Disorders of Lexical Selection Garret 1992b Brian Nisonger

4 types of Linguistic errors Message to Lemma Representation Message to Lemma Representation Lemma to Word Form Representation Lemma to Word Form Representation Word Forms to phonetic representation for connected speech Word Forms to phonetic representation for connected speech Speech representation to motor representation Speech representation to motor representation This paper deals with the first two This paper deals with the first two

Lexical Disorders Aphasias Aphasias Loss of usage or comprehension of words Loss of usage or comprehension of words Broca’s Aphasia Broca’s Aphasia Characterized by the inability to produce complete grammatical sentences Characterized by the inability to produce complete grammatical sentences May be missing function words, pronouns or other categories May be missing function words, pronouns or other categories Comprehension may or may not be impaired Comprehension may or may not be impaired Wernicke’s Aphasia Wernicke’s Aphasia Can produce “fluent” sentences Can produce “fluent” sentences Usually semantically nonsensical Usually semantically nonsensical Comprehension is impaired Comprehension is impaired

Lexical Disorders-II Dyslexias Dyslexias A reading based learning disability that impairs the ability to read A reading based learning disability that impairs the ability to read Deep Dyslexia Deep Dyslexia A reading disorder where semantic errors occur A reading disorder where semantic errors occur Bush=>Tree Bush=>Tree Antique=>Vase Antique=>Vase Uncle=>Nephew Uncle=>Nephew Alzheimer's disease Alzheimer's disease More on this later More on this later

Semantic Deficits of Lexical Selection Normal Errors vs Lexical Disorders Normal Errors vs Lexical Disorders Similarities Similarities Word Substitution Errors Word Substitution Errors Synonymic Synonymic Antonymic Antonymic Associative Associative TOT states TOT states Differences Differences Grammatical Categories Grammatical Categories Hypernyms Hypernyms

Hypernym Problems Object Oriented Programming Object Oriented Programming Inheritance Inheritance Animal=>Horse Animal=>Horse Plant=>Flower Plant=>Flower Supertype Supertype Generally if W1 entails W2 then W2 is a hypernym of W1 Generally if W1 entails W2 then W2 is a hypernym of W1 Substitution rare in normal speech errors, common in lexical disorders Substitution rare in normal speech errors, common in lexical disorders

Categorical Organization Alzheimer’s Patients Alzheimer’s Patients Visual Naming Task Visual Naming Task Hypernym substitution Hypernym substitution General substituted for Specific General substituted for Specific Errors may be related to normal speech when a word is unavaliable Errors may be related to normal speech when a word is unavaliable I bought a plant I bought a plant I bought a flower I bought a flower

So what does it mean so far? Lexical Representations in the brain Lexical Representations in the brain Message=>Lemma Message=>Lemma Lemma=>Word Form Lemma=>Word Form Word Form=>Phonetic/Orthographic representation Word Form=>Phonetic/Orthographic representation Specifically divided Phonetic from Orthographic Specifically divided Phonetic from Orthographic Deep Dyslexia only orthographic Deep Dyslexia only orthographic Other aphasias can be both phonetic and orthographic Other aphasias can be both phonetic and orthographic More on this later More on this later Concepts Space Concepts Space Hierarchical in nature Hierarchical in nature Semantic Fields Semantic Fields More on this later More on this later Garret 1992a Garret 1992a

Lexical Retrieval System Parallel Featural Tests Parallel Featural Tests Linked Decision Tables Linked Decision Tables Table internal test parallel Table internal test parallel Table -> Table serial Table -> Table serial Might account for loss within categories Might account for loss within categories But ability to categorize within fields But ability to categorize within fields

Semantic Field Effects Selective Impairments Selective Impairments Loss of ability to generate words from specific domains Loss of ability to generate words from specific domains Major Major Concrete/Abstract Concrete/Abstract Living/non-living Living/non-living Animate/Non Animate Animate/Non Animate Interesting cross phenomena with Worlds Languages? Interesting cross phenomena with Worlds Languages? Minor Minor Color Items Color Items Food Items Food Items Numbers Numbers Baseball Players Baseball Players Still possible to recognize words are of a certain category for some aphasia and other disorders but not produce them Still possible to recognize words are of a certain category for some aphasia and other disorders but not produce them

More Field Effects Affected categories Affected categories As low as 10% generation As low as 10% generation Non-affected categories Non-affected categories Near normal performance Near normal performance Field Effects stable across time Field Effects stable across time Rare or common words had no affect on Field effects Rare or common words had no affect on Field effects For example For example Animal->Bear Animal->Bear Fruit->Prickly Pear Fruit->Prickly Pear

How does it fit in with the model? Semantic Fields are a set of Lemmas Semantic Fields are a set of Lemmas Grouped by specified functional similarity of concepts Grouped by specified functional similarity of concepts Possibly used for rapid evaluation of alternatives in production Possibly used for rapid evaluation of alternatives in production Lexical Ambiguities Lexical Ambiguities In normal errors we see this affect as well In normal errors we see this affect as well Garret 1992a Garret 1992a Aphasic Loss Aphasic Loss Major vs Minor categories Major vs Minor categories

Some Distinctions and Cross Classification Examples Examples Possible to have losses in Concrete Inanimate category Possible to have losses in Concrete Inanimate category No loss in Concrete Animate category No loss in Concrete Animate category Living vs NonLiving Living vs NonLiving Seems to have less cross classifications Seems to have less cross classifications Sensory description Sensory description May not be relevant for inanimate non-concrete May not be relevant for inanimate non-concrete Functional Functional Not relevant for living things but very relevant for inanimate Not relevant for living things but very relevant for inanimate May be explained by other factors, but interesting May be explained by other factors, but interesting

Higher Level Feature Errors Wheel->Foot Wheel->Foot Analogical relation between target and intrusion Analogical relation between target and intrusion Function Function Mode of motion Mode of motion Limbs Limbs Foot Foot Mode of motion Mode of motion Drive Train system Drive Train system Wheel Wheel

Where are we at Clear field effects in aphasic errors Clear field effects in aphasic errors Similar to effects noted in normal speech Similar to effects noted in normal speech Evidence for difference between Evidence for difference between concept representation=>lemma representation concept representation=>lemma representation concept representation=>perceptional represention concept representation=>perceptional represention

Causes of Semantic Error Need to categorize errors Need to categorize errors Components of lexical system Components of lexical system Production Production Comprehension Comprehension Most accounts don’t separate Most accounts don’t separate Concept Concept Lemma Lemma Two major categories of errors Two major categories of errors Conceptual impairment Conceptual impairment Lemma processing Lemma processing Concept=>Lemma Concept=>Lemma Lemma Replacement Failure Lemma Replacement Failure Lemma=>Word Form Lemma=>Word Form Word Form Output System Error (Possible 4 th category) Word Form Output System Error (Possible 4 th category)

Possible Reasons for Multiple Semantic Activation Semantic Spreading Semantic Spreading Multiple words are activated Multiple words are activated Message=>Lemma Message=>Lemma Message fragments can activate multiple lemmas which then are filtered through by more completed message fragments Message fragments can activate multiple lemmas which then are filtered through by more completed message fragments

Failure of the Output System Generation Generation Failure to filter alternative lexical candidates Failure to filter alternative lexical candidates Failure to produce lexical candidates Failure to produce lexical candidates Possible correlation to normal speech errors Possible correlation to normal speech errors No real evidence besides intuition No real evidence besides intuition

Auditory vs Orthographic Loss of category can be specific to either auditory or orthographic forms Loss of category can be specific to either auditory or orthographic forms Loss of abstract for example may be present in auditory experiments but absent in orthographic experiments Loss of abstract for example may be present in auditory experiments but absent in orthographic experiments

Modality-Specific Failures Modality Modality Verbal Verbal Non-verbal systems Non-verbal systems Semantics may be independent of the verbal system Semantics may be independent of the verbal system

Semantic Modality Tactile naming experiments Tactile naming experiments Ability to mime usage of object Ability to mime usage of object Inability to name the object Inability to name the object No knowledge of name No knowledge of name Not TOT Not TOT May cross classify with semantic field effects May cross classify with semantic field effects Loss of specific categories in non-verbal naming tasks such as tactile naming Loss of specific categories in non-verbal naming tasks such as tactile naming

What is semantics? Possible that semantics may not be just limited to “ lexical meaning” Possible that semantics may not be just limited to “ lexical meaning” Usage Usage Visual recognition Visual recognition Relative Size Relative Size Relative Location Relative Location Visual problem solving intersections Visual problem solving intersections

Syntactic Category Effects Open Class Open Class Nouns, verbs, adjective, adverbs Nouns, verbs, adjective, adverbs Closed Class Closed Class Determiners, Prepositions, modals, negation, predicate markers Determiners, Prepositions, modals, negation, predicate markers

Closed Class Retrieval Failures Comprehension Comprehension May or may not have inability to comprehend grammatical function words May or may not have inability to comprehend grammatical function words Production Production “Telegraphic” “Telegraphic” “Doctor office Monday teeth” “Doctor office Monday teeth” No link between inability to produce grammatical words and comprehension of grammatical words No link between inability to produce grammatical words and comprehension of grammatical words

Types of closed class failures Agrammatical Agrammatical Inability to produce grammatical categories Inability to produce grammatical categories Paragrammatical Paragrammatical Producing the wrong grammatical categories Producing the wrong grammatical categories Usually comprehension problems Usually comprehension problems Overlap Overlap In Hebrew grammatical category cannot be omitted In Hebrew grammatical category cannot be omitted Broca’s aphasia patients often pick incorrect endings Broca’s aphasia patients often pick incorrect endings Broca’s aphasia = Agrammatical Broca’s aphasia = Agrammatical

Closed Classes Failures of Deep Dyslexia Fewest errors with concrete nouns Fewest errors with concrete nouns Highest errors for closed classes Highest errors for closed classes Inability to read closed class words in isolation Inability to read closed class words in isolation Longer passages may provide context for guessing Longer passages may provide context for guessing Possible failure of lemma=>word processing Possible failure of lemma=>word processing

Alternate Retrieval System for Closed Classes Failures in open class not found in closed class Failures in open class not found in closed class Phonemic paraphasias Phonemic paraphasias Substitutions of non-correct sounds Substitutions of non-correct sounds Neologisms Neologisms Non-words being introduced as words Non-words being introduced as words Possibility that grammatical structure selects for specific words within specific domains within the closed classes instead of as a whole Possibility that grammatical structure selects for specific words within specific domains within the closed classes instead of as a whole Activation of multiple meanings may be different in closed classes and open classes Activation of multiple meanings may be different in closed classes and open classes

Major Category Contrasts Normal speech substitutions do not cross grammatical categories Normal speech substitutions do not cross grammatical categories Nouns substitute for Nouns, etc. Nouns substitute for Nouns, etc. Wernicke’s Aphasia’s patients Wernicke’s Aphasia’s patients Substitutions do not cross grammatical category Substitutions do not cross grammatical category

Nouns and Verbs Categories can be lost in modality specific tasks Categories can be lost in modality specific tasks Ex: Two patients showed loss of verbs in oral output, but not in written Ex: Two patients showed loss of verbs in oral output, but not in written Agrammatics Agrammatics More Loss of verbs in tasks across all modalities More Loss of verbs in tasks across all modalities Anomics Anomics Disorder associated with dysfunction in “word finding” Disorder associated with dysfunction in “word finding” No other disorder-frequent circumlocution No other disorder-frequent circumlocution More loss of nouns across all modalities More loss of nouns across all modalities

Nouns and Verbs-II What does it mean? Anomics the failure may be at the word- form retrieval level Anomics the failure may be at the word- form retrieval level Agrammatics the failure may be at the phrasal construction or lemma level Agrammatics the failure may be at the phrasal construction or lemma level

Frequency and Grammatical Category Effects Be/Bee wood/would Be/Bee wood/would Show opposite effects for Broca’s vs. Wernicke’s aphasia regardless of frequency Show opposite effects for Broca’s vs. Wernicke’s aphasia regardless of frequency Case study of Wernicke’s aphasia patient with no difference between high frequency and low frequency words Case study of Wernicke’s aphasia patient with no difference between high frequency and low frequency words Possibly only affects open class words and not closed class words Possibly only affects open class words and not closed class words

Summary The effects of aphasia illustrate some of the mechanisms of the lexical retrieval system The effects of aphasia illustrate some of the mechanisms of the lexical retrieval system Specifically Specifically Concept=>Lemma=>Phonological/Orthograp hic form Concept=>Lemma=>Phonological/Orthograp hic form By studying aphasias we can understand how lexical retrieval works and what that means for lexical ambiguity By studying aphasias we can understand how lexical retrieval works and what that means for lexical ambiguity