Vicarious Learning: more than common ground

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dialogue, vicarious learning, common ground,overhearers, alignment. 1. ... arrangements of Tangram figuresto the other, whose task, repeated over 6 trials, is to ...
Vicarious Learning: more than common ground John Lee, Jean McKendree, Richard Cox and Keith Stenning Human Communication Research Centre University of Edinburgh john, jeanmck, rcox, [email protected] Finbar Dineen Centre for Learning and TeachingInnovation Glasgow Caledonian University

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ABSTRACT The Vicarious Learner project is investigating the roleof dialogue in learning and, more specifically, how learners benefit fromopportunities to ’overhear’ other learners. A direct challenge to thisconcept comes from a study by Schober and Clark which claims that only direct participants can learneffectively from dialogue. We dispute this claim both on grounds thattheir own data indicate otherwise and also from a more theoreticalchallenge to their underlying model. Basically, we argue that Clark’smodel relies too heavily on a notion of common ground as being primarilyabout naming discourse objects. We see educational dialogues in particularas being much more aboutthe complex alignment of concepts where the participants know that aninitial misalignment is fairly certain. We focus instead on thedistinction between reasoning from a particularinterpretation, the focus of Clark’s model, and reasoning to an interpretation and how this might better describe whathappens in learning dialogues and why they might be more beneficial foroverhearers than Clark believes. KEYWORDS dialogue, vicarious learning, common ground,overhearers, alignment.

1.

LEARNING FROM OVERHEARING

Dialogue is clearly an important aspectof a rich learning experience, of the sort one hopes to provide in highereducation for example. We have argued elsewhere (McKendree et al1998) that dialogue is central to the learner’s "enculturation" into thepatterns of language and thought, discussion and criticism, that arecharacteristic of an academic discipline; we have noted also that, on amore detailed and local level, dialogue is often the most effective way for a learner to overcome e.g.a particular impasse during problem-solving, or to resolve a difficultconceptual issue. We have proposed, further, that learning can occur notonly through participation in dialogue, but also through observing others participating in it. We call this vicariouslearning, and we believe that in some manifestations it is very common, as whensilent students in a tutorial group learn from discussions between thetutor and others. We seek to understand this process more clearly, and toinvestigate the waysin which we can take advantage of it to create databases of re-usabledialogues as a helpful resource for distance learners and others. One challenge to our conception of re-use is presented by Schober and Clark(1989), who claim that in fact dialogue is only really useful to those whodirectly participate. They describe a study in which "overhearers" hearrecordings of dialogues betweenpairs where one partic ipant is describing arrangements of Tangram figuresto the other, whose task, repeated over 6 trials, is to copy them.

The participants cannot see each other, but can talkas much as they like. Some overhearers ("early") hear all 6 trials, others("late") only the last three; their task is also to copy the Tangramarrangements. In this task, there was a clear tendency for the participants to usefewer words over a number of trials, as they were able to refine the ways theyreferred to the figures. At the same time, they became more accurate(perfect after trial 4). Overhearers also became more accurate through the trials, early overhearers ultimately achieving 95%. Lateoverhearers also improved, to a best of 73%. Much the same happened in asecond experiment where the overhearers were present at the dialogue(instead of listening to tapes later),despite the fact that the participants were told theoverhearers had no interest in the content of the dialogue. Schober and Clark’s objective is to establish that collaboration is anabsolutely essential part of effective communication indialogue; hence they point to a range of ways in which the overhearers perform less well, and conclude that "thesocial role of interacting in conversation plays acentral role in the cognitive process of understanding" (p. 228), and that "[u]nderstanding can only beguaranteed for listeners who actively participate" (p. 230). However, itseems clear to us that these conclusions at least demand furtherinspection. That the overhearers do notdo as well as the participants is true, but it is strikinghow well they do in fact perform. Our view of these experiment is that they show people to have a range ofinterpretative strategies that they are capable of bringing to bear, andwhich can compensate remarkably well for the inevitable disadvantage of notreceiving direct, tailored feedback from a conversational partner. The second point is that understandingcan never be "guaranteed", but Clark’s model does littleto elucidate what happens to resolve misunderstandings except at verysimple levels. We think it is apparent from their own data that people, even overhearers,can resolve many misunderstandings but also that the confusions that dooccur, even in this straightforward task, and do have an impact onunderstanding. These misinterpretations are even more likely to be critical in more complex, conceptual discourse.In the rest of the paper, we why we think Clark’s model is insufficient forour situation, both because it underestimates the ability of overhearers tobenefit from ’vicarious learning’ and because it might overestimate the ease with which common ground isestablished among speakers. 2.

ESTABLISHING THE COMMON GROUND OF ’COMMON GROUND’

Schober and Clark’s analysis depends onthe concept, standard in theories of dialogue, of commonground. The common ground (CG) is essentially the information which is shared bythe participants in a dialogue and which forms the basis on which they understand each other. It evolves continuously,though in a task such as the Tangram matching much work in establishing itis done in the earlier trials. Each dialogue participant’s utterances arebased on assumptions about the interlocutor’s apprehension of the CG, and modified or supplemented in the lightof the responses they receive (utterances, and many kinds of non-verbalfeedback where available). The participants thus collaboratively createthe CG in a dynamic process which is conditioned by many subtle influences that amount to a certain attunementbetween the speakers, so that their communication becomes more economicaland fluent. The argument is that the position of the overhearer, lackingthis attunement, is highly disadvantaged in developing and maintaining a coherent view of the CG. Thisposition is naturally much worse still for late overhearers who are notexposed to the main activity of establishing the CG. (Of course, all theoverhearers have heard the original task instructions, otherwise their lack of CG would be disastrous!) We do not challenge the basis of this analysis, but we note again that theoverhearers are actually quite successful. Their descriptions of what isgoing on, recorded by Schober and Clark, suggest that they are very good atusing what cues they can find to make conjectures about the CG, and to correct their notion of it in thelight of later evidence. Like the participants, they improve in theirsuccess at the task, despite the fact that words become fewer. Even the late overhearers, though never as successful,improve at a remarkable rate. This is not to imply that their cognitiveprocesses are the same as those of the participants; they may be ratherdifferent. Perhaps they are more akinto

developing implicit theories about the participants’ language use, andno doubt it is true that the overhearers "kept descriptions that they hadnot understood in mind and went back to work on them when they had achance" (p. 221). But they certainly achieve significant understanding, and indeed learning. We accordingly want to modify Schober and Clark’s conclusion in thatunderstanding for the overhearer can be, if not perhaps guaranteed, atleast quite typically expected. Their conclusion about the social role ofdialogue we do not dispute: rather, we embrace it. We believe that the social role of interaction is indeedcritical in achieving full understanding, through enculturation, but weurge that the relation between the cognitive and the socialis more complex than Schober and Clark suggest. The relevant socialrelations are not limited to "interacting in conversation"; we proposethat the overhearer can get some vicarious access to the social role. Thiswill confer a significant benefit not perhaps in comparison to the direct participants, but at least in comparisonto someone who has not been exposedto the dialogue at all. Even as adialogue pair’s language converges on a shared understanding, Garrodand Doherty (1994) have shown how interactions betweenpairs of people among a population result in theemergence of shared conventions among the population — enculturation under laboratory conditions. It seems to us an importantphenomenon that overhearers are able to participate in this sharing, whichindeed may be of great value in some situationse.g. to otherwise isolated distance learners. These considerations suggest that critical factors in vicarious learningwill be 1) the extent to which the learner already shares a good deal ofcommon ground with the participants in the dialogue which is being"overheard",not only about the domain, but about the context of the discussion, and 2)the explicitness of cues to establish CG and further develop it as thedialogue develops. The dialogue will be immediately understoodinasmuch as CG is shared, but on the other hand it will result in an expansionof the CG (and hence at least one kind of learning) in so far as theoverhearer can somehow infer those aspects not already shared. 3.

EXTENDING COMMON GROUND

We need to expand our understanding ofwhat is referenced through language. Schober and Clark are concerned withthe level of nominal grounding, definition and identification. However, therelationship of terminology to actual conceptualdistinctions is hardly one to one. Rather, we need to establish thecontextual uses of words to denote several possible distinctions: consensus, the same word for the sameconcept; conflict, the same word for different concepts; correspondence, different words for the same concept; or contrast, different words for different concepts.When listening or participating in a learning dialogue,we must be constantly monitoring our own orientation toward the words beingused. Vicarious learning may actually allow us to do this more consciouslythan those involved in 'the heat of the moment', having to generate thediscussion. It is at the higher processes of meaning, function, and conceptual integrationthat the overhearing of discourse may provide the means for grounding whichwould otherwise be missed. How can we develop this wider picture of the importance of vicariouslearning? We believe that such dialogues might provide a model forlearners to analyse and emulate. In particular, our concern is witheducational dialogues, not typical'everyday' conversations. Many of the best learning dialogues involve themaking explicit of inferences which would normally remain unspoken.Assumptions are made by the participants, which often turn out not to beshared — not to be part of the CG — and a process has to occur that resultsin these assumptions being aligned. Often, though not necessarily, thismeans that the student has to be brought more into line withthe tutor; but this occurs not through the student simply being told(accepting an exposition) as much as being shown, through a more or less logical process of derivation, in which theauthority of the tutor is largely abrogated in favour of the more abstract authority of reasoning norms. The student thus learns, not only aboutthe subject matter, but also about the process of argumentation. Suchargumentation, we notice, is to an important degree essentially explicit; it's a procedure that can be observed. The development of the CG beingthus relatively out in the open, derivational dialogues are well suited tovicarious following of the process by overhearers.

It is likely that in many cases of vicarious learning, dialogues are alsoin other respects specifically developed in such a way as to facilitate theoverhearer’s construction of the CG. Ourhypothesis in the Vicarious Learning project is that, by capturing such learningdiscourse, new learners listening in may be included in a morediverse conversation; the alternative is that much grounding may remain unexplored andavailable only to the expert. This facilitation ofCG often happens in tutorial sessions, where the tutor may, for the benefit of theothers, be more explicit than he knows is necessary for the student he istalking to. It certainly happens in other homely examples such as radiodiscussion and interview programmes, for example with politicians, where the presenter will (if sometimes in arelatively heavy-handed manner) interrupt to demand expansion of abbreviations, to elicit repetition and clarification, or even to interpolateinformation which the speaker is taking for granted but which might not beshared by all of the audience. In cases like these, the dialogueparticipants are well aware that there are or will be overhearers, and they take this into account.The very fact that this happens, of course, acts on the one hand asevidence that overhearers are known to have effective interpretativestrategies, but on the other as evidence that these strategies require specific assistance from the dialogue participants. It leaves unclear how necessary this assistance is, and how effectiveoverhearers’ strategies can still be in its absence. Given that Schoberand Clark’s results arose where subjects were unaware that there would beoverhearers, it is tempting to supposethat there is likely to be a continuum of cases in which varying degrees of"scaffolding" support for overhearers’ construction of the CG is provided,and that this will result in varying degrees of ease and success forvicarious learners. 4.

