Discussion of: Discourse Referents and External Anchors in Developmental Thought by Josef Perner

1. Discussion of: Discourse Referents and External Anchors in Developmental Thoughtby Josef Perner Alan Garnham Psychology University of Sussex alang@susx.ac.uk

2. Karttunen, 1969 • Karttunen’s 1969 paper, published in Jim McCawley’s 1976 “Linguistic Underground” volume of Syntax and Semantics, was a precursor of modern theories of reference in both formal semantics (e.g. DRT) and cognitive science (e.g. Mental Models Theory) ESF Eurocore Programme Consciousness in a natural and a cultural context

3. Hence,…. • My own interest in Discourse Referents! • Mental models contain representations of entities that may stand in various relations to each other and to actual entities. • Compare discourse referents and external anchors ESF Eurocore Programme Consciousness in a natural and a cultural context

4. Karttunen, 1969 / 1976…. • Uses the notion of discourse referent to analyse a number of linguistic phenomena, In particular.. • The logic of complement constructions • Presupposition • He developed accounts of both of these in more detail later. ESF Eurocore Programme Consciousness in a natural and a cultural context

5. However,…. • The point of more general interest… • As noted by McCawley in his introduction to Karttunen’s paper • …is the idea of indefinite NPs as both binding variables (asserting existence - as in Russell’s account) - AND introducing “constants” (DRs) that can be referred to again ESF Eurocore Programme Consciousness in a natural and a cultural context

6. Mental Models, DRs and DRT • Psychological factors, findings etc, may constrain psychological theories based on Mental Models containing DRs. • BUT, it is hard to deny that discourse is about things in the real world, imaginary worlds and abstract domains, and that there must be a good deal of veracity in the representations of them. • Entities are represented as having various properties and from various “perspectives”. ESF Eurocore Programme Consciousness in a natural and a cultural context

7. Computational Theory • I have argued elsewhere (Garnham, 1996 - Johnson-Laird Festschrift) that the Mental Models theory of text processing is a computational theory in the sense of David Marr - the result of a logical task analysis of the processes involved. • Some of Karttunen’s article can be read in a similar way • THIS is what a theory of referent tracking MUST be like ESF Eurocore Programme Consciousness in a natural and a cultural context

8. Perner’s Analysis • The interesting and crucial point here… • Which is not a major issue in showing how a (psychological version of) a theory based around DRs can be applied to adult “language, inference and consciousness” • …is that the “Defining Label” plays a role the importance of which only becomes apparent when certain other (metarepresentional) processes on DRs don’t occur. • Defining Labels also define perspectives on entities ESF Eurocore Programme Consciousness in a natural and a cultural context

9. Adults and Identity Statements • Not problematic for adults! • We make use of known identities to group information in memory • Anderson and Bower (1973) • George Washington had good health • The first president of the US had good health • Not distinguished in memory ESF Eurocore Programme Consciousness in a natural and a cultural context

10. Anderson and Hastie (1974) • Not-previously-known identities • James Bartlett is the lawyer • James Bartlett rescued the kitten • The lawyer rescued the kitten • If identities are learned first, verification of second and third sentence is equally quick, no matter which was presented • If presented later, actually seen sentences are verified quicker ESF Eurocore Programme Consciousness in a natural and a cultural context

11. Semantic Networks • Anderson’s theoretical position (at the time - early 1970s) was based on semantic network-like representations (Anderson and Bower, HAM) • Nodes in semantic networks don’t need to have the structure that DR-based representations have • Perner’s arguments indicate constraints on the representations ESF Eurocore Programme Consciousness in a natural and a cultural context

12. And in Conclusion… • A major advantage of Perner’s account of is that is provides a theoretical underpinning for a wide variety of developmental changes that appear at a similar time. • The account of problems with identity statements confirms an “unexpected” prediction of this kind of account ESF Eurocore Programme Consciousness in a natural and a cultural context