Reference and Working Memory: What Discourse Can Tell us about Cognition

Reference and Working Memory: What Discourse Can Tell us about

Cognition

Andrej A. Kibrik (kibrik@chat.ru) (Institute of Linguistics, Moscow, and MPI for Evolutionary Anthropology, Leipzig)

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INTRODUCTION The phenomenon: Referential choice in discourse

When people speak or write, they constantly mention various referents (persons, animals, objects, abstract notions, etc.) Basic referential choice: full noun phrase (full NP) pronoun zero form

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An example (from the web page of the city of Dresden)

1. Johann Friedrich B?ttger ? Alchemist and inventor, ? born 4.2.1682 in Schleiz, ? died 13.3.1719 in Dresden. B?ttger was imprisoned as an alchemist in K?nigstein Fortress in 1703. In 1707 his laboratory was transferred to the Jungfernbastei, a bastion of the Dresden City fortifications. It was here, a year later, that he discovered the formula for the first European porcelain and the world's first hard porcelain. B?ttger also achieved certain results as a botanist in Dresden, ? setting up a greenhouse with over 400 rare plants. In 1710 he was ordered to Meissen as administrator of the royal porcelain manufactory.

zero

Full NP

pronoun

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Summary of the talk

Part I: A linguistic study of referential choice in natural discourse Part II: Consequences of that study for the broader field of working memory research

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PART I: THE LINGUISTIC STUDY The problem

How does the speaker make the referential choice between full noun phrases and reduced noun phrases, such as pronouns? Note: This problem is really fundamental; at least every third word in natural discourse depends on referential choice.

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Prior studies: huge literature, including:

Linguistics, e.g.: Fox, Barbara. 1987. Discourse structure and anaphora in written and conversational English. Cambridge: CUP Psycholingustics, e.g.: Gernsbacher, Morton Ann. 1990. Language comprehension as structure building. Hillsdale, NJ: Erlbaum. Cognitive psychology and neuroscience, e.g.: Streb, Judith & Roesler, Frank & Henninghausen, Erwin. 1999. “Event-related responses to pronoun and proper name anaphors in parallel and nonparallel discourse structures”. Brain and Language 70: 273-286.

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Different terminologies

Coreference Anaphora Reference tracking Reference maintenance Management of reference Referential choice

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Important terms

Johni was sitting at the table. Hei was daydreaming about the weekend

coreferential

antecedent

Referential device/expression

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Goal

To construct a model of referential choice in discourse

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Properties of the present model

speaker-oriented (rather than addressee-oriented or text-centered) sample-based (rather than based on a heterogeneous set of examples) general (rather than tolerant to exceptions) predictive and finite (rather than post-hoc repairing to account for individual cases) explanatory (rather than based on the black box ideology) cognitively based (rather than relying on home-made quasi-cognitive concepts) multi-factorial (rather than assuming one omnipotent factor) testable and calculative (rather than declarative)

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The cognitive assumptions

The primary cognitive determiner of referential choice is activation of the referent in question in the speaker’s working memory (WM). Referent’s activation score (AS) varies within a certain range (e.g. between 0 and 1). If the current activation score is above a certain threshold, then a semantically reduced (pronoun or zero) reference is possible, and if not, a full NP is used.

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This model continues the lines of:

Cognitively minded linguistic research, such as: Chafe, Wallace. 1994. Discourse, consciousness, and time. The flow and displacement of conscious experience in speaking and writing. Chicago: University of Chicago Press. Tomlin, Russell & Pu, Ming-Ming. 1991. “The management of reference in Mandarin discourse”. Cognitive Linguistics 2: 65–93 Kibrik, Andrej A. 1991. “Maintenance of reference in sentence and discourse”. In: Lehmann, Winfred P. & Hewitt, Helen?Jo J. (eds.) Language typology. Amsterdam: Benjamins, 57-84.

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And attempts to be compatible with:

Cognitive-psychological and neuropsychological work on working memory Baddeley, Alan. 1990. Human Memory: Theory and Practice. Needham Heights, Mass: Allyn & Bacon. Cowan, Nelson. 1995. Attention and Memory: An Integrated Framework. New York – Oxford: Oxford University Press. Smith, E.E. & Jonides J. 1997. “Working memory: A view from neuroimaging”. Cognitive Psychology 33, 5–42.

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The cognitive multifactorial model of reference in discourse

production

Discourse context

Referent’s activation score (AS)

Referential choice

Filters

Properties of the referent

Activation factors

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The original study

Referential choice in Russian narrative discourse (Kibrik 1996) Main results About seven to ten significant activation factors Numerical model of factor interaction Complete prediction of the data in corpus Almost complete prediction in the test corpus

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A study of referential choice in English narrative discourse

“The Maggie B.” by Irene Haas Discourse type: written narrative simple, clear style basic event types: physical events, interaction of people, human reflections… Number of discourse units: 117 Number of referents: 76 Number of referent mentions: 225 Number of “important” referents: 14 Number of protagonist referents’ mentions: Margaret – 72, James – 28, the ship – 12 Number of “relevant” referential devices: full NPs – 39, activation-based pronouns – 40

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Stages of model construction

I will explain the heuristics of model construction in terms of five consecutive stages, “A” through “E”.

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Stage A: Identify alterable vs

unalterable referential devices

1502 A storm was coming! 1503 Margaret must make the boat ready at once. 1601 She (~Margaret) took in the sail 1602 and tied it tight. 1603 She (*Margaret) dropped the anchor 1604 and stowed all the gear <...> Alterable and unalterable devices correspond to different activation levels

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Attribution of referent mentions to “potential referential form”

categories

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Stage B: Identify the significant activation factors, as opposed to

insignificant

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Stage C: Specify the list of the significant activation factors

with the indication of: the distinction between primary and secondary factors logical structure of each factor values of each factor corresponding numerical weights of each value

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Primary activation factors (variables), their values, and numerical

activation weights

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An example of a rhetorical graph (in accordance with the Rhetorical

Structure Theory of Mann and Thompson)

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Example of RhD

LinD (RhD is low and LinD is high)

1201 After juice-and-cookie time, she gave James his counting lesson, 1202 and this is how she did it. 1203 One, two, three, four, five, once I caught a fish alive, 1204 six, seven, eight, nine, ten, but I let him go again. 1205 Why did you let him go? 1206 because he bit my finger so. 1207 Which finger did he bite? 1208 This little one upon the right. 1209 And she gave James' little finger a nibble …

RhD=1

LinD=7

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Reference and discourse structure

Referential choice is fundamentally conditioned by discourse structure The strongest activation factor is the rhetorical (hierarchical) distance to the antecedent Reduced NPs are more likely to occur in coherent contexts

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Primary activation factors

.. (continuation)

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Reference and the properties of antecedent/referent

Antecedent role is the second strongest activation factor: subjects make very good antecedents More permanent referent properties (protagonisthood, animacy) play the role of correction/compensation factors

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Activation weights

Present model: weights found through a trial-and error procedure, by hand Ideal model: weights found through a computational procedure, automatically

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Stage D: Identify the mechanism of factor interaction

Present model: addition of all relevant activation weights; the resulting AS varies within the limits from 0 to a bit over 1. Ideal model: multiplication or more complex interaction of the factors’ activation weights

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Stage E: Identify referential strategies, or mappings “AS

referential choice”

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A probabilistic reinterpretation of referential strategies: 4

thresholds

Pronoun only

Pronoun OK

Full NP OK

Full NP only

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An example of calculating a referent’s current AS

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PART II: Consequences for working memory studies

Some classical issues in WM research: (1) WM capacity: how much information can WM hold at one time? (2) Control of WM: through what mechanism does information enter WM? (3) Forgetting: through what mechanism does information quit WM?

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Issue 1: Capacity

The procedure of calculating the referents’ ASs does not depend on whether a given referent is actually mentioned at the present point For any referent, its AS can be identified at any time Therefore, summary (grand) activation of all referents can be calculated for any moment of discourse

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The dynamics of two protagonist referents’ activation and of grand

activation in an excerpt of English narrative

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Generalizations about WM capacity

Grand activation is an estimate of the specific-referent portion of WM The maximal values of grand activation are between 3 and 4 (cf. an identical estimate in Cowan 2000) Grand activation varies much less than activation of individual referents In the course of coherent stretches of discourse (paragraphs) grand activation gradually builds up At the points of incoherence (paragraph boundaries) WM is reset or updated.

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Issue 2: Control of WM

WM is controlled by the attentional system of the brain (Baddeley 1990, Cowan 1995, Posner & Raichle 1994: 173). Focal attention is linguistically rendered by the syntactic status of subject (Tomlin 1995) Subjects are the best antecedents, both discourse- and sentence-wide

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Cognitive and linguistic interplay between attention and WM

Attention feeds WM: What is attended at moment tn becomes activated in WM at moment tn+1 Linguistic moments are discourse units Focally attended referents (moment tn) are coded by subjects Activated referents (moment tn+1) are coded by reduced NPs (pronouns)

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Cognitive and linguistic interplay between attention and WM: Summary

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Issue 3: Forgetting

“Trace decay” theory: Forgetting is a function of time “Interference theory”: Forgetting is a result of displacement by new incoming information

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Linguistic data are compatible with the trace decay theory

Activation decreases as distance to the antecedent becomes greater The limit on the number of concurrently activated referents can be explained by WM capacity limitations The balanced system of activation factors activates and deactivates referents in accordance with WM capacity limitations

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Conclusions

Capacity of WM for referents is severely limited (3 to 4 times maximal activation of a single referent) Referents enter WM through the mechanism of attentional control Referents can be forgotten from WM through the mechanism of decay

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Really final conclusions

Linguistic discourse analysis can indeed contribute to explorations of the human cognitive system It is the time for a close cooperation between linguistics and psychology in the study of cognition

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