博弈論-耶魯大學(xué)公開課第一次課電子版

SothisisGameTheoryEconomics159.歡送來到經(jīng)濟(jì)學(xué)159博弈論Ifyou'rehereforarthistory,如果你是來上藝術(shù)史的you'reeitherinthewrongroomorstayanyway,那你走錯(cuò)教室了不過你不妨留下來maybethisistherightroom;butthisisGameTheory,okay.沒準(zhǔn)你會喜歡這門課這里是博弈論Youshouldhavefourhandouts;everyoneshouldhavefourhandouts.你們每人都應(yīng)該有四頁講義人手一份Thereisalegalreleaseform--里面有一張授權(quán)書we'lltalkaboutitinaminute--aboutthevideoing.是關(guān)于視頻采集的我們一會再說這個(gè)Thereisasyllabus,whichisapreliminary,it'salsoonline.有一張初步教學(xué)大綱網(wǎng)站上也有AndtherearetwogameslabeledGame1andGame2.有兩頁分別印有游戲1和游戲2的傳單CanIgetyoualltolookatGame1andstartthinkingaboutit.大家先瀏覽下游戲1然后思考一下Andwhileyou'rethinkingaboutit,iamhopingyoucanmultitaskabit.你們一邊思考一邊聽我說I'lldescribeabitabouttheclass我來簡單介紹下這門課程andwe'llgetabitofadminunderourbelts.還有這門課程的評分細(xì)則Butpleasetryandlookat--somebody'snotlookingatit,請大家看下游戲1我知道有人沒看becausethey'reusingitasafanhere--他們用那張紙扇風(fēng)呢SolookatGame1andfilloutthatformforme,okay?快瀏覽下游戲1然后填完好嗎Sowhileyou'refillingthatout,letmetellyoualittle你們一邊寫一邊聽我說bitaboutwhatwe'regoingtobedoinghere.我來簡單地介紹一下這門課SowhatisGameTheory?什么是博弈論GameTheoryisamethodofstudyingstrategicsituations.博弈論研究策略形勢Sowhat'sastrategicsituation?那什么是策略形勢呢Welllet'sstartoffwithwhat'snotastrategicsituation.我們先看看什么不屬于策略形勢InyourEconomics-inyourIntroEconomicsclassin115or110,在你們經(jīng)濟(jì)學(xué)基礎(chǔ)課115或者110中yousawsomeprettygoodexamplesofsituationsthatwerenotstrategic.應(yīng)該講過一些不是策略形勢的案例Yousawfirmsworkinginperfectcompetition.比方說自由競爭企業(yè)Firmsinperfectcompetitionarepricetakers:這些企業(yè)是價(jià)格接受者theydon'tparticularlyhavetoworryabout他們不必?fù)?dān)憂theactionsoftheircompetitors.他們的競爭對手的策略Youalsosawfirmsthatweremonopolists又比方說壟斷企業(yè)andmonopolistsdon'thaveanycompetitorstoworryabout,壟斷企業(yè)沒有競爭對手sothat'snotaparticularlystrategicsituation.所以這也不是策略形勢They'renotpricetakersbuttheytakethedemandcurve.他們不是價(jià)格接受者但面對需求曲線Isthislookingfamiliarforsomeofyouwhocanremember對于你們這些學(xué)過經(jīng)濟(jì)學(xué)115的來說doing115lastyearormaybetwoyearsagoforsomeofyou?這些聽起來都不陌生吧Everythinginbetweenisstrategic.介于這兩種情況之間的就是策略形勢Soeverythingthatconstitutesimperfectcompetition也就是說不完全競爭的情況isastrategicsetting.就是策略形勢Thinkaboutthemotorindustry,themotorcarindustry.比方汽車產(chǎn)業(yè)在汽車產(chǎn)業(yè)里FordhastoworryaboutwhatGMisdoingandwhatToyotaisdoing,福特關(guān)注通用和豐田的決策andforthemomentatleast現(xiàn)在可能暫時(shí)whatChryslerisdoingbutperhapsnotforlong.還得關(guān)注克萊斯勒的決策Sothere'sasmallnumberoffirmsandtheiractionsaffecteachother.少數(shù)幾家公司的決策會互相影響Soforaliteraldefinitionofwhatstrategicmeans:策略形勢書面定義是it'sasettingwheretheoutcomesthataffectyoudependonactions,行為影響結(jié)果然而結(jié)果不僅notjustonyourownactions,butonactionsofothers.取決于你的行為還取決于其他人的行為Allright,that'sasmuchasI'mgoingtosayforpreviewrightnow.好了暫時(shí)就先介紹這么多We'regoingtocomebackandseeplentyofthis通過學(xué)習(xí)本學(xué)期的課程overthecourseofthenextsemester.你們會接觸更多類似案例SowhatIwanttodoisgetontowherethisapplies.下面我們講講博弈論適用于什么領(lǐng)域ItobviouslyappliesinEconomics,butitalsoappliesinpolitics,顯然適用于經(jīng)濟(jì)學(xué)但也適用于政治學(xué)andinfact,thisclasswillcountasaPoliticalScienceclass實(shí)際上對政治專業(yè)的同學(xué)來說ifyou'reaPoliticalSciencemajor.它也算作政治課YoushouldgocheckwiththeDUSinPoliticalScience.Itcounts.回去咨詢下本科教學(xué)主管確實(shí)算的GameTheoryisveryimportantinlawthesedays.近年來博弈論在法學(xué)上也舉足輕重Soforthoseofyou--forthehalfofyou我估計(jì)你們多數(shù)人可能會去讀法學(xué)院--thataregoingtoendupinlawschool,thisisprettygoodtraining.博弈論對你們來說是門不錯(cuò)的基礎(chǔ)課GameTheoryisalsousedinbiology博弈論同樣適用于生物學(xué)andtowardsthemiddleofthesemester在本學(xué)期期中的時(shí)候we'reactuallygoingtoseesomeexamplesof我們會探討一下GameTheoryasappliedtoevolution.博弈論應(yīng)用于生物進(jìn)化論的案例Andnotsurprisingly,GameTheoryappliestosport.而且毫不奇怪博弈論適用于體育Solet'stalkaboutabitofadmin.我們接下來談?wù)勗u分標(biāo)準(zhǔn)Howareyoudoingonfillingoutthosegames?這兩個(gè)游戲你們填好了沒有Everyonemanagingtomultitask.每個(gè)人都要學(xué)會一心多用啊FillinginGame1?Keepwriting.還在填游戲1好吧繼續(xù)填I(lǐng)wanttogetsomeadminoutoftheway我們繼續(xù)講評分標(biāo)準(zhǔn)andIwanttostartbygettingoutoftheway不過我得先介紹一下whatisobviouslytheelephantintheroom.教室里的大家伙Someofyouwillhavenoticedthatthere'sacameracrewhere,okay.有些人注意到了這幾位攝像人員Soassomeofyouprobablyknow,可能你們已經(jīng)知道了Yaleisundergoinganopeneducationproject耶魯大學(xué)正在開展一個(gè)教育項(xiàng)目andthey'revideoingseveralclasses,我們在錄制一些課程的錄像andtheideaofthis,這樣做的目的是讓istomakeeducationalmaterialsavailablebeyondthewallsofYale.耶魯外的人也能享受到這些教學(xué)資源Infact,ontheweb,internationally,課程將被發(fā)布到網(wǎng)絡(luò)上sopeopleinplaces,maybeplacesintheU.S.全球各地的人都能看到比方美國人orplacesmilesaway,maybeinTimbuktuorwhatever,或者更遙遠(yuǎn)的國度像廷巴克圖whofinditdifficulttogeteducationalmaterials他們可能在當(dāng)?shù)卮髮W(xué)fromthelocaluniversityorwhatever,不容易得到這樣的教育資源canwatchcertainlecturesfromYaleontheweb.他們就可以到耶魯網(wǎng)站觀看這些視頻Someofyouwouldhavebeeninclassesthatdothatbefore.有些同學(xué)可能之前參加過這種課程What'sgoingtodifferentaboutthisclassisthat這門課的不同之處在于you'regoingtobeparticipatinginit.大家都要參與到課程中來Thewayweteachthisclassiswe'regoingtoplaygames,課堂上我們通過做游戲來博弈we'regoingtohavediscussions,we'regoingtotalkamongtheclass,課上會有隨堂討論課堂交流andyou'regoingtobelearningfromeachother,我們相互學(xué)習(xí)這樣看視頻的學(xué)生andIwantyoutohelppeoplewatchingathometobeabletolearntoo.也能收到良好的教學(xué)效果Andthatmeansyou'regoingtobeonfilm,attheveryleastonmike.但同時(shí)這意味著你要被拍到視頻中來Sohow'sthatgoingtowork?至少也會被錄音課程怎么拍攝呢AroundtheroomarethreeT.A.Sholdingmikes.教室里有三位助教持有麥克風(fēng)Letmeshowyouwheretheyare:onehere,onehere,andonehere.我來告訴大家助教坐在哪里WhenIaskforclassroomdiscussions,當(dāng)我們進(jìn)行隨堂討論時(shí)I'mgoingtohaveoneoftheT.A.Sgotoyouwithamicrophone我會請一位助教拿著麥克風(fēng)到你那muchlikein"Donahue"Orsomething.Okay.就想多納休那樣Atcertaintimes,you'regoingtobeseenonfilm,有時(shí)候你會被拍攝到sothecameraisactuallygoingtocomearoundandpointinyourdirection.此時(shí)攝像時(shí)機(jī)轉(zhuǎn)到你所在的方向NowIreallywantthistohappen.我希望大家多多配合Ihadtoargueforthistohappen,causeIreallyfeelthat我來解釋一下我的理由我覺得thisclassisn'taboutme.這門課不應(yīng)該僅僅由我來講I'mpartoftheclassobviously,沒錯(cuò)我是課程的一部分butit'saboutyouteachingeachotherandparticipating.但你們也要參與到課堂中來Butthere'sacatch,thecatchis,但是這會有個(gè)條件thatthatmeansyouhavetosignthatlegalreleaseform.你們都要簽署授權(quán)書Soyou'llseethatyouhaveinfrontofyoualegalreleaseform,你們的面前應(yīng)該有張授權(quán)書youhavetobeabletosignit,andwhatthatsaysisthat授權(quán)書的大概內(nèi)容是wecanuseyoubeingshowninclass.允許我們把你拍攝進(jìn)來Thinkofthisasabadhairdayreleaseform.大家考慮好日后你要是在視頻里Allright,youcan'tsueYalelaterifyouhadabadhairday.發(fā)現(xiàn)你糟糕的發(fā)型可別起訴耶魯大學(xué)ForthoseofyouwhoareontherunfromtheFBI,被FBI通緝的簽證失效的yourVisahasrunout,oryou'resittingnexttoyourex-girlfriend,還有前女友就坐在旁邊的nowwouldbeagoodtimetoputapaperbagoveryourhead.趕快找個(gè)紙袋子把臉給蒙上Allright,nowjusttogetyouusedtotheidea,還要說一下每節(jié)課我們都會ineveryclasswe'regoingtohaveIthinkthesametwopeople,看到這兩名工作人員soJudeisthecameraman;whydon'tyouallwavetoJude.裘德是攝影師大家跟裘德打個(gè)招呼ThisisJudeokay.AndWesisouraudioguy:thisisWes.這位就是裘德韋斯是錄音師AndIwilltryandremembernotto我會盡量注意includeJudeandWesintheclassroomdiscussions,不要讓他們兩位加入課堂討論的butyoushouldbeawarethatthey'rethere.但是你們也要注意到他們的存在Now,ifthisismakingyounervous,要是這令你很緊張ifit'sanyconsolation,it'smakingmeverynervous.它會讓我更緊張這權(quán)當(dāng)撫慰了吧So,allright,we'lltryandmakethisclass我會盡量讓workassmoothlyaswecan,allowingforthisextrathing.課堂順利地進(jìn)行下去還有一件事Letmejustsay,noone'smakinganymoneyoffthis--讓我說完沒有人會從中得到好處atleastI'mhopingtheseguysarebeingpaid--雖然我也希望他們會得到酬勞butmeandtheT.A.Sarenotbeingpaid.但至少我和助教們是沒有酬勞的Theaimofthis,thatIthinkisagoodaim,it'saneducationalproject,這完全出于好意這是個(gè)教育項(xiàng)目andI'mhopingyou'llhelpuswithit.我也希望你們也能盡己所能把它做好Theonedifferenceitisgoingtomean,isthat還有希望大家都能相互理解一下attimesImightholdsomeofthediscussionsfortheclass,當(dāng)我們舉行課堂討論的時(shí)候comingdownintothispartoftheroom,here,請你們靠前站出來一點(diǎn)tomakeitalittleeasierforJude.這樣便于裘德拍攝Allright,howarewedoingnowonfillingoutthoseforms?言歸正傳你們填好了沒Haseveryonefilledintheirstrategyforthefirstgame?各位是否都填好第一個(gè)游戲了Notyet.Okay,let'sgoondoingabitmoreadmin.還沒有那我們多介紹下評分標(biāo)準(zhǔn)Thethingyoumostlycareabouti'mguessing,isthegrades.我猜你們最關(guān)心的應(yīng)該是成績了Allright,sohowisthegradegoingtoworkforthisclass?那么這門課是怎么評分的呢30%oftheclasswillbeonproblemsets,課堂作業(yè)占總分?jǐn)?shù)的30%30%ofthegrade;30%onthemid-term,期中考試占30%and40%onthefinal;so30/30/40.期末考試占40%即30/30/40Themid-termwillbeheldinclassonOctober17;期中考試在十月十七日thatisalsoinyoursyllabus.教學(xué)大綱上也寫了Pleasedon'tanybodytellmelate-所以以后千萬別跟我說anytimeaftertodayyoudidn'tknowwhenthemid-term你不知道什么時(shí)候期中考試wasandthereforeitclasheswith17differentthings.然后還在考試那天安排大一堆事兒去做Themid-termisonOctober17,whichisaWednesday,inclass.期中考試在十月十七號周三隨堂舉行Allright,theproblemsets:關(guān)于課堂作業(yè)therewillberoughlytenproblemsets我應(yīng)該會安排十次左右的課堂作業(yè)andI'lltalkaboutthemmorelateronwhenIhandthemout.在留作業(yè)的時(shí)候我再細(xì)說ThefirstonewillgooutonMondaybutitwillbeduetendayslater.周一留第一份作業(yè)十天之內(nèi)交上來Roughlyspeakingthey'llbeeveryweek.差不多每周都有課堂作業(yè)Thegradedistribution:有關(guān)分?jǐn)?shù)的分布allright,sothisistheroughgradedistribution.我介紹下大體的分?jǐn)?shù)的分布Roughlyspeaking,asixthoftheclassaregoingtoendupwithA's,總體來說六分之一的人會得到AasixtharegoingtoendupwithA-,六分之一的人會得到A-asixtharegoingtoendupwithB+,六分之一的人會得到B+asixtharegoingtoendupwithB,六分之一的人會得到BasixtharegoingtoendupwithB-,六分之一的人會得到B-andtheremainingsixth,ifIaddedthatupright,剩下的六分之一如果我沒算錯(cuò)aregoingtoendupwithwhatIguesswe'renowcalling這些人將會得到thepresidentialgrade,isthatright?傳說中的"超優(yōu)"成績That'snotliterallytrue.I'mgoingtosqueezeitabit,但我可能稍微壓縮下分?jǐn)?shù)段I'mgoingtocurveitabit,我會讓分?jǐn)?shù)段更有彈性soactuallyslightlyfewerthanasixthwillgetstraightA's,實(shí)際上略少于六分之一的人會得到AandfewerthanasixthwillgetC'sandbelow.略少于六分之一會得到CWe'llsqueezethemiddletomakethembemoreB's.我們這樣壓縮會使更多的人得到BOnethingIcanguaranteefrompastexperienceinthisclass,不過從教學(xué)經(jīng)驗(yàn)看isthatthemediangradewillbeaB+.中間成績應(yīng)該是B+ThemedianwillfallsomewhereintheB+'s.分?jǐn)?shù)中位數(shù)會在B+的附近Justasforewarningforpeoplewhohaveforgottenwhatamedianis,稍微提示下忘記中位數(shù)含義的同學(xué)thatmeanshalfofyou--notapproximatelyhalf,這也就是說不是一半左右itmeansexactlyhalfofyou--是絕對一半的同學(xué)willbegettingsomethinglikeB+andbelow會得到B+的成績或更低的成績andhalfwillgetsomethinglikeB+andabove.另一半會到B+的成績或更高的成績Now,howareyoudoinginfillingintheforms?那兩張表你們填得怎么樣了Everyonefilledtheminyet?每個(gè)人都填好了嗎Surelymustbeprettyclosetogettingeveryonefilledin.應(yīng)該差不多每個(gè)人都填好了吧Allright,solastthingstotalkabout在我把表收回之前beforeIactuallycollectthemin-textbooks.我再講最后一件事課本Therearetextbooksforthisclass.這門課的課本Themaintextbookisthisone,Dutta'sbookStrategyandGames.主要是這本杜塔的《策略與博弈》Ifyouwantaslightlytougherbook,morerigorousbook,要是你想要一本更難更有挑戰(zhàn)的tryJoelWatson'sbook,Strategies.試試喬爾?沃森的《策略》Bothofthosebooksareavailableatthebookstore.這兩本書在書店都有賣的ButIwanttowarneverybodyaheadoftime,不過我先提個(gè)醒Iwillnotbefollowingthetextbook.我不會完全參照課本Iregardthesebooksassafetynets.課本只不過是救命稻草Ifyoudon'tunderstandsomethingthathappenedinclass,要是你課堂上沒聽懂youwanttoreinforceanideathatcameupinclass,或者你課下想深入了解下課上的內(nèi)容thenyoushouldreadtherelevantchaptersinthebook你應(yīng)該去讀書上對應(yīng)的章節(jié)andthesyllabuswilltellyouwhichchapterstoreadforeachclass,教學(xué)大綱會告訴你每堂課講哪章orforeachweekofclass,allright.或者每周講哪幾章ButIwillnotbefollowingthesebooksreligiouslyatall.但是我不會嚴(yán)格按照課本來講課Infact,they'rejustthereasbackup.重申一下課本就是救命稻草Inaddition,IstronglyrecommendpeoplereadThinkingStrategically.對了我強(qiáng)烈建議讀一讀《戰(zhàn)略思想》Thisisgoodbedtimereading.Doanyofyousufferfrominsomnia?這是本不錯(cuò)的睡前讀物你們失眠嗎It'sverygoodbedtimereadingifyousufferfrominsomnia.你要是失眠它絕對是最好的睡前讀物It'sagoodbookandwhat'smore這也確實(shí)是本好書there'sgoingtobeaneweditionofthisbookthisyear而且今年會有新版上市andNortonhaveallowedustogetadvancecopiesofit.出版商會讓我們提前得到新版的Soifyoudon'tbuythisbookthisweek,如果你這周不買Imaybeabletomaketheadvancecopyofthenew可能下周你們editionavailableforsomeofyounextweek.就能買到新版的了I'mnottakingacutonthateither,allright,我不會從中得到提成there'snomoneychanginghands.這不是推銷Allright,sectionsareonthesyllabussignup小組討論的安排在教學(xué)大綱上sorryonthewebsite,signupasusual.哦我說錯(cuò)了像平常一樣在網(wǎng)上注冊Putyourselfdownonthewaitlist如果你想換個(gè)小組ifyoudon'tgetintothesectionyouwant.請?jiān)诘群蛎浝镱A(yù)約Youprobablywillgetintothesectionyouwantoncewe'redone.一般你只需要預(yù)約一次就可以了Allright,nowwemustbedonewiththeforms.你們現(xiàn)在應(yīng)該填完了吧Arewedonewiththeforms?都填完了嗎Allright,sowhydon'twesendtheT.A.S,withorwithoutmikes,我們把表交給助教吧upanddowntheaislesandcollectinyourGame#1;讓他們來幫我收一下游戲1notGame#2,justGame#1.不要游戲2只要游戲1Justwhilewe'redoingthat,Ithinkthereputationofthisclass--收表的時(shí)候我來說說這門課的名聲Ithink--ifyoulookatthecourseevaluationsonlineorwhatever,你們要是在網(wǎng)站上看了教學(xué)評估isthatthisclassisreasonablyhardbutreasonablyfun.就會發(fā)現(xiàn)這門課有點(diǎn)難但也很有趣SoI'mhopingthat'swhatthereputationoftheclassis.我也希望這門課是這樣的Ifyouthinkthisclassisgoingtobeeasy,你要是認(rèn)為這門課挺簡單Ithinkitisn'tactuallyaneasyclass.It'sactuallyquiteahardclass,這不是輕松的課事實(shí)上它有點(diǎn)難butIthinkIcanguaranteeit'sgoingtobeafunclass.我保證這門課一定很有趣Nowonereasonit'safunclass,為什么這門課很有趣isthenicethingaboutteachingGameTheory因?yàn)閷W(xué)習(xí)博弈論-quietendownfolks--大家安靜一下onethingaboutteachingGameTheoryis,yougettoplaygames,在課堂上我們通過一些游戲來學(xué)習(xí)博弈andthat'sexactlywhatwe'vejustbeendoingnow.我們不剛做完一個(gè)游戲嗎Thisisourfirstgameandwe'regoingtoplaygamesthroughoutthecourse,這是第一游戲整個(gè)課程充滿了游戲sometimesseveraltimesaweek,sometimesjustonceaweek.有時(shí)候一周做幾次有時(shí)一周一次Wegotallthesethingsin?表收齊了嗎Everyonehandedthemin?每個(gè)人都交了吧SoIneedtogetthosecounted.下面要開始統(tǒng)計(jì)了HasanyonetakentheYaleAccountingclass?有人上過會計(jì)課嗎Noonewantsto-hasaspirationstobe-onepersonhas.有人想幫助統(tǒng)計(jì)嗎這有一個(gè)人想I'llhaveaT.A.doit,it'sallright,we'llhaveaT.A.doit.我還是安排助教做吧SoKaj,canyoucountthoseforme?Isthatright?卡茄你幫我統(tǒng)計(jì)一下好嗎Letmereadoutthegameyou'vejustplayed.我們回憶一下剛剛進(jìn)行的游戲"Game1,asimplegradeschemefortheclass."游戲1是一個(gè)簡單的成績博弈Readthefollowingcarefully.請仔細(xì)閱讀以下條款Withoutshowingyourneighborwhatyouaredoing,在不被你同桌看到的情況下putitintheboxbeloweithertheletterAlphaortheletterBeta.在方框中填寫字母a或者字母BThinkofthisasagradebid.把這看成成績的賭注Iwillrandomlypairyourformwithanotherform我會隨機(jī)把你們分成兩兩一組andneitheryounoryourpairwilleverknowwithwhomyouwerepaired.你們不知道會跟誰分到一組Here'showthegradesmaybeassignedfortheclass.按如下方法給出你們的成績Welltheywon'tbe,純屬娛樂大家別當(dāng)真IfyouputAlphaandyou'repairedwithBeta,如果你選a而你對手選BthenyouwillgetanAandyourpairaC.那么你得A你對手得CIfyouandyourpairbothputAlpha,you'llbothgetB-.如果你們都選a那么你們都得B-IfyouputBetaandyou'repairedwithAlpha,如果你選B你對手選ayou'llgetaCandyourpairanA.你得C你對手得AIfyouandyourpairbothputBeta,thenyou'llbothgetB+."如果你們都選B你們都得B+"Sothat'sthethingyoujustfilledin.這就是你們之前填的東西Nowbeforewetalkaboutthis,在我們討論之前l(fā)et'sjustcollectthisinformationinamoreusefulway.先有效地整理一下這些信息SoI'mgoingtoremovethisfornow.我先把它們擦掉We'lldiscussthisinasecond,一會再開始分析butwhydon'tweactuallyrecordwhatthegameis,thatwe'replayingfirst.我們先記錄一下這個(gè)游戲的內(nèi)容Sothisisourgradegame,andwhatI'mgoingtodo,就是我們的成績博弈sinceit'skindofhardtoabsorballtheinformation因?yàn)檫@么長一段文字justbyreadingaparagraphoftext,從中摘取信息有點(diǎn)困難I'mgoingtomakeatabletorecordtheinformation.不如我們列表整理信息SowhatI'mgoingtodoisI'mgoingtoputmehere,那么我把我寫在這里andmypair,thepersonI'mrandomlypairedwithhere,我對手就是被隨機(jī)分到的人寫在這andAlphaandBeta,whicharethechoicesI'mgoingtomakehere還有是a和B就是我要做的選擇andonthecolumnsAlphaandBeta,thechoicesmypairismaking.還有我對手要做的選擇Inthistable,I'mgoingtoputmygrades.我把我的成績填到表格里SomygradeifwebothputAlphaisB-,ifwebothputBeta,wasB+.如果我們都選a我得B-都選B我得B+IfIputAlphaandsheputaBeta,IgotanA,如果我選a她選B我得AandifIputBetaandsheputanAlpha,IgotaC.如果我選B她選a那么我得CIsthatcorrect?That'smoreorlessright?這些都對吧Yeah,okaywhilewe'rehere,whydon'twedothesameformypair?好了我們再把對手的情況也寫下來Sothisismygradesonthelefthandtable,我的成績寫在左邊的表格里butnowlet'slookatwhatmypairwilldo,whatmypairwillget.我們再看看我對手她會得到什么成績SoIshouldwarnthepeoplesittingattheback提醒一下坐在后面的人thatmyhandwritingisprettybad,that'sonereasonformovingforward.我的板書寫得很糟所以最好往前坐TheotherthingIshouldapologizeatthisstageoftheclassismyaccent.還有我得檢討的是我的口音Iwilltryandimprovethehandwriting,我會努力寫好板書there'snotmuchIcandoabouttheaccentatthisstage.但是口音暫時(shí)不太好改SoonceagainifyoubothputAlphathenmypairgetsaB-.如果我們都選a我對手得B-IfwebothputBeta,thenwebothgetaB+;如果我們都選B我們都會得到B+inparticular,mypairgetsaB+.此情況下我對手得B+IfIputAlphaandmypairputsBeta,thenshegetsaC.如果我選a我對手選B那么她得CAndifIputBetaandsheputsAlpha,thenshegetsanA.如果我選B她選a那么她得ASoInowhavealltheinformation由此我就把這張紙上的thatwasonthesheetofpaperthatyoujusthandedin.所有信息都包含進(jìn)來了Nowthere'sanotherwayoforganizingthisthat'sstandardinGameTheory,下面再用博弈論的標(biāo)準(zhǔn)方式來整理信息sowemayaswellgetusedtoitnowonthefirstday.從今天以后大家要習(xí)慣用這種標(biāo)準(zhǔn)Ratherthendrawingtwodifferenttableslikethis,與其畫兩個(gè)不同的表格whatI'mgoingtodoisI'mgoingtotakethesecondtable不如把第二個(gè)表格的內(nèi)容插入到andsuper-imposeitontopofthefirsttable.第一個(gè)表中Okay,soletmedothatandyou'llseewhatImean.我來做個(gè)示范你就明白我的意思了WhatI'mgonnadoisdrawalargertable,thesamebasicstructure:我要畫個(gè)結(jié)構(gòu)相同的大表格I'mchoosingAlphaandBetaontherows,用列來表示我選a還是BmypairischoosingAlphaandBetaonthecolumns,用行來表示我對手選a還是BbutnowI'mgoingtoputbothgradesin.但我要把兩人成績寫在一個(gè)單元格里Sotheeasyonesareonthediagonal:這樣就更直觀了youbothgetB-ifwebothchooseAlpha;如果我們都選a的話得B-webothgetB+ifwebothchooseBeta.如果我們都選B的話得B+ButifIchooseAlphaandmypairchoosesBeta,要是我選a我對手選BIgetanAandshegetsaC.我得A她得CAndifIchooseBetaandshechoosesAlpha,如果我選B她選athenit'smewhogetstheCandit'sherwhogetstheA.我得C而她得ASonoticewhatIdidhere.注意下我的表示方法Thefirstgradecorrespondstotherowplayer,meinthiscase,單元格內(nèi)第一個(gè)成績是我的成績andthesecondgradeineachboxcorrespondstothecolumnplayer,每個(gè)單元格第二個(gè)成績是mypairinthiscase.我對手的成績Sothisisanicesuccinctwayof這樣就把前兩張表格的信息recordingwhatwasintheprevioustwotables.更簡明地表述出來了Thisisanoutcomematrix;thistellsuseverythingthatwasinthegame.它是一個(gè)列出了博弈所有內(nèi)容的矩陣Okay,sonowseemsagoodtimetostarttalkingaboutwhatpeopledid.現(xiàn)在我們來考慮一下我們的選擇Solet'sjusthaveashowofhands.我們舉手表決吧HowmanyofyouchoseAlpha?多少人選了a?LeaveyourhandsupsothatJudecancatchthat,先不要放下手讓裘德拍一下sopeoplecanseeathome,okay.這樣看視頻的人也能看到AllrightandhowmanyofyouchoseBeta?多少人選了B?There'sfarmoreAlphas-waveyourhandstheBeta'sokay.遠(yuǎn)遠(yuǎn)少于選a的先不要放下手Allright,there'saBetahere,okay.這里有一個(gè)選B的Soitlookslikealotof-wellwe'regoingtofindout,我們來數(shù)一下確認(rèn)一下we'regoingtocount--butalotmoreAlpha'sthanBeta's.選a的人要遠(yuǎn)遠(yuǎn)多于選BLetmetryandfindoutsomereasonswhypeoplechose.我們來探討下你們?yōu)槭裁催@么選SoletmehavetheAlpha'supagain.來看看都誰選a了So,thewomanwho'sinredhere,穿紅色衣服的女士canwegetamiketothe-yeah,isitokayifweaskyou?遞給她一個(gè)麥克風(fēng)You'renotontherunfromtheFBI?Wecanaskyouwhy?請問沒被FBI通緝吧？Okay,soyouchoseAlpharight?SowhydidyouchooseAlpha?你選了a對吧你為什么要選a呢Realizedthatmypartnerchosealpha,thereforeIchose.我感覺我對手會選a因此我也選aAllright,soyouwroteoutthesesquares,這么說你也寫下了這些矩陣yourealizedwhatyourpartnerwasgoingtodo,andrespondedtothat.你分析出了對手的選擇并依此做出的選擇AnyotherreasonsforchoosingAlphaaroundtheroom?還有別的原因使你們選a嗎Canwegetthewomanhere?把麥克風(fēng)遞給那位女士好嗎Trynottobeintimidatedbythesemicrophones,它們只不過是麥克風(fēng)而已they'rejustmikes.It'sokay.別緊張ThereasonIchoseAlpha,regardlessofwhatmypartnerchose,我選a是因?yàn)椴还芪覍κ诌x什么IthinktherewouldbebetteroutcomesthanchoosingBeta.我選a得到的成績總會比選B的要好Allright,soletmeaskyournamesforasecond-soyournamewas?請問你叫什么名字?Courtney.考特尼Courtneyandyournamewas?考特尼另一位女士的名字是ClaraElise.克萊拉?埃莉斯Soslightlydifferentreasons,samechoiceAlpha.雖然原因不盡相同但她們都選了aClaraElise'sreason-whatdidClaraElisesay?克萊拉?埃莉斯的理由是她怎么說Shesaid,nomatterwhattheotherpersondoes,她說無論別人怎么選shereckonsshe'dgetabettergradeifshechoseAlpha.她覺得選a會使自己得到最優(yōu)的結(jié)果Soholdthatthoughtasecond,we'llcomebackto先保留這個(gè)說法我們稍后再做討論isitClaraElise,isthatright?這是克萊拉?埃莉斯的理由We'llcomebacktoClaraEliseinasecond.我們一會再討論這個(gè)理由Let'stalktotheBeta'sasecond;我們先來討論一下選B的理由letmejustemphasizeatthisstagetherearenowronganswers.我要強(qiáng)調(diào)一下這里沒有錯(cuò)誤的答案Lateronintheclassthere'llbesomequestionsthathavewronganswers.在以后在課上可能會有錯(cuò)誤的答案Rightnowthere'snowronganswers.但是現(xiàn)在沒有錯(cuò)誤的答案Theremaybebadreasonsbutthere'snowronganswers.有不充分的理由但沒有錯(cuò)誤的理由Solet'shavetheBeta'supagain.Let'sseetheBeta's.請選B的再舉下手看看有誰選了BOhcomeon!TherewasaBetarighthere.之前這里有選B的啊YouwereaBetaright?YoubackedofftheBeta,okay.你選過B對嗎？哦你改變主意了SohowcanIgetamikeintoaBeta?能不能把麥克風(fēng)給一位選了B的同學(xué)Let'sstickinthisaisleabit.我們往過道這邊來一點(diǎn)IsthataBetarightthere？AreyouaBetarightthere？那有人選B對嗎你是不是選了BCanIgettheBetainhere？WhowastheBetainhere？這邊有人選B的嗎Canwegetthemikeinthere？Isthatpossible？能把麥克拿到那里嗎Inhere-youcanleaveyourhandsothat-therewego.這有一個(gè)選B的先別放下手對了Justpointtowards-that'sfine,justspeakintoit,that'sfine.把麥克對著他請講Sothereasonright？為什么選B對嗎Yeah,goahead.沒錯(cuò)繼續(xù)說Ipersonallydon'tlikeswingsthatmuch我不喜歡成績波動很大的andit'stheB-/B+range,比方B-/B+這個(gè)范圍soI'dmuchratherpreferthattoaswingfromAtoC,所以我還是喜歡像A到C這樣小點(diǎn)的andthat'smyreason.這就是我的原因Allright,soyou'resayingitcompressestherange.你說的意思是壓縮范圍I'mnotsureitdoescompresstherange.但是我不太確定這是否壓縮了范圍ImeanifyouchoseAlpha,you'reswingingfromAtoB-;要是你選a你的分?jǐn)?shù)會在A到B-andfromBeta,swingingfromB+toC.選B分?jǐn)?shù)范圍會在B+到CImeanthosearesimilarkindofranges這兩個(gè)范圍大小差不多butitcertainlyisareason.但這也算是個(gè)原因Otherreasonsforchoosing？還有別的原因嗎Yeah,theguyinbluehere,yep,good.好的穿藍(lán)色衣服的小伙子That'sallright.Don'tholdthemike;沒錯(cuò)就是你不要拿走麥克風(fēng)justletitpointatyou,that'sfine.對著它說就可以的WellIguessIthoughtwecouldbemorecollusive我覺得我們本可以團(tuán)結(jié)合作的andkindofworktogether,butIguessnot.但是我看在這個(gè)博弈中不行SoIchoseBeta.所以我選了BThere'sasireninthebackgroundsoImissedtheanswer.抱歉剛剛警報(bào)響了我太沒聽清Standupasecond,sowecanjusthearyou.站起來再答復(fù)一下好嗎Sorry,sayagain.請?jiān)俅饛?fù)一下好嗎Sure.MynameisTravis.好的我叫特拉維斯Ithoughtwecouldworktogether,butIguessnot.我本想讓大家合作的但實(shí)際不行Allrightgood.That'saprettygoodreason.很好這確實(shí)是個(gè)不錯(cuò)的理由IfyouhadchosenBetawewouldhaveallgottenB+'sbutIguessnot.如果大家都選B都能得B+但不太可行Good,soTravisisgivingusadifferentreason,right?特拉維斯給出了不同的理由He'ssayingthatmaybe,someofyouintheroommight他說或許你們中的有些人actuallycareabouteachother'sgrades,right?會在意其他人的成績Imeanyouallknoweachotherinclass.你們互相都很熟悉Youallgotothesamecollege.你們來自同一個(gè)學(xué)院Forexample,ifweplayedthisgameupinthebusinessschool--假設(shè)我們要在商學(xué)院進(jìn)行這個(gè)博弈arethereanyMBAstudentsheretoday?Oneortwo.這里有念MBA的嗎有一兩個(gè)Ifweplaythisgameupinthebusinessschool,要是我們在商學(xué)院進(jìn)行這個(gè)博弈Ithinkit'squitelikelywe'regoingtogetalotofAlpha'schosen,right?我覺得會有很多人選aButifweplayedthisgameupinlet'ssaytheDivinitySchool,但是我們要是在神學(xué)院做此博弈I'mguessingthatTravis'answer我猜特拉維斯的答復(fù)isreflectingwhatyouguysarereasoninghere.反映了你們的理由IfyouplayedintheDivinitySchool,如果我們在神學(xué)院做這個(gè)游戲youmightthinkthatpeopleintheDivinitySchool你們都同意吧神學(xué)院的學(xué)生mightcareaboutotherpeople'sgrades,right?會在意別人的成績對嗎Theremightbeethicalreasons--perfectlygood,那就涉及到道德的因素了sensible,ethicalreasons--forchoosingBetainthisgame.人們出于道德的原因可能會選BTheremightbeotherreasonsaswell,應(yīng)該還有其他的原因butthat'sperhapsthereasontofocuson.但這個(gè)原因值得我們注意Andperhaps,thelessonIwanttodrawoutofthis我希望大家從中發(fā)現(xiàn)isthatrightnowthisisnotagame.這并不是真正意義上的博弈Rightnowwehaveactions,strategiesforpeopletotake,目前我們涉及行為策略局中人andweknowwhattheoutcomesare,而且我們知道不同的結(jié)果butwe'remissingsomethingthatwillmakethisagame.但是我們忽略了一個(gè)博弈必備的因素Whatarewemissinghere?我們忽略了什么Objectives.動機(jī)We'remissingobjectives.We'remissingpayoffs.我們忽略了動機(jī)我們忽略了收益We'remissingwhatpeoplecareabout,allright.我們忽略了局中人關(guān)心什么Sowecan'treallystartanalyzingagame只有明白人們關(guān)心什么untilweknowwhatpeoplecareabout,知道人們的收益是什么之后anduntilweknowwhatthepayoffsare.我們才能真正開始分析這個(gè)博弈Nowlet'sjustsaysomethingnow,這里我們要解釋一下whichI'llprobablyforgettosayinanyothermomentoftheclass,我差點(diǎn)就忘記說了buttodayit'srelevant.GameTheory,me,professorsatYale,博弈論還有我耶魯大學(xué)教授cannottellyouwhatyourpayoffshouldbe.無法說出你的收益應(yīng)該是什么樣的Ican'ttellyouinausefulwaywhatitis我也不能告訴你thatyourgoalsinlifeshouldbeorwhatever.你人生目標(biāo)應(yīng)該是什么That'snotwhatGameTheoryisabout.這不是博弈論能解決的However,onceweknowwhatyourpayoffsare,然而一旦你知道了個(gè)人的收益onceweknowwhatyourgoalsare,一旦你確立了目標(biāo)perhapsGameTheorycanyouhelpyougetthere.博弈論能幫助你達(dá)成目標(biāo)Sowe'vehadtwodifferentkindsofpayoffsmentionedhere.我們現(xiàn)在有兩種不同的收益Wehadthekindofpayoffwherewecareaboutourowngrade,一種是只在意自己的收益andTravishasmentionedthekindofpayoff另一種像特拉維斯提到的whereyoumightcareaboutotherpeople'sgrades.在意其他人的收益Andwhatwe'regoingtodotodayisanalyzethisgame接下來我們分別用不同收益underboththosepossiblepayoffs.來分析一下這個(gè)博弈Tostartthatoff,let'sputupsomepossiblepayoffsforthegame.我們先寫出來這個(gè)博弈可能的收益AndIpromisewe'llcomebackandlookatsomeotherpayoffslater.我們一會再來討論另一個(gè)收益We'llrevisittheDivinitySchoollater.神學(xué)院的稍后再討論Allright,sohereonceagainisoursamematrixwithmeandmypair,我們首先討論我和我對手choosingactionsAlphaandBeta,選擇a或B的矩陣butthistimeI'mgoingtoputnumbersinhere.不過這次我們用數(shù)字來表述Andsomeofyouwillperhapsrecognizethesenumbers,有些人可能事先見過這些數(shù)字butthat'snotreallyrelevantfornow.但是現(xiàn)在這都無關(guān)緊要Allright,sowhat'stheideahere?為什么要引入數(shù)字呢Wellthefirstideaisthatthesenumbersrepresentutilesorutilities.首先這些數(shù)字代表了效用或者說功利Theyrepresentwhatthesepeoplearetryingtomaximize,他們代表了人們想要最大化的東西whatthey'retoachieve,theirgoals.和想要達(dá)成的目標(biāo)Theideais-justtocomparethistotheoutcomematrixis和那個(gè)結(jié)果矩陣相比forthepersonwho'smehere,這樣能更直觀顯示收益(A,C)yieldsapayoffof,so(A,C)isthisbox比方說(A,C)這個(gè)單元格so(A,C)yieldsapayoffofthree,(A,C)代表了3單位效用whereas(B-,B-)y