Individual differences are indeed an important aid to our understanding of human cognition, but the importance of the rationality debate is open to question. An understanding of the process involved, and how and why differences occur, is fundamental to our understanding of human reasoning and decision making

Newton, EJ

Roberts, MJ

English

UCL Discovery

Behavioral and Brain Scienceshttp://journals.cambridge.org/BBSAdditional services for Behavioral and Brain Sciences:Email alerts: Click hereSubscriptions: Click hereCommercial reprints: Click hereTerms of use : Click hereIndividual differences transcend the rationality debateElizabeth J. Newton and Maxwell J. RobertsBehavioral and Brain Sciences / Volume 26 / Issue 04 / August 2003, pp 530 ­ 531DOI: 10.1017/S0140525X03230119, Published online: 29 March 2004Link to this article: http://journals.cambridge.org/abstract_S0140525X03230119How to cite this article:Elizabeth J. Newton and Maxwell J. Roberts (2003). Individual differences transcend the rationality debate. Behavioral and Brain Sciences,26, pp 530­531 doi:10.1017/S0140525X03230119Request Permissions : Click hereDownloaded from http://journals.cambridge.org/BBS, IP address: 144.82.107.35 on 08 Aug 2012Continuing Commentary530 BEHAVIORAL AND BRAIN SCIENCES (2003) 26:4principles (and, for that matter, an array of rules of inference aswell), is not, we daresay, very easy. Logicians can crack syllogismsin seconds, yes. But if you tried to configure your 403(b) in athoroughly rigorous, decontextualized way, how long did it takeyou?Other, arguably even deeper, problems spring from the sim-plicity of the problems that currently anchor the rationality de-bate. It seems bizarre to define general intelligence as the capac-ity to solve very easy problems. For example, Raven’s ProgressiveMatrices, that vaunted “culture-free” gauge of g, can be mechan-ically solved (Carpenter et al. 1990). Once one assimilates and de-ploys the algorithm, does one suddenly become super-intelligent?Would a computer program able to run the algorithm and therebyinstantly solve the problems, be counted genuinely intelligent?Hardly. (For more on this issue, see Bringsjord 2000. And recallSternberg’s continuous complaint that “being smart” in the ordi-nary sense has precious little to do with solving small, tightly de-fined test problems, a complaint communicated to some degreein his first-round commentary; cf. Sternberg 2000.)Another problem arising from the fact that the rationality de-bate is tied to very easy problems is that psychology of reasoningis thereby structurally unable to articulate theories of robust hu-man reasoning. Mental logic (championed, for example, by Rips1994) cannot account for disproofs of the sort we gave above (because such disproofs are necessarily meta-proofs carried outoutside a fixed set of inference schemas); and mental models the-ory (Johnson-Laird 1983), which rejects elaborate sequences ofpurely syntactic inferences, would seem to at least have a difficulttime accounting for solutions to the problem we leave you with be-low (about which we’ve just given you a hint). What is needed is atheory of human reasoning that partakes of both the proof theo-retic and semantic sides of symbolic logic, and the formal metathe-ory that bridges these two sides. (For a synoptic presentation of allthis terrain, in connection to cognition and reasoning, seeBringsjord & Ferrucci 1998. For a theory of human reasoning de-signed to cover all of this terrain, Mental MetaLogic, see (Yang &Bringsjord, under review.)Finally, what would be an example of a reasoning problem thatisn’t very easy, and the solving of which might justify confidencethat the solver is both poised for success in the high-tech twenty-first century, and genuinely intelligent? Well, here’s one; we referto it as “The Bird Problem”: Is the following statement true orfalse? Prove that you are correct.(7) There exists something which is such that, if it’s a bird, theneverything is a bird.Individual differences transcend therationality debateElizabeth J. Newtona and Maxwell J. RobertsbaDepartment of Human Communication Science, University College London,London, WC1N 1PF, United Kingdom; bDepartment of Psychology, Universityof Essex, Colchester, Essex, CO4 3SQ, United Kingdom.liz.newton@ucl.ac.uk mjr@essex.ac.ukAbstract: Individual differences are indeed an important aid to our un-derstanding of human cognition, but the importance of the rationality de-bate is open to question. An understanding of the process involved, andhow and why differences occur, is fundamental to our understanding ofhuman reasoning and decision making.The main thesis of Stanovich & West (S&W) is that differences inindividuals’ performance can be used to cast light on the rational-ity debate. Even if we accept that this issue is important, and thathumans occasionally behave irrationally, we still need clear crite-ria to identify such behaviour. Responses by themselves are oftentaken to be sufficient, but these are only informative if the cogni-tive processes underlying them are also understood. Otherwise,there is little to gain by addressing the rationality question. Thisproblem applies equally to the interpretation of psychometric testscores. Intelligence is a poorly understood construct, and the sug-gestion that it reflects only working memory capacity is by nomeans fully accepted.Although highly intelligent people may be more likely to givenormative responses in reasoning and decision-making tasks thanless intelligent people, correlations between test score and rea-soning performance can occur for a variety of reasons. Hence,differential correlations are not necessarily informative, and thefocus on individual differences in terms of outputs rather thanprocesses means that important qualitative differences are over-looked. The most straightforward reason for a correlation be-tween intelligence test score and performance at a reasoning taskis that highly intelligent people use the same processes as less in-telligent people, but execute them more effectively. However,this merely leads us back to a “cognitive limitations” account ofirrational behavior. Alternatively, perhaps highly intelligent peo-ple are better able to use different, more complex processes. Afurther possibility is that they are more likely to use differentprocesses, but these are simpler, and hence more efficient. Ei-ther possibility leads into a debate about whether the strategy se-lections, rather than the responses themselves, are rational. A res-olution depends crucially upon the ability to identify reasoningstrategies accurately at the level of the individual. However, evenwhere this is possible, we have to be certain that a suboptimalstrategy, that is, one that is linked to poor performance, is reallyfailing because of fundamental flaws. If, instead, a strategy is po-tentially normative, but too demanding to be executed accurately,then this turns the rationality issue into a debate concerningwhether a person has made a strategy choice commensurate withhis or her own ability to execute it accurately – and, ultimately,we are again returned to a cognitive limitations explanation of ir-rational behavior.Given that people differ in the strategies they use, the rational-ity debate forces a dichotomy on us: are these choices normativeor non-normative? Suppose you are presented with a series of tri-als, each consisting of compass point directions given together(e.g., one step north, one step east, one step north, one step west,one step south, one step south, one step west, one step north). Thetask is to determine the end point, relative to the start, after tak-ing the steps. The natural strategy for this task is spatial: The fullpath is traced in the mind or by using a finger. For the cancella-tion strategy – a task specific short-cut – opposite steps are can-celled, with the remainder forming the correct response. Bothstrategies are normative: where applied accurately, they will yieldthe correct response. However, the spatial strategy is slower, lessaccurate and more demanding to execute. People are oftenpainfully aware of the need to find an alternative. Surprisingly,even amongst university students, cancellation is used only by theminority. This is because it is only available to people with suffi-ciently high spatial ability to be able to identify the redundantprocesses of the spatial strategy and delete them, leading to thediscovery of cancellation. Hence, people with high spatial abilityoutperform the rest, not because they are executing the spatialstrategy more efficiently, nor because they are better able to usean enhanced spatial strategy in which additional processes in-crease accuracy, but because they have dispensed with spatial rep-resentations altogether, increasing accuracy and minimising effort(see Newton & Roberts 2000; Roberts et al. 1997).So, are the spatial strategy users irrational for this task?Granted, if we focus on outputs only, they are less accurate thancancellation users; but, as suggested earlier, the rationality de-bate is only served crudely in this way. Errors when using thespatial strategy are due to capacity limitations in any case. Therationality debate is not served at all by considering whether selected strategies are normative – both will yield correct re-sponses if executed accurately. Are the spatial strategy users lessrational because they made an inappropriate choice? No, thereis no alternative available to them, and hence no choice. If thespatial strategy users must be branded as irrational, this can onlybe because they lack the necessary resources to discover themore efficient method. This conceptualisation of irrationality asa lack of creativity may be unappealing to some, but for this ex-ample the categorisation of these people as irrational is artificialand driven only by the perceived need to address the rationalityquestion.Overall, S&W make many valid points. We agree that individ-ual differences are an important aspect of human cognition. Butto use them merely to resolve the rationality debate is problem-atic and neglects their full potential. Issues of how people reason,and how these processes change and develop with experience canbe better answered by not being side-tracked in this way.Continuing CommentaryBEHAVIORAL AND BRAIN SCIENCES (2003) 26:4 531Image removed due to third party copyrightImage removed due to third party copyright

Individual differences trancend the rationality debate

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