Implicit and explicit theory of mind: Relation to language

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Implicit and explicit theory of mind Relation to
language

• Ted Ruffman

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Normal Development
Explicit ToM ? Implicit ToM? (Elderly)
Implicit ToM
Explicit ToM
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Developmental Progression

• Initial theory of mind insights are implicit and
  possibly based on insights into behaviour rather
  than mental states
• Implicit insights are based on statistical
  learning (Boucher Dienes, 2003)
• Infants are good at statistical learning (e.g.,
  Saffran, Aslin, Newport, 1996 discerning
  word boundaries in strings of nonsense
  syllables tupirodapikugoladu)

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Developmental Progression

• Initial implicit insights become explicit over
  time and as language develops (Ruffman, 2000)
• language provides terms and means for reflecting
  on implicit insights to make them explicit

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Desire and Statistical Learning

• Initial social insights might be based on infant
  predicting behaviours
• Phillips et al. (2002) 12-month-olds who witness
  an adult repeatedly reaching for and cuddling one
  of two teddies, look for longer when adult then
  reaches for other teddy
• Mental Interpretation child understands adults
  desire
• Behaviour Interpretation child understands adult
  tends to reach for a particular teddy

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Intention and Statistical Learning

• Meltzoff (1995) 18-month-olds who witness an
  adult unsuccessfully trying to pull apart a
  dumbbell complete the action themselves
• Mental interpretation inferred mental state of
  intention and completed intention
• Behaviour interpretation inferred possible
  outcome (dumbbell apart) because can predict
  behavioural sequence of events (likely outcome
  given pulling action)

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False Belief and Statistical Learning

• Child sees behavioural consequences of true and
  false beliefs
• People search for things where they last see them
• Eventually child infers belief behind behaviour

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Section I Verbal/Nonverbal Dissociations in
Typical Development
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Emotion-Behaviour Task

• 39 2- to 4-year-olds

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Emotion-Behaviour Task

• Training whenever Sam goes into a room, he
  appears in the rooms window
• Experimental Sam asks Dad if he can look inside
  the orange house. Dad says, One of the rooms in
  the orange house isnt safe. Sam goes into the
  orange house. Sam comes to a red room and a green
  room. Sam doesnt know which room is the safe
  room. He shouts out to Dad, Dad, is the red room
  safe? Lets see what Dad says
• Look at Dads face! (happy or fear face)

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Emotion-Behaviour Task (cont.)

• Sam knows which room to go into now. Sam is a
  good boy and he always does what Dad says. Sam
  goes back into the orange house.
• Nonverbal Prompt He will go to one of the
  windows now. I wonder which window Sam will go
  to?
• Verbal Question Which window will Sam go to?

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Emotion-Behaviour Task
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Emotion Recognition 7- to 9-Year-Olds

• 20 7-year-olds, 20 9-year-olds
• 3 blocks of trials match, mismatch, verbal

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Match Block

• Sad Fear

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Match Block
Fear
Sad Fear
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Mismatch Block

• Sad Fear

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Mismatch Block
Sad (1/2 time) Fear (1/2 time)
Sad Fear
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Verbal Block
Sad Fear
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Two Reaction Time Blocks

• Two Reaction Time Blocks
• Match 100 match between emotion photo (e.g.,
  fear) target word (e.g., fear)
• Mismatch 50 match between emotion photo
  target word
• Verbal Block
• Children asked directly to label each of 12
  emotions used in Match Mismatch blocks

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Reaction Time (seconds)
Block (Matched vs. Mismatched) F(2, 37) 9.99,
p lt .01 Block x Verbal Score F(2, 37) 0.36,
n.s.
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Verbal Understanding of False Belief

• Not until around 4 years that children pass
  standard false belief task
• Where will John look for the chocolate?

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Eye Gaze and False Belief

• Clements Perner (1994) Garnham Ruffman
  (2001) children aged 2-11 and above looked
  correctly but gave incorrect verbal answers

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Skin Conductance Response (SCR) False Belief

• Would a physiological index such as SCR also
  reveal earlier fb understanding?

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Participants

• 30 children aged 3 to 4 years

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Prompt

• Prompt I feel very hungry now. Ill go and get
  that piece of cheese. I wonder where Sam is going
  to look

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SCR and False Belief Training

• Training
• 1/2 kids hear 1-second burst of white noise (85
  db) whenever Sam goes to left-hand box
• 1/2 kids hear 1-second burst of white noise
  whenever Sam goes to right-hand box
• Measure SCR 1 to 2.5 seconds after prompt/white
  noise (at 1.5, 2.0, 2.5, and 3.0 seconds)

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SCR and False Belief Design

• 3 noise training trials
• 3 no-noise training trials
• Test story 1 (e.g., fb)
• 1 noise training trial 1 no-noise trial
• Test story 2 (e.g., tb)

