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PSY 369: Psycholinguistics

PSY 369: Psycholinguistics. Language Comprehension: Introduction & Perception of language. Announcements. Homework 2 is due on Thursday

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PSY 369: Psycholinguistics

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  1. PSY 369: Psycholinguistics Language Comprehension: Introduction & Perception of language

  2. Announcements • Homework 2 is due on Thursday • Read: Samuel, A. (2001). Knowing a word affects the fundamental perception of the sounds within it. Psychological Science, 12(4). 348-351. (you can download it from the assignment page on the course website) • After you've read the article, write a summary of it. Make sure that you include the following in your summary: • what is/are the issues • what is/are the hypotheses • what methodology was used • what were the basic findings • what conclusions were drawn

  3. Visual word recognition Speech Perception Where are you going Different signals • Some parallel input • Orthography • Letters • Clear delineation • Difficult to learn • Serial input • Phonetics/Phonology • Acoustic features • Usually no delineation • “Easy” to learn

  4. Visual word recognition Speech Perception Where are you going Different signals • Some parallel input • Orthography • Letters • Clear delineation • Difficult to learn • Serial input • Phonetics/Phonology • Acoustic features • Usually no delineation • “Easy” to learn

  5. Visual perception of language • Why so much research using visual language? • We do use it • Easy to use in research • The parts • Letters • Words • Eye movements

  6. Invariance a problem in vision too? G G G G G G G Same object category (‘G’) may have different shapes, sizes, and orientations G G G G G G G G G G G G G G G Perhaps the brain is able to represent these objects in a way that is “translationally invariant” and “size invariant”.

  7. Letter Recognition • How do we recognize a group of lines and curves as letters? • Two common explanations: • Template matching • Feature detection • Okay, I’m going to show you a stimulus really fast and you need to tell me what it was

  8. Template matching • Store in brain a copy of what every possible input will look like. • Match observed object to the proper image in memory

  9. Perceptual Representation Template matching Memory Representations

  10. FROG E Problems with Template matching • Costly: Massive numbers of templates are required (remember all those E’s?).. • Normalization before matching - ”mentally cleaning it up” before matching to templates • Predicts no transfer to novel views of the same object • Objects are often obstructed/occluded

  11. Prolblems with Template matching • Costly: Massive numbers of templates are required (remember all those E’s?).. • Normalization before matching - ”mentally cleaning it up” before matching to templates • Predicts no transfer to novel views of the same object • Objects are often obstructed/occluded E FROG • Objects are often disamiguated by context

  12. C T Read aloud the following word

  13. T E Read aloud the following word

  14. C T T E So what is the middle letter? • Clearly, top-down influences. However it is unclear how this works with template matching

  15. Feature detection • Analysis-by-synthesis 1. Letter broken down to its constituent parts 2. List of parts compared to patterns in memory 3. Best matching pattern chosen

  16. Feature detection A fixed set of elementary properties are analyzed Independently and in parallel across visual field. Possible examples Free line endings: +45deg. -10deg. Line Orientations: Different Sizes: Curvature: Colors:

  17. A simple theory of Feature detection Perceptual Representation Memory Representation E 3 Horizontal lines 1 Vertical line 4 Right angles 3 Horizontal lines 1 Vertical line 4 Right angles F 2 Horizontal lines 1 Vertical line 3 Right angles

  18. Evidence for Features: The visual search task is straightforward, you are given some target to look for, and asked to simply decide, as quickly as possible, whether the target is present or absent in a set of objects. For example, let’s try a few searches to give you a feel for this. Search 1 - Is there an O present in the following displays?

  19. Is an O present? T T T T T O T T T

  20. Is an O present? T T T T TTT T T T T T T T T T T O TTT T TT TT T TT T T TT T T T TT T TTT T TT

  21. Is an O present? Q Q Q Q Q Q O Q Q Q Q Q Q

  22. Is an O present? Q QQ Q Q QQQ QQQ Q QQQ Q O Q Q QQ Q Q QQ Q Q Q Q QQQ Q QQ Q Q QQQ Q QQQQ Q

  23. Is an O present? T T T T T O T T T T T T T TTT T T T T T T T T T T O TTT T TT TT T TT T T TT T T T TT T TTT T TT Q QQ Q Q QQQ QQQ Q QQQ Q O Q Q QQ Q Q QQ Q Q Q Q QQQ Q QQ Q Q QQQ Q QQQQ Q Q Q Q Q Q Q O Q Q Q Q Q Q

  24. A theory of Feature detection Selfridge’s Pandemonium system, 1959

  25. Another theory of Feature detection

  26. Interactive Activation Model (AIM) McClelland and Rumelhart, (1981) Previous models posed a bottom-up flow of information (from features to letters to words). IAM also poses a top-down flows of information • Nodes: • (visual)feature • (positional) letter • word detectors • Inhibitory and excitatory connections between them.

  27. Interactive Activation Model (AIM) • Inhibitory connections within levels • If the first letter of a word is “a”, it isn’t “b” or “c” or … • Inhibitory and excitatory connections between levels (bottom-up and top-down) • If the first letter is “a” the word could be “apple” or “ant” or …., but not “book” or “church” or…… • If there is growing evidence that the word is “apple” that evidence confirms that the first letter is “a”, and not “b”…..

  28. The Word-Superiority Effect (Reicher, 1969) + Until the participant hits some start key

  29. The Word-Superiority Effect (Reicher, 1969) COURSE Presented briefly … say 25 ms

  30. The Word-Superiority Effect (Reicher, 1969) U &&&&& A Mask presented with alternatives above and below the target letter … participants must pick one as the letter they believe was presented in that position.

  31. The Word-Superiority Effect (Reicher, 1969) + + + E KLANE PLANE E & T E &&&&& T E &&&&& T Letter only Say 60% Letter in Nonword Say 65% Letter in Word Say 80% Why is identification better when a letter is presented in a word?

  32. IAM & the word superiority effect • We are processing at the word and letter levels simultaneously • Letters in words benefit from bottom-up and top-down activation • But letters alone receive only bottom-up activation.

  33. Other Relevant Findings? • Bias towards “well-formed” stimuli • Bisidentify words with uncommon spelling patterns • BOUT as BOAT • misidentify nonwords (e.g., SALID) as words that are like it (SALAD). • Difficulty identifying nonwords with irregular spelling patterns (e.g., ITPR) more than those with regular spelling patterns (e.g., PIRT).

  34. Sublexical units • Sublexical units bigger than phonemes and graphemes? • onsets and rimes • onset: initial consonant or consonant cluster in a word or syllable • rime: following vowel and consonants • if words broken at onset-rime boundary, resulting letter clusters more easily recognized as belonging together than if broken at other points • example: FL OST ANK TR vs. FLA ST NK TRO

  35. Adding a bigram level By adding a frequency-sensitive bigram level, we can account for the findings of well-formedness along with the others.

  36. Summing up • Word recognition is based on a feature-detector system • Biased to perceive common or recently occurring features

  37. Studying Word Identification • Generally people ask: what makes word identification easy or difficult? • The assumption: • Time spent identifying a word can be a measure of difficulty • Measures of identification time are usually indirect

  38. Some Identification Time Measures • Measure how long people take to say a string of letters is (or is not) a word (lexical decision) • Measure how long people take to categorise a word (“apple” is a fruit) • Measure how long people take to start saying a word (naming or pronunciation time) • Measure how long people actually spend looking at a word when READING • Line by line reading • Word by word reading • using eye movement monitoring techniques

  39. Line-by-line A banker is a fellow

  40. Line-by-line who lends you his umbrella

  41. Line-by-line when the sun is shining

  42. Line-by-line but wants it back

  43. Line-by-line the minute it begins to rain.

  44. Line-by-line • Problem: • Overall reading time for entire sentence or phrase • need for more “on-line” measurements • Timing on a smaller scope • See effects at level of word

  45. Word-by-word • RSVP (rapid serial visual presentation)

  46. Word-by-word A

  47. Word-by-word lie

  48. Word-by-word can

  49. Word-by-word travel

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