Psycholinguistics I

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Psycholinguistics I

• LING 640

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What is psycholinguistics about?
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Guiding Questions

• What do speakers of a language mentally
  represent?
• How did those representations get there?
• How are those representations constructed?
• How are those representations encoded?

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Language is a Human Specialization

• Species specificity
• Within-species invariance
• Spontanous development, insensitivity to input
• Independence of general intelligence
• Selective brain damage
• The Language Instinct Pinker 1994 see
  Gleitman Newport chapter readings for nice
  summary
• These arguments suggest that theres a coherent
  object of study, but tell us very little about
  its form

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We need explicit answers

• What do speakers of a language mentally
  represent?
• How did those representations get there?
• How are those representations constructed?
• How are those representations encoded?

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Explicit models quickly reveal surprising
complexity
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A Simple(-ish) Example

• Distribution of pronouns/reflexives
• John likes him/himself.
• John thinks that Mary likes him/himself.
• Infinitival clauses
• John appeared to Bill to like himself.
• John appeared to Bill to like him.
• But
• John appealed to Bill to like himself.
• John appealed to Bill to like him.
• Abstract solution
• Johni appealed to Billj PROj to like himselfj

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Abstraction is a double-edged sword
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Abstraction

• Abstraction is valuable
• Provides representational power
• Provides representational freedom
• Abstraction is costly
• Linguistic representations are more distant from
  experience
• This places a burden on the learner - motivation
  for innate knowledge
• This places a burden on comprehension/production
  systems
• (and it makes it harder to know what to look for
  in the brain)

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Sensory Maps Internal representations of the
outside world. Cellular neuroscience has
discovered a great deal in this area.
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Lab 1
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Acoustic Continua andPhonetic Categories
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Frequency - Tones
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Frequency - Tones
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Frequency - Tones
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Frequency - Tones
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Frequency - Complex Sounds
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Frequency - Complex Sounds
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Frequency - Vowels

• Vowels combine acoustic energy at a number of
  different frequencies
• Different vowels (a, i, u etc.) contain
  acoustic energy at different frequencies
• Listeners must perform a frequency analysis of
  vowels in order to identify them(Fourier
  Analysis)

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Frequency - Male Vowels
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Frequency - Male Vowels
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Frequency - Female Vowels
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Frequency - Female Vowels
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Synthesized Speech

• Allows for precise control of sounds
• Valuable tool for investigating perception

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Timing - Voicing
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Voice Onset Time (VOT)
60 msec
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English VOT production

• Not uniform
• 2 categories

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Perceiving VOT
Categorical Perception
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Discrimination
A More Systematic Test
Same/Different
D
D
0ms 60ms
0ms
20ms
D
T
20ms
40ms
Same/Different
0ms 10ms
T
T
40ms
60ms
Same/Different
Within-Category Discrimination is Hard
40ms 40ms
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Quantifying Sensitivity
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Quantifying Sensitivity

• Response bias
• Two measures of discrimination
• Accuracy how often is the judge correct?
• Sensitivity how well does the judge distinguish
  the categories?
• Quantifying sensitivity
• Hits MissesFalse Alarms Correct Rejections
• Compare p(H) against p(FA)

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Quantifying Sensitivity

• Is one of these more impressive?
• p(H) 0.75, p(FA) 0.25
• p(H) 0.95, p(FA) 0.45
• A measure that amplifies small percentage
  differences at extremesz-scores

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Normal Distribution
Standard Deviation A measure of dispersionaround
the mean.
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The Empirical Rule
1 s.d. from mean 68 of data
2 s.d. from mean 95 of data
3 s.d. from mean 99.7 of data
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Quantifying Sensitivity

• A z-score is a reexpression of a data point in
  units of standard deviations.(Sometimes also
  known as standard score)
• In z-score data, µ 0, ? 1
• Sensitivity score d z(H) - z(FA)

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See Excel worksheetsensitivity.xls
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Quantifying Differences
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(Näätänen et al. 1997)
(Aoshima et al. 2004)
(Maye et al. 2002)
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Normal Distribution
Standard Deviation A measure of dispersionaround
the mean.
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The Empirical Rule
1 s.d. from mean 68 of data
2 s.d. from mean 95 of data
3 s.d. from mean 99.7 of data
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Normal Distribution
Standard deviation ? 2.5 inches
Heights of American Females, aged 18-24
Mean (µ) 65.5 inches
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• If we observe 1 individual, how likely is it that
  his score is at least 2 s.d. from the mean?
• Put differently, if we observe somebody whose
  score is 2 s.d. or more from the population mean,
  how likely is it that the person is drawn from
  that population?

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• If we observe 2 people, how likely is it that
  they both fall 2 s.d. or more from the mean?
• and if we observe 10 people, how likely is it
  that their mean score is 2 s.d. from the group
  mean?
• If we do find such a group, theyre probably from
  a different population

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• Standard Erroris the Standard Deviation of
  sample means.

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• If we observe a group whose mean differs from the
  population mean by 2 s.e., how likely is it that
  this group was drawn from the same population?

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Development of Speech Perception in Infancy
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Voice Onset Time (VOT)
60 msec
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Perceiving VOT
Categorical Perception
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Discrimination
A More Systematic Test
Same/Different
D
D
0ms 60ms
0ms
20ms
D
T
20ms
40ms
Same/Different
0ms 10ms
T
T
40ms
60ms
Same/Different
Within-Category Discrimination is Hard
40ms 40ms
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Cross-language Differences
L
R
L
R
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Cross-Language Differences
English vs. Japanese R-L
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Three Classics
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Development of Speech Perception

• Unusually well described in past 30 years
• Learning theories exist, and can be tested
• Jakobsons suggestion children add feature
  contrasts to their phonological inventory during
  development

Roman Jakobson, 1896-1982Kindersprache, Aphasie
und allgemeine Lautgesetze, 1941
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Developmental Differentiation
UniversalPhonetics
Native Lg.Phonology
Native Lg.Phonetics
0 months
6 months
12 months
18 months
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1 - Infant Categorical Perception

• Eimas, Siqueland, Jusczyk Vigorito, 1971

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Discrimination
A More Systematic Test
Same/Different
D
D
0ms 60ms
0ms
20ms
D
T
20ms
40ms
Same/Different
0ms 10ms
T
T
40ms
60ms
Same/Different
Within-Category Discrimination is Hard
40ms 40ms
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English VOT Perception
To Test 2-month olds Not so easy! High Amplitude
Sucking Eimas et al. 1971
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General Infant Abilities

• Infants show Categorical Perception of speech
  sounds - at 2 months and earlier
• Discriminate a wide range of speech contrasts
  (voicing, place, manner, etc.)
• Discriminate Non-Native speech contrastse.g.,
  Japanese babies discriminate r-le.g., Canadian
  babies discriminate d-D

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Universal Listeners

• Infants may be able to discriminate all speech
  contrasts from the languages of the world!

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How can they do this?

• Innate speech-processing capacity?
• General properties of auditory system?

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What About Non-Humans?

• Chinchillas show categorical perception of
  voicing contrasts!

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2 - Becoming a Native Listener

• Werker Tees, 1984

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When does Change Occur?

• About 10 months

Janet Werker U. of British Columbia
Conditioned Headturn Procedure
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When does Change Occur?

• Hindi and Salishcontrasts testedon English kids

Janet Werker U. of British Columbia
Conditioned Headturn Procedure
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What do Werkers results show?

• Is this the beginning of efficient memory
  representations (phonological categories)?
• Are the infants learning words?
• Or something else?

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Korean has l r

• rupi ruby
• kiri road
• saram person
• irmi name
• ratio radio
• mul water
• pal big
• s\ul Seoul
• ilkop seven
• ipalsa barber

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3 - What, no minimal pairs?

• Stager Werker, 1997

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A Learning Theory

• How do we find out the contrastive phonemes of a
  language?
• Minimal Pairs

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Word Learning

• Stager Werker 1997bih vs. dihandlif
  vs. neem

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PRETEST
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HABITUATION
TEST
SAME
SWITCH
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Abstraction

• Representations
• Sound encodings - clearly non-symbolic, but
  otherwise unclear
• Phonetic categories
• Memorized symbols /k/ /æ/ /t/
• Behaviors
• Successful discrimination
• Unsuccessful discrimination
• Step-like identification functions
• Grouping different sounds

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Word learning results

• Exp 2 vs 4

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Why Yearlings Fail on Minimal Pairs

• They fail specifically when the task requires
  word-learning
• They do know the sounds
• But they fail to use the detail needed for
  minimal pairs to store words in memory
• !!??

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One-Year Olds Again

• One-year olds know the surface sound patterns of
  the language
• One-year olds do not yet know which sounds are
  used contrastively in the language
• and which sounds simply reflect allophonic
  variation
• One-year olds need to learn contrasts

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Maybe not so bad after all...

• Children learn the feature contrasts of their
  language
• Children may learn gradually, adding features
  over the course of development
• Phonetic knowledge does not entailphonological
  knowledge

Roman Jakobson, 1896-1982
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Werker et al. 2002
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Swingley Aslin, 2002

• 14-month olds did recognize mispronunciations of
  familiar words

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Alternatives to Reviving Jakobson

• Word-learning is very hard for younger children,
  so detail is initially missed when they first
  learn words
• Many exposures are needed to learn detailed word
  forms at early stages of word-learning
• Success on the Werker/Stager task seems to be
  related to the vocabulary spurt, rapid growth in
  vocabulary after 50 words

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Questions about Development
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6-12 Months What Changes?
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Structure Changing
Patricia KuhlU. of Washington
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Structure Adding

• Evidence for Structure Adding(i) Some
  discrimination retained when sounds presented
  close together (e.g. Hindi d-D contrast)(ii)
  Discrimination abilities better when people hear
  sounds as non-speech(iii) Adults do better than
  1-year olds on some sound contrasts
• Evidence for Structure Changing(i) No evidence
  of preserved non-native category boundaries in
  vowel perception

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Sources of Evidence

• Structure-changing mostly from vowels
• Structure-adding mostly from consonants
• Conjecture structure-adding is correct in
  domains where there are natural articulatory (or
  acoustic) boundaries

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So how do infants learn?

• Surface phonetic patterns
• Tests of experimentally induced changes

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5 hours exposure to Mandarin human interaction
2003, Proceedings of the National Academy of
Sciences
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Jessica Maye, Northwestern U.
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• Infants at age 6-8 months are still universal
  listeners, cf. Pegg Werker (1997)
• Infants trained on bi-modal distribution show
  novelty preference for test sequence with fully
  alternating sequence
• How could the proposal scale up?

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Invariance
(Jusczyk 1997)
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Training on g-k or d-t, generalization across
place of articulation.(Dis-)habituation paradigm.
Maye Weiss, 2003
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So how do infants learn?

• Phoneme categories and alternations
• Perhaps more like a phonologist than like a
  LING101 student - look directly for systematic
  relations among phones
• Gradual articulation of contrastive information
  encoded in lexical entries
• Much remains to be understood

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Abstraction in Infant Speech Encoding

• From a very early age infants show great
  sensitivity to speech sounds, possibly already
  with some category-like structure
• Although native-like sensitivity develops early
  (lt 1 year), this should be distinguished from
  adult-like knowledge of the sound system of the
  language
• Children still need to learn how to efficiently
  encode words (phoneme inventory)
• Children presumably still need to learn how to
  map stored word forms onto pronunciations
  (phonological system of the language)
• Popular distributional approaches to learning the
  sound system address rather non-abstract
  encodings of sounds, at best