REASONSBEHIND REASONING

In a brief example from a classroom,Clark (1996, p.298) states that the classroom is a closed situation in which the teacher hasthe greater ’goods’ to transfer and there is generally no more negotiationneeded. It is true that his examples are ones in which that might be the case, requesting a student to sit down or toanswer a simple factual question. However, in the more complex situationsthat we would consider examples of more effective learning dialogues, there is a great deal of negotiation and the unequalequity that assumes power is assigned tothe teacher is not nearly as straightforward. Clark’s model, fundamentally, focuses on CG as the naming and identifyingof discourse objects. It does not address building and organising anarrative aimed at, in our case, the particular goal ofbringing almost guaranteed misalignment of conceptual knowledge into betteralignment. It is true that his model is not attempting to accountnecessarily for learning dialogues and most of his examples are from more mundane exchanges in shops and onstreet corners. However, the Schober and Clark paper at least isimplying that the model should apply to suchdialogues and that only direct participants in a discourse are able to establishsuch alignment. Clark’s model seems to agree with Sperber and Wilson’s (1986) claim from’relevance theory’ that the first interpretation is the one speakers aremost likely to ’latch into’, whereas in educational conversationsthis first reading is very likely to be wrong or at least incomplete andthe students are well aware of that. (Note, though, that Clark rejectsother aspects of Sperber and Wilson, see p. 146 and 370-373of Clark, 1996.)Clark’s model does not deal with conversations in whichparticipants know that a conceptual misalignment in ’common ground’ is just about guaranteed. In thesecircumstances, we want the students to challenge a speaker in ways that might be unacceptable inanother context. Such dialogues may provide a very goodmeans for indirect participants, overhearers, to vicariously establish not only the common ground, but to challenge their ownunderstanding through comparison with the example dialogues. To encapsulate the distinction we are making, Clark’s Common Groundfocusses on the problems of establishing the particulars of reference in acommunicative episode. Because we are focussed on educational discourse, weconcentrate on the issue of establishing conceptual alignment where conceptual misalignment is the default expectation. Clark’s uses exampleswhich involve little need for making conceptual inferences explicit so thatlearners can internalise them. But this "reasoning to

aninterpretation" is what educational dialogues are about, rather thanreasoning from a relatively nonproblematic initialinterpretation. It involves the speakers holding tentative interpretations that must be probed, questioned, refined,negotiated, and constantly revisited. We believe it is also very likely that much of the dialogue incomputer mediated cooperative systems will also involve a need for thisnegotiation to an acceptable mutual understanding, whether the dialogue is between the human and a computer, or between twohumans mediated by technology. Thus, we think that designers need toconsider a more complex situation involving more tentative negotiation of’common ground’ than that inClark’s model. System builders need to think, also, about how todesign such systems for indirect participants who might be watching,listening or reading information without directly contributing -lurkers, in some current Internet terms. It is also important to keep in mind that complexunderstanding will evolve and may require revisiting of concepts at variouspoints. Thus, we feel that Clark’s model is too limited to address what may be themost crucial aspects of design of effective cooperative systems, both inits characterisation of common ground as primarily a ’one-shot’problem of naming and identification, and also in its claim, atleast in Schober and Clark, that only directparticipants can learn effectively from discourse. ACKNOWLEDGEMENTS This research is supported by the UKESRC Cognitive Engineering programme and UK EPSRC Multimedia and NetworkingApplications programme. HCRC is an Interdisciplinary Research Centrefunded by ESRC. We are grateful to Professor J. Terry Mayes, Richard Tobin and Padraic Monaghanfor many helpful discussions. REFERENCES Clark, H. H. (1996).Using Language. Cambridge University Press. Garrod, S. and Doherty, G (1994). Conversation, coordination andconvention: An empirical investigation of how groups establish linguisticconventions. Cognition, 53, 181-215. McKendree, J., Stenning, K., Mayes, T., Lee J., and Cox, R.(1998). Why Observing a Dialogue may Benefit Learning: TheVicarious Learner. Journal of Computer Assisted Learning, (June), Vol. 14, No. 2. Schober, M.F. and Clark, H.H. (1989). Understanding byaddressees and observers. Psychology, 21,11-232. Sperber, D. and Wilson, D. (1986). Relevance. Cambridge,MA: Harvard University Press.

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