Word recognition in normal reading Sara C. Sereno Collaborators: RAs/PGs: Paddy O’DonnellSébastien Miellet Hartmut LeutholdGraham Scott Christopher Hand

Word Recognition What factors affect word recognition? How can word recognition processes be accurately measured? How can effects be interpreted?

Orthography of language –English vs. Hebrew or Japanese Intraword (sublexical) variables –word-initial bi/tri-gramsclown vs. dwarf –spelling-to-sound regularityhint vs. pint –neighborhood consistencymade vs. gave –morphemes prefix vs. pseudo-prefixremind vs. relish compound vs. pseudo-compoundcowboy vs. carpet What factors affect word recognition?

Word (lexical) variables –word lengthduke vs. fisherman –word frequencystudent vs. steward –AoArabbit vs. violin –expert vocabularyvoxel –syntactic classopen/closed-class; A,N,V –ambiguitybank vs. edge, brim –concreteness/imagabilitytree vs. idea –animacydog vs. cup –affective tonelove vs. farm vs. fire

What factors affect word recognition? Extraword (supralexical) variables –Contextual predictability Neutral He bought a large plant for his garden. Biasing Terry went to the new gardening centre. He bought a large plant for his garden. –Syntactic complexity Trans. Mary took the book VERBMary knew the book Intrans. Mary hoped the book on the table. was good. on the table. was good. on the table. was good.

Extraword (supralexical) variables –Discourse factors Focus The dog chased the cat today. The cat was chased by the dog today. What the dog chased was the cat today. It was the cat that was chased by the dog today. Elaborative inferences & anaphora What factors affect word recognition? weapon … The mugger her with his weapon… He threw the knife into the bushes and ran away. stabbed assaulted

What factors affect word recognition? Language skill –beginning (novice) vs. skilled (expert) readers –normal vs. dyslexic vs. neuropsychological patient How can word recognition processes be accurately measured?

Measure Task Time Res. “electrical” imaging single word presentation ~ ms (EEG, MEG) word-by-word reading (P1,N1,EPN,N400) Eye movements in fixation time, location & ~250 ms normal reading sequence of EM’s Stnd. word recogn. naming ~500 ms ± priming, masking, lexical decision RT ~600 ms lateralized present. categorization ~800 ms “blood flow” imaging single word presentation seconds (PET, fMRI)

Thisisawordbywordpresentationofasentenceatafastreading-likerate. Word-by-word reading: 200 ms per word

Thisisawordbywordpresentationofasentenceataslowratetypically usedinERPstudies. Word-by-word reading: 600 ms per word

Normal Reading

This is an approximation of normal reading in real time. *

This is an approximation of normal reading in real time. *

This is an approximation of normal reading in real time. *

This is an approximation of normal reading in real time. *

This is an approximation of normal reading in real time. *

This is an approximation of normal reading in real time. *

This is an approximation of normal reading in real time. *

This is an approximation of normal reading in real time. *

This is an approximation of normal reading in real time. *

This is an approximation of normal reading in real time. *

The importance of making eye movements in normal reading Cond1 There was a box of… Cond2 There was an enormous box of… Cond1 She saw a cat in the… Cond2 She saw a cup in the… The measure affects what is being measured: –Perception of text influences how EMs made. –Location/duration of EMs affect perception.

Theoretical approaches –Interactive (top-down) vs. Modular (bottom-up) Additive factors How can effects be interpreted? Stimulus Quality Context Frequency RT

Modelling How can effects be interpreted?

Modelling –Repeated measures multiple regression analyses: Oculomotor-related factors launch distance to word location of fixation within word number of fixations on word word length word frequency contextual predictability Language-related factors How can effects be interpreted?

FactorsMeasuresApproach orthography bi-/tri-grams regularity neighborhood morphology length frequency jargon word class ambiguity imagability animacy emotionality predictability syntactic prefs. focus inference anaphora skill ERPs + word-by-word (slow) presentation Eye movements + normal reading EM-ERP co-registration? Additive factors Repeated measures multiple regression

Distributed hierarchical visual processing in primates lexicalhumans higher-level semantics syntax meanings word forms letters features

Why? Precisely delineate the time course of different levels of linguistic processing. Help inform a temporally realistic neural circuitry of normal reading.

Measurement EMs = best on-line measure of visual word recognition in the context of normal reading ERPs = best real-time measure of brain activity associated with the perceptual and cognitive processing of words

(Sereno & Rayner, Trends in Cognitive Sciences, 2003)

Sereno, Rayner, & Posner (1998). NeuroReport. Sereno, Brewer, & O’Donnell (2003). Psych. Sci.