Lexical Access: Generation & Selection

1. Lexical Access:Generation & Selection

2. Main Topic • Listeners as active participants in comprehension process • Model system: word recognition

3. Outline • Speed & Robustness of Lexical Access • Active Search • Evidence for Stages of Lexical Access • Autonomy & Interaction

4. Outline • Speed & Robustness of Lexical Access • Active Search • Evidence for Stages of Lexical Access • Autonomy & Interaction

5. The mental lexicon sport figure sing door carry turf turtle gold turk turkey turn water turbo turquoise turnip turmoil

6. How do we recognize words? • The Simplest Theory • Take a string of letters/phonemes/syllables, match to word in the mental lexicon • (That’s roughly how word processors work) • …is it plausible?

7. Word Recognition is Fast • Intuitively immediate - words are recognized before end of word is reached • Eye-tracking studies indicate effects of access within 200-300ms • Speech shadowing at very brief time-lags, ~250ms (Marslen-Wilson 1973, 1975)

8. Marslen-Wilson 1975 Speech shadowing involves on-line repetition of a speaker… Speech shadowing involves on-line repetition of a speaker… 250-1000ms Shadowing latency The new peace terms have been announced… They call for the unconditional surrender of …universe of …already of … normalsemanticsyntactic

9. Marslen-Wilson 1975

10. “If the interaction between higher and lower levels of of analysis takes place only after the initial phonetic and lexical identification of the word, then restoration of disrupted words should be equally frequent in all Context conditions. The shadower would have no basis, in his initial repetition, for rejecting contextually anomalous restorations. However, if immediate identification does interact on-line with the semantic and syntactic context, then it becomes possible for context variables to determine word restoration frequency.” (Marslen-Wilson, 1975, p. 226)

11. “The high incidence of WR errors in Normal2 illustrates the speed and the precision with which structural information can be utilized. If the first syllable indicates a word that matches the context, then the close shadower can immediately start to restore that word in his repetition. This implies, first, that the constraints derived from the preceding items of the string are available to guide the analysis of even the first syllable of the target word. Second, these constraints can specify the permissible form-class and meaning of the target word with sufficient precision to enable the shadower to assess the appropriateness of just its first syllable.” (Marslen-Wilson 1975, p. 227).

12. Lexical Access is Robust • Succeeds in connected speech • Succeeds in fast speech • Survives masking effects of morphological affixation and phonological processes • Deleted or substituted segments • Speech embedded in noise

13. But… • Speed and robustness depends on words in contextsentence --> word context effects • In isolation, word recognition is slower and a good deal more fragile, susceptible to error • …but still does not require perfect matching

14. Questions • How does lexical access proceed out of context? • Why is lexical access fast and robust in context? • When does context affect lexical access? • does it affect early generation (lookup) processes? • does it affect later selection processes?

15. Classic Experimental Paradigms

16. Reaction Time Paradigms • Lexical Decision • Priming

17. List 1sicklecathartic torrid gregarious oxymoron atrophy List 2parabola periodontist preternatural pariah persimmon porous Looking for Words

18. List 1sicklecathartic torrid gregarious oxymoron atrophy List 2parabola periodontist preternatural pariah persimmon porous Looking for Words Speed of look-up reflects organization of dictionary

19. Looking for Words +

20. Looking for Words DASH

21. Looking for Words +

22. Looking for Words RASK

23. Looking for Words +

24. Looking for Words CURLY

25. Looking for Words +

26. Looking for Words PURCE

27. Looking for Words +

28. Looking for Words WINDOW

29. Looking for Words +

30. Looking for Words DULIP

31. Looking for Words +

32. Looking for Words LURID

33. (Embick et al., 2001)

34. Looking for Words • Semantically Related Word Pairsdoctor nurse hand finger speak talk sound volume book volume

35. Looking for Words • In a lexical decision task, responses are faster when a word is preceded by a semantically related word • DOCTOR primes NURSE • Implies semantic organization of dictionary

36. Outline • Speed & Robustness of Lexical Access • Active Search • Evidence for Stages of Lexical Access • Autonomy & Interaction

37. Active Recognition • System actively seeks matches to input - does not wait for complete matchThis allows for speed, but …

38. Cost of Active Search… • Many inappropriate words activated • Inappropriate choices must be rejected • Two Stages of Lexical Accessactivation vs. competitionrecognition vs. selectionproposal vs. disposal

39. The mental lexicon sport figure sing door carry turf turtle gold turk turkey turn water turbo turquoise turnip turmoil

40. The mental lexicon sport figure sing door carry turf turtle gold turk turkey turn water turbo turquoise turnip turmoil TURN

41. Automatic activation sport figure sing door carry turf turtlegold turk turkey water turn turbo turquoise turnip turmoil TURN

42. Lateral inhibition sport figure sing door carry turf turtle gold turk turkey water turn turbo turquoise turnip turmoil TURN

43. What is lexical access? Activation Competition Selection/Recognition TURN TURNIP level of activation TURF TURTLE resting level time Stimulus: TURN (e.g. Luce et al. 1990, Norris 1994)

44. S song story sparrow saunter slow secret sentry etc. Cohort

45. SP spice spoke spare spin splendid spelling spread etc. Cohort

46. SPI spit spigot spill spiffy spinaker spirit spin etc. Cohort

47. SPIN spin spinach spinster spinaker spindle Cohort

48. SPINA spinach Cohort

49. SPINA spinach Cohort word uniqueness point

50. SPINA spinach spinet spineret Cohort