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The role of structural prediction in rapid syntactic analysis

Ellen Lau, Clare Sroud, Silke Plesch, Colin Phillips, 2006

PSYC 525

10-6-2010

Soondo Baek

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Pre-introduction

She did not kiss Dana’s of the bride.

• Very fast detection of category violation (Neville et al, 1991)

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Pre-introduction

she did not kiss Dana’s of the bride.

• Very fast detection of category violation (Neville et al, 1991)

• Modulation of this effect by the strength of prediction for a certain syntactic category

Although Erica kissed Mary’s mother,

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Introduction

• Syntactic processing is very fast, beginning within 300ms after word onset

• But the nature of early syntactic processes largely remains unspecified

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Introduction

• Early Left Anterior Negativity (ELAN)– Increased left anterior negativity in 100-250ms

induced by grammatical category violations– Observed in very specific contexts unlike other

ERP components

e.g., The scientist criticized ..

Max’s of proof the theorem.

Max’s proof of the theorem.

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Introduction

• Other ERP components associated with a variety of syntactic processes

– Left Anterior Negativity (LAN) in 300-500ms

• inflection/agreement violation, some case violation, word category violation, violation of constratins on wh-fronting, syntactic garden-path

– P600 (Syntactic Positive Shift) in 500-900ms

• category violation, agreement violation, syntactic garden-path, subcategorization violation

• ambiguity, long-distance dependecy construction, unexpected thematic role assignment

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Introduction

• How can category violation be detected so fast?

– Earlier account (e.g., Friederici, 1995)• Only category information is avaliable at the earliest stage of

structure building (e.g., Frazier, 1987)

• Syntactic structure building is generally fast and ELAN results when the category of a word cannot integrate to the preceding structure

– New proposal tested• Preceding contexts strictly constrain the possible category of an

upcoming word, dramatically reducing possibilities to be considered

• Max’s [(ADJ) NOUN]

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Introduction

• Ellipsis construction used to test the proposal

– *He met John, but I met Mary’s.

– The possessor Mary’s requires a noun phrase, leading to a strong prediction for an upcoming noun phrase

– He met Jonh’s mother, but I met Mary’s.

– The possessor Mary’s can be followed by a null element referring to mother, not necessarily predicting an upcoming noun phrase

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Materials (32 items per condition)and predictions

• +Ellipsis

Grammatical

Ungrammatical

• -Ellipsis

Grammatical

Ungrammatical

• Agreement

Grammatical

Ungrammatical

Although Erica kissed Mary’s mother,

she did not kiss the daughter of the bride.

she did not kiss Dana’s of the bride.

Although the bridesmaid kissed Mary,

she did not kiss the daughter of the bride.

she did not kiss Dana’s of the bride.

Although Matt followed the directions closely,

Although Matt follow the directions closely,

he had trouble finding the theater.

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Materials

• Sentence completion test to verify that ellipsis manipulation works

– Although Erica kissed Mary’s mother, she did not kiss Dana’s …

– Although Erica kissed Mary, she did not kiss Dana’s …

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Methods

• 32 participants

• Each word presented for 300ms

• 200ms blank between words

• Press buttons to judge acceptability

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+AlthoughEricakissedMary’smother,shedidnotkissDana’softhebride.?

Demonstration: +Ellipsis ungrammatical condition

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+AlthoughthebridemaidkissedMary,shedidnotkissDana’softhebride.?

Demonstration: -Ellipsis ungrammatical condition

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Results: Pre-critical word

• Effect of grammaticality at pre-criticial words at the latency of 300-500ms

– she did not kiss the daughter of the bride.

– she did not kiss Dana’s of the bride.

This made it undesirable to directly compare grammatical and ungrammatical condition

• A significant main effect of ellipsis at pre-criticial word, but with small amplitude difference

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Results: Critical word (of)Ungrammatical conditions (~ Dana’s of)

• 0-200ms inteval

– Overall, slightly greater negativity in the +ellipsis condition than in the –ellipsis condition, but no difference at any individual region

• 200-400ms interval (ELAN)

– Greater negativity at the left anterior region in the –ellipsis condition than in the +ellipsis condition

– Slightly greater positivity at the right posterior region in the –ellipsis condition than in the +ellipsis condition

• 600-1000ms interval (P600)

– No differences between +ellipsis and –ellipsis condition

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Results: Critical word (of)Grammatical conditions (~ daughter of)

• 0-200ms interval

– Slightly greater negativity at the right anterior region in the –ellipsis condition than in the +ellipsis condition

• 200-400ms interval

– No effect on ellipsis at any individual region

• 300-500ms interval

– Greater negativity at the right posterior region in the +ellipsis than in the –ellipsis condition

• Scarce reliable contrasts between thet two ellipisis conditions

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Results: Agreement violation

• 0-200, 200-400, 300-500ms intervals

– No effect of grammaticality

• 600-1000ms interval (P600)

– Posterior positivity & anterior negativity

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Discussion

• Earlier account of ELAN effect to category violations

– reflects an initial stage of structure building

– predicts that any kind of category violations should yield a response with a similar latency

• Alternative account

– Eearly response to category violations reflects strong local prediction for an upcoming word

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Discussion

• Results showed that

– Left anterior negativity was reduced when preceding context allowed ellipsis interpretation of possesors (e.g., Dana’s) as compared with when there was no such context

• Not all category violations are diagnosed in the same fashion

• Strong local prediction may explain early detection of category violations, without need to appeal to an initial parse stage sensitive only to category information

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Discussion

• Strong local prediction for an upcoming word may work in two ways to enable early detection of (category) violations

– Detection of mismatch with prediction is simpler and faster than evaluation of all possible ways to attach an incoming word to the existing structure

But this predicts ELAN to grammatical sequences like ‘Max’s clever proof’, which was shown not to be the case in Austin & Phillips (2004)

– Very restricted possibilities induced by preceding context enables faster detection of violations as compared with cases where more possibilities must be searched before decision

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Discussion: things to note

• Comparisons within each level of grammaticality conditions

– Traditional ELAN based on the difference between ungrammatical and grammatical condition

– do not show whether the availability of ellipsis interpretation removed or just reduced ELAN

– do not allow the test of P600 effect

• Delayed onset of ELAN at 200ms as compared with some studies that showed earlier onet at 100-150ms

– (together with the presence of posterior positivity) makes it unclear whether the finding is really about ELAN