interference in short-term memory the magical number two (or three) in sentence processing `06. 11....

Interference in Short-Term Interference in Short-Term MemoryMemory

The Magical Number Two (or Three) in Sentence The Magical Number Two (or Three) in Sentence ProcessingProcessing

`06. 11. 4 (Sat.) / Chan-hoon ParkHypernetwork Models of Learning and Memory

(Artificial Neural Networks)

© 2006 SNU CSE Biointelligence Lab

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ContentsContents

Introduction

Definition

Parsing related problems

Other STM Phenomena

Limitation

Conclusion


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IntroductionIntroduction

The purpose of this chapter

Syntactic processing + Memory research

Limited syntactic working memory capacity – 2 (or 3)

Interference effects

Similarity-based interference

Within independently motivated architectural

mechanisms and principles and their associated

constants


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Definition (1/2)Definition (1/2)

Problems to deal for the purpose Center embedding

[The salmon that [the man that [the dog chased]

smoked] fell.] Almost every parsing theories about C.E. have

• No psychological motivation for structure or limit

ex) Stack, Look-ahead buffers, 4 , 2, 1 …

Interference in multifaceted working memory Retroactive interference / Within-Category similarity

effects

The independence of parsing from phonological STM


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Definition (2/2)Definition (2/2)

An interference theory of syntactic working memory NL-Soar : computational model of sentence comprehension

(from Soar : a theory of the human cognitive architecture) NL-Soar’s working memory : H/D Set – buffers partial constituents X-bar position : Surface structure


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Parsing related problems Parsing related problems (1/5)(1/5) Embedded relative clauses

The boy that the man the woman hired hated cried.

What the woman that John married likes is smoked salmon.


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Parsing related problems Parsing related problems (2/5)(2/5) Center embedding or Gap-filling

Without Gap-filling

With Gap-filling Fred is tough for the man to please. Fred is easy for the woman who the man who hired me married to

please.


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Parsing related problems Parsing related problems (3/5)(3/5) Embedding or stacking

Difficulty of C.E is Consecutive occurrences of NPs (= Stacking), rather than

C.E. per se.

In head-final languages (Japanese, Korean...),


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Parsing related problems Parsing related problems (4/5)(4/5) Limitations on ambiguity resolution

At most two nodes are available to assign the same structural relation at any given time.

Amparo saw the dog under the box on the table in the room next to the library.

Closure principle Keep a small set of syntactic nodes open for further attachment.

• Two most recent nodes


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Parsing related problems Parsing related problems (5/5)(5/5) Length effects in garden path structures

The horse (raced past the barn fell). Distance to disambiguation

But, Ron (believed the ugly little linguistics professor). Ron (believed the ugly little linguistics professor he had met

the week before in Prague disliked him). A limited repair mechanism

Length-induced garden path effect in NL-Soar The girls believe the man who believes the very strong ugly

boys struck the dog killed the cats.


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In other STM phenomenaIn other STM phenomena

Immediate verbal memory task Average word span of 2.6

The limited capacity of human memory – 2~3 similar chunks


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LimitationLimitation

Possibility of Three Three NPs occupying spec-IP, but acceptable

Average span is more than just 2. There are may be additional cost associated with adjuncts in

general, regardless of whether they involve relativization.


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ConclusionConclusion

Sentence processing theories can benefit from incorporating ideas from traditional work in short-term memory.

NL-Soar’s working memory The source of memory load is open or unsatisfied syntactic

relations. This leads naturally to a focus on stacking, as a source of difficulty.

Increasing similarity makes things more difficult.

interference in short-term memory the magical number two (or three) in sentence processing `06. 11....

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