Co-operation and co-ordination in dialogue.

Sarah Haywood (1), Martin J. Pickering (1&2) and Holly P. Branigan (1&2)
Department of Psychology (1) and HCRC (2), University of Edinburgh

What motivates the choice of a particular linguistic form in production? According to Clark (1992) and colleagues, speakers behave 'co-operatively' by paying close attention to addressee needs. Other evidence suggests that
formulation is more likely to be driven by speaker-centred factors, such as lexical availability (Ferreira & Dell, 2000) or some kind of input-output co-ordination (Garrod & Anderson, 1987; Cleland & Pickering, 2002). Co-operation seems to require extra processing resources (Horton & Keysar, 1996), and it may be that audience design can only be seen at certain levels of processing, such as conceptualisation and lexical choice (Wilkes-Gibbs & Clark, 1992; Brennan & Clark, 1996). In this paper, we investigate the interplay between co-ordination and co-operation at the level of syntactic
encoding, using a novel variant of the confederate scripting technique (Branigan, Pickering & Cleland, 2000).

Participants played a communication game in which they described coloured wooden blocks to a partner. The blocks were selected from two chests of drawers. Drawers in box 1 had coloured labels to indicate that one drawer contained only red blocks, one drawer contained blue blocks, etc. Box 2 had shape labels: one drawer contained square blocks, one contained triangular blocks, and so on. Players took turns to describe picture cards showing which block their partner should select, and from which box. One speaker was a confederate of the experimenter, who always used an adjective-noun description ("the red square") to describe a block from box 1, and a noun-relative structure ("the square that's red") to describe a block from box 2. This is co-operative behaviour in the sense that noun-relative descriptions map easily onto box 2, which is organised by shape.

We found dissociable effects of co-ordination and co-operation on the kind of noun phrases produced by participants. Speakers are significantly more likely to produce a noun-relative structure following a noun-relative prime description from the confederate; this is an automatic priming effect. They are also significantly more likely to produce a noun-relative structure when describing a block from box 2, i.e. when it is helpful to mention shape before colour. This suggests that choice of form can also be under strategic control. We interpret these findings as evidence that co-ordination and
co-operation can have independent effects at the same level of processing. Speakers show a tendency towards syntactic co-ordination with an interlocutor, but this is moderated to some extent by a drive to produce language which is easily interpreted by the addressee.

References

Branigan, H. P., Pickering, M. J., & Cleland, A. A. (2000). Syntactic coordination in dialogue. Cognition, 75, B13-B25.

Clark, H. H. (1992). Arenas of Language Use. London: The University of Chicago Press Ltd.

Cleland, A.A., & Pickering, M.J. (2002). The use of lexical and syntactic information in language production: Evidence from the priming of noun phrase structure. (Manuscript submitted for publication).

Ferreira, V. S., & Dell, G. S. (2000). Effect of ambiguity and lexical availability on syntactic and lexical production. Cognitive Psychology, 40, 296-340.

Garrod, S., & Anderson, A. (1987). Saying what you mean in dialogue: A study in conceptual and semantic co-ordination. Cognition, 27, 181-218.

Horton, W. S., & Keysar, B. (1996). When do speakers take into account common ground? Cognition, 59, 91-117.

Wilkes-Gibbs, D., & Clark, H. H. (1992). Coordinating beliefs in conversation. Journal of Memory and Language, 31, 183-194.