Cooperation, Punishment and Organized Crime: A Lab-in-the-Field Experiment in Southern Italy

Abstract

This paper reports the results of an experimental investigation which allows a deeper insight into the nature of social preferences amongst organized criminals and how these differ from “ordinary” criminals on the one hand and from the non-criminal population in the same geographical area on the other. We provide experimental evidence on cooperation and response to sanctions by running Prisoner’s Dilemma and Third Party Punishment games on three different pools of subjects; students, ‘Ordinary Criminals’ and Camorristi (Neapolitan ‘Mafiosi’). The latter two groups being recruited from within prisons. We are thus able to separately identify ‘Prison’ and ‘Camorra’ effects. Camorra prisoners show a high degree of cooperativeness and a strong tendency to punish, as well as a clear rejection of the imposition of external rules even at significant cost to themselves. In contrast, ordinary criminals behave in a much more opportunistic fashion, displaying lower levels of cooperation and, in the game with Third Party punishment, punishing less as well as tending to punish cooperation (almost as much) as defection. Our econometric analyses further enriches the analysis demonstrating inter alia that individuals’ locus of control and reciprocity are associated with quite different and opposing behaviours amongst different participant types; a strong sense of self-determination and reciprocity both imply a higher propensity to cooperate and to punish for Camorra inmates, but quite the opposite for ordinary criminals, further reinforcing the contrast between the behaviour of ordinary criminals and the strong internal mores of Camorra clans.

Full text

Forschungsinstitut
zur Zukunft der Arbeit
Institute for the Study
of Labor
DISCUSSION PAPER SERIES
Cooperation, Punishment and Organized Crime:
A Lab‐in‐the‐Field Experiment in Southern Italy
IZA DP No. 9901
April 2016
Annamaria Nese
Niall O’Higgins
Patrizia Sbriglia
Maurizio Scudiero

Cooperation, Punishment and
Organized Crime: A Lab‐in‐the‐Field
Experiment in Southern Italy
Annamaria Nese
University of Salerno
Niall O’Higgins
ILO, University of Salerno and IZA
Patrizia Sbriglia
University of Naples II
Maurizio Scudiero
Ministry of Justice, Italy
Discussion Paper No. 9901
April 2016
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IZA Discussion Paper No. 9901
April 2016
ABSTRACT
Cooperation, Punishment and Organized Crime:
A Lab‐in‐the‐Field Experiment in Southern Italy
This paper reports the results of an experimental investigation which allows a deeper insight
into the nature of social preferences amongst organized criminals and how these differ from
“ordinary” criminals on the one hand and from the non‐criminal population in the same
geographical area on the other. We provide experimental evidence on cooperation and
response to sanctions by running Prisoner’s Dilemma and Third Party Punishment games on
three different pools of subjects; students, ‘Ordinary Criminals’ and Camorristi (Neapolitan
‘Mafiosi’). The latter two groups being recruited from within prisons. We are thus able to
separately identify ‘Prison’ and ‘Camorra’ effects. Camorra prisoners show a high degree of
cooperativeness and a strong tendency to punish, as well as a clear rejection of the
imposition of external rules even at significant cost to themselves. In contrast, ordinary
criminals behave in a much more opportunistic fashion, displaying lower levels of cooperation
and, in the game with Third Party punishment, punishing less as well as tending to punish
cooperation (almost as much) as defection. Our econometric analyses further enriches the
analysis demonstrating inter alia that individuals’ locus of control and reciprocity are
associated with quite different and opposing behaviours amongst different participant types; a
strong sense of self‐determination and reciprocity both imply a higher propensity to cooperate
and to punish for both students and Camorra inmates, but quite the opposite for ordinary
criminals, further reinforcing the contrast between the behaviour of ordinary criminals and the
strong internal mores of Camorra clans.
JEL Classification: A13, D63, D23, C92, K42, Z13
Keywords: economics of crime, models of identity, prisoner’s dilemma,
third party punishment, experimental economics
Corresponding author:
Niall O’Higgins
Department of Economics and Statistics
University of Salerno
Via Giovanni Paolo II
132-84084 Fisciano (SA)
Italy
E-mail: nohiggins@unisa.it

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1.Introduction
ThisstudyismotivatedbythebeliefthatourpracticalunderstandingoftheMafia,Camorra
andotherItaliancriminalorganizationsmaypotentiallybeenrichedbyrecognizingthattheirwell‐
knowncodesofbehaviouraremorethananecdotalcuriosities,andindeed,constitutearealand
distinctcriminalculturewhichisbothuniqueand,whilstoftenmentionedinmoviesandbooks,
rarelyseriouslystudied.Suchabeliefclearlyinformsthepublicdebateinthemedia,butitisalso
evidentinpolicyinitiatives;mafiosiareunderstoodtosharecommonmoralvaluescharacterizedby
strongin‐groupcooperativenessandloyalty,parochialism,totaldisregardofexternal(public)
institutionalrules,profoundreligiousbeliefsandself‐reportedpositiveidentityvalues.Crucialto
theserulesare,forexample,thesecrecycodesofomertàwhichMafiosiconsiderhonourabletrust
amongmembersofthesamegroup.Theimportanceofsuchcodeshasbeendemonstratedbythe
successofsomeofthestrategieswhichhavebeenusedtofightMafiaandMafia‐typegroups.1For
example,theprovidingofincentivestoinformants,astrategyadoptedtofighttheMafiainthe
1980s,turnedouttobeapowerfulinstrumenttounderminethesecrecycodesofomertà.Atthe
sametime,morerecently,newrulesofconductoftheCatholicChurchwhichthreatenthose
responsibleforviolentcrimeswithexcommunicationorimpedecriminalsinsmallcitiesfrom
exertinganinfluentialroleasfarasreligiousmattersareconcerned,havebeenseenasanimportant
stepstofightanddeprivethecriminalcultureofsomekindofstatus.2
Scholarsoftenclaimthatsuchcultureproducesimportantdistortionsinthesocialand
economiclifeoftheneighbourhoodswhereorganizedcrimegroupsoperate.Concernhasalsobeen
expressedthattheproliferationofMafiaorganizationsintheEUandUScouldleadtotheexporting
ofacultureofcrimewithalltherelatedconsequencesonthelevelofcorruptionandthefunctioning
ofthelocalmarkets.
Inarecentstudy,Meieretal.(2014)haveexperimentallyanalysedsocialpreferencesintwo
groupsofhigh‐schooladolescentswholiveintwodistinctneighbourhoodsofPalermo,oneofwhich

1Tobeprecise,wedrawsubjectsformapoolofmembersoftheCamorraorganization.However,asiscommoninsimilar
studies,inthispaperweusethewords:Camorra,MafiaandMafia‐typeorganizationswithoutdistinction,sincethere
appeartobefewdifferences–asfarasthe“criminalculture”isconcerned–betweenthesegroups.
2ThereareanumberofpolicieswhicharedirectlyaimedatfightingtheMafia’scodesofbehaviourandreducingthe
importanceofMafiosiintheirnativetownsandvillages.Forexample,theItalianParliamentiscurrentlydiscussinga
newlawtodeprivesentencedMafia‐typeleadersofparentalcustody,andthepolicyallowingwealthconfiscatedfrom
Mafiositobere‐allocatedfortheprovisionofbasicpublicgoodsinlocalcommunitieshasalreadyprovedsuccessful.
Finally,LuigiCantone,theItalianHighCommissionerforthefightofcriminalityandcorruption,hasrecentlystatedthat
apolicywhichdoesnotfightthecultureofcrimebutaimsonlyatarrestingMafiabossesmaybackfirebecauseitjust
leavesroomfornewstrugglesforsupremacyamongstcriminalfamilies.