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Training Trials

• 7 children show no elevation in SCR when hear
  white noise
• Remaining 23 children do show elevated SCR

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Typical Training SCR
Prompt/ Prompt/ Prompt/ Prompt/ White Noise
White Noise No Noise No Noise
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SCR in Noise and No Noise Training Trials
F(1, 20) 31.13, p lt .001
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FB and TB Conditions

• FB Sam places cheese in left-hand box, goes
  away, Katy moves it to right-hand box
• TB Sam places cheese in left-hand box, watches
  Katy move it to right-hand box, goes away
• Prompt I feel very hungry now. Ill go and get
  that piece of cheese. I wonder where Sam is going
  to look
• Examine SCR from 2.5 to 4.0 seconds (at 2.5, 3.0,
  3.5, and 4.0 seconds) after look in FB and TB
  conditions

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FB and TB conditions

• What happens to SCR when anticipating characters
  return in fb and tb conditions?
• Note. White noise never sounds in fb tb
  conditions
• 1/2 kids trained noise occurs when Sam goes to
  left-hand box ? elevated SCR in fb condition
• 1/2 kids trained noise occurs when Sam goes to
  right-hand box ? elevated SCR in tb condition

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Mean SCRs at 2.5, 3.0, 3.5, and 4.0 Seconds After
the Prompt
F(1, 22) 5.08, p lt .05
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False Belief vs. True Belief

• 1/2 kids noise expected in fb task 1/2 kids
  noise expected in tb task
• Task (fb vs. tb) x condition (noise on left vs.
  right) interaction
• F(1, 21) 4.74, p lt .05

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SCR vs. Verbal

• SCR pass higher SCR after prompt in story in
  which white noise should occur
• Verbal pass ascribe correct belief in tb fb
  stories

• SCR significantly easier p lt .05, Binomial Test

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Summary

• Both eye gaze and SCR suggest earlier nonverbal
  understanding of fb
• But is the earlier understanding implicit
  (unconscious)?
• Or is nonverbal sensitivity to false belief due
  to conscious awareness that Sam might go to
  left-hand box but low confidence in this outcome?
• Use betting to get at confidence (Ruffman et al.,
  2001)

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Betting Study
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Percentage of Children Betting all Counters On
the Dominant Location
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Children With Autism
Explicit ToM (Impaired, slow development)
Implicit ToM (Substantially Impaired)
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TasksDesire-Action (Social Task)- Desired
object in left-hand box ??boy should go down left
slide- Desired object in right-hand box ??boy
should go down right slide Yes-No (Social
Task)- Boy asks if target room is safe, Dad says
Yes ??boy should go to target room- Boy asks
if target room is safe, Dad says No ??boy
should go to non-target roomControl- 10
red, 0 green ??object should go down left slide-
0 red, 10 green ??object should go down right
slide
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Mean Eye Gaze andVerbal Scores
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Correlations with Severity of Autism
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Section III How Language Relates to Verbal
Nonverbal ToM
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Language and Verbal ToM

• Parents language about mental states facilitates
  childrens later theory of mind (Dunn et al.,
  1991 Meins et al., 2002 Ruffman et al., 2002)
• Childrens verbal ability correlates with their
  verbal performance on theory of mind tasks
• Some have claimed only syntax that correlates
  (Astington Jenkins, 1999 deVilliers Pyers,
  2002 Hale Tager-Flusberg, 2003)
• But both semantics and syntax correlate (Ruffman
  et al., 2003 Slade Ruffman, in press)

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How Language HelpsVerbal ToM

• Language gives child the terms to (a) think
  explicitly about a person pretending x versus
  thinking x (making fine distinctions between
  different propositional attitudes and contents)
• Language gives child the terms to (b) think
  through the causal origins and implications
  (e.g., subsequent actions) of mental states,
  enabling explicit predictions

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2- to 4-Year-OldsEmotion Behaviour
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7- to 9-Year-OldsEmotion Recognition Reaction
Time
Verbal Measure Number of items correct on verbal
question Reaction Time Number of items for which
quicker reaction time on match block than
mismatched block
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Children with Autism and MLD
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Summary

• Language - verbal performance 4/4 correlations
  significant
• Language - nonverbal performance 1/4
  correlations significant

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Conclusions

• Several examples of nonverbal understanding
  preceding verbal understanding in normal and
  autistic development
• Nonverbal is core understanding (a) more likely
  to differentiate autistic and MLD children, (b)
  higher correlate of autistic severity
• Eye gaze in false belief task taps implicit
  performance in youngest children
• Verbal but not nonverbal performance correlates
  with language language provides terminology to
  develop explicit knowledge or theories

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Part IV Statistical Learningand False Belief
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Is Statistical Learning a Basis for False Belief?

• False belief is initially implicit and later
  becomes explicit
• Implicit knowledge is thought to be based on
  statistical redundancies (Boucher Dienes,
  2003)
• So false belief - even an explