,butdonotdefinitivelydemonstrate,thatthe withtheideathatoutwardevidenceofreligious godsbufferedagainstsuchfreeloading,thenbelief m
o
greater longevity of religious communes with devotionmayengendermoretrust,althoughtwo insuchgodsshouldbemorelikelyinlargerhu- r
costlierrequirementswasduetogreaterintragroup issuesremainunresolved:Theydonotshowthat man groups where the threat of freeloading is d f
e
cooperationandtrustlevels,whichhavenotbeen costly religious behavior elicits more trust and most acute. Because there is considerable var- d
a
measured directly. These results also imply that cooperationthanlesscostlybehaviorundercon- iabilityintheculturaldistributionofmorallycon- o
greater costly commitment is at best a partial trolledconditions,asrequiredbycostlysignaling cerneddeities,researcherscouldmeasurewhether nl
w
explanation as to why religious communes out- explanations of religion; or that members of re- this variability correlates with group size across o
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lasted secular ones. Other aspects of religion that ligious groups that impose more costly require- cultures.Inaquantitativecross-culturalanalysisof
mightpromotegreatercommunitystabilityareopen ments are more trusting and less likely to take the 186 societies in the Standard Cross-Cultural
forinvestigation. advantage of others, particularly ingroup mem- Sample,thispredictionwasconfirmed.Thelarger
Thefewrelevantlaboratorystudiescorroborate bers, as would be expected from cultural group thegroupsize,themorelikelythegroupculturally
thatthereisanempiricalassociationbetweenreli- selectionaccounts. sanctioneddeitieswhoaredirectlyconcernedabout
gion and trusting behavior. Trust can be oper- The relation between religion and trust is, humanmorality(39).Althoughmostculturesinthe
ationalizedasacostlyinvestmentinapersonor therefore,anarearipeformoreresearch.Exper- world do not promote morally concerned deities,
entity,withthefutureexpectationofreturn.Inone imental studies and alternative mathematical thosethatdotendtohavedisproportionatelylarger
well-researched laboratory game of trust (35), models of costlyreligious behavior (either as a populations. As a consequence, the majority of
participants were randomly assigned to be a stablestrategycharacteristicofindividualsorasa religious adherents in the world worship moral-
proposer(truster)oraresponder(trustee).Inthe stablestrategythattakesintoaccountintergroup izinggods.
firststep,theproposerdecideshowmuchmoney socialcompetition)willplacethesetheoretical Onealternativeexplanationisthat Christian
toforwardtotheresponder,whichgetsmultiplied. predictionsonfirmerempiricalground.Theex- andMuslimmissionaryactivitymayhavecaused
In the second step, the responder decides how isting evidence, however, suggests the possi- both more belief in the moralizing Abrahamic
much money to send back to the proposer. By bilitythatreligiousbelief,totheextentthatit God and may have favored larger group size.
transferringmoneytotheresponder,theproposer could be advertised with sincerity, may en- Another,isthatbecauselargesocietiesaremore
stands to gain, but only if the responder can be hance within-group interpersonal trust, lower socially stratified, belief in moralizing gods
trustedtoreciprocate. Ina variation of this trust monitoring costs, and so further reinforce in- serves to preserve political and economic in-
experiment(36),researchersmeasuredindividual tragroupprosocialtendencies.Beliefinmorally equality.However,althoughmissionizedsocieties
differencesinthereligiosityoftheproposerand concerned gods may stabilize prosocial norms and caste-stratified societies were indeed more
the responder. In addition, in some trials, pro- evenintheabsenceofsocialmonitoringmech- likelytoendorseamoralizingGod,theassociation
posersknewaboutthelevelofreligiosityofthe anisms.This,inturn,wouldbeexpectedtoexpand between large group size and the prevalence of
www.sciencemag.org SCIENCE VOL322 3OCTOBER2008 61
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liablesecularinstitutions,suchascourts,policing ReferencesandNotes 44. J.Haidt,Science316,998(2007).
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theIndividual(OxfordUniv.Press,NewYork,1993). R.Sosis,andthreeanonymousreviewersfortheir
the course of human prosociality. Consequently, 3. E.Durkheim,TheElementaryFormsofReligiousLife commentsandcriticisms.Thewritingofthisarticlewas
activemembersofmodernsecularorganizations (FreePress,NewYork,1995). supportedbyaSocialSciencesandHumanities
areatleastaslikelytoreportdonatingtocharityas 4. D.S.Wilson,Darwin’sCathedral(Univ.ofChicagoPress, ResearchCouncilofCanadagrant(410-2007-0222)
activemembersofreligiousones(42).Supporting Chicago,2002). tothefirstauthor.
5. W.Irons,inEvolutionandtheCapacityforCommitment,
thisconclusion,experimentallyinducedreminders
R.Nesse,Ed.(RussellSageFoundation,NewYork,2001),
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62 3OCTOBER 2008 VOL322 SCIENCE www.sciencemag.org