IELTS雅思阅读真题.docx
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IELTS雅思阅读真题
蚂蚁智力
Collectiveintelligence:
:
Antsandbrain'sneurons
STANFORD-Anindividualantisnotverybright,butantsinacolony,operatingasacollective,doremarkablethings.
Asingleneuroninthehumanbraincanrespondonlytowhattheneuronsconnectedtoitaredoing,butallofthemtogethercanbeImmanuelKant.
ThatresemblanceiswhyDeborahM.Gordon,StanfordUniversityassistantprofessorofbiologicalsciences,studiesants.
"I'minterestedinthekindofsystemwheresimpleunitstogetherdobehaveincomplicatedways,"shesaid.
Noonegivesordersinanantcolony,yeteachantdecideswhattodonext.
Forinstance,anantmayhaveseveraljobdescriptions.Whenthecolonydiscoversanewsourceoffood,anantdoinghousekeepingdutymaysuddenlybecomeaforager.Orifthecolony'sterritorysizeexpandsorcontracts,patrollerantschangetheshapeoftheirreconnaissancepatterntoconformtothenewrealities.Sincenooneisinchargeofanantcolony-includingthemisnamed"queen,"whichissimplyabreeder-howdoeseachantdecidewhattodo?
Thiskindofundirectedbehaviorisnotuniquetoants,Gordonsaid.Howdobirdsflyinginaflockknowwhentomakeacollectiverightturn?
Allanchoviesandotherschoolingfishseemtoturninunison,yetnoonefishistheleader.
GordonstudiesharvesterantsinArizonaand,bothinthefieldandinherlab,theso-calledArgentineantsthatareubiquitoustocoastalCalifornia.
ArgentineantscametoLouisianainasugarshipmentin1908.TheyweredrivenoutoftheGulfstatesbythefireantandinvadedCalifornia,wheretheyhavedisplacedmostofthenativeantspecies.OneofthethingsGordonisstudyingishowtheydidso.NoonehaseverseenanantwarinvolvingtheArgentinespeciesandthenativespecies,soit'snotclearwhethertheyarequietlyaggressiveorjustfindwaysoftakingoverfoodresourcesandterritory.
TheArgentineantsinherlabalsoarebeingstudiedtohelpherunderstandhowtheychangebehaviorasthesizeofthespacetheyareexploringvaries.
"Theantsaregoodatfindingnewplacestoliveinandgoodatfindingfood,"Gordonsaid."We'reinterestedinfindingouthowtheydoit."
HerantsareconfinedbyPlexiglaswallsandanastyglue-likesubstancealongthetopsoftheboardsthatkeepstheantsinside.Shemovesthewallsinandouttochangethearenaandvideotapestheants'movements.Acomputertrackseachantfromitsimageonthetapeandreadsitspositionsoshehasadiagramoftheants'activities.
Themotionsoftheantsconfirmtheexistenceofacollective.
"Acolonyisanalogoustoabrainwheretherearelotsofneurons,eachofwhichcanonlydosomethingverysimple,buttogetherthewholebraincanthink.Noneoftheneuronscanthinkant,butthebraincanthinkant,thoughnothinginthebraintoldthatneurontothinkant."
Forinstance,antsscoutforfoodinaprecisepattern.Whathappenswhenthatpatternnolongerfitsthecircumstances,suchaswhenGordonmovesthewalls?
"Antscommunicatebychemicals,"shesaid."That'showtheymostlyperceivetheworld;theydon'tseeverywell.Theyusetheirantennaetosmell.Sotosmellsomething,theyhavetogetveryclosetoit.
"Thebestpossiblewayforantstofindeverything-ifyouthinkofthecolonyasanindividualthatistryingtodothis-istohaveananteverywhereallthetime,becauseifitdoesn'thappenclosetoanant,they'renotgoingtoknowaboutit.Ofcourse,therearenotenoughantsinthecolonytodothat,sosomehowtheantshavetomovearoundinapatternthatallowsthemtocoverspaceefficiently."
Keepinginmindthatnooneisinchargeofacolonyandthatthereisnocentralplan,howdotheantsadjusttheirreconnaissanceiftheirterritoryexpandsorshrinks?
"Noanttoldthem,'OK,guys,ifthearenais20by20....'Somehowtherehastobesomerulethatindividualantsuseindecidingtochangetheshapeoftheirpathssotheycovertheareaseffectively.Ithinkthatthatruleistherateinwhichtheybumpintoeachother."
Themorecrowdedtheyare,themoreofteneachantwillbumpintoanotherant.Iftheareaoftheirterritoryisexpanded,thefrequencyofcontactdecreases.Perhaps,Gordonthinks,eachanthasathresholdfornormalityandadjustsitspathshapedependingonhowoftenthenumberofencountersexceedsorfallsshortofthatthreshold.
Iftheterritoryshrinks,thenumberofcontactsincreasesandtheantaltersitssearchpattern.Ifitexpands,contactdecreasesanditaltersthepatternadifferentway.
IntheArizonaharvesterants,Gordonstudiestasksbesidespatrolling.Eachanthasajob.
"Idividethetasksintofour:
foraging,nestmaintenance,midden[pilingrefuse,includinghusksofseeds]andpatrolling-patrollersaretheonesthatcomeoutfirstinthemorningandlookforfood.Theforagersgowherethepatrollersfindfood.
"Thecolonyhasabouteightdifferentforagingpaths.Everydayitusesseveralofthem.Thepatrollersgooutfirstonthetrailsandtheyattracteachotherwhentheyfindfood.Bytheendofanhour'spatrolling,mostpatrollersareonjustafewtrails....Alltheforagershavetodoisgowheretherearethemostpatrollers."
Eachanthasitsprescribedtask,buttheantscanswitchtasksifthecollectiveneedsit.Anantonhousekeepingdutywilldecidetoforage.NoonetoldittodosoandGordonandotherentomologistsdon'tknowhowthathappens.
"Noantcanpossiblyknowhowmuchfoodeverybodyiscollecting,howmanyforagersareneeded,"shesaid."Ananthastohaveverysimplerulesthattellit,'OK,switchandstartforaging.'Butanantcan'tassessgloballyhowmuchfoodthecolonyneeds.
"I'vedoneperturbationexperimentsinwhichImarkedantsaccordingtowhattaskthey'redoingonagivenday.Theantsthatwereforagingforfoodweregreen,thosethatwerecleaningthenestwereblueandsoon.ThenIcreatedsomenewsituationintheenvironment;forexample,IcreateamessthatthenestmaintenanceworkershavetocleanuporI'llputoutextrafoodthatattractsmoreforagers.
"Itturnsoutthatantsthatweremarkeddoingacertaintaskonedayswitchtodoadifferenttaskwhenconditionschange."
Ofabout8,000speciesofants,onlyabout10percenthavebeenstudiedthusfar.
"It'shardtogeneralizeanythingaboutthebehaviorofants,"Gordonsaid."Mostofwhatweknowaboutantsistrueofavery,verysmallnumberofspeciescomparedtothenumberofspeciesoutthere."
天才儿童
TIME:
5-7'
HOWIQBECOMESIQ
In1904theFrenchministerofeducation,facinglimitedresourcesforschooling,soughtawaytoseparatetheunablefromthemerelylazy.AlfredBinetgotthejobofdevisingselectionprinciplesandhisbrilliantsolutionputastamponthestudyofintelligenceandwastheforerunnerofintelligencetestsstillusedtoday.Hedevelopedathirty-problemtestin1905,whichtappedseveralabilitiesrelatedtointellect,suchasjudgmentandreasoning.Thetestdeterminedagivenchild'smentalage'.Thetestpreviouslyestablishedanormforchildrenofagivenphysicalage.Forexample,five-year-oldsonaveragegettenitemscorrect,therefore,achildwithamentalageoffiveshouldscore10,whichwouldmeanthatheorshewasfunctioningprettymuchasothersofthatage.Thechild'smentalagewasthencomparedtohisphysicalage.
Alargedisparityinthewrongdirection(e.g.,achildofninewithamentalageoffour)mightsuggestinabilityratherthanlazinessandmeansthatheorshewasearmarkedforspecialschooling.Binet,however,deniedthatthetestwasmeasuringintelligenceandsaidthatitspurposewassimplydiagnostic,forselectiononly.Thismessagewashoweverlostandcausedmanyproblemsandmisunderstandingslater.
AlthoughBinet'stestwaspopular,itwasabitinconvenienttodealwithavarietyofphysicalandmentalages.So,in1912,WilhelmSternsuggestedsimplifyingthisbyreducingthetwotoasinglenumber.Hedividedthementalagebythephysicalageandmultipliedtheresultby100.Anaveragechild,irrespectiveofage,wouldscore100.anumbermuchlowerthan100wouldsuggesttheneedforhelpandonemuchhigherwouldsuggestachildwellaheadofhispeer.
ThismeasurementiswhatisnowtermedtheIQ(intelligencequotient)scoreandithasevolvedtobeusedtoshowhowaperson,adultorchild,performedinrelationtoothers.ThetermIQwascoinedbyLewism.Terman,professorofpsychologyandeducationofStanfordUniversity,in1916.HehadconstructedanenormouslyinfluentialrevisionofBinet'stest,calledtheStanford-Binettest,versionsofwhicharestillgivenextensively.
Thefieldstudyingintelligenceanddevelopingtestseventuallycoalescedintoasub-fieldofpsychologycalledpsychometrics(psychofor‘mind'andmetricsfor'measurements').Thepracticalsideofpsychometrics(thedevelopmentanduseoftests)becamewidespreadquiteearly,by1917,whenEinsteinpublishedhisgrandtheoryofrelativity,mass-scaletestingwasalreadyinuse.
Germany'sunrestrictedsubmarinewarfare(whichledtothesinkingoftheLusitaniain1915)provokedtheUnitedStatestofinallyenterthefirstworldwarinthesameyear.Themilitaryhadtobuildupanarmyveryquicklyandithadtwomillioninducteestosortout.Whowouldbecomeofficersandwhoenlistedmen?
Psychometriciansdevelopedtwointelligenceteststhathelpedsortallthesepeopleout,atleasttosomeextent.Thiswasthefirstmajoruseoftestingtodecidewholivedandwhodiedsinceofficerswerealotsaferonthebattlefield.Theteststhemselvesweregivenunderhorrendouslybadconditionsandtheexam