1. 1 B idirectional optimization from the perspective of experimental pragmatics Reinhard Blutner Universiteit van Amsterdam June 11, 2007 ∙ ZAS Berlin

2. 0 Introduction “With four parameters I can fit an elephant, and with five I can make him wiggle his trunk” (John von Neumann)

3. 3 Grice and His Followers Relevance Theory Presumptive Meanings Neo- Gricean Theories (Horn, Atlas) OT-Pragmatics

4. 4 Experimental Pragmatics “Properly devised experimental evidence can be highly pertinent to the discussion of pragmatic issues, and pragmatics might greatly benefit from becoming familiar with relevant experimental work and from contributing to it ” (Noveck & Sperber 2007, p. 210)

5. 5 Optimality Theoretic Pragmatics  Like generally in OT: no artificial separation between competence and performance –NL comprehension as interpretive optimization –NL production as expressive optimization  Open issues: –Are the two optimization processes integrated with each other (bidirectional optimization)? –Are there asymmetries between comprehension and production? –The role of fossilization?

6. 6 The Idea of Fossilization  ‘Invited Inferences’ (Geis & Zwicky 1971). Mechanism of conventionalization for implicatures  Short-circuited implicatures (Morgan 1978; Horn & Bayer 1984)  Lexicalization (Cole 1975)  Traugott (1989…2005) applied the idea to explain language change (conventionalization and language change)  Levinson (2000) und Mattausch (2004) used the idea for explaining the development of binding principles.

7. 7 Outline  Pronouns/Reflexives with children and adults 1.1 Hendriks & Spenader‘s bidirectional processing account 1.2 The fossilization account  R-expressions/Pronouns with young and elderly adults  All/Some (Scalar Implicatures) with children and adults  Conclusions

8. 1 Pronouns/Reflexives In an important recent article Hendriks and Spenader (2004) give a new interpretation of children‘s delay of the comprehension of pronouns. I discuss the validity of this interpretation and present an alternative account in terms of iterated learning

9. 9 The Pronoun Interpretation Problem  Bert saw himself  Bert saw him  Children correctly interpret reflexives like adults from the age of 3;0 but they continue to perform poorly on the interpretation of pronouns even up to the age of 6;6 (50 % errors)  E.g. Jakubowicz (1984); Koster and Koster (1986); Chien and Wexler (1990); McDaniel, Smith Cairns and Hsu (1990); McDaniel and Maxfield (1992).

10. 10 Children‘s Production of Pronouns and Reflexives  I hit myself.  John hit me  * I hit me.  Bloom et al. (1994): Even in the youngest age groups investigated (ranging from 2;3 or 2;4 to 3;10), the children consistently used the pronoun me to express a disjoint meaning (99.8% correct), while they used the reflexive myself to express a coreferential interpretation (93.5% correct).  Conclusion: very young children have competence in binding principles.

11. 11 The problem  Usually, comprehension of a given form precedes production of this form –Bates, Dale and Thal 1995; Benedict 1979; Clark 1993; Fraser, Bellugi and Brown 1963; Goldin- Meadow, Seligman and Gelman 1976; Layton and Stick 1979.  Thus how do we reconcile children’s poor performance on comprehension tasks with their near-perfect production data?

12. 12 Previous accounts  Reject the comprehension data (Bloom et a. 1994) –the tasks used in the comprehension experiments did not adequately test children’s grammatical competence  Dissociation between a comprehension grammar and a production grammar. –requires some ad hoc stipulations  Revise the binding principles, making a distinction between coindexation and coreference (Chien and Wexler 1990; Grodzinsky and Reinhart 1993). –This is based on the observation that children seem to correctly interpret pronouns in the scope of quantified noun phrases.

13. 1.1 Hendriks & Spenader‘s account “Our account, formulated in the framework of Optimality Theory handles the comprehension data as well as the production data by arguing that children acquire the ability to reason about alternatives available to other conversation participants relatively late. It is this type of bidirectional reasoning, we argue, that is necessary for correctly interpreting pronouns.” (H&S 2004)

14. 14 Optimality Theory as a Framework Contraint-Hierarchy: C1 >> C2 >> C3 Evaluator Output Input Generator 1 23 45 Candidates

15. 15 Unidirectional OT  Consider two directions of optimization (Hearer-oriented, Speaker-oriented)  Use the same set of constraints and the same ranking for both perspectives  Hence, the evaluator evaluates pairs of representations (e.g. form-meaning pairs)

16. 16 Constraints (slidely modifying Burzio 1998)  PRINCIPLE A: A reflexive must be bound locally  REFERENTIAL ECONOMY: Avoid R-expressions >> Avoid pronouns >> Avoid reflexives pro self disjconj pro self disjconj PRINCIPLE A REFERENTIAL ECONOMY

17. 17 Assuming a Ranking  PRINCIPLE A >> REFERENTIAL ECONOMY  Hearer‘s perspective: one optimal interpretation for self but two optimal interpretations for pro.  Speaker‘s perspective: correct unique form for each interpretation. pro self disjconj pro self disj conj

18. 18 Bidirectional OT  Strong bidirection requires that an interpretation is optimal for a form (interpretive optimization) and that a form is optimal for an interpretation (expressive interpretation)  In the example there is only one bidirectionally optimal form-meaning pair but two optimal interpretation pairs: (pro, disj) and (self, disj) pro self disjconj

19. 19 Delayed Bidirection  The proposal is that children begin with unidirectional optimization, and only later acquire the ability to optimize bidirectionally.  A child must, when hearing a pronoun, reason about what other non-expressed forms the speaker could have used, compare the interpretation associated with the pronoun and realize that a coreferential meaning is better expressed with a reflexive. Then, by a process of elimination, the child must realize the pronoun should be interpreted as disjoint.  Optimizing bidirectionally inherently involves reasoning about alternatives not present in the current situation, which may be a skill acquired very late, thus explaining the lag in acquisition.

20. 20 Delayed Bidirection  Unidirectional Optimization  Bidirectional Optimization  What‘s essential for this solution is that the hearer has to take a potential speaker into account pro self disjconj pro self disj conj

21. 21 Advantages  The authors are able to derive Principle B effects from Principle A alone, through bidirectional optimization.  The analysis clearly distinguishes the task of a speaker from the task of a hearer. As a result the analysis is able to model different results for production and comprehension.  Besides the stipulation of the constraints and their ranking no other stipulations are required  The approach nicely combines a pragmatic explanation with a processing account (lack of processing resourses)

22. 22 Disadvantages  The constraints are partly stipulated - no constraint grounding  Theory of Mind (Perner, Leekam and Wimmer 1987) requires awareness of other conversation participant’s choices. Hence, theory of mind is based on controlled rather than automatic processing. However, the effects of pronoun processing are automatic rather than controlled. There is no explicit hint for mind reading capacities in such tasks

23. 1.2 A Reinterpretation in Terms of Learning/Fossilization I will propose a reinterpretation of the Hendriks/Spenader account based on the idea that the ranked system of constraints is changed during learning. Rather than stipulating a change from unidirectional to bidirectional processing I account for the effects of (weak) bidirection by changing the constraint ranking.

24. 24 Measuring the Success of Communication  Speaker‘s strategy: given the possible utterance meanings m, the OT system specifies a function S(m)  Hearer‘s strategy: given the possible language forms F, the OT system specifies a function H(F) 1 if m = H(S(m))  U(S,H,m) = 0elsewhere  EU(S,H) =  P(m i ) U(S,H,m i )

25. 25 Learning as utility optimization  Learning consists in improving the value of expected utility.  In OT-learning theories the ranking of a given system of constraints is (stepwise) changed  Learning leads to a stable outcome if the relevant EU(s) reach its maximum value

26. 26 Very Simple Algorithm m f m’ SpeakerHearer m = m’ ? If yes, nothing happens If no, adjustment: All constraints that favour (f, m) over (f, m’) are promoted All constraints that favour (f, m’) over (f, m) are demoted

27. 27 Application: Fossilization  Principle A: self  conjoint  Referential Economy: self >> pro  Principle B: pro  disjoint; …. pro self disj conj pro self Constraint B strengthened disj conj conj Speaker sel f Hearer nothing happens conj Speaker pro Hearer nothing happens disj

28. 28 More Natural Constraints  Bias Constraints –PRINCIPLE A: A reflexive must be bound locally –PRINCIPLE B: A pronominal is free (in its governing cat)  Markedness Constraints –DISJOINT REFERENCE: disj > conj –EXPRESSIVE ECONOMY: pro > self pro self disjconj pro self disjconj Bias Constraints Markedness Constraints A B

29. 29 Why delayed principle B? Teacher pro self disjconj pro self disjconj A B Learner pro self disjconj A pro self disjconj B L0L0 L 1: A-first (ambiguous pro L 1: B-first (ambiguous self A-first B-first Initial State

30. 30 The Final Step Teacher pro self disjconj pro self disjconj A B pro self disjconj A L0L0 L 1 : A-first L2L2 pro self disjconj A B

31. 31 Conclusions  Two different views –Processing account (unidirectional vs. bidirectional processing) –Fossilization account (applying OT learning theory). This view is memory-based  Conceptual advantages of the fossilization account  Two kinds of fossilization –Individual fossilization via learning/automatication on an ontogenetic time scales (seconds-years) –Cultural fossilization via iterated learning / cultural evolution on a historical time scale (years-centuries) Meanings are partly conventionalized within speech communities and partly negotiated anew during each individual interaction (Traugott & Dasher 2002)

32. 32 Explaining Universals FunctionalFormal Genetic evolution Evolutionary Psychology (Pinker) Minimalist program (Chomsky) Cultural evolution Recruitment theory (Steels) Iterated learning (Kirby, Hurford, Zuidema)

33. 2 R-Expressions/Pronouns A recent article by Petra Hendriks, Christina Englert, & Ellis Wubs * investigates whether choosing the appropriate referring expression requires taking into account the hearer’s perspective, as is predicted under some versions of bidirectional OT but is unexpected under other versions. * Age differences in adults’ use of referring expressions (unpublished manuscript, University of Groningen 2007 )

34. 34 Sentence Elicitation Study A woman hold- ing an ice cream cone is walking past a road sign. The woman comes across a girl. She gives the girl an ice cream cone. The girl is eating from the ice cream cone. Well, the woman passes again an ice cream van. The woman buys another ice cream come. Topic shift Target Picture she

35. 35 Main Results

36. 36 Discussion  Elderly adults produce (non-recoverable) pronouns significantly more often than young adults when referring to the old topic in the presence of a new topic.  With respect to the comprehension task, no significant differences were found between elderly and young adults.  These results support the hypothesis that speakers optimize bidirectionally and take into account hearers when selecting a referring expression.  If the use of a pronoun will lead to an unintended interpretation by the hearer, the speaker will use an unambiguous definite noun phrase instead.  Because elderly adults are more limited in their processing capacities as speakers they will not always be able to reason about the hearer’s choices.

37. 37 Constraints  PRO  TOP: Pronouns refer to topics  REFERENTIAL ECONOMY * Avoid R-expressions >> Avoid pronouns R pro N-TopTop R pro N-TopTop PRO  TOPIC REFERENTIAL ECONOMY * REFERENTIAL ECONOMY = EXPRESSIVE ECONOMY in the case of comparing pronouns & R-expressions

38. 38 A bidirectional optimization account that fits the observations  REFERENTIAL ECONOMY >> PRO  TOP  Hearer‘s perspective: one optimal interpretation for pro and one R-dependent optimal interpretations for R-expression (not represented!)  Speaker‘s perspective: pro is the the optimal form for both the Top and the N-Top interpretation  Bidirectional Optimization: Speaker choses pro for Top and a R-expressions for N-Top. R pro N-TopTop R pro N-Top Top

39. 39 Discussion  Fits nicely with the earlier approach for pro/self  Prediction for elicitation studies: elderly adults behave similar to children ☺  Prediction for pronoun/reflexive interpretation studies: elderly adults behave similar to children ☹  Conceptual problem: What is the motivation for the ‘inverted ranking’ REFERENTIAL ECONOMY >> PRO  TOP ??  (In the paper, Hendriks et al. wrongly assume the earlier ranking PRO  TOP >> REFERENTIAL ECONOMY which doesn’t fit their data)

40. 40 A fossilization account that fits the observations  EXPRESSIVE ECONOMY, TOPIC  Child can not learn anything if it takes the listener‘s role only! R pro N-TopTop R pro N-Top Top Speaker pro Hearer nothing happens Top Speaker R Hearer nothing happens Top N-Top

41. 41  EXPRESSIVE ECONOMY, TOPIC R pro N-TopTop R pro N-Top Top PRO  TOP strengthened Speaker pro Hearer nothing happens Top Speaker pro Hearer Top N-Top A fossilization account that fits the observations R

42. 42 Discussion  The fossilization accounts is able to describe the difference between children and adults  However, it predicts that elderly adults behave similarly to younger adults in case of R- expressions/pronouns  Wrong prediction! They should behave like children. Defossilization doesn‘t make any sense here.

43. 3 All/Some (Scalar Implicatures) Recent experimental work by Noveck & Sperber investigates the case of scalar implicatures. Their experimental method has helped sharpen a theoretical debate and has provided uniquely relevant evidence.

44. 44 Some and all  Experimental Pragmatics: Noveck u.a. –Some elephants live in the zoo (appropriate) yes 90% 99% –All elephants live in the zoo (inappropriate) no 99% 99% –Some elephants have trunks (inappropriate) yes 85% 41% –All elephants have trunks (appropriate) yes 99% 96% –Some elephants have wings (absurd)no 99% 98% –All elephants have wings (absurd)no 99% 99%  Why do children sometimes think more logical than adults? Adults10-11

45. 45 Potential Answers  RT (see Noveck)  Chierchia’s defaults  OT pragmatics has two potential answers (1)Metalinguistic ability for perspective changing (bidirectional reasoning) not yet developed (2)Fossilization not yet progressed RT (see Noveck) Chierchia’s defaults  OT pragmatics has two potential answers (1)Metalinguistic ability for perspective changing (bidirectional reasoning) not yet developed (2)Fossilization not yet progressed

46. 46 The implementation of answer 1  Lexical Constraint A: all  Set-inclusion  Strength: all >> some  Bidirectional Solutions som e all some all

47. 47 Answer 2: Fossilization  Lexical Constraint A:all  Set-inclusion  Strength: all >> some  Potential lexical Constraint B: some  Set-intersection; …. som e all some all Speaker all Hearer nothing happens Constraint B strengthened Speaker som e Hearer nothing happens

48. 48 Comparing two cases of blocking pro self disjconj pro self disj conj som e all some all 7 years old 12 years old

49. 49 Emergence of Bidirection or Fossilization?  According to the solution of evolutionary psychology (processing account) the crucial developmental stages should appear synchronously for the different domains  According to the fossilization solution (iterated learning) the time course of the development is not necessarily synchronized but may crucially depends on factors of frequency and other use factors  The processing view predicts similarities between the behavior of children and elderly adults –True for the production of (non-recoverable) pronouns –False for interpretation of pronouns –Unclear for scalar implicatures

50. 4 General Conclusions The idea of fossilization as a starting point for resolving puzzles in experimental pragmatics -Some elephants have a trunk: why children sometimes think more logical than adults (Noveck) -The acquisition of binding principles: why children sometimes misinterpret pronouns while correctly producing them (Hendriks & Spenader) -Production of (non-recoverable) pronouns when referring to the old topic in the presence of a new topic (Hendriks, Englert, & Wubs)

51. 51 Final Scores: Comprehension/Generation Bidir. Processing (Hendriks et al.) Asymmetric OT (Zeevat) OT with Fossilization Pronouns & Refl Children Young adults Elderly adults +/+ −/+ +/+ R-Exp & Refl Children Young adults Elderly adults +/+ −/+ All & Some Children Young adults Elderly adults +/+ ?/+ +/+ ?/+ +/+ ?/+

52. 52 Possible Solution  Combining the idea of Fossilization with asymmetric OT  In asymmetric OT the speaker takes the listener into account but not vice versa  We need independent motivation for that. At the moment it’s a data fitting only! With four parameters I can fit an elephant, and with five I can make him wiggle his trunk