Why do humans reason? Arguments for an argumentative theory

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Commentary/Mercier & Sperber: Why do humans reason?some aspect of the world, followed by formulation of hypothesesthat are tested and immediately abandoned if disconfirmed bydata. I propose that the following account is more accurate.Research for professional reasoners begins with an emotionalattraction to certain ideas, an attraction Tomkins (1965) called“ideo-affective resonance.” This emotional resonance can causescientists to cling tenaciously to ideas, even in the face of counterevidence.In some ways, science resembles legal proceedings inwhich the very best case for guilt or innocence is presented byuncompromising prosecuting and defense attorneys, respectively.Scientists who resonate to different views clash in conferencesand in journals. Each seeks to convince others that he or she iscorrect. M&S review research indicating that when members ofgroups holding disparate views debate, each arguing for a differentview, “truth wins” (sect. 2.3, para. 1). Perhaps truth does win oftenenough in jury trials and scientific debates, but as we all know,sometimes it does not. M&S might be expressing unwarranted optimismhere.I want to close my commentary with some observations aboutmoral reasoning. Research by Haidt (2001), mentioned by M&S,and by Joshua Greene (2003) strongly supports a dual-processmodel wherein people instantaneously decide if an act is “good”and therefore something we “ought” to do by taking note of theimmediate, reflexive feelings that emerge when thinking aboutthe act. In the second stage of the dual process, they mayattempt to defend their feelings in terms of rational argument. Professionalphilosophers are much better at the reasoning part of theprocess, but are still guided initially by emotional reflexes. Theimmediacy and inevitability of certain emotions (e.g., revulsionon contemplating the torture of a child) can lead philosophersand nonphilosophers alike into making pronouncements suchas “That we ought to refrain from torturing children is a moraltruth.”But only propositions about what is the case can be true or false.Moral pronouncements express reflexive feelings about how weought to behave and are therefore not truth-apt. “Moral truth” isa category mistake. I have a yet-untested two-part hypothesisabout why so many people (including moral philosophers) makethis apparent category mistake (Johnson 2007). First, humanbeings are prone to mistakenly assuming that when they feel astrong and immediate emotion, this is a reliable sign of a selfevidenttruth. Second, although moral systems evolved becausethey conferred benefits on all participants (compare M&S’s observationthat persuasive communication must be sufficiently beneficialto both parties, else the capacity for being persuadedwould be selected against and go out of existence), the propensityof a person to be responsive to moral “oughts” can be exploited bysomeone who benefits at that person’s expense. Compare, forexample, the persuasiveness of “Give me ten percent of yourmoney because I want it” with “That we have a duty to tithe tothe church is a venerable moral truth.” Scrutiny of any rhetoricaleffort is wise, particularly those in the moral domain.True to the power of one? Cognition,argument, and reasoningdoi:10.1017/S0140525X10002992Drew Michael Khlentzos and Bruce StevensonLanguage and Cognition Research Centre, Psychology, School of Behavioural,Cognitive and Social Sciences, University of New England, Armidale 2351,Australia.dkhlentz@une.edu.au bstevens@une.edu.auhttp://www.une.edu.au/staff/dkhlentz.phphttp://www.une.edu.au/staff/bstevens.phpAbstract: While impressed by much of what Mercier & Sperber (M&S)offer through their argumentative hypothesis, we question whetherthe specific competencies entailed in each system are adequate. Inparticular, whether system 2 might not require independent reasoningcapabilities. We explore the adequacy of the explanations offered forconfirmation bias and the Wason selection task.For Mercier and Sperber (M&S), what appears as poor reasoningis actually appropriate argument – social dialogue facilitatesreasoning by prompting agents to formulate arguments anddefend them from objections. M&S propose a dual-processmodel with system 1 (S 1 ) a consortium of inference mechanismsand system 2 (S 2 ), an S 1 apologist. We identify some features wethink require clarification and provide alternative interpretationsof phenomena used by M&S to support their model.If S 1 generates conclusions without revealing their derivation(modular-like), then where does S 2 acquire the competence tosupport these arguments? What type of reasoning is requiredfor it to construct these arguments, or does it run data backthrough S 1 for a reasoned result? Related to this is the issue ofargumentative contexts which trigger S 2 . These appear to bericher in information, creating a potential confound for the argumentativehypothesis: Is it the argumentative feature or theincreased information that is critical?The social psychology findings M&S adduce to support theirview present a puzzle for it: How can truth win out amongstsophistical S 2 s committed not to discovering the facts but todefending S 1 ’s representation of them? Convergence-on-truthsuggests there’s more to S 2 than defence of S 1 . One alternativeviews S 2 as a dynamic, defeasible reasoner that sifts through S 1outputs, independently generating conclusions to be updated inthe light of new information.Presumably S 1 must support probabilistic as well as deductiveinferences. In which case, some regulatory role for S 2 is inescapable.Suppose S 1 has both deductive and probabilistic mechanismsand these produce compatible results with input X bothdeductively entailing and probabilistically supporting Y. Imaginenew evidence E emerging that undermines Y so that X þ Emakes Y not probable. Nonetheless, E cannot affect the derivationof Y from X. So X þ E still entails Y. Whence S 2 has to decidewhether to defend Y since it is derivable from X þ E or surrenderY as X þ E makes Y improbable. How would it make this decision?Consider now M&S’s views on confirmation bias. M&S denyconfirmation bias is a flaw in reasoning. Yet if the aim of eachagent’s S 2 is to persuade others, confirmation bias would justpolarize views with no agent prepared to listen to another’s arguments.Alternatively, if each S 2 defends an agent’s beliefs againstobjections, amassing evidence for those beliefs is important butanticipating likely objections and preparing a defence is no lessso. Relative to aims of persuasion or defence, then, confirmationbias registers as a fault in reasoning.Compare an M&S-styled S 2 -reasoner Aaron with a defeasibleS 2 -reasoner Belle. Aaron is convinced the river mussels are goodto eat since he’s eaten them the past five days. Belle felt ill aftereating them the day before. She advises Aaron to refrain. Aaron’sS 2 considers positive evidence and discounts negative evidence.So Aaron eats the mussels and falls ill. In contrast, Belle’s S 2 constructsfast generalizations on the fly. Having eaten them for fourdays, Belle inferred (G) the mussels are good to eat. But now herS 2 enables Belle to adopt a position appropriate to the evolvingevidence. The crucial difference between Aaron and Belle isthis: Were they to swap roles, Belle would feel no internalpressure from her S 2 to eat the mussels (unlike Aaron fromhis): Evidence someone else fell ill can prompt a defeasible reasonerto update (G) as disconfirming and confirming evidenceare weighted equally. Whilst M&S’s model allows S 1 to updateinformation, reasoning to a new conclusion (belief revision)appears anomalous.Does the argumentative hypothesis yield the best explanationof reasoning performance? Take the Wason selection task. M&Sclaim that when agents are asked to assess the truth of (W) Ifthere’s a vowel on one side of a card, there’s an even number onits other side for an E, K, 4, 7 array, their S 1 matches cards to82 BEHAVIORAL AND BRAIN SCIENCES (2011) 34:2
Commentary/Mercier & Sperber: Why do humans reason?verbal cues, prompting them to choose the E card and 4 card.Their S 2 then defends this choice against objections.This matching hypothesis belies the semantic complexity of(W), which contains an indefinite “a card” nested within thescope of a conditional. Such constructions can vary in meaning.“If Ralph has a credit card, he buys tickets with it” is true ifRalph has four different credit cards but uses only one to buytickets. However “if Sue has a pet, she feeds it” is false if Suefeeds her goldfish, starving her three kittens: “A pet” meansevery pet where “a credit card” means some credit card. Indefinitessuch as “a card” in (W) could be assigned a default existentialreading (some) by an S 1 semantic module. If contextual cluesor background information don’t subsequently override it, this(mistaken) interpretation could become fixed, leading subjectsto look for some card with an even number on one side and avowel on the other, as the majority do. Alternatively, if thesemantic module defaults to a generic reading of (W), since generics(like the mussels are good) tolerate exceptions, the 7 card’srole becomes opaque, rendering it non-salient once more.For defeasible reasoners used to generic generalisations, figuringout the minimum number of occluded elements that need tobe revealed to determine whether (W) is true is no trivial task.They fail not because they aren’t called on to defend theirview, as M&S contend, but because they have little or no experiencetesting exceptionless generalisations.Why then do they succeed in group settings? A rival problemsolvingmodel of reasoning says this is due to two factors:1. Group settings are informationally rich with alternativehypotheses articulated, reasons for them explained and discussed,and2. Subjects’ semantic modules are specifically designed tocompute the logical implications of others’ statements to determinewhat those statements mean (Crain & Khlentzos 2010).Further, since this model assumes subjects share a commongoal of finding the correct solution, it is no mystery why subjectsshould converge on that solution.What people may do versus can dodoi:10.1017/S0140525X10002864Deanna KuhnDepartment of Human Development, Teachers College, Columbia University,New York, NY 10027.dk100@columbia.edu www.educationforthinking.orgAbstract: It warrants examining how well people can come to argueunder supportive conditions, not only what they do under ordinaryconditions. Sustained engagement of young people in dialogicargumentation yields more than the temporary “contextual effect” thatMercier & Sperber (M&S) identify in the target article. If suchengagement were to become the norm, who can say what theargumentive potential of future generations is?In the target article, Mercier & Sperber (M&S) make the strongclaim that epistemic goals are not well served by argumentivereasoning because it does not enhance the accuracy or validityof one’s claims. Evidence is too ample to deny that people commonlyinvoke argumentive reasoning to support their assertionsin ways that are habitual, often mindless, and self-serving.Where I would fault M&S, rather, is in their focus on how argumentivereasoning most often does function, to the exclusion ofhow it can (and for some does) come to function, as a consequenceof education, engagement, and a recognition of its epistemicvalue. Although people may use argument in self-servingways that they are in limited command of, it doesn’t follow thatthey cannot achieve greater conscious command and come todraw on it in a way that will enhance their cognitive power.Moreover, as my own most recent research clearly shows(Goldstein et al. 2009; Kuhn & Crowell, in press; Kuhn et al.2008), sustained engagement of young people in dialogic argumentationyields more than the temporary “contextual effect”of a social setting that M&S identify. In their review of ourresearch, they focus on earlier work in which on a single occasionparticipants are asked to generate an argument to support theirview regarding the cause of a particular social problem (Kuhn1991). The participants generally do poorly, with little sign ofimprovement from adolescence through old age, tending todescribe a plausible scenario of how the problem could ariseand failing to differentiate that scenario from actual or potentialevidence that this is how it does in fact arise.In more recent work, we have engaged young people in sustaineddialogic argumentation about significant issues. We focuson middle school as an optimal period to undertake this effort,and we follow Billig (1987), Graff (2003), and, before him, thesociocultural tradition of Vygotsky (1978) and others, in takingthe everyday social practice of argumentation as a starting pointand pathway for development of individual argumentive skill.The dialogic context provides the “missing interlocutor” (Graff2003) that gives expository argument its point. The medium of discourseis electronic, yielding the significant advantage of providinga transcript of the exchange that remains available throughout andfollowing the discourse. Contributions to face-to-face discourse, incontrast, disappear as soon as they are spoken. In addition toserving as a reference point and framework during the dialogs,these transcripts become the object of various reflective activitiesparticipants engage in.With sustained engagement over multiple months, dialogic argumentationprogresses from what starts out as the norm amongyoung adolescents – exposition of one’s own views with scantattention to those of the opponent – to recognition of the needto attend to the opponent’s claims and identify weaknesses, andfrom there to sustained sequences of counterargument and rebuttal.Perhaps most important, not immediately but with time, thesenewly developed skills transfer to the individual context that M&Sfocus on. Relative to a carefully matched comparison group at thesame school, our participants wrote superior individual essays on anew topic, ones more often addressing strengths and weaknesses ofboth sides of an issue. Equally important is young people’s progressin the epistemological domain of recognizing the centrality ofcounterargument and of evidence to sound argumentation. Againrelative to the comparison group, participants showed greater recognitionof the role of both, for example in seeking information tobring to bear on their arguments.In a word, we need to examine how argument may come to beused under these favorable, supportive conditions, not onlyunder more ordinary conditions. If broader engagement of thissort were to become the norm, who can say what the argumentivepotential of future generations is? With education systems worldwideclaiming commitment to the broad goal of students learningto use their minds well, so as to be able to apply them to new,unknown problems, we should at least seriously explore thequestion.The world looks small when you only lookthrough a telescope: The need for a broad anddevelopmental study of reasoningdoi:10.1017/S0140525X10002918Darcia NarvaezDepartment of Psychology, University of Notre Dame, Notre Dame, IN 46556.dnarvaez@nd.edu http://www.nd.edu/≏dnarvaezAbstract: If the target article represents the summary findings of thefield, reasoning research is deeply flawed. The vision is too narrow andBEHAVIORAL AND BRAIN SCIENCES (2011) 34:2 83
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