题目内容：
Whilecontactbetweenadolescents(betweentheagesoffifteenandnineteen)andtheirpeerscrd龄人)isauniversalcharacteristicofallcultures,thenatureandthedegreeofsuchcontactvaryagreatdeal.InAmericancontemporarysociety,adolescentsspendmuchmoretimewiththeirpeersthanwithyoungerchildrenoradults.Thispatternofagesegregation(隔离)inAmericansocietydidnotbecomeusualuntilthebeginningoftheindustrializedsociety.Changesintheworkplaceseparatedchildrenfromadults,withadultsworHngandchildrenattendingschool.Thedramaticincreaseofmothersintheworkplacehasfurthercontributedtothereductionintheamountoftimeadolescentsspendwithadults.Schoolreformeffortsduringthenineteenthcentury,whichresultedinage-segregatedschoolsandgrades,havereducedtheamountoftimeadolescentsspendwithyoungerchildren.Finally,thechangesinpopulationareconsideredafactorthatmayhavecontributedtotheemergenceofadolescentpeerculture.From1955t01975,theadolescentpopulationincreaseddramatically,from11percentt020.9percent.Thisincreaseinthenumberofadolescentsmightbeacontributingfactortotheincreaseinadolescentpeercultureintermsofgrowthinsize.
Researchsupportstheviewthatadolescentsspendagreatdealoftimewiththeirpeers.ReedLarsonandhiscolleaguesexaminedadolescents'dailyactivitiesandfoundthattheyspendmoretimetalkingtotheirfriendsthanengaginginanyotheractivity.Inatypicalweek,highschoolstudentswillspendtwiceasmuchtimewiththeirpeersaswithadults.Thisgradualwithdrawalfromadultsbeginsinearlyadolescence.Lnsixthgrade,adults(excludingparents)accountforonly25percentofadolescentsocialnetworks.Anotherimportantcharacteristicofadolescentpeercultureisitsincreasinglyautonomous(白治的)function.Whilechildhoodpeergroupsareconductedundertheclosesupervisionofparents,adolescentpeergroupstypicallymakeanefforttoescapeadultsupervisionandusuallysucceedindoingso.
(Note:Answert.hequesnonsorcompletethestatementsinNOMORETHANEIGHTWORDS.)
"Thispatternofagesegregation"referstothephenomenonthatadolescentssegregatethemselvesfrom
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