Language Use and Understanding

1. Language Use and Understanding BCS 261 LIN 241 PSY 261 CLASS 10: BRAIN AND LANGUAGE

2. Additional recommended reading • Two pages on interactive activation model (assigned for March 15)

3. Coming up • Next Monday: discuss group projects • Next Wednesday: Snedeker et al. ( Nicole presenting) • Following Monday: Branigan et al. (Jesse presenting) • Following Wednesday: MIDTERM

4. FYI: Midterm format • All essay • You will get a superset of the questions ahead of time to study from

5. Dell (1988) • Linguistic tradition -- errors reflect the rules of the language production system • Two stages in production: • Functional level: put words and phrases together • Errors are thematically/syntactically constrained • E.g., nouns exchange with nouns, verbs with verbs • E.g., semantic effects • Positional level: build phonological forms • Phonological constraint on errors • E.g., even nonwords follow rules of English phonology (cf. Beth’s Discussion question) • Phonemes in same position exchange

6. Psychological tradition - speech errors influenced by factors outside intended utterance • Freud’s version -- little support • Weaker version: errors at one level of processing can be affected by factors outside that level • E.g., Mixed errors -- BOTH semantic or associative and phonological effects at the same time (Liszt’s 2nd Hungarian restaurant) • E.g., Lexical Bias effect (darn bore vs. deal back)

7. Modern version of the contrast(not ling vs. psych anymore) • Modular approach • language production is modular • Can be characterized by categorical rules • Interactive approach • Processes can be influenced by information at different levels of language production • Constraints can be partial, multiple constraints combine probabilistically • Dell’s contribution: an interactive model that accounts for same data as ling. rules

8. Discussion Question • Is Dell's research important because it provides a new paradigm to connect linguistic and psychological approaches or is there more to it? (MR) • Answer: • Dell’s model accounts for processes of production • Represents one side of a huge debate between interactive and modular approaches to language processing that goes beyond just word retrieval

9. Why model? • Examine hypotheses about the architecture of the processing system in concrete terms • Requires being very specific about what’s going on • Also requires simplifying assumptions • Existence proof that certain architectures can yield known patterns • Make predictions to be tested with new experiments

10. Dell’s production model INPUT message kaet dawg raet lemma Phonological errors K T phonological AE R OUTPUT

11. Features of the model • Connections between word and phoneme nodes are • Excitatory • Bidirectional • Consequence: positive feedback to word level from phoneme level

12. message kaet dawg raet lemma K T AE R Bottom-up vs. Top-down processing TOP-DOWN phonological BOTTOM-UP

13. How is information transferred in the model? • Activation • Activation of a node = • Sum of activation sent from other nodes • Minus a decay rate • W.R.T. Jesse Blake’s discussion question: the spreading rule is linear, which means activation of different nodes is summed linearly (not, e.g., logarithmically). It still flows bidirectionally.

14. How are phonemes selected? • After a certain amount of time has passed (which depends on speech rate), most highly activated phonemes are selected. • Errors occur when the wrong phoneme is more active than the right one • Spreading activation means that lots of words/phonemes are activated • Previously spoken words or upcoming words are active • Unintended words may be active because of other cognitive/perceptual processes (cf Anthony’s Q about context)

15. Postselection feedback • After phonemes are selected, their activation is set to 0 • Prevents stuttering and rampant perseveration • Connected activated nodes help the phoneme rebound • What happens when a lexical phrase contains two words that start with the same letter, as in "deal down"? Does the error mechanism block the "d” and reset its activation to zero because it's already been used? Do perseveration and anticipation errors have anything to do with this? (Beth Riina)

16. Built-in features of the model • Anticipatory priming • accounts for anticipations, e.g. “deal dack” for “beal dack” • Syllabic position encoding • Accounts for syllable position constraint, e.g. “deal back” doesn’t become “deal bad” • Selection of phonemes • Most phonological errors involve phonemes (rather than features)

17. Built-in features, cont. • Postselection inhibition • accounts for exchange errors • Frequency-sensitive resting levels • phonological errors more likely for low frequency words • *** Bottom-up excitatory connections • Familiarity biases • Similarity effects

18. Familiarity biases • Mechanism: bottom-up flow of activation • Lexical bias effect: word activation combines with phoneme activation • Frequent phoneme bias: those that are in many common words get more activation • A scaled-up model could account for Freudian and similar familiarity effects

19. Similarity effects • Two sounds more likely to participate in an error if their neighboring sounds are identical • Deal beak -> beal beak MORE • Deal back -> beal back LESS • Model accounts for it with interactive spread of activation • When two words share a phoneme, that phoneme tends to equalize activation

20. Model Predictions • Nonadjacent repeated-phoneme effects • Speech-rate effects • e.g., lexical bias effect increases as speech slows (as PROPORTION of errors, c.f. Nicole’s discussion Q) • Error-type interactions • Lack of a frequency effect for homophonic words