COGNITIVE MORPHOLOGY

Laura Westmaas November 24, 2009

Outline

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Cognitive Morphology

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Theories of morphology

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Methods for studying morphology

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Inflectional morphology

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Derivational moprhology

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Theoretical implications

Psycholinguistics • Definition • Goals

Cognitive Morphology • Getting into the headspace of psycholinguistic literature • Formal definitions/conceptualizations of morphology • Goals of theory/research/models

What is the morpheme?

• Traditional definition “smallest meaningful bearing unit in a language” (Whitley, 2001) • Classes of morphemes • Inflectional • Derivational

Experimental methodology • behavioural •

priming

• lexical decision tasks • Electrophysiological, neuroimaging • Bilinguals and special populations (children, aphasics, dyslexics) • Rationale of methodology

Morphological Theory

Whole word (e.g., Feldman & Fowler, 1987) Dual route (e.g., Marslen-Wilson, Tyler, Waksler & Older, 1994) Obligatory morphemic decomposition (e.g., Taft & Forster, 1975; Taft, 2004; Rastle et al.) Connectionist ( E.g Plaut & Gonnerman, 2000; Seidenberg & Gonnerman, 2000, Rueckl et al, 1997))

Whole Word Approach Stimuli

HAPPINESS HAPPINESS

Lexicon Stimuli

HAPPY HAPPY

Lexicon Example from Marslen-Wilson, et al, 1994

Dual route theory • Words and Rules theory (Pinker & Ullman, 2002) • Grammatical rules + stem in lexicon • Irregulars and monomorphemic words in lexicon

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Obligatory Decomposition Stimuli

HAPPINESS HAPPY

Lexicon

-NESS

Connectionist Models The triangle model QuickTime™ and a decompressor are needed to see this picture.

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Inflectional morphology • The case of past tense • (Masked) priming paradigm • Lexical decision task • Behavioural predictions/ findings • Interpretations • Frequency by regularity interaction • Some recent research

+

BAKED

+

Lexical decision: Y/N

BAKE

+

TOOK

Lexical decision: Y/N

+ TAKE

Classic findings • Response times (ms) are faster for regular than irregular words • Dual route would say this is because try to apply rule, blocked then access lexicon • Connectionist would say that this is a by-product of the degree of semantic, orthographic and phonological overlap between the prime and target word • Also note that there is a frequency by regularity interaction.

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Interpretation of frequency by regularity interaction • Dual route: highly frequent irregulars get stored directly in lexicon, direct access just like regulars • Connectionist: overlap from prime lowers the threshold of activation, mapping between sound, meaning and orthography not as clear • -greater reliance on semantics (v.s. phonology) • -picture task to see if activation via meaning rather than form would wipe out differences between irregular and regular verbs • Dual route prediction: it shouldn’t, need to activate stem than past tense • Connectionist prediction: should get rid of effect of regularity

Woolams, Joanisse & Patterson (2009, JML) QuickTime™ and a decompressor are needed to see this picture.

Derivational morphology • Questions of interest • Predictions • Rastle findings • Feldman findings • Thesis

Question • What happens when a reader encounters a multi-morphemic word?

Predictions?

• • Obligatory decomposition: • • If it looks like a morpheme, take it apart!

VERSUS

• • Connectionist: Graded- take it apart, sometimes - but

not

just about the morphemes.

Semantic Transparency Rastle et al (2004) • Semantically transparent • e.g. harden-hard • Semantically opaque • e.g. corner-corn • Form • e.g. brothel-broth morpheme

not

a morpheme

Connectionist • Graded Effects Semantically related Not related PAINTER DRESSER Transparent *** CORNER Opaque BROTHEL Form Examples from Rastle et al, 2004,

The Case of Opaque Words Has supported decomposition, under a certain set of experimental conditions characteristics of study seem to matter: – Prime duration; non-word stimuli, orthographic neighbours, word length, word frequency, etc.

Masked Priming • Logic: – if morphemes are used to decompose words, should see priming effects between a multi-morphemic word and its stem compared ton unrelated baseline

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CORNER CHAIR

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Lexical decision: Y/N

CORN

Masked priming Main findings (Eg. Rastle et al, 2004)  HARDEN-HARD

priming

CORNER-CORN BROTHEL-BROTH

no priming

Taken as evidence for obligatory decomposition during early stages of visual word recognition.

My thesis, currently in progress • ERP investigation of differences in the N400 component between pseudo suffixed and suffixed words by using a color-morpheme boundary manipulation.

• Predictions: • Dual route theory: no difference between suffixed and pseudo-suffixed • Connectionist: differences between suffixed and pseudo-suffixed words; congruency by word type interaction.

Experimental Paradigm Prinzmetal, Treiman, & Rho (1986) Carreiras, Vergara, & Barber (2005) Explore the effects of mis/match of morpheme boundaries Word in 2 colours and in/congruent – E.g. CONGRUENT • INCONGRUENT WALK WAL ED KED

• • Procedure 4 Word Lists congruent congruent

dress er dress er

incongruent incongruent

dres ser dres ser

• Transparent, opaque, form +

intermediate

cases (eg. dresser) • Only one list seen by each participant.

Conclusions • Current state of the art • Current directions of the field • what psycholinguistic research can tell us about morphology • need for inter-disciplinary research

• Questions/Comments?

• Thanks!