Charles Clifton, Jr. grateful acknowledgments to Mohamed Mohamed Matt Traxler Rihana Williams

1. On using eyetracking data to evaluate theories of on-line sentence processing: The case of reduced relative clauses Charles Clifton, Jr. grateful acknowledgments to Mohamed Mohamed Matt Traxler Rihana Williams Keith Rayner Robin Morris Sungryong Koh Lyn Frazier

2. Eye movements and sentence comprehension • Existing measures not a transparent window into cognitive processes • Lexical processing: some good ideas about mapping • Comprehension: another story • Consider one case of garden-path sentences…

3. Garden Paths in Reduced Relative Clause Sentences(the curse of Tom Bever) • The horse raced past the barn fell. • But sometimes reduced relative clauses are easy to comprehend.

4. McKoon & Ratcliff, 2003 • The window broken by John couldn’t be repaired • The window examined by John needed repairing • Both cases: (easy) reduced relative construction denotes an entity that participates in an externally caused event

5. Trueswell, Tanenhaus, & Garnsey, 1994 • The defendant examined by the lawyer proved to be unreliable • Produces clear reading disruption in disambiguating region compared to full relative clause (The defendant who was…) • The evidence examined by the lawyer proved to be unreliable • Initial NP inanimate, and a good theme but a poor agent • Claimed to eliminate difficulty of reduced relative clause • TTG 1994 actually a followup to Ferreira & Clifton, 1986

6. Animate: The defendant examined by the lawyer… Inanimate: The evidence examined by the lawyer…

7. Criticism: Trueswell, Tanenhaus, & Garnsey, 1994 • Some of the Ferreira & Clifton inanimate sentences weren’t all that implausible as main clause sentences • The trash smelled…. (pretty bad) • The car towed…(the trailer) • TTG, better materials, first noun normed for plausibility as agent and as patient of first verb

9. Why the differences? • Maybe TTG were right – the F&C materials were bad • But maybe something else: parafoveal preview of “by the…” • Evidence from Burgess, Spivey, McRae, etc, in self-paced reading • Possible display limitations in F&C (42 character display, line break typically before PP would have prevented effective preview)

10. Clifton, Traxler, Mohamed, Williams, Morris, Rayner, in press • Redo Ferreira & Clifton using Trueswell et al. materials (thanks to John et al.) • Add boundary change manipulation to permit or deny parafoveal preview of “by the noun” • Perform additional analyses

11. Clifton et al. details • Used materials from Trueswell, Tanenhaus, & Garnsey • 8 conditions • Animate (“difficult”) vs inanimate (“easy”) initial noun • Reduced vs full (control) relative clause • Parafoveal preview vs. no preview of “by the” (reader saw random 6-letter string instead of “by the”) • Measured eye movements while reading for comprehension (24 Ss)

12. Overall: 66 ms ambiguity effect for animate nouns, 34 ms ambiguity effect for inanimate nouns (sig. smaller, but > 0)

13. Overall: 68 ms ambiguity effect for animate nouns, 83 ms ambiguity effect for inanimate nouns (n.s. different)

14. Interim Conclusion and Question • Looking only at first pass times gave an incomplete picture of sentence comprehension • RPD measure indicated garden-pathing even with inanimate initial noun • Trueswell et al. experiment not an adequate basis to reject modular serial parsing model • But do the increased RPDs reflect the usual behavior of the eyes?

15. More regressions for No Preview than Preview, and for Animate than Inanimate, but apparent effect of Reduction and interactions not significant.

16. A similar pattern for: regression path duration (outside the region) second pass on target (coming from left)

17. Combined data: First pass regressions • Combine data with parallel experiment conducted at U South Carolina • Always preview of “by the” phrase • Vary high vs low span readers • Total n = 68, more stable data

18. Significant effects of animacy, ambiguity, no interaction

19. Summary • Eye movement measures show comparable ambiguity effects for sentences with animate and with inanimate subjects • It is premature to conclude that inanimacy blocks garden-pathing • Other data are needed to evaluate models that give logical priority to syntactic structure

20. A problem for understanding eye movements • Regression path durations are inflated by processing difficulty • This inflation can only come from trials where there were regressions • But regressions were very infrequent, < 10% of the trials

21. A similar effect in other experiments • Reduced relative clauses with various classes of verbs (manner of motion, theta-grid changing, unaccusatives) • No garden-pathing in first pass times, big garden-pathing in RPD, but < 30% regressions

22. Conclusions • Sentence processing difficulty is only variably mirrored in the ET record • Doesn’t always show up in FPT • One clear response to difficulty: a regression • But only happens 5-30% of time • A common response to difficulty: fuggettabottit • Just get the words, `mam

23. I’d like to be shown wrong, but… • ET response to comprehension difficulty is variable: linger, regress, nothing • Effects seen in means may actually occur on only a minority of trials • Eye movements may be controlled by word recognition, and only exceptionally affected by higher-level factors

24. Put on those rose-colored glasses • Maybe all these problems will disappear if people read texts they really care about, not just single sentences • But I wouldn’t bet on it

25. Stevenson & Merlo, 1997 • The troops marched across the fields all day resented the general. • Manner of movement verbs hard in reduced relatives; transitive use of these verbs requires an operation of “syntactic causativisation” • But…The witch melted in the Wizard of Oz was played by a famous actress. • Seems easy. Suggestion: Unaccusative verbs OK in reduced relatives

26. Eyetracking Experiment • Sentences with Manner of Movement (MOM) verbs • Sentences with verbs whose thematic grid changes (agent-theme to goal-theme) with passivization • Sentences with unaccusative verbs (theme in both active and passive subject position)

27. MOM (manner of movement) sentences • The horse raced along the beach frightened the onlookers • The craft sailed to the island served as a makeshift ferry • Controls • The horse that was raced to to the beach frightened the onlookers. (full relative clause) • The horse raced along the beach and frightened the onlookers. (main clause) • Disambiguating region indicated in boldface

28. Thematic Grid Change Sentences • The secretary brought the forms filled them out. • The client asked the question received no thanks. • Main clause structure: Agent – verb – theme • Relative clause structure: Goal – verb – theme • Control: The client asked the question but received no thanks

29. Unaccusative Verbs • The leaves burned today smoked a lot. • The potatoes baked in the oven smelled terrific. • Main clause structure: theme – verb • Relative clause structure: theme – verb • Control: The potatoes baked in the oven and smelled terrific.

30. Predictions • Manner of movement sentences: Hard, on everybody’s story • Thematic grid change sentences: Comparably hard, if thematic grid, not causal structure, the root • Unaccusative sentences: Relatively easy, if thematic grid change not syntactic structure change the underlying problem

31. First Pass Times

32. Regression Path Durations

33. Comprehension Accuracy • Questions were asked following 2/3 of the items (half of these were relevant to the RC) • MOM questions:The boy marched to school looked unhappy. • How did the boy get to school? Someone marched him there/He marched there on his own • Theta-grid changing questions:The client asked the question received no thanks. • Who asked the question? The client / someone • Unaccusative questions:The potatoes baked in the oven smelled terrific • What was happening with the potatoes? Someone had baked them in the oven / They were sitting in the oven, baking.

34. Note: accuracy for Unaccusative verb sentences is not shown. The questions were bad – only 67% correct for main clause items.

35. Conclusions • Intuitions of sentence processing difficulty not transparently mirrored in the ET record • Typical response to difficulty: a regression • May be specific to this experiment; lots of hard, tricky RC sentences • But even here, only about 1/3 of the trials • Another response to difficulty: fughetabottit • Just get the words, `mam

36. For the future: I’d like to be shown wrong, but… • ET response to comprehension difficulty seems to be variable: linger, regress, nothing • Eye movements may generally be controlled by word recognition, and only exceptionally affected by higher-level factors • Effects seen in means may actually occur on only a minority of trials • Maybe all these problems will disappear if people read texts they really care about, not just single sentences • But I wouldn’t bet on it

39. MacDonald, Pearlmutter, Seidenberg, 1994 • In all cases, the examples cited here were not the only reduced relatives in these articles. • The pattern of results obtained with global reading times is reflected by differences located on the critical disambiguating phrase.

40. Ferreira & Clifton 1986 – An early attempt to find easy RRCs • Ambiguous animate:The defendant examined by the lawyer was unreliable • Ambiguous inanimate:The evidence examined by the lawyer was unreliable • Controls:The defendant/evidence who/that was examined by the lawyer was unreliable. • Disambiguating region indicated in boldface