Posner AA vs Aa RT Data

32 Pages·2005·20.37 MB·English

by  Thomas Busey

Posner AA vs Aa RT Data
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Posner: Reaction Times to
Different Pairs
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Language
The Mental Lexicon
How is information about words stored in the
brain? – “Mental Lexicon”, semantic
information, syntactic information, word forms.
One or several?
Production vs. comprehension
Input - output
Orthographic - phonological
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Language
Words
How many are there?
Problems for counting: inflected forms,
separate senses, dialect, scientific
nomenclature, slang, addition of word-forming
elements, etc.
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Language
Words
Words:
Cambridge Encyclopedia of the English Language: >
1,000,000.
Oxford Companion to the English Language: > 1,000,000.
Vocabulary:
Shakespeare’s plays: 29,066 distinct forms, incl. proper
names., est. 18,000-25,000.
18-month old: ~50 – two years: ~300, 3-year old:
~1,000 (adding 3/day)
16-year old: 10,000-12,000.
College grad.: 20,000-25,000.
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Language
The Mental Lexicon
Semantic network: representation of word meanings.
Semantic priming studies:
prime-target: “chair-table”
unrelated: “chair-nurse”
pseudoword pairs: “chair-flark”
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Language
Lexical Semantic Networks
Nodes: concepts, words
Links: connection strengths reflect the amount
of conceptual or semantic relatedness between
nodes.
Stimulus presentation activates one (or several)
nodes, activation spreads along links
Problems:
How are links determined?
What are neural equivalents of nodes and links
(single neurons or cell assemblies)?
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Language
Lexical Semantic Networks
Distributed processing models:
Feature-based representation, input is a
stimulus vector and network “settles” towards a
target semantic vector.
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PET data: Hierarchical
Experiment
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Language
Neural Basis of the Mental Lexicon
Evidence from brain lesions (dissociations between naming
of non-living and living things, selective deficits in
semantic memory after stroke etc.)
Study by Damasio et al., 1996:
Propose that lexical knowledge is organized among three
separate neural systems:
1. Conceptual content (meaning, semantic features)
2. Phonological elements (sounds)
3. Modality-independent lexical knowledge (left temporal
lobe)
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