Visual Word Recognition II

1. Visual Word Recognition II Language Use and Understanding Class 4

2. Announcements • Electronic syllabus is up, with most links. (Those missing are often available electronically). • Copy room in Meliora is closed on weekends. • “Supplemental reading” should be available as a powerpoint presentation on the course web page.

3. Why study reading? • People study it for the following reasons: • 1. reading, its development and pedagogy • 2. front end of language processing system • 3. testing-ground for models of attention, memory, information processing • E.g. debate about models: rules vs. patterns

4. Issues in reading: What kind of cognitive processes could account for the data? • Is phonology involved? • (Van Orden, 1987, Gernsbacher, 1993) • Normal reading of Nonwords, irregulars, regulars, and dyslexia (Castles and Coltheart) • Use of context to disambiguate (e.g., Gernsbacher 1993).

5. The dual-route model • Evidence: irregulars vs. nonwords • Patterns of dyslexia • Orthography to phonology • Orthography to meaning to phonology • What kind of system must this look like?

6. Competition(Activation of non-target words or meanings) • What things might get activated in the process of trying to read a word? • Homophones, e.g. patients vs. patience • Ambiguous words, e.g. spade, bug, etc. • Semantically related words, e.g. bread/butter

7. Gernsbacher: Clarification • In Exp. 3 they measured only the time it took to reject an item, so no items were used that were related to the thing they were supposed to be focusing on. (correct?) Were there trials where the item was related to the item they focused on? They weren't mentioned but if they weren't included I would think subjects would pick up on the fact that the answer was always no and this would affect their reaction times. • In experiment 5, wouldn't the target item stand out more in an atypical scene? Why would this not show an effect? • What did Gernsbacher mean about less skilled readers appreciating a biasing context more than a more skilled reader? I was somewhat confused by this point.

8. Gernsbacher discussion • Is suppression really what is occuring in skilled readers, or are they maybe just so skilled that the correct meaning is "pulled" right away and the inappropriate meaning is never fully activated? • Are the "suppression mechanisms" that Gernsberger proposes a subcategory of attentional abilities, or are they a seperate modality? • Gernsbacher says that skill at reading comprehension was highly correlated with skill at comprehending nonverbal picture stories, possibly due to general cognitive mechanisms. Can it also be said that this correlation is due in some way neurovisual abilities?

9. Gernsbacher discussion • In the typical/atypical scenic array, couldn't the results be attributed to differences in short term memory or schemata rather than differences in suppression mechanisms?

10. Castles and Coltheart discussion • Why did it take so long for Developmental Dyslexia to gain respect as a "real" disorder? • The pattern of deficits wasn’t unified…. • What is this pattern? • Why is it important to note that the dissociation demonstrated between irregular word reading and nonword reading was bidirectional? • What of the 15% of dyslexic subjects who did not show a dissociation? They have trouble with both the lexical and sublexical procedures, so does this put them into a third category that the authors are simply ignoring? • How do their results support the dual-access model fo reading?

11. Delay vs. Deficit • If CD performs at a normal 10 year old level (even though she is 17) isn't the theory presented here that she will eventually get up to a normal level (which we know isn't true)?

12. C&C Further discussion • Is it known what areas of the brain are associated with adult acquired dyslexias? If so, what are they? • Yes - see Hinton, Plaut, and Shallice for neural-net simulations of acquired dyslexias • In the experiment, all of the participants were male. This seems to suggest a highly genetic component of dyslexia that may hold some clues into what makes it occur? • Can people with phonological dyslexia read non-words when they're presented as regular words, like in Dr. Seuss books (which include context clues and pictures)?

13. C&C further discussion • In this article, the experiments on developmental dyslexia are done with English-speaking subjects. What can the proposed model say about subjects using other languages such as Chinese in which the correspondence between the orthography and phonology is highly arbitrary? • Both developmental and acquired dyslexia have some common features. Would a brain scan be a useful tool to look at which part of the neural systems function differently from a normal person?

14. Is this the only way to account for the results? • Why isn't the presence of different dyslexias and their impacts on different aspects of reading (regular vs. irregular words, nonwords, rare words, etc.) irrefutable proof that there must be at least two routes through which written words are processed? • Is there another model that could account for the double dissociation between the types of errors made by dyslexics?

15. The connectionist model (Seidenberg and McClelland 1989) CONTEXT MEANING ORTHOGRAPHY PHONOLOGY Input: MAKE Output: /mAk/

16. Manis et al. 1996 • Replicated C&C’s data pattern • Also found: • 1) most kids poor on both irregulars and nonwords • 2) phonological dyslexics followed a deficit pattern, surface dyslexics followed a delay pattern • Dual-route model needs additional assumptions to account for these

17. SM89 can account for patterns • Learning algorithim picks up systematic aspects of spelling-sound correpondance, and exceptions to these patterns • Accounts for frequency x regularity pattern • Accounts for dyslexic patterns • Degraded phonological representations impairs nonword performance more than words (nonwords are harder) • More severe deficits involve exceptions and regulars as well

18. Frequency by regularity interaction in naming irregular regular Naming Time HF LF

19. Next Class • Fodor’s Precis of the Modularity of Mind • Highly influential book / paper • Reading Questions to come by email