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istraditionallyconnectedtoMafia.TheirresultsclearlyshowthatthepresenceofMafiastrongly
affectssocialbehaviour,alsoforyoungadultswhohavecomparablelevelsofeducationandsocio‐
economicfamilyconditionsasthoselivinginMafia‐freeareasofthesamecity.Specifically,they
foundthatpeoplelivinginneighbourhoodswithhighMafiainvolvementexhibitedlower
generalizedtrustandtrustworthinessaswellasgreaterparochialism,andthatpunishmentnorms
didnotaltertheirbehavioursignificantly.Intheirconclusions,theauthorsarguethatinregionsin
whichcriminalorganizationsoperatetherearenegativeexternalities;specifically,informal
institutionalcriminalculturetendstoprevailovertheformalinstitutionalcultureandtoaffecteven
youngergenerationsbelongingtothenon‐criminalpopulation.3Thisargumentisnotnewandithas
beenwidelyexamined.Gambetta(1996)andBandiera(2003)arguethattheriseandsuccessofthe
MafiainthenineteencenturywasconnectedtotheweaknessoftheItalianStateandtheMafia’s
abilitytoprovideefficientandotherwiseabsentcrediblelegalframeworks;theMafiathusprovided
analternativeinstitutionalstructure,fillingavacuumwheneverithadtheopportunity.4The
weaknessoflegitimateinstitutionsandthe“viciouscycle”(Meieret.al.;2014)arealsoclaimedas
oneofthemainreasonsforSouthernItalianeconomicunderdevelopmentandthepersistenceof
regionaleconomicdisparities(BeugelsdijkandSchaik,2005),sinceitproduces–andreproduces‐a
lowlevelofsocialcapitalintheSouthofItaly.5
Thepresentpaperproposesanexperimentalinvestigationwhichallowsadeeperinsightinto
thenatureofsocialpreferencesamongst“organized”criminalsandhowthesedifferfrom
“ordinary”criminalsontheonehandandfromthenon‐criminalpopulationinthesame
geographicalareaontheother.WefocusonCampaniawheretheCamorra,perhapscurrentlythe
mostimportantItalianMafia‐typeorganization,thrives.Weprovideexperimentalevidenceon

3QuotingfromMeieretal.;2014paper(p.1):“Ourstudyexperimentallydemonstratesthatinformalinstitutionsfrom
thepastcanundermineinstitutionsfromthepresent,eveninreligiouslyandethnicallyhomogeneouspopulations.A
cultureoforganizedcrimecanaffectnormsandattitudesinadolescentsthatmightcreateaviciouscyclewhere
organizedcrimeaffectsnormsandviceversa”.
4Inthecaseofotherorganizedgroups,liketheCamorrainCampania,whichconstituteour‘Mafia’sample,thereare
verysimilarhistoricalpatterns.SpecifictotheCamorra,however,theorganizationexperiencedextraordinarilyfast
growthfollowingtheearthquakeof1980astheresultofthesubstantialpublicrelieffundsdirectedtoCampania(See
Pinotti,2013).
5AcarefulinvestigationintotheimportanceofthesedisparitieshasbeenconductedbyCasarietal.(2015).Theauthors
experimentallytestsocialpreferencesintwodistinctareas;theNorth\CentreandtheSouthofItaly.Theirtestsonrisk
attitudes,trustandtrustworthinesssuggestthatobservedeconomicdifferencesmaybetheresultofdifferencesin
unobservedpreferences.TherecentexperimentalfieldinvestigationsconductedinItalyinthelastfewyearsis
particularlyinterestinginasmuchastheyprovidesuggestiveinsightsintotheunderpinningofeconomicdevelopment
inWesterncountrieswhereheterogeneousandconflictingsocialpreferencesco‐exist,sometimesinthesame
geographicalareaandoftenwithingroupsofpopulationwhootherwisesharesimilarsocio‐economicconditions.

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cooperationandresponsetosanctionsbyrunningPrisoner’sDilemmaandThirdPartyPunishment
gamesonthesethreedifferentpoolsofsubjects.Specifically,theexperimentspresentedinthis
paperwereconductedinSouthernItaly(2012‐2013)withasampleofuniversitystudentsandtwo
samplesofprisoninmates.Thetwogroupsofprisoninmatesdifferedinthatonegroupwere
membersoftheCamorrawhilsttheotherwerenotinvolvedinorganizedcrime.Infact,the
experimentalsessionswererunintwodifferentprisonslocatedinCampania,oneofwhichhosted
convictedmembersoftheCamorra,andtheother,“ordinary”criminals.Furthermore,we
conductedthesameexperimentsonapoolofstudentsenrolledinseveralfacultiesoftheUniversity
ofNaplesII,whichislocatedintheCasertaarea,aterritorynotoriousforthestrongpresenceof
Camorrafamilies.
Asexplainedbelow,membersoftheCamorraand“ordinary”criminalswereconvictedfor
similartypesofcrimes(crimesagainstproperty)andhadsimilarcriminalcurriculawiththe
exceptionthatonepoolofinmateswereconvictedasmembersoftheCamorraandwere
consequentlyhostedinaseparatehigh‐securityunit.6
Inadditiontotheexperimentalsessions,wecompletedouranalysisbyaskingallsubjectsto
filloutaquestionnairewhichmeasuredthepropensityforindividualstocooperateandtopositively
(ornegatively)reciprocateothers’behaviour.Also,thequestionnaireincludedtwoquestionsbased
ontheRotterscaleintendedtobroadlymeasurethelocusofcontrolofparticipants(Rotter,1966).
Individualswithanexternallocusofcontrol(externals)tendtobelievethattheyareunabletobe
themasteroftheirownlivesandeventsareoutsideoftheircontrol.Onthecontrary,internallocus
ofcontrol(internals)indicatesatendencytobelieveinself‐determinationandtobeendowedwith
highself‐esteem.ThereisrobustevidencethatpsychologicalmeasuressuchastheRotterscaleare
positivelyrelatedtopro‐socialbehaviour,inthesensethataninternallocusofcontrolisassociated
withcooperativenessandreciprocity(Booneetal.;2002;CarpenterandSeki;2011).Therefore,
althoughtheRotterscaleisbasicallyapersonalitymeasure,ithasbeenoftenusedasaproxyofthe
individuals’willingnesstocooperateinasocialdilemmacontext.
Thepurposeofthequestionnaireistointegratethebehaviouraldatawithmeasuresofthe
individuals’preferencesandpersonalityvalues.7Furthermore,asweillustrateinafurthersection,

6InItaly,prisonerswhohavebeensentencedasmembersofacriminalorganizationsuchastheMafiaortheCamorra
arealwayshostedinsegregatedunitsandthespecificprisonrulesappliedtothemcandifferfromthosetowhich
ordinaryprisonershavetoadhere,evenwhenthelatterhavebeensentencedforsimilarcrimes.
7BecausepoorliteracyiscommonamongstItalianprisoninmates,whetherthesebeordinaryinmatesorCamorristi,the
questionnairecontainedonlysixquestionsandtheywereframedinanextremelysimplemanner.Ourmeasureoflocus


6

thequestionnaire’sanswersallowsustoidentifysimilarsocialpreferenceprofilesandtoevaluate
howindividualswhohavesimilarattitudestocooperationandreciprocityactuallybehave
differently,dependingonwhethertheyadheretothestronginternalmoresofCamorraclansor
not.
OurmainfindingisthatCamorraprisoninmatesaresignificantlydifferentfrombothofthe
othertwogroups(studentsandordinarycriminals)understudy.TheCamorraprisonersshowahigh
degreeofcooperationandstrongpunishingbehaviour,aswellasastrongrejectionofthe
impositionofexternalrulesevenatsignificantcosttothemselves.Onthecontrary,ordinary
criminalsbehaveinamuchmoreopportunisticfashion,displayinglowerlevelsofcooperationand,
intheGamewithThirdPartypunishment,punishinglessaswellaspunishingcooperation(non‐
opportunisticbehaviour)(almost)asmuchasdefection(opportunisticbehaviour).Oureconometric
analysesofbehaviourduringthegamealsosuggestthatlocusofcontrolandreciprocityserve
differentpurposesaccordingtothespecificsampleunderinvestigation.Highdegreesofself‐
determinationandreciprocityimply–infact–ahigherpropensitytobothcooperateandpunish
forstudentsandCamorrainmatesbutnotsoforordinarycriminals;forthelatterthese
characteristicstendtostrengthentheirtendencytowardsopportunisticbehaviour.8

2.AbriefnoteonCamorra
Beforeproceedingtotheexperimentitself,abriefexaminationofthespecificcriminalgroup
understudyisinorder.TheCamorra,similarlytotheMafia,hasitsoriginsinnineteenthcentury

ofcontrolisthenhighlysimplifiedsincesuchpersonalitytraitsaregenerallyidentifiedusingmore(andmoredetailed)
questions(rangingfromsix‐asinCarpenterandSeki,2011‐totwentythreequestions).Wedonotclaim,therefore,to
havefullymeasuredindividuals’locusofcontrol,butratherusethequestionnairetodefinebroadindividualpreference
‘types’.
8Theanalysispresentedherefallswithinthegrowingareaofliteratureontheapplicationofeconomicexperimentsto
theeconomicsofcrimetypicallythrough–ashere‐theimplementationofexperimentsoncooperation,trustand
altruismconductedwithsamplesofconvictedprisoners(Birkelandetal.,2014;Kadjevietal.,2013andChmuraetal.,
2013).Themotivationunderlyingthesepapersistoevaluatewhethertherearedifferencesbetweenthesocial
behaviourofprisonersandordinarycitizens,suchasstudentsorthegeneralpopulation,sincecriminalsclearlymanifest
anti‐socialbehaviourintheirprofessionallife.Thepresenceofsuchdifferencesstronglysuggestthatcriminalactivity
cannotusefullybestudiedfocusingexclusivelyoneconomicincentivesandopportunities,astraditionaltheoriesclaim,
butrathershouldalsoincludeabehaviouralperspective.Acommonfindingofthesepapersisthatconvictedprisoners
donotappeartobelesspro‐sociallymotivatedthan‘normal’citizens.Twoexplanationshavebeenputforwardforthis.
Firstly,theexperimentalfindingsseemtoconfirmthateconomicopportunitiesplayanimportantroleindeciding
whetheranindividualwillcommitteeacrime;secondly,alabenvironmentmaybeapoorproxyofarealworld
environment(seeBirkelandetal.;2014),thusthecomparisonmaygenerateinconclusiveresults.


