《创新的扩散》(diffusion of innovation)(英文.文字版)

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DiffusionofInnovations

EverettM.Rogers

UniversityofNewMexico

ArvindSinghal

UniversityofTexas–ElPaso

andMargaretM.Quinlan

OhioUniversity

AchapterinDonStacksandMichaelSalwen(Eds)(inpress).Anintegratedapproachtocommunicationtheoryandresearch.NewYork:Routledge.

EverettM.RogersandDiffusionofInnovations

Thischapterisdedicatedtoourseniorco-authorEverettM.Rogers,aprolificscholarofcommunicationandsocialchangeandawonderfulhumanbeing,whopassedawayinAlbuquerque,NMinOctober2004(Photo26-1).Bestknownforhisbook,DiffusionofInnovations(publishedinthefiftheditionin2003),EvRogers’life–all73years–representedacuriousengagementwiththetopicofinnovationdiffusion.

ThestorybeginsonthefamilyPinehurstFarminCarroll,Iowa,whereEvRogerswasbornonMarch6,1931

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.TheGreatDepressionwasraging,andlifeonPinehurstFarmwastoughforeveryone,especiallyforayoungEv,whowasresponsibleforcarryingoutsuchdailychoresasmilkingcows,feedingchickens,andcleaningthebarn.Evcreditedthatdailyhardworkethic,learnedearlyonanIowafarm,tohisillustriousscholarlycareer,completewith36books,over300peer-reviewedessays,andcountless

researchreports.

WhowouldnowbelievethatEvalmostneverwenttoCollege?HewouldhavestayedhomeandfarmedifitwerenotforPepMartens,ahighschoolteacher,whopackedabunchofpromisingseniorsinhiscaranddrovethemtoAmes,Iowa,thehomeofIowaStateUniversity.ItwasEv’sfirstvisittoAmes,located60milesfromthefamilyfarm.EvlikedAmes,anddecidedtopursueadegreeinagriculture.

IowaStateinthoseyearshadgreatintellectualtraditioninagricultureandinruralsociology.NumerousagriculturalinnovationsweregeneratedbyscientistsatIowaState.Ruralsociologists–includingBryceRyanandGeorgeBeal,Ev’sdoctoraladvisor--wereconductingpioneeringstudiesonthediffusionoftheseinnovations--likethehigh-yieldinghybridseedcorn,chemicalfertilizers,andweedsprays.Questionswerebeingaskedaboutwhydosomefarmersadopttheseinnovations,andsomedon’t?ThesequestionsintriguedEv.

Atthefarm,Evremembersthathisfatherlovedelectro-mechanicalfarminnovations;butwasresistanttobiological-chemicalinnovationssuchasthenewhybridseedcorn,eventhoughityielded20percentmorecrop,andwasresistanttodrought.

However,duringtheIowadroughtof1936,whilethehybridseedcornstoodtallontheneighbors’farm;thecropontheRogers’farmwilted.Ev’sfatherwasfinallyconvinced.Ittookhimeightyearstomakeuphismind.

Thesequestionsaboutinnovationdiffusion,includingthestrongresistances,andhowtheycouldbeovercome,formedthecoreofEv’sgraduateworkatIowaStateUniversityinthemid-1950s.Ev’sdoctoraldissertationsoughttoanalyzethediffusionofthe2-4-Dweedspray(andaclusterofotheragriculturalinnovations)inCollins,Iowa,acommunityclosetoPinehurstFarm.Inthereviewofliteraturechapter,Evreviewedtheexistingstudiesofthediffusionofallkindsofinnovations--agriculturalinnovations,educationalinnovations,medicalinnovations,andmarketinginnovations.Hefoundseveralsimilaritiesinthesestudies.Forinstance,innovationstendtodiffusefollowinganS-Curveofadoption.

In1962,Evpublishedthisreviewofliteraturechapter,greatlyexpanded,enhanced,andrefined,astheDiffusionofInnovationsbook.Hearguedthatdiffusionwasageneralprocess,notboundbythetypeofinnovationstudied,bywhotheadopterswere,orbyplaceorculture.Byreviewingdiffusionstudiesacrossarangeofdisciplines,heconcludedthatthediffusionprocessdisplayedpatternsandregularities,acrossarangeofconditions,innovations,andcultures(Rogers,2004).

Thebookprovidedacomprehensivetheoryofhowinnovationsdiffused,orspread,inasocialsystem.Thebook’sappealwasglobal(Hornik,2004).Itstimingwasuncanny.Nationalgovernmentsofnewly-independentcountriesofAsia,Africa,andLatinAmericawerewrestlingwithhowtodiffuseagricultural,health,andfamilyplanninginnovationsintheirnewly-independentcountries(Barker,2004;Bertrand,2004;Haider&Kreps,2004;Murphy,2004).Herewasatheorythatwasuseful.Duringthe

1960sand1970s,foreverycopyofDiffusionofInnovationsthatwaspurchasedintheU.S.,EvestimatedthatfourwerebeingpurchasedincountriesofAsia,Africa,andLatinAmerica.

WhenthefirsteditionofDiffusionofInnovationswaspublished,Evwas31-yearsold.Buthehadalsobecomeaworld-renownedacademicfigure.AspertheSocialScienceCitationIndex,DiffusionofInnovationsisthesecondmostcitedbookinthesocialsciences.

NotbadforanIowafarmboywhoalmostdidnotgotocollege!

WhatisDiffusion?

WhentheWorldHealthOrganizationlaunchedaworldwidecampaigntoeradicatesmallpox,itwasengagedindiffusion.WhenApplelaunchedI-POD,itwasdiffusinganewproduct.WhenBobDylanwrote“TheTimesTheyAreA-Changin,’”hewasdescribingdiffusion(Dearing&Meyer,2006).Whenprofessionaldancers–bothstandingupandsittingdown(inwheelchairs)--performonstage,asdotheartistesoftheDancingWheelsdancecompanyinCleveland,theyarediffusinganewimageofwhatconstitutes(dis)ability

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.

Diffusionistheprocessbywhichaninnovationiscommunicatedthroughcertainchannelsovertimeamongthemembersofasocialsystem(Rogers,2003).Aninnovationisanidea,practice,orobjectperceivedasnewbyanindividualorotherunitofadoption.Thediffusionprocesstypicallyinvolvesbothmassmediaandinterpersonalcommunicationchannels.And,intoday’sworld,informationtechnologiessuchastheInternetandcellphones–whichcombineaspectsofmassmediaandinterpersonalchannels,representformidabletoolsofdiffusion(Morris&Ogan,1996).Considerthefollowingexperienceofco-authorSinghalinthePhilippines.

InMay2006,asSinghalstrolleddownEpifaniodelosSantasAvenue(knownas“Edsa”)inManila,Philippines,aFilipinacolleaguenotedthat“EdsawasthestreetwherethegovernmentofPresidentEstradawasbroughtdownbycellphones.

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”GraspingthepuzzledexpressiononSinghal’sface,sheelaborated:“Somefiveyearsago,atextmessageappearedonmycellphone.Itsaid‘Go2EDSA.’”Withinafewhours,EdsawasteemingwithtensofthousandsofFilipinoswhohadreceivedthesamemessage.

TheyweredemonstratingagainstthecorruptEstradaregime.Withinafewdays,thecrowdswelledtooveramillion.Estradawastoppled.

UponreturningtotheU.S.,authorSinghal’sInternetsearchrevealedthatinJanuary2001,theimpeachmenttrialagainstPresidentEstradawashaltedbysenatorswhosupportedhim.Withinminutes,usingcellphones,theoppositionleadersbroadcastatextmessage“Go2EDSA.Wearblck”tofolksontheirtelephonelists.Therecipients,inturn,forwardedthemessagetoothers.Therapid(almostinstant)diffusionofatextmessageledthemilitarytowithdrawsupport;thegovernmentfellwithoutasingleshotbeingfired.

AfterreadingthestoryontheInternet,Singhalforwardeditbyemailtothe28undergraduatestudentsenrolledinhisCommunicationandInformationDiffusionclassatOhioUniversity,askingthemtoshareitwithinterestedfamilyandfriends.Manydid.SohereweseehowaninnocuousinterpersonalexchangeonastreetinManila--abouttheconsequentialspreadofanSMSmessage–wasitselfdiffusedfromasinglesource(theinstructorofacourse)tomanyrecipientsand,inturn,toothersinmultiplecascadingdiffusionwaves.

Thischapteranalyzestheresearchtraditionofthediffusionofinnovations,focusingontheoriginsofthediffusionparadigm,itsmethodologicaltenets,anditsinfluenceoncommunicationresearch.Weidentifythedistinctiveaspectsofdiffusionresearch,detailtheseminalIowahybridseedcornstudy,explainthestrengthsandlimitationsofthedominantparadigmthatguideddiffusionstudyforseveraldecades,andlookintothefutureofdiffusionpracticeandresearch.Weendourchapterbydiscussingthepositivedevianceapproachwhich,webelieve,providesanalternative(“inside-out”)wayofthinkingaboutdiffusinginnovations,andonethatcapitalizesonpeoples’indigenouswisdom.

DistinctiveAspectsofDiffusionResearch

Severaldistinctiveaspectsofthediffusionofinnovationssetitofffromotherspecializedfieldsofcommunicationstudy.

ThestudyofthediffusionofinnovationsbeganduringWorldWarII,priortotheestablishmentofcommunicationstudyinuniversityschoolsanddepartments(Rogers,2003).Sodiffusionresearchwaswellunderwayasaresearchactivitybeforecommunicationscholarsenteredthisresearchfront.

Althoughmostobserversagreethatthediffusionofinnovationsisfundamentallyacommunicationprocess,communicationscholarsconstituteonlyoneofthedozenresearchtraditionspresentlyadvancingthediffusionfield(alongwithgeography,education,marketing,publichealth,ruralsociology,agriculturaleconomics,generaleconomics,politicalscience,andothers).Othercommunicationresearchareassuchaspersuasionandattitudechangeandmasscommunicationeffectsalsobeganpriortotheinstitutionalizationofcommunicationstudyinuniversityunits(Rogers,1962,1983,1995;2003;Singhal&Dearing,2006).

Diffusionresearchisalsodistinctiveinthatthecommunicationmessagesofstudyareperceivedasnewbytheindividualreceivers.Thisnoveltynecessarilymeansthatanindividualexperiencesahighdegreeofuncertaintyinseekinginformationabout,anddecidingtoadoptandimplementaninnovation.Inthesenseofthenewnessofthemessagecontent,thediffusionofinnovationsisunlikeanyothercommunicationstudyexceptthediffusionofnews.Diffusionofnews,however,studiesthespreadofnewsevents,concentratingmainlyonsuchmattersashowwebecomeawareofnews.Incontrast,researchonthediffusionofinnovationscentersnotonlyonawareness-knowledge,butalsoonattitudechange,decision-making,andimplementationoftheinnovation.Thenewideasinvestigatedbyscholarsofthediffusionofinnovationsare

mainlytechnologicalinnovations,sothebehaviorstudiedisquitedifferentfromthatinvestigatedinnewsdiffusionstudies.Obviously,however,bothcommunicationresearchareasinvolveasimilardiffusionprocess,andbothhavebeeninformedbytheother(Rogers,2003).

Diffusionresearchconsiderstimeasavariabletoamuchgreaterdegreethandootherfieldsofcommunicationstudy.Timeisinvolvedindiffusionin(a)theinnovation-decisionprocess,thementalprocessthroughwhichanindividualpassesfromfirstknowledgeofanewidea,toadoptionandconfirmationoftheinnovation;(b)innovativeness,thedegreetowhichanindividualisrelativelyearlierinadoptingnewideasthanothermembersofasystem;and(c)aninnovation’srateofadoption,therelativespeedwithwhichaninnovationisadoptedbymembersofasystem(Rogers,2003).

Thediffusionofinnovationsfieldemphasizesinterpersonalcommunicationnetworksmorethananyothertypeofcommunicationresearch.Fromthefirstdiffusionstudiesconductedabout60yearsago,thenatureofdiffusionwasfoundtobeessentiallyasocialprocessinvolvinginterpersonalcommunicationamongsimilarindividuals(Rogers&Kincaid,1981;Rosen,2002;Valente,1995;2006).Apersonevaluatesanewideaanddecideswhetherornottoadoptitonthebasisofdiscussionswithpeerswhohavealreadyadoptedorrejectedtheinnovation.Themainfunctionofmassmediacommunicationinthediffusionprocessistocreateawareness-knowledgeabouttheinnovation.Studyofthediffusionofinnovationsinvolvesbothmasscommunicationandinterpersonalcommunication,andthusspansthedichotomythatotherwisedividescommunicationintotwosub-disciplines.ThesedichotomiesblurfurtherwhendiffusionoccursthroughtheInternet,cellphones,andblackberrydevices.

BackgroundofDiffusionResearch

Thestudyofthediffusionofinnovationsinitspresent-dayformcanbetracedfromthetheoriesandobservationsofGabrielTarde,aFrenchsociologistandlegalscholar(Rogers,2003).Tardeoriginatedsuchkeydiffusionconceptsasopinionleadership,theS-curveofdiffusion,andtheroleofsocioeconomicstatusininterpersonaldiffusion,althoughhedidnotusesuchconceptsbythesenames.SuchtheoreticalideasweresetforthbyTarde(1903)inhisbook,TheLawsofImitation.

TheintellectualleadssuggestedbyTardeweresoonfollowedupbyanthropologists,whobeganinvestigatingtheroleoftechnologicalinnovationsinbringingaboutculturalchange.IllustrativeoftheseanthropologicalstudieswasClarkWissler’s(1923)analysisofthediffusionofthehorseamongthePlainsIndians.Asinotheranthropologicalworks,theemphasiswasontheconsequencesofinnovation.Forexample,Wissler(1923)showedthataddinghorsestotheircultureledthePlainsIndians,whohadlivedinpeacefulcoexistence,intoastateofalmostcontinualwarfarewithneighboringtribes.

ThebasicresearchparadigmforthediffusionofinnovationscanbetracedtoBryceRyanandNealC.Gross’sclassic1943studyofthediffusionofhybridseedcornamongIowafarmers.Thisinvestigationwasgroundedinpreviouslyconductedanthropologicaldiffusionwork,whichRyanhadstudiedwhileearninghisdoctoraldegreeatHarvardUniversity,priortobecomingafacultymemberinruralsociologyatIowaStateUniversity,whereGrosswasagraduatestudent.Wediscussthehybridcornstudyindetaillaterinthischapter.

Duringthe1950smanydiffusionstudieswereconducted,particularlybyruralsociologistsatland-grantuniversitiesinthemidwesternUnitedStates.TheyweredirectlyinfluencedbytheRyanandGrossinvestigation.Assoonascommunicationstudybegantobeinstitutionalized,thisnewbreedofscholarsbecameespeciallyinterestedinthediffusionofnewsevents,particularlythroughaninfluentialstudybyPaulJ.DeutschmannandWayneA.Danielson(1960).

CommunicationResearchonDiffusion

Deutschmann,aformernewspaperreporterandeditor,earnedhisPh.D.incommunicationatStanfordUniversity,gainingcompetenceinquantitativemethods,communicationtheory,andsocialpsychology.HebecameafriendandresearchcollaboratorwithDanielson,hisfellowdoctoralstudentatStanford,andanindividualwithasimilarbackgroundofprofessionalnewspaperexperience.

EvRogersmetDanielsonin1959atthenewlyestablishedDepartmentofCommunicationatMichiganStateUniversity,whereDeutschmannshowedhimtheS-shapeddiffusioncurvesforthespreadofthenewseventsthathewasthenstudying.

ComparedtothediffusioncurvesfortheagriculturalinnovationsthatRogerswasinvestigating,thenewseventsspreadmuchmorerapidly.AsDeutschmannstatedatthetime,thiswas“damnfastdiffusion”(personalcommunication).ThankstoDeutschmannandDanielson’s(1960)articleonthediffusionofnewsevents,thisresearchtopicbecamepopularamongcommunicationscholars.Workonthistopichasebbedconsiderablyalthoughspectacularnewsevents–suchas9/11orthe2003spaceshuttleColumbiadisaster–continuetoattractscholars(Singhal,Rogers,&Mahajan,1999;Rogers&Seidel,2002).

Intheearly1960s,DeutschmannmovedtoSanJosé,CostaRica,andcollaboratedwithDr.OrlandoFalsBorda,asociologistattheNationalUniversityofColombiainBogotá,whohadbeenstudyingdiffusionpatternsintheColombianvillageofSaució,asmallAndeancommunityof71farmhouseholds.DeutschmannandFalsBorda’s(1962)diffusionstudyinSauciórepresentedoneofthefirstdiffusioninvestigationsinadevelopingnation.Soontherewouldbeseveralhundredsuchdiffusionstudies,manyconductedbycommunicationscholars.ThesixagriculturalinnovationsofstudyinSaució(suchaschemicalfertilizer,anewpotatovariety,andapesticide)hadbeenintroducedinpreviousyearsbyFalsBorda,whoactedasanagriculturalchangeagent--oronewhointroducedinnovationstothepublic.ThefamiliarS-shapedcurve

characterizedtherateofadoptionforeachoftheseinnovationsintheColombianvillage(Deutschmann&FalsBorda,1962).

Deutschmann’sstudywithFalsBordainColombiastimulatedinterestamongcommunicationscholarsinthediffusionoftechnologicalinnovations.HeattracteddoctoralstudentstoMichiganStateUniversitywhowereinterestedindiffusionresearch.WhenDeutschmann’slifewascutshortin1962,EverettRogerswashiredashisreplacementatMichiganStateUniversitytocontinuediffusionresearchindevelopingnations.Thenumberofdiffusionstudiescompletedbycommunicationscholarsexpandedrapidlysince1960.Bymid-2007,anestimated600diffusionpublicationsbycommunicationscholarswereavailableoutofthecacheof6,000diffusionstudies

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,morethananyotherdiffusionresearchtraditionafterruralsociologyandmarketing.Unlikeruralsociologists,whoaremainlyconcernedwithagriculturalinnovations,oreducationdiffusionscholars,whoareinterestedinneweducationalinnovations(forexample,modernmathorthemulticulturalcurriculum),communicationscholarsinvestigateawiderangeofdifferenttypesoftechnologicalinnovations.Communicationscholarsareinterestedindiffusionasacommunicationprocess,independentofthetypeofinnovationsthatarediffused.

TheIowaHybridSeedCornStudy

WhenRyanarrivedinAmes,Iowa,in1938,hewasintriguedwiththescholarlyquestionofnoneconomicinfluencesoneconomicbehavior.ThisissuehadbecomeimportanttohimduringhisdoctoralstudiesintheDepartmentofSociologyatHarvardUniversity,whereRobertK.Merton,ayoungfacultymemberwhohadrecentlycompletedhisowndissertationresearchonthesociologyofscience,wasRyan’sdoctoraladvisor.TheHarvarddoctoralprograminsociologywasrelativelynew,andsomewhatinterdisciplinaryinnature.Studentsearningdegreesinsociologywereencouragedtotakecoursesineconomics,anthropology,andinsocialpsychology.ProfessorTalcottParsons,theintellectualleaderofHarvardsociology,hadbeentrainedineconomicsinEuropeandhelpedintroducethetheoriesofVilfredoParetotoAmericansociology.ThisinterdisciplinaryintellectualbackgroundwasgoodpreparationforRyan,theindividualwho,morethananyother,wastoformulatetheparadigmforresearchonthediffusionofinnovations.

IowaStateUniversitywasanagriculturalcollege,andsoRyandecidedtoinvestigatethediffusionofhybridseedcorn.ThisinnovationwasaprofoundlyimportantnewideaforIowafarmers,leadingtoincreasedcornyieldsofabout20percentperacre.RyanreceivedfundingforhisproposedstudyofthediffusionofhybridseedfromtheIowaAgriculturalExperimentStation,IowaStateUniversity’sresearchanddevelopmentorganization,whichhadplayedanimportantroleindevelopinghybridseed.ThisimportantinnovationhadspreadwidelytoIowafarmersinpreviousyears,butIowaStateadministratorswereconcernedthatsuchanobviouslyadvantageousagriculturaltechnologyhadrequiredsomanyyears(aboutadozen)forwidespreaduse.Thistypeoffrustrationonthepartofofficialswhocannotunderstandwhyaseeminglyadvantageous

innovationisnotadoptedmoreimmediatelyexplainswhymanydiffusionstudiescontinuetobesponsored.

RyancollaboratedwithseveraleconomicsprofessorsatIowaStateUniversityindesigningthehybridcornstudy,andhisfamiliaritywithanthropologicalresearchalsoaffectedthestudy’sdesign.HoweverRyanproposedtheseedcornstudymainlyasasurveyrelyingonquestionnaire-generateddata,ratherthanusingtheethnographicapproachesofthepreviousanthropologicalresearch.

Anewlyarrivedmaster’sstudentatIowaState,NealC.Gross,wasassignedasRyan’sresearchassistant.RyantoldGrossthatifhewouldpersonallyinterviewtheseveralhundredfarmersinthetwoIowacommunitiesofstudy,hecouldusethedataforhismaster’sthesis.Gross,whocamefromanurbanbackground,wasunfamiliarwiththewaysofIowafarmers.SomeonetoldGrossthatfarmersbeganworkearlyinthemorning,soheappearedatthefarmsteadofhisfirstrespondentat4a.m.

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ThechoiceofhybridseedcornastheinnovationofstudyintheRyanandGrossinvestigationwastocastalongintellectualshadowoverfuturegenerationsofdiffusionscholarship.Hybridseedwasanoverwhelminglybeneficialinnovation,boostingcornyieldsconsiderably.Giventhesponsorshipofthehybridcornstudy,itisunderstandablethatRyanandGrosstendedtoassumethatIowafarmersoughttoadopttheinnovation,andthattherateofadoptionshouldhavebeenmorerapid.Thispro-innovationbiasstillcharacterizesmostdiffusionstudiestoday.RyanandGross(1943)indicatedtheirsurprisethatthediffusionofhybridcornrequired12yearstoreachwidespreaddiffusion,andthattheaveragefarmerneededsevenyearstoprogressfrominitialawarenessoftheinnovationtofull-scaleadoption(indicatedbyplantingallofthecornacreageonhisfarminhybridseed).

Statedanotherway,thehybridcornstudydemonstratedjusthowdifficultitwasformostindividualstoadoptaninnovation.Hybridcornhadtobepurchasedfromaseedcorncompany,atapriceperbushelnottrivialtoIowafarmersintheDepressionyears.

Further,adoptingtheinnovationmeantthatIowafarmersnolongerselectedthemorebeautiful-appearingearsofcornforuseasseedthefollowingyear.Sotheadoptionofhybridcornmeanttheunadoptionofapreviouslyexistingpractice,thevisualselectionofopen-pollinatedseed.HybridcornwasoneofthefirstofthenewwaveofscientificallybasedfarminnovationsthatweretoradicallychangethenatureofMidwesternagricultureintheensuingdecades.In1939,Iowafarmerswerenotaccustomedtoagriculturalinnovationsthatwerelatertoflowfromtheland-grantuniversitieslikeIowaStateandtheU.S.DepartmentofAgriculture.

IowaStateUniversitywastheperfectplaceforfoundingtheparadigmfordiffusionresearchinyetanothersense:AmeswastheprincipalpointofimportationfortheintroductionofstatisticalmethodsinAmerica.ThesetechniquesforquantitativedataanalysisbeganamongagriculturalstatisticianssuchasSirRonaldFisherandKarlPearsoninEngland.Theywerecreatedtotesthypothesesabouttheeffectsoffertilizers,newcropvarieties,andlivestockrations.Suchstatisticalmethodsasanalysisof

varianceandregressioncametotheUnitedStatesintheearly1930swhenSirRonaldvisitedIowaStateUniversity,wherehehelpedestablishtheStatisticalLaboratory.

GeorgeSnedecor,leaderoftheIowaStateprograminstatistics,namedtheFstatistic(fordeterminingthesignificanceofanalysesofvarianceandregression)afterFisher.

Snedecorpopularizedstatisticalmethodsforagriculturalresearchinhisbook,StatisticalMethods(1931).IowaState’sStatisticalLaboratorywentontodeveloptheareasamplingmethodswidelyusedinsurveyresearch.ProfessorsintheDepartmentofStatistics,suchasPaulG.Homemeyer,RayJ.Jessen,andSnedecor,servedasinformalconsultantstoRyaninplanningthehybridcornstudy,andthispioneeringdiffusioninvestigationwasdesignedasahighlyquantitativeanalysis,utilizingstatisticalmethodstotesthypotheses.Asnotedearlier,thiswasamarkeddeparturefromanthropologicalethnographicdiffusionresearch.

Inthelate1930ssociologicalresearchintheUnitedStateswasmovingtowardquantification,awayfromthequalitativemethodsthathadbeenpioneeredbytheChicagoSchoolinthe1915to1935era(Rogers,2003).Sociologiststhoughtthattobecomescientificwastopatternthemselvesafterthebiologicalandphysicalsciences,atleastintheirresearchmethods.Thismovetoquantificationimpliedtheuseofindividualsasunitsofresponseandasunitsofanalysis,sothatstatisticalmethods,borrowedfromagricultural-biologicalresearch,couldbeutilizedinsociologicalstudies.

RyanandGross’shybridcorndiffusionresearchexpressedthissociologicalsearchforscientificrespectabilityinitschoiceofmethods.DataweregatheredbypersonalinterviewswithallofthefarmersinthetwoIowacommunitiesofJeffersonandGrandJunction(bycoincidence,thesecommunitieswerelocatedwithin30milesofwhereRogersgrewuponafarm).Eachfarmerwasregardedbythetworuralsociologistsasadecision-makingunitfortheadoptionofhybridcorn.

Thefocusonindividualfarmersledtothegreatestshortcomingofthehybridcorninvestigation.SociometricquestionstomeasuretheinterpersonalnetworklinksamongtheIowafarmersofstudywerenotasked.Thismistakeisallthemorepuzzlinggiventhatdiffusionisessentiallyasocialprocess.Whilethemassmediaoftencreateawareness-knowledgeofaninnovation,interpersonalcommunicationwithpeersisnecessarytopersuademostindividualstoadoptanewidea(Rogers&Kincaid,1981).

RyanandGrossgathereddatafromacompletecensusofthefarmersinJeffersonandGrandJunction,Iowa,anidealsamplingdesignformeasuringnetworklinksandthusfordeterminingpeerinfluencesonfarmers’decisionstoadopttheinnovation.The

farmer-respondentswereaskedaboutthesourcesandchannelsfromwhichtheyfirstlearnedabouthybridcorn(commercialseeddealersandsalespeoplewerementionedasmostimportant)versusthesourcesandchannelsthatconvincedthemtoadopt(otherfarmerslikeneighborsandfriendswerereportedasmostimportant).SoRyanandGrossestablishedtheimportanceofsocialnetworksindiffusion,butfailedtoinvestigatetheminanappropriateway.

ApplyingtheDiffusionModelinSanFrancisco’sSTOPAIDSProgram

IntheearlydaysoftheAIDSepidemicinSanFrancisco,in1981and1982,considerabledisagreementexistedwithinthegayandbisexualcommunityabouthowtocopewithHIV/AIDS.By1992,anastounding48percentoftheminthiscitywereHIV-positive.SomeoutspokenindividualsquestionedwhethersexualbehaviorspreadHIV(theysuspectedthatstraightsocietywasusingtheAIDSthreattoclosetheSanFranciscobathhouses,inordertolimitthesexualfreedomofgaymen).Eventually,gayorganizationspulledtogethertocombattheepidemicthroughtheS