How to Make Decisions.docx

How to Make Decisions.docx

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HowtoMakeDecisions

HowtoMakeDecisions:

Coherence,Emotion,andPracticalInference

PaulThagard

PhilosophyDepartment

UniversityofWaterloo

pthagard@uwaterloo.ca

Thagard,P.（2001）.Howtomakedecisions:

Coherence,emotion,andpracticalinference.InE.Millgram（Ed.）,Varietiesofpracticalinference.Cambridge,MA:

MITPress.355-371.

Studentsfacemanyimportantdecisions:

WhatcollegeoruniversityshouldIattend?

WhatshouldIstudy?

WhatkindofjobshouldItrytoget?

WhichpeopleshouldIhangoutwith?

ShouldIcontinueorbreakoffarelationship?

ShouldIgetmarried?

ShouldIhaveababy?

WhatkindofmedicaltreatmentshouldIuse?

Atheoryofpracticalreasoningshouldhavesomethingtosayabouthowstudentsandotherpeoplecanimprovetheirdecisionmaking.

Iregularlyteachafirst-yearcourseoncriticalthinkingintendedtohelpstudentsimprovetheirreasoningaboutwhattobelieveandaboutwhattodo.Afterspendingabouttwothirdsofthecourseonwaysofimprovingjudgmentsaboutthetruthandfalsityofcontroversialclaimsinareassuchasmedicineandpseudoscience,Idevotethelastthirdtopracticalreasoning,withthefocusonhowpeoplecanmakebetterdecisions.Idiscussboththekindsoferroneousreasoningthatdecisionmakerscommonlyfallinto,andsomesystematicmodelsthathavebeenproposedbypsychologists,economists,andphilosopherstospecifyhowpeopleshouldmakedecisions.

Manystudentsinthecoursedislikethesemodels,andresisttheclaimthatusingthemispreferabletomakingdecisionssimplybyintuition.Theytrusttheir"gutfeelings"morethantheytrusttheanalyticalmethodsthatrequireasystematicandmathematicalcomparativeassessmentofcompetingactionsthatsatisfymultiplecriteria.ThetextbooksIuse（mostrecentlyGilovich1991,RussoandSchoemaker1989,SchickandVaughn1999）encouragepeopletoavoidtheuseofintuitionandinsteadtobasetheirjudgmentsanddecisionsonreasoningstrategiesthatarelesslikelytoleadtocommonerrorsinreasoning.Fromthisperspective,decisionmakingshouldbeamatterofcalculation,notintuition.

WhileIagreethatintuition-baseddecisionmakingcanleadtomanyproblems,Ialsothinkthatcalculation-baseddecisionmakingofthesortrecommendedbypsychologistsandeconomistshassomeseriouspitfalls.Inthischapter,Iwilltrytoofferasynthesisandpartialreconciliationofintuitionandcalculationmodelsofdecision,usingarecentlydevelopedtheoryofemotionalcoherence（Thagardinpress）.Thistheorybuildsonapreviouscoherence-basedtheoryofdecisionmakingdevelopedincollaborationwithElijahMillgram.Understandingdecisionmakingintermsofemotionalcoherenceenablesustoappreciatethemeritsofbothintuitionandcalculationascontributorstoeffectivepracticalreasoning.

DecisionasIntuition

Supposeyouareastudenttryingtodecidewhethertostudy

（1）anArtssubjectsuchasphilosophyorarthistoryinwhichyouhaveastronginterestor

（2）asubjectsuchaseconomicsorcomputersciencewhichmayleadtoamorelucrativecareer.Tomakethisdecisionintuitivelyisjusttogowiththeoptionthatissupportedbyyouremotionalreactionstothetwoalternatives.Youmayhaveastronglypositivegutfeelingtowardthemoreinterestingsubjectalongwithastronglynegativefeelingaboutthemorecareer-orientedone,oryourfeelingsmaybejusttheopposite.Morelikelyisthatyoufeelpositivefeelingstowardbothalternatives,alongwithaccompanyinganxietycausedbyyourinabilitytoseeaclearlypreferableoption.Intheend,intuitivedecisionmakerschooseanoptionbasedonwhattheiremotionalreactionstellthemispreferable.

Thereismuchtobesaidforintuitivedecisionmaking.Oneobviousadvantageisspeed:

anemotionalreactioncanbeimmediateandleaddirectlytoadecision.Ifyourchoiceisbetweenchocolateandvanillaicecream,itwouldbepointlesstospendalotoftimeandeffortdeliberatingabouttherelativeadvantagesanddisadvantagesofthetwoflavors.Instead,anemotionalreactionsuchas"chocolateyum!

"canmakeforaquickandappropriatedecision.Anotheradvantageisthatbasingyourdecisionsonemotionshelpstoensurethatthedecisionstakeintoaccountwhatyoureallycareabout.Ifyouarepleasedandexcitedaboutapossibleaction,thatisagoodsignthattheactionpromisestoaccomplishthegoalsthataregenuinelyimportanttoyou.Finally,decisionsbasedonemotionalintuitionsleaddirectlytoaction:

thepositivefeelingtowardanoptionwillmotivateyoutocarryitout.

Butemotion-basedintuitivedecisionmakingcanalsohavesomeseriousdisadvantages.Anoptionmayseememotionallyappealingbecauseoffailuretoconsiderotheravailableoptions.Intuitionmaysuggestbuyingchocolateicecreamonlybecauseyouhavefailedtoconsideralower-fatalternativethatwouldbeahealthierchoice.Intuitionisalsosubjecttotheintensecravingthatdrugaddictscall"jonesing".Ifyouarejonesingforcocaine,orforapizza,orforaMercedes-Benzconvertible,yourintuitionwilltellyoutochoosewhatyoucrave,butonlybecausethecravinghasemotionallyswampedotherdesiresthatyouwillbemoreawareofwhenthecravingislessintense.

Anotherproblemwithintuitionisthatitmaybebasedoninaccurateorirrelevantinformation.Supposeyouneedtodecidewhomtohireforajob.Ifyouareprejudicedagainstpeopleofaparticularsex,race,orethnicity,thenyourintuitionwilltellyounottohirethem,eveniftheyhavebetterqualificationsfordoingthejobwell.Itisdifficulttodetermineintrospectivelywhetheryourintuitionsderivefromreliableandrelevantinformation.

Finally,intuitivereasoningisproblematicingroupsituationswheredecisionsneedtobemadecollectively.Ifotherpeopledisagreewithyourchoices,youcannotsimplycontendthatyourintuitionsarestrongerorbetterthantheintuitionsofothers.Defendingyouremotionalreactionsandattemptingtoreachaconsensuswithotherpeoplerequiresamoreanalyticalapproachthansimplyexpressingyourgutfeelings.

DecisionasCalculation

Expertsondecisionmakingrecommendamoresystematicandcalculatingapproach.Forexample,Bazerman（1994,p.4）saysthatrationaldecisionmakingshouldincludethefollowingsixsteps:

1.Definetheproblem,characterizingthegeneralpurposeofyourdecision.

2.Identifythecriteria,specifyingthegoalsorobjectivesthatyouwanttobeabletoaccomplish.

3.Weightthecriteria,decidingtherelativeimportanceofthegoals.

4.Generatealternatives,identifyingpossiblecoursesofactionthatmightaccomplishyourvariousgoals.

5.Rateeachalternativeoneachcriterion,assessingtheextenttowhicheachactionwouldaccomplisheachgoal.

6.Computetheoptimaldecision,evaluatingeachalternativebymultiplyingtheexpectedeffectivenessofeachalternativewithrespecttoacriteriontimestheweightofthecriterion,thenaddinguptheexpectedvalueofthealternativewithrespecttoallcriteria.

Wecanthenpickthealternativewiththehighestexpectedvalueandmakeadecisionbasedoncalculation,notonsubjectiveemotionalreactions.Usingslightlydifferentterminology,RussoandShoemaker（1989,ch.6）recommendessentiallythesamekindofdecisionmakingprocessbasedonmultipleweightedfactors.

Somestudentsdismissthiskindofprocessasrobot-like,andfinditoffensivethatimportantdecisionsintheirlivesmightbemademathematically.AcartoonintheNewYorker（Jan.10,2000,p.74）showsamansittingatacomputerandsayingtoawoman:

"I'vedonethenumbers,andIwillmarryyou."Somedecisions,atleast,seeminappropriatelybasedondoingthenumbers.ButistheemotionaldismissalofBazerman's6-stepcalculationmethodjustified?

Wecancertainlyseesomenotableadvantagesofthecalculationmethodovertheintuitionmethod.First,itissetuptoavoidneglectingrelevantalternativesandgoals.Second,itmakesexplicittheconsiderationofhowthevariousalternativescontributetothevariousgoals.Third,itputsthedecisionmakingprocessoutintheopen,enablingittobecarefullyreviewedbyaparticulardecisionmakerandalsobyothersinvolvedinagroupdecisionprocess.

However,thecalculationmethodofdecisionmakingmaybemoredifficultandlesseffectivethandecisionexpertsclaim.Supposeyouaretryingtodecidebetweentwocoursesofstudy,sayphilosophyversuscomputerscience,andyousystematicallylistalltherelevantcriteriasuchashowinterestingyoufindthesubjectsandhowwelltheyfitwithyourcareerplans.Youthenweightthecriteriaandestimatetheextenttowhicheachoptionsatisfiesthem,andproceedtoacalculationoftheexpectedvalueofthecompetingchoices.Havingdonethis,youfindthattheexpectedvalueofoneoption,sayphilosophy,exceedsthatoftheother.Butwhatifyouthenhavethereaction"Idon'twanttodothat!

"Youremotionalreactionneednotbecrazy,becauseitmaybethatthenumericalweightsthatyouputonyourcriteriadonotreflectwhatyoureallycareabout.Moreover,yourestimatesabouttheextenttowhichdifferentactionsaccomplishyourgoalsmaybeverysubjectiveandfluid,sothatyourunconsciousestimationisatleastasgoodasyourconsciousone.Ionceknewsomeonewhotoldmethatshemadedecisionsbyfirstflippingacoin,withheadsforoneoptionandtailsforanother.Whenthecoincameupheads,shewouldnoteheremotionalreaction,whichgaveherabetterideaofwhethershereallywantedtheoptionassociatedwithheads.Shethenusedthisemotionalinformationtohelphermakeachoicebetweenthetwooptions.

Thereisempiricaleviden