7

Campania;and,againincommonwiththeMafia,theCamorrawasoriginallycomposedofordinary
out‐lawswhosharedcommoncodesofhonourbasedonomertà,in‐groupcooperativeness,self‐
definedheroicidentities,strongreligiosity,andsoforth.
However,similaritiestotheMafia,however,shouldnotbeoveremphasized.TheNew
Camorra(NCO),whichemergedinCampaniainthe1980s,hasatleastthreespecificcharacteristics
whichmarkitapartfromtheSicilianMafia(andindeedformtheothermafiatypeorganizations
operatinginItaly).First,theCamorraisaparticularlyviolentorganization.Comparingthenumber
ofhomicidesinCampaniawiththeremainingItalianregions,inthe1990s,theCamorraemergedas
themostviolentMafia‐typeorganisationinItaly.9Second,andnotunrelated,theCamorrais
constitutedbyabout100competingfamilieswhichoperateinasmallgeographicalarea(Naples
andCaserta),whichitselfprovidesanexplanationforthesubstantialamountofviolenceassociated
withtheorganisation.TheCamorrahasanetworkstructure,quitedifferentformthepyramidal
structureoftheSicilianMafia,andallclanssharesimilarsocio‐demographicandethnicalfeatures.
ThisclearlycontributestomakingCamorramobstersmorecompetitiveandhencemoreviolent
thantheMafia.ThethirdaspectwhichcharacterizestheCamorragroupconsistsinthefactthat
Camorrahasalwaysbeenaveryprofitableorganization,oftenwithrevenueshigherthanMafia,and
withtheabilitytodiversifyitsinvestmentsandtoinvestacrossEurope.10,11

3.Thesamples,theprisonsandtherecruitingprocedures
Thestudentsamplewasrecruitedatthe2ndUniversityofNapleswhichislocatedinCaserta
Province.Thestudentswereenrolledindifferentfaculties(Law,Psychology,PoliticalScience,
Economics)andwererecruitedbyadvertisementsonthefacultywebsites.Thesessionswere
conductedovertwodaysintheCentralUniversitylaboratory.CasertaProvincehasseveralCamorra
familygroups(Saviano,2006),andtherearelargeprisonslocatedinthearea.FortheCamorra’s

9RapportosullaCriminalità,Ministerodell’Interno,severalyears.Saviano(2006).
10SeveralreportsindicatethatCamorrahasastrongpresenceintheNorthofItalyandinsomeNorthernEuropean
countries(seeEuropol,2013).ItisdifficulttopreciselyidentifytheprofitabilityofMafia‐typegroups.However,Eurispes
(2007‐2009)reportsMafiaandMafia‐typeclansrevenuesinItalyyearly,anditisoftennoticedthat,outof4Southern
groups,Camorraisoneofthemostsuccessful.Togiveanexample,Europol(2013)reportsthevalueofthegoodsand
propertyconfiscatedfromasingleCamorraboss(Polverino)afterhisarrestwhichsummedtoavalueofmorethanone
billioneuros.
11TheCamorra’sabilitytopenetratefinancialEuropeanmarketshasbeenrecognizedbyseveralstudies.Thisabilityalso
marksitapartfromtheMafiawhichtraditionallyhasstrongeconomicinterestsintheUS.


8

inmatesample,weselectedadifferentprison.Specifically,theCamorrasamplewasrecruitedin
oneofthemostimportantNeapolitanprisons,Secondiglianojail.12Secondiglianoisadetention
centrecomposedofseveralsections,someofwhichare“highsecurity”andhostCamorristiand
Mafiosi.InItaly,ifsentencedasmembersoftheMafiaorCamorra,prisonersarelocatedinseparate
unitsofcorrectioncentresorinprisonsdestinedtohostonlyMafiosiorCamorristiand
SecondiglianojailisoneofthemostimportantsuchprisonsinSouthernItaly.
Therearefourhighsecurityunits.Eachunithousesapproximately400inmates.Camorra
inmateswererecruitedthroughadvertisementspostedintheprison'srecreationareas.The
advertisementsstatedthatanumberofresearchersfromtheUniversitiesofNaplesandSalerno
wereconductingastudyonseveralpopulationgroupsinCampania;thattheresearcherswould
conductsessionsintheprison;and,thatparticipationwouldberewardedwithafeeof10‐18euros
(whichcorrespondstoroughly1–1.5timesthe(pro‐rata)amountaninmateisallowedtospendat
theprisoncanteenforcigarettesandfoodinoneday13).Theinmateswerefreetochoosebetween
enrollmentintheexperiments,participationincoursesorsportsactivitiesorremaininginthe
recreationarea.Thus,thesessionsdidnotoverlapwiththeinmates'usualdailyoutdoorshoursand
participationwasvoluntary.Weconductedbothsessionsonthesameday,oneaftertheother,and
eachsessionwasadvertisedinadifferentsectionofthejail.
“Ordinarycriminals”wereenrolledinadifferentprisonlocatedintheCasertaarea(The
SantaMariaCapuaVetereprison,hereafterSMCV).SMCVhostsallsortsofcriminalswiththe
exceptionofmembersofmafia‐typeorganisations.14Herewefollowedpreciselythesame
procedurestorecruitinmatesasinSecondiglianoJail,advertisingtheexperimentsinthe
recreationalareasoftheprisonandrunningthesessionsintheprison“classrooms”duringthetime
ofthedaytheydevotedtotrainingandsportsactivities.AlsoincommonwithSecondigliano,the
sessionstookplaceovertwodays.15Allsessionswereconductedin2012‐2103.Atotalof109

12Theexperimentswereconductedintwodifferentphases:1)in2012weranexperimentsinNaplesandinthe
University(seealso:Nese,etal.;2013);2)in2013,experimentswereruninSantaMariaCapuaVetere.
13Specifically,inmatesareallowedtospenduptoamaximumof€350permonthinthecanteen,whichcorrespondsto
alittleunder€12perday.
14Wedecidednottousethesameprisonforthespecificsampleofordinarycriminals,inordertominimizethe
probabilityofcommunicationbetween‘Mafia’inmatesandordinaryinmates.Finally,weselectedSMCVbecause–at
thetimeoftheexperiments–thiswasthebiggestprisonfacilityintheregion.
15Giventheunusualnatureofoursamples,itisimportanttoclarifysomeproceduralaspectsoftheresearch.For
securityreasons,wedidnotpre‐announcetheprecisedaysoftheexperiments;however,inmatesknewthatwewould
beworkinginthemonthsofJuneandJuly.InordertoconductexperimentsinItalianprisonswehadtofollowthe
relevantrulesandproceduresestablishedbytheMinistryofInternalAffairs,CourtJudges,thePrisonAuthoritiesand
thespecialItalianGovernmentalDepartmentregulatingalldetentioncentres(DPRA).Thebasicrulewasthatprisoners’


9

students,129Camorraand109“ordinary”inmatesparticipatedinthesessions.Thespecificsamples
ofinmateshadcomparablelegalandsocio‐economicalcharacteristics.Infact,inSMCVweexcluded
foreigners,sexoffendersanddrugaddicts,focusingoninmateswhowereconvictedforcrimes
againstproperty(suchasthefts,robberies,housebreaking,etc.)16.TheCamorrasamplewas
constitutedbyinmatesconvictedforcrimesagainstproperty,homicidesanddrugdealing.The
exclusionofsomespecificcrimesandcriminalsdoesnotimplythatwehadtooperateaselection
afterrecruitmentwasover,sinceallCamorrainmatesmettherequirementsand,inSMCV,we
simplyadvertisedinrecreationalareaswhereforeigners,sexoffendersanddrugaddictsdidnot
socialize.Thetwosamplesbelongtothesameage‐groups,intherange20‐35.Onefurtherelement
ofcomparisonwasthatthemajorityofinmatesinbothsamplescamefromthesameregion,
Campania.Thepurposeofthesecomparisonsisthatwewishedtostudybehaviourintwodefined
“types”ofprisoners–Camorristiand“ordinary”criminals–whocamefromotherwisesimilar
backgrounds,similarcriminalcurriculaandhence,similaroutsideopportunities.Allsubjects–
includingstudents–completedaquestionnaireinwhichthreetypesofquestionswerereported.
Thequestionnaireswereanonymouslydistributedinrecreationalareastoallinmates,eventothose
whodidnotparticipateintheexperiments.Theonlyrequirementweimposedwasthattheinmates
whodecidedtojointhesessionshadtobringthequestionnaireswiththemandtogiveittothe
monitoroftheirsession(seethesectionbelow).Themonitorswouldidentifythequestionnaireby
reportingtheinmateidentitycodeonthesheetofpaper.Weimplementedthisprocedureinorder
topreservethecompleteanonymityoftheinmates,asrequiredbytheinmatesthemselvesandthe
prisonmanagement.Asforthestudents,weusedtheusualprocedure,askingthestudentstofill
thequestionnairebeforeleavingtheexperiment.
Conductingexperimentsinprisonscreatestwodifferenttypesofproblem,asfarthe
measurementofsocialpreferencesisconcerned.Firstly,theremaybeunobservableprisoneffects

anonymityhadtobepreservedandnopersonalinformationcouldbedisclosed.Alltheexperimentalmaterialshadto
beviewedandapprovedbyeachoftheseauthorities.Inordertopreservetheprivacy,rightsandsecurityofinmates
(andalsotherightsandsecurityoftheresearchersconductingthesessions),nopersonalinformationonindividuals’
crimecurriculacouldbedisclosed(inSecondigliano,wewereallowedtoviewthegeneralstatisticsontheprison’s
populationcollectedbytheprisonauthorities).Finally,asinlabexperimentstheinmates'participationwasentirely
voluntaryandanonymous.Recruitmenttotheexperimentsprovedverysuccessfulforseveralreasons.Firstly,inSMCV,
thefinancialincentiveplayedanimportantrole;whilst,inSecondigliano,theexperimentsubstitutedtasks(coursesand
psychologists’assessmentandmeetings)whichinmatesstronglydislike.Secondly,theexperimentalsessionslasted
fromtwotothreehours‐muchlongerthanthecourseswhichtheyreplaced‐thusallowinginmatestospendmore
timethannormaloutsidetheircells.Theaveragedurationofthesessionswasreportedintheadvertisement.
16Sinceinformationontheindividuals’crimeswerenotdisclosed,however,wedonotknowexactlythepercentagesof
(participating)prisonerswhocommittedaspecifictypeofcrime.

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10

determinedbythefactthatprisonrulesmayaffectaninmate’ssociallifeandrelationshipsinaway
thatexperimenterscannotcontrolfor(seealso:Birkelandetal.;2014).Thus,theinclusionofagroup
of‘ordinarycriminals’(OCs)allowsustoidentifyacommonprisoneffect.Secondly,theprisoneffect
islikelytoincreaseifinmateshavespentallthetimeoftheirincarcerationinthesameprisonand
withthesamegroupofpeople.Fortunatelyfortheexperimentaldesign,intheItalianprisonsystem,
inmatesareregularlymovedforsecurityreasons.EspeciallyinthecaseofCamorrainmates,there
isahighmobilityamongspecialprisonunitsandinmatesdonotsharethesameroomswith
membersofthesamecriminalfamilyorofcompetingfamilies,norindeedwiththesamepeoplefor
verylong.Naturally,thereisachancethatinmateshavemetbeforeenteringprison,however,the
Italiansystemdoesguaranteethatinmatesmovecellsfairlyofteninordertoavoidthe
establishmentofviolentanddomineeringgangs.This“mobilityrule”canbeclaimedasa(partial)
randommatchingmechanismamongexperimentalsubjects.ItisappliedtobothCamorraandnon‐
Camorrainmates,althoughforfairlyobviousreasonsitisappliedmorestringentlytotheformer.
Moregenerally,inallaspectsoftheexperiments,wetriedtoreproduceasfaraspossible
thesamelaboratoryenvironmentintheprisonsaswereusedforstudentsandabove‐allapplying
thesamerulesandprotocolsforallparticipants,studentsandinmates.Thesessionstookplacein
classroomsinwhichinmatesusuallyattendedgeneraltrainingcourses.Prisonguardsremained
outsidetherooms(asisthecaseduringtraining)andtwoexperimenters(inthesameagerangeas
theinmates)supervisedthesessions;wealsochosemonitorsfromamongsttheparticipants,in
ordertoincreasecommitmentandtoguaranteeanonymityasrequiredbybothinmatesandprison
authorities.Inotherwords,wetriedtopreservethebasicrulesoflab‐experiments,guaranteeing
voluntaryparticipationinthesessions,anonymity,andsimilarrulesbetweentheexperimentsrun
intheprisonsandthoserunintheUniversity.17

4.Experimentaldesignandbehaviouralhypotheses
Theexperimentaldesignalsoadoptedstandardprotocolsforalaboratoryexperimentwith
formalInstructions,theselectionofmonitorsandthepublicreadingoftheInstructionsheetbefore
thesessionsstarted.Theexperimentscomprisedtwodifferentdesigns:aone‐shotPrisoners’

17Wedeliveredmorethan250questionnairesinbothprisons,howeverwedidnotknowhowmanysubjectswouldturn
uptilltheactualmomentthesessionstarted.

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11

Dilemma(PD)andaone‐shotPrisonersdilemmawiththirdpartypunishment(TPP).Forthelatter,
wereproducedthedesignofFehrandFischbacher(2004).Inallofthesessions,experimentswere
conductedonpencilandpaper.InthePDdesign,atthebeginningofthesessions,eachsubjectwas
providedwithanenvelopethatwaslabelledAorBandanumberthatidentifiedthesubject.The
envelopecontainedaninstructionsheet,adecisionsheetandacopyofthequestionnaire.18The
instructionswerereadaloudbytheexperimentersandinbothsessionswestatedthatthe
participantscouldaskquestionsonlyprivatelyandafterthereading.ThegameinthePDsession
wasone‐stage;thegameconsistedofasingledecisionthattheparticipantswererequiredtoreport
onthedecisionsheet.A(B)subjectswereendowedwith10experimenttokensandwerepaired
withB(A)subjects.The(AandB)subjectshadto(simultaneously)determinewhethertokeepthe
tokensorsendthemtothepartner.Ifsubjectssentthetokenstotheir(anonymous)partner,the
researcherwouldtripletheamount.Thus,thegamehadfourpossibleoutcomes:(10,10),(40,0),
(0,40),(30,30).
TheTPPisatwo‐stagedesigninvolvingthreetypesofsubject(A,BandC).Thefirststage
correspondstothePDandourprocedureswerepreciselythesame;thefundamentaldifference
beingthatAandBwereawarethattheCplayercouldinterveneatthesecondstageandcouldthus
influencetheirfinalpayoffbyawardingdeductionpointstoone(orboth)ofthem.Infact,atthe
beginningofthesecondstage,afterAandBhaddeterminedwhetherornottosendthetokens,
playerCwasendowedwith40tokensandhadtodecidewhethertokeepthetokensorspendthe
endowmentsoastodeductpointsfromAand/orB.OnedeductionpointwoulddecreaseAandB's
totalpayoffbythreetokens(Cwasallowedtoattributeamaximumof20deductionpointsforeach
player).WeretainedcertainimportantfeaturesofthedesigncreatedbyFehretal.;2004.First,at
thebeginningofthesecondstage,AandB'sendowmentswereincreasedby15tokens(avoiding
thefocalpoint:40,40,40).Second,theparticipantsreceivedashow‐upfeeof10tokenstoprevent
asubjectfromexperiencingalossafterC'sdecision.Finally,C'sdecisionswererecordedusingthe
strategymethod(Selten,2003).19Thus,Cwasaskedtoindicateonthedecisionsheethowmany
deductionpointshewouldallocateforeachofthefourpossibleoutcomesinthePD:(CC),(DD),
(CD),(DC).Inourdesign,thethreesubjectsactedatthesametimeindifferentroomswithdifferent

18Asexplainedinapreviousfootnotewedeliveredcopiesofthequestionnairestothecommonroomsoftheprisons,
however,sincestudentsfoundtheirquestionnairesintheenvelope,weincludedacopyintheenvelopesalsofor
inmates.
19WeonlystudyThirdPartyPunishment,therefore,CplayersdonotparticipateinthePDgameinthefirstphaseofthe
game.


12

experimenters.Thepairingprocedurewasconductedaftertheexperiments.Ineachroom,the
experimentercollectedtheclosedenvelopesandaskedoneparticipanttomixtheenvelopesand
formpairs.Thepairsandtheiridentificationnumberswerethenreadaloud.Next,inthepresence
ofonlytheparticipantwhohadrandomlyselectedthepairs,weopenedtheenvelopesand
calculatedthegains.Thefinalgainswerethenpostedintheprisonrecreationareaor–inthecase
ofuniversitystudents‐onthefacultywebsites.FortheTPPtheprocedurewasthesame.However,
theparticipantAorBofthefirststageformedtripletsratherthanpairs.Tomakeformingtriplets
possible,theCdecisionswerecollectedfirstandbroughttothefirstroom.Oncethetripletshad
beenformed,alwaysprivatelybutinthepresenceofoneparticipantAorBorC(selectedrandomly)
theexperimenterscalculatedthefinalgains.Theseearningswerereportedinatableandtheresults
postedintheprisonrecreationareaorontheuniversitywebsite.Theexchangeratewas1token=
€0.30andaverageearningswereintherange€12‐15,bothforthestudentsandinmates.Thefinal
payoffwasgivendirectlytostudentsaftertheexperimentsor,forprisoners,wascreditedtothe
inmates'internalaccount.Finally,itisimportanttoemphasiseoneimportantaspectofthedesign.20
Subjectsinteractedwithpartnersbelongingtothesamesample,thatis,Camorristiinteracted(of
courseanonymously)withotherCamorristiandsoforth.Eventhoughweareawarethatstudying
theinteractionbetweenCamorristiandindividualsofthetwoalternativesampleswouldbean
importantextensionofthepresentanalysis,wedidnottrytoimplementthisextensionheresince
theprimarygoalofthisanalysisistoassesstheexistenceandnatureoftheMafiosocultureandits
effectsonbehaviour,thusidentifyingtheexistenceandeffectsofaunique‘Mafiaculture’separate
anddifferentfromamoregeneral‘culture’ofcrime.21
ThepurposeoftheexperimentswastostudythebehaviourofindividualsAandBinthePD
gameandofindividualsA,BandCintheTPPgame,bearinginmindthewell‐knowncodesof
behaviourofcriminalorganizations.Weexpectedthatallthreegroupswoulddifferintheir
behaviour.Thestudentsprovideabaselinecontrolgroup,whilsttheinclusionoftwodistinctgroups
ofprisoners–‘ordinarycriminals’andCamorristi‐allowedustoidentifyageneralprisoneffect
(contrastingwiththestudents’behaviour)aswellasidentifyingspecificitiesofCamorracultureby
comparingtheirbehaviourwiththatoftheOCs.

20Wethankarefereeforhiscommentsonthisspecificpoint.
21WearenotsurethatsuchanextensioncouldbeimplementedsinceMafiaandCamorrainmatesaregenerally
separatedbytheremainingsectorsofthepopulationevenwhenleavinginthesameprison.


13

Giventhewellknownsolidaristicformsofmafiaculture,weexpectedthatCamorrainmates
wouldhaveahighertendencytocooperatewhenplayingintheAandBrolesinbothcontexts,even
thoughtheyarepairedwithfellowcriminalsofdifferentfamilies.Wealsoexpectedthatthe
behaviourofCamorramemberswoulddifferfromothergroups–studentsandordinarycriminals‐
bothinthereactiontothepresenceofexternalsanctionsandinthechoicesofimposingsanctions
whenplayingintheroleoftheCplayer,showingahigherpropensitytopunishdefectors.Usingdata
fromthequestionnaires,weareabletocontrolforanindividual’spropensitytocooperateand
reciprocateinasocialdilemmacontext.

5.TheEmpiricalAnalysis
5.1DescriptiveStatistics
Afirstlookatthedescriptivestatisticsthrowssomelightonthedifferencesinbehaviour
acrossthethreesubjectgroups.Figure1reportsthepercentageofplayerswhoco‐operateacross
thethreegroupsinthetwotreatments;Table1reportstheresultsofthechi‐squaretests,
comparingbehaviouracrossthedifferentgroupsandtreatments.
InthePDgame,Camorristiprovedtobemorecooperativethaneitherstudentsorordinary
criminals(Figure1)andthisdifferenceisstatisticallysignificant(Table1).Ordinarycriminalswere
lesscooperativethanstudents–inlinewiththefindingsofKhadjaviandLange(2013)‐butthey
arealsomuchlessco‐operativethanCamorristi.Withtheintroductionofexogenoussanctions,
studentsandCamorristibecamelesscooperative–withthenegativeshiftbeingstatistically
significantinbothcases,whilstincontrast,theproportionofordinarycriminalswhocooperated
increased.Theintroductionofsanctionsisoftenfoundtobedetrimentalforcooperation(Fehrand
Rockenback,2003),thereforeitisofparticularinterestthatinthecaseoftheordinarycriminals’,
sanctionsledtoan(albeitnotstatisticallysignificant)increaseincooperation.Itisalsotruethatthe
reductioninco‐operationarisingwithpunishmentislessforCamorristithanforStudents.Although
onewouldnotwishtoover‐emphasizetheimportanceofthisspecificobservation,itisplausible
(andcertainlyconsistentwiththeidea)thatthisisaconsequenceofa‘double’effectforCamorristi
–a‘prison’effecttendingtopromoteopportunisticcooperationanda‘Camorra’effectinvokingthe
rejectionoftheexternalimpositionofrules(aswellasgreatercooperationwithoutsuch
imposition).Certainlythisissuewouldbearfurtherinvestigation.


14


Figure1:CooperationinthePDandinthePD‐TPPGame

Table 1:χ2 tests of difference between groups and treatments
PD PD-TPP
Students vs. Ordinary Criminals - ***
Students vs. Camorristi ** ***
Ordinary Criminals vs. Camorristi *** -
PD vs. PD-TPP
Students ***
Ordinary Criminals -
Camorristi ***
Note: The table indicates whether the null hypothesis of equality across participant types (upper
portion of the table) or across treatments (lower portion of the table) are rejected at p < .01 (***),
p < .05 (**) or are not rejected at at least p >.10 (-).

Result1:Wefindsignificantdifferencesincooperationamongstthethreedifferentsamples,with
theCamorrainmatesbeingthemostcooperativeandordinarycriminalstheleast.
86,67%
67,50%
50,00%
65,22%
34,78%
66,67%
CAMORRISTI STUDENTI COMUNI
PD
TP‐PD
CAMORRISTI  STUDENTS ORDINARYPRISONERS


15

Result2:Wealsofindthatsanctionsleadtoanincreasecooperationonlyinthecaseofordinary
criminals,whilsttheyleadtoafallincooperationintheothertwosamples.
Asecondimportantissueconcernsthetendencytopunishamongstthethreegroups.Table
2reportstheaveragesizeofpunishmentinflictedbyThirdPartiesandtheproportionofThird
Partieswhopunish(inparentheses)accordingtothebehaviouroftheparticipants.Bothtypesof
prisonerpunishmoreandmoreoftenthanstudentsandincontrasttothem,bothtypesofprisoner
sometimespunishco‐operatorsaswellasdefectors.Thisisreasonablytobeattributedtoa‘prison
effect’;beingsubjecttopunishmentthemselves,itwouldappearthatbothtypesofprisonertend
topunishmoreoftenevenwhenbehaviourisnotobviouslyoffensive.Moreover,thereisalsoan
importantdifferencebetweenOCandCamorristipunishmentofco‐operators;OCspunishco‐
operatorsmore(andmoreoften)whentheotherplayerdefectscomparedtowhenbothplayers
co‐operate.Itisnotunreasonabletoseethisasanindicatorofopportunisticbehaviouronthepart
ofOCs22.

Table2:Punishmentinflictedoneachplayeraccordingtohisbehaviourandthatofhiscorrespondent


Punishedplayer
is:
StudentsOrdinaryCriminalsCamorristi
Otherplayer
cooperates
Otherplayer
defects
Otherplayer
cooperates
Otherplayer
defects
Otherplayer
cooperates
Otherplayer
defects
co‐operator 0 (0%) 0 (0%) 1.57(15.2%)4.37(52.2)

2.91(45.7%)0.54(8.7%)
defector6.09(56.5%)1.48(43.5%)6.67(67.4%)1.76(41.3%)

9.65(95.7%)1.76(39.1%)
Notes: The first number in each cell indicates the average punishment of player C, whereas the number in parentheses indicates the
percentage of C players who punish.

Somewhatmoreinlinewithasenseofnaturaljustice,Camorrainmatespunishless(andless
often)co‐operatorswhentheyfallfoulofadefectorascorrespondent.Allthreegroupspunish
defectorsmorewhentheotherplayercooperates,indicatingforallthereisasensethatsuchplayers

22InthesensethatOCs(appearto)punishplayersfortheirnaivetyintrustingtheotherplayerwhendefectionisthe
obviousoption(foranopportunist).Althoughindicativeratherthanconclusive,thisisoneindicationamongstseveral
emergingfromOCsbehaviour,whichleadustolabelOCs’behaviourasopportunistic.


16

aretakingunfairadvantage.Thus,thegeneralimpressionemergingisthatthereisastrongtendency
towardsfavouringcooperativebehaviouramongsttheCamorra(andstudents)whilstOCbehaviour
ismorecharacteristicofopportunism.Ontheotherhand,bothtypesofprisonerspunishco‐
operators,suggestinganunderlyingtendencyorwillingnesstopunish.

Result3:FocusingonthebehaviourofThirdParties,differentbehaviouralpatternsemergeacross
allthreegroups:CamorristiandOCspunishmorethanstudents,suggestingacommon‘prison
effect’.
Ontheotherhand,Camorristiandstudentsbothtendtopunishdefectorsmorewhenthey
arecoupledwithco‐operators,whilstordinarycriminalsalsosignificantlypunishco‐operatorswhen
coupledwithdefectors,suggestingopportunismonthepartofthelattercontrastingwithsome
senseofnaturaljusticeprevailinginthebehaviouroftheformer.
AsexplainedintheIntroduction,wecomplementedtheexperimentalevidencewith
attitudinalquestionnaires,whichweredistributedtoallsubjectswhoparticipatedinthesessions.
Specifically,Weaskedindividualswhetherandtowhichextent(onascalefrom1to423)theyshared
thefollowingstatements:a)“Ibelievemysuccessdependsonabilityratherthanluck;”b)“Ibelieve
thatunfortunateeventsoccurbecauseofbadluck;c)“Itisgoodtocompete;”d)“Itisgoodto
cooperate;e)Itisgoodtobefairtofairpeople;”f)“Peopleshouldrevengewrongsdonetothem.”
Thecooperationindexisdrawnfromstatementc)andd),whereassentencese)andf)measure
individuals'reciprocity.Thequestionsa)andb)arebasedontheRotterscale(1966).Relyingon
theseattitudinaldata,wealsoderivemoresyntheticindexestomeasureindividualattitudes:
respectively,the"Coopindex",the"Reciprocityindex"andthe"Locusofcontrolindex".24Table3
presentssummarystatisticsfromtheattitudinalsurvey.
Overall,withrespecttothe"Coopindex"Camorristiaremorecooperativethanstudents(p
<0.01),inlinewiththeresultsreportedinFigure1;however,ordinarycriminals‐theleast
cooperativegroupduringthegame(atleastinthePDgame)‐inthesurveyexhibitagreater

231indicates"completelydisagree",4means"completelyagree".
24Thoughthisvariableisonlyaproxyoftheindividuals’locusofcontrol(seeIntroduction),inthisandinthefollowing
sectionweusethisdenominationforsimplicityreason.


17

tendencytowardscooperativenessthaneitherstudentsorCamorristi(andagainthesedifferences
arestatisticallysignificantat1%level).25

Table3‐Mainstatisticsfromtheattitudinalsurvey
Students
Mean(stderrors)
OrdinaryCriminals
Mean(stderrors)
Camorristi
Mean(stderrors)
Cooperationindex
Competitionindex
Positivereciprocity
Negativereciprocity
Locusofcontrol(goodevents)
Locusofcontrol(badevents)
Coopindex
Reciprocityindex
Locusofcontrolindex
2.463(0.131)
3.102(0.115)
3.741(0.054)
3.129(0.117)
3.462(0.079)
1.361(0.062)
2.361(0.224)
4.870(0.148)
5.102(0.15)
3.518(0.082)
2.983(0.109)
3.743(0.066)
1.569(0.087)
3.231(0.098)
2.462(0.122)
3.543(0.131)
3.342(0.115)
3.781(0.161)
3.379(0.085)
3.20(0.096)
3.78(0.057)
1.629(0.093)
3.156(0.091)
2.149(0.108)
3.189(0.128)
3.341(0.095)
4.017(0.142)
Legenda:
Cooperationindex:scorereportedonquestiond);Competitionindex:scorereportedonquestionc);Positivereciprocity:score
reportedonquestione);Negativereciprocity:scorereportedonquestionf);Locusofcontrol(goodevents):scorereportedon
questiona);Locusofcontrol(badevents):scorereportedonquestionb).
Coopindexwasobtainedasfollows:scorereportedonquestiond)‐scorereportedonquestionc)+3;hence,highervaluesindicate
higherpropensitytocooperate.Reciprocityindex:e)+f)‐2;hence,highervaluesindicatehigherpropensitytoreciprocateothers'
kindness(orbadness).Locusofcontrolindex:a)‐b)+3;hence,highervaluesindicatehigherpropensitytobelievethatpeoplecan
controleventsaffectingthem.

RegardingtheReciprocityindex,nostatisticallysignificantdifferencesemergerespecttothe
answersonthe"positivereciprocity"whereasboththetwogroupsofcriminalsappeartobeless
inclinedtorevengethanstudents(thereporteddifferencesarestatisticallysignificantat1%level).
Whilstsomewhatimplausible,andindeednegatedbythebehaviouralresults,webelievethishas
todowithaprisoneffectwhichrequiresformalcompliancewithcertainbehaviour;inparticular,
prisonersattendrehabilitativetrainingseekingtocountertherevengeculture,sothattheymight
wellconsiderascompromising"sincereanswers"toquestionf).Moreover,suchapparent
contradictionsarecertainlynotunknownamongstCamorristi;memberspracticeviolentand
harmfulcriminalactivitybut,atthesametime,areassiduousinchurchattendanceandareoften,
atleastovertly,highlyreligious26.Finally,studentsexhibitamoreinternallocusofcontrol(or,lesser
degreeoffatalism)thanthetwogroupsofcriminals;thisdifferenceislikelyduetothedifferent
culturalbackgroundsand,inparticular,tocriminals'higherpropensitytobelievethatbadluckis

25Thedifferencesbetweenthethreegroupsarealwaysstatisticallysignificantwhenconsideringthe"Cooperationindex"
only;whenwelookatthe"Competitionindex",ontheotherhand,a(statisticallysignificant)differenceemergesonly
betweenCamorristiandOC.
26WitnesstherecentfuneralofamajorClanbossinRomewhichcausedconsternationamongstthepopulation.


18

responsibleforfailures,particularlywhenconsideringtheOrdinaryCriminals(inthisrespect,
statisticallysignificantdifferencesemergealsobetweenOCandCamorristi).
Result4:Fromtheattitudinalsurveystatisticallysignificantattitudinaldifferencesemergeacross
thethreesamplesaboutindividuals'locusofcontrol,(positiveandnegative)reciprocityandco‐
operativeness.

5.2Econometricanalysis
Inthissectionwelookattheevidenceinamorestructuredframeworkmainlyfocusingon
whether,andtowhichextent,individualattitudeselicitedthroughthequestionnairesareconsistent
withbehaviourexhibitedduringthegame.Furthermore,weareinterestedinassessingwhether
individualswhohavesimilarattitudestocooperationandreciprocitybehavedifferently,according
towhethertheybelongtooneorotherofthegroupsunderinvestigation.
Table4,columnsI‐III,reportstheresultsofProbitestimatesoftheprobabilityofcooperation
runforallparticipantsinbothtypesoftreatment.Thespecificationofthemodelinfirstcolumn
includesonlydummiesforparticipanttypeandtreatmenttype.Inthiscase,averagingoverthetwo
treatments,Camorristiaremuchmorelikely,andOCsalittlemorelikely,toco‐operatethan
students,althoughthedistinctionisnotstatisticallysignificantforOCs.Giventhenegativereaction
ofbothstudentsandCamorristitoTPP,thetendencytoco‐operateoverallfallsoncepunishmentis
introduced.
Thediscussionaboveisbasedonthespecificationsthatestimatean"averagetreatment
effect"throughthevariable(TPP).GiventheopposingreactiontopunishmentbetweenOCsonthe
onehandandCamorristiandstudentsontheother,itmakessensetointeracttreatmentwith
participanttype.ThisisaccomplishedinColumnII.Thereluctancetocooperatewithoutpunishment
amongstOCsandtheiropportunisticreactiontoTPPemergeswithastrongdivergencebetween
thereactionofOCstoTPPcomparedtostudents.Theinteractiondummiesalsobringoutthestrong
negativereactionofbothstudentsandCamorristitoTPP.Camorristitendtobemoreco‐operative
thaneitherstudentsorOCs,and,incontrasttotheothertwogroupsOCschangetheirbehaviour
becomingmoreco‐operativewhen(potential)sanctionsareintroduced.Thus,theoutcomes
revealedbysimpledescriptivestatisticsareconfirmedalsohere.


19

Inordertotaketheanalysisonestepfurther,thethirdcolumnallowsustolookmoreinto
theunderlyingmotivation,includingtermstorepresentattitudesdrawnfromthequestionnaireon
co‐operation,reciprocityandlocusofcontrol.Wewillreturntothisbelow,however,theresults
suggestthatattitudestoco‐operationare,somewhatunsurprisingly,themotivationunderlying
cooperationamongstplayers,inadditiontotheplayertype.
ThelasttwocolumnsinTable4whichestimatestheprobabilityofco‐operationseparately
forcamoristiandOCs,allowustolookinmoredetailatthebehaviourandmotivationsofthesetwo
groups.Inthiscase,interactiontermsareintroducedinthesetofthecovariatesbetweenthe
attitudinaldummies(namely,"Locus","Cooperator"and"Reciprocator")andthedummy"TPP".Of
particularrelevance,theresultsreportedincolumnIVdemonstratethatthenegativereactionto
TPPisrelatedtoparticipants’locusofcontrolandtotheirattitudestowardsco‐operationinthe
caseofCamorristi;thatis,bothinternallocusandamoreco‐operativeattitudetendtostrengthen
Camorristis’negativereactiontotheimpositionofTPP.Ontheotherhand,theresultsforOCsare
almostdiametricallyopposedtothese(columnV):whereas,astrongerinternallocusleadstoa
strengtheningofCamorristi’srejectionofexternalauthority,itsroleforOCsistoenhance
cooperationinthefaceofexternallyimposedpunishment.Again,thisisstronglyindicativeof
opportunismonthepartofOCs–themoretheyfeelincontroloftheoutcome,themorelikelythey
aretoco‐operateunderthreatofsanctions,whilstforCamorra,itisquitetheopposite,themore
theyfeelincontrol,themoretheyarelikelytoexplicitlyrejecttheexternalauthorityandrefuseto
co‐operatewithitsexternalimposition,despitethelikelycostofdoingso.

Result5:Wedonotfindsimilarpatternsofcooperationamongthethreesamples,particularly
betweenthetwosamplesofprisoners;aninternallocusofcontrolandattitudinalcooperativeness
arepositivelycorrelatedwithpro‐socialbehaviourintheexperimentamongstCamorristi,whilst
internallocusofcontrolreducesco‐operativenessfollowingtheimpositionofpotentialsanctions‐
reflectingtheexplicitnatureoftherejectionoftheexternalauthority;amongstOCs,thestrongand
statisticallysignificantpositiveassociationbetweeninternallocusofcontrolandco‐operationinTPP
maybeconsidered,incontrast,asfurtherevidenceofopportunisticbehaviouronthepartofOCs.




20

TABLE4‐ProbabilityofcooperationamongAandBplayers‐Probitestimates  
Variables Coeff.(std.err.)
I
Coeff.(std.err.)
II
Coeff.(std.err.)
III
Coeff.(std.err.)
Camorristi
IV
Coeff.(std.err.)
Ordinarycriminals
V
Ordinary Criminals [1]
Camorristi [2]
TP - PD[3]
Cooperator [4]
Reciprocator [5]
Locus [6]
Ordin. Criminals*TPP
Camorristi*TPP
Cooperator*TPP
Reciprocator*TPP
Locus*TPP
Constant
0.220 (0.195)
0.731*** (0.190)
-0.374** (0.159)
0.201 (0.159)
-0.454 (0.286)
0.657** (0.290)
-0.845*** (0.280)
1.275** (0.396)
0.125 (0.395)
0.454** (0.206)
0.019 (0.237)
0.493** (0.217)
-0.268° (0.181)
0.420*** (0.176)
-0.323° (0.201)
-0.178 (0.178)
0.338 (0.231)
0.064(0.504)
0.300***(0.123)
-0.175(0.168)
0.204*(0.108)
-1.197** (0.566)
0.111 (0.641)
-1.223** (0.569)
-0.025 (0.834)
0.086 (0.416)
-0.098 (0.131)
-0.002 (0.150)
-0.259**(0.126)
0.073 (0.533)
-0.297 (0.509)
1.446***(0.551)
1.402 (0.814)
N.ofobservations
Log.Lik.
Waldχ2
277
‐171.075
23.03
277
‐165.70
32.23
265
‐148.544
59.24
98
22.68
‐44.529
81
12.853
‐47.47
Legend:OrdinaryCriminals:dummy=1forordinarycriminals,0otherwise;Camorristi:dummy=1forCamorrainmates,0otherwise;excludedcategoryarestudents;TPP:secondsessioninthegame;
Cooperator:dummyequalto1ifthepropensitytocooperate,asmeasuredbythecoopindex,ishigherthanthemedianvalueinthesample;Reciprocator:dummyequalto1ifthepropensityto
reciprocate,asmeasuredbythereciprocityindex,ishigherthanthemedianvalueinthesample;Locus:dummyequalto1ifthepropensitytobelievethatpeoplecancontrolevent,asmeasuredbythe
lucusofcontrolindex,ishigherthanthemedianvalueinthesample.Coopindex,reciprocityandlocusofcontrolindexesaredescribedinTable3;thevariablesReciprocator,LocusandCooperatorin
columnsIVandVarecalculatedwithreferencetothemedianvaluesreportedforcamorristiandordinarycriminalsrispectively.
Notes:Robuststandarderrorsclusteringonindividuals.°statisticallysignificantat20%confidencelevel;*statisticallysignificantat10%;**statisticallysignificantat5%;***statisticallysignificantat1%.


21



TurningnowtoThirdParties,Table5reportsFGLSestimatesofpunishmentdecisions:the
dependentvariableistheamountoftokensspentbyCplayersinordertopunishplayersA&Bin
theTPPsessionofthegame.Thesetofindependentvariablesincludesdummiesrepresentingthe
differentpossiblesituations:i)mutualcooperation;ii)thepunishableplayerdefectedandtheother
playercooperated,iii)theotherplayerwasadefectorandthepunishableplayercooperatedandiv)
the(default)situationofmutualdefection.

TABLE5–DeterminantsoftheamountofpunishmentbyCplayers‐FGLSestimates
VarsCoefficients(std.err.)
III III
OrdinaryPrisoners
Camorristi
Bothplayerscooperate
Punishableplayerdefects
Otherplayerdefects
Cooperator
Reciprocator
Locus
Bothplayerscooperate*Ord.Criminals
Punishedplayerdefects*Ord.Criminals
Otherplayerdefects*Ord.Criminals
Bothplayerscooperate*Camorristi
Punishedplayerdefects*Camorristi
Otherplayerdefects*Camorristi
Constant
0.659**(0.324)
1.264***(0.259)
‐0.089(0.310)
5.216***(0.310)
‐1.099***(0.310)









0.803***(0.237)
1.307***(0.365)
1.412***(0.274)
‐0.075(0.311)
5.134***(0.311)
‐1.136***(0.311)
‐0.661***(0.269)
0.754***(0.259)
‐0.547**(0.261)






0.724***(0.270)
1.137(0.599)
0.565(0.498)
‐1.292***(0.316)
5.131***(0.316)
‐1.292***(0.316)



3.034***(0.846)
‐2.135**(0.846)
0.456(0.846)
2.199***(0.705)
1.717**(0.705)
‐0.437(0.705)
1.292***(0.223
Numberofobservations
Waldχ2
552
530.42
488
497.78
552
833.67
Legend:Bothplayerscooperate:dummy=1ifbothplayers(A&B)hadcooperatedduringtheTP‐PDsession;Punishedplayerdefects:
dummy=1ifthepunishedplayer(AorB)haddefeatedduringtheTPPsessionwhiletheotherplayerhadcooperated;Punishedplayer
cooperates:dummy=1ifthepunishedplayer(AorB)hadcooperatedduringthesessionTP‐PDwhiletheotherplayerhaddefeated;
theexcludeddummyreferstobothplayersdefeating.ThevariablesCooperator,Reciprocator,Locus,aredefinedinTable4.Notes:°
statisticallysignificantat20%confidencelevel;*statisticallysignificantat10%;**statisticallysignificantat5%;***statistically
significantat1%.


22


TheestimatesincolumnIconfirmthat,onaverage,sanctionsondefectorsaremoreseverewhen
theotherplayercooperates.Takingtheanalysisalittlefurther,controllingforindividual
preferences,thesecondcolumnshowsthatamoreco‐operativeattitudeandastrongerinternal
locusofcontrolnegativelyaffectthesizeofpunishmentwhiletheoppositeevidenceisreported
amongco‐operators.ThemodelspecificationreportedincolumnIIIincludesinteractiveterms
betweendummiesrepresenting,respectively,thedifferentpossiblesituationsofthegame(i.e.,
mutualcooperation,punishedplayerdefects,theotherplayerdefects)andthetypeofsample
(ordinarycriminalsorcamorrainmates).ThisshowsthatonlyCamorrainmatesaremorelikelyto
punishdefectorswhentheotherplayercooperates,whiletheoppositeevidenceisreportedfor
ordinarycriminals,confirmingthesuggestiveresultsofthedescriptiveanalysis.Finally,whenboth
playerscooperate,thesanctionsimposedbyordinaryprisonersarealsomoreseverethatthose
inflictedbyCamorrainmates:thisconfirmsthefindingofastrongtendencytowardspunishing
"unfairbehaviour"amongsttheCamorrainmates,whereasOPsaremorelikelytopunishco‐
operators.
Beyondconfirmingtheresultsofthedescriptiveanalysis,theseparateresultsforCamorra
andOCsreportedinTable6offeradeeperinsightintothedifferencesbetweenthetwosamplesof
prisoners.Introducingtermsforindividualpreferencestowardscooperation,reciprocityandlocus
ofcontrol,itemergesthatwhereasforCamorristi,thetendencytopunishincreaseswithbeliefin
the‘correctness’ofreciprocity–andparticularlypositivereciprocity–andwithamoreinternal
locusofcontrol(i.e.thebeliefthatindividualsareinfluentialindeterminingoutcomesaffecting
them),againabove‐allasregardspositiveoutcomes,forOrdinaryPrisoners,thesignoftheeffects
isreversed.Inotherwords,amongsttheCamorra,subjectswhoaremoreorientedtowards
reciprocity,cooperativenessandwithahigherinternallocusofcontrolaremorelikelytopunish
"unfairbehaviour".Wefindquitetheoppositerelationamongstordinaryprisoners:more
cooperativesubjectsaremorelikelytopunish,whilethe"kindreciprocators"punishless.This
providesfurtherandmoreconcreteevidenceoftheopportunismofOPswhichcanbecompared
withthemore‘Honour’boundmoresofCamorristiandtheconsequentstrongpunishmentof
betrayal.
Result6:Withrespecttotheseverityofpunishment,thethreesamplesexhibitquitedifferent
behaviour;inparticular,Camorrainmatesaremorewillingtopunish"betrayal".Consistentwithour


23

expectations,apositivecorrelationbetweenreciprocity,internallocusofcontrolandsanctioning
behaviouremergesamongstCamorrainmates,whereco‐operatorsarelesslikelytopunish.Quite
theoppositeresultsarefoundforordinarycriminals.



24


TABLE6‐AmountofpunishmentbyCPlayers‐FGLSEstimates
Camorrainmates OrdinaryCriminals
VariablesCoeff(std.err.)

Coeff(std.err.)


Bothplayerscooperate
Punishedplayerdefects
Otherplayerdefects
Cooperator
Reciprocator
Locus
Competitionindex
Cooperationindex
Positivereciprocity
Negativereciprocity
Locusofcontrol(good
events)
Locusofcontrol(bad
events)
Constant
I
0.939*(0.549)
5.670***(0.549)
‐1.710***(0.549)
‐1.655***(0.423)
1.145***(0.424)
0.682°(0.430)








2.265***(0.487)
II
0.934*(0.527)
6.034***(0.526)
‐1.258**(0.527)



0.290(0.243)
‐0.643**(0.290)
1.038***(0.335)
0.515**(0.221)
0.605**(0.308)

0.226(0.209)

‐4.718**(1.987)
III
2.209***(0.787)
3.399***(0.786)
‐0.992°(0.787)
‐0.783°(0.609)
‐1.326**(0.620)
‐1.566***(0.590)








3.051***(0.766)
IV
2.081**(0.766)
3.261***(0.766)
‐0.875(0.766)



0.079(0.338)
0.894**(0.348)
‐1.336**(0.578)
‐0.234(0.353)
‐0.095(0.266)

1.162***(0.256)

1.829(0.73)
Numberofobservations
Waldχ2
152
219.12
152
253.71
160
52.53
160
64.38
Legend:
Competitionindex:highervaluesindicatehigherpropensitytocompete;Cooperationindex:highervaluesindicatehigher
propensitytocooperate;Positivereciprocity:highervaluesindicateahighertendencytowardsreciprocatingkindness;Negative
reciprocity:highervaluesindicatehighertendencytowardsreciprocatingunkindness;Locusofcontrolbadevents:highervalues
indicateahigherpropensitytobelievethatpeoplecancontrolbadeventsaffectingthem;Locusofcontrolgoodevents:higher
valuesindicateahigherpropensitytobelievethatpeoplecancontrolgoodeventsaffectingthem.Seealsolegendintables3‐5.
Notes:°statisticallysignificantat20%confidencelevel;*statisticallysignificantat10%;**statisticallysignificantat5%;***
statisticallysignificantat1%.


6.ConcludingRemarks
Recentresearchinexperimentaleconomicshassoughttoassesswhetherconvicted
criminalssharecomparablesocialpreferenceswithothersectorsofthepopulation.Ontheother
hand,whendealingwithMafiaorCamorra,economistsandsocialscientistshavetendedtoinvert
thequestionarguingthatthepresenceofMafiageneratesnegativeexternalities.Specifically,in
areaswhereorganizedcrimeoperates,citizens’socialbehaviourisaffectedbythepresenceofthese
powerfulgroupsandpositedtobelesscooperative,trusting,honestandtrustworthythancitizens’
socialbehaviourlivinginareaswherethecriminalgroupsareabsent.
Theresultspresentedheresuggestamorecomplexpattern.Weexaminedin‐group
behaviourandattitudesoftheCamorra.Usingathree‐waycomparison,withtwocontrolgroups,
studentsand‘Ordinaryprisoners’allowedustoclearlyidentifydistinctpatternsofbehaviourand
attitudesvis‐à‐visco‐operationandpunishmentpeculiartotheCamorra.


25

Ingeneral,wefoundmuchdissimilarityinthebehaviourofordinaryprisoners,Camorristi
andstudents.Interalia,thesedifferencesareindicativeof,oratleastconsistentwith,alackof
contaminationornegativeexternalitiesassociatedwiththeCamorra.
ThereisadegreeoffatalismobservableinthebehaviourandattitudesofbothCamorristi
andordinaryprisonersasevidenced,forexample,bythepunishmentofco‐operatorsbybothtypes
ofprisonerintheroleofthirdpartyadjudicator,and,moredirectly,inthemoreexternallociof
controlobservableinbothtypesofprisonerabove‐allwhenitcomesto‘bad’events.Thiswethink
canreasonablybeattributedtoacommonprison‘effect’.
Ontheotherhand,thereisclearevidenceofanattachmenttoco‐operative(in‐group)norms
ofbehaviouramongstCamorristiandrejectionofsuchruleswhentheyareexternallyimposed–
leadingtoasignificantreductioninco‐operationonceanexternal‘judge’isintroduced–whichis
notobservedamongstordinaryprisonerswhotendtobecomemoreco‐operativeunderthethreat
ofexternallyimposedpunishment.Thebehaviourofordinaryprisonerthussuggestsanimportant
elementofopportunismwhichisentirelylacking–orperhapsmoreaccurately–completely
overwhelmedbythemorehonour‐boundmoresoftheCamorra,withitsemphasisonthenegative
natureofbetrayalandtherejectionofexternalauthority.
Thestudyoffersacontributiontothegrowingareaofexperimentalworkontheeconomics
ofcrimecomparingcriminalsandordinarycitizens'socialbehaviour.Inthisregard,interalia,the
studyprovidesclearevidenceofbehaviouraldifferencesbetweencitizens(students)ordinary
criminalsandCamorristiwhichemphasizetheneedtoadoptbehaviouralperspectivesindealing
withorganizedcrime,ratherthananapproachbasedonpurelyeconomicincentives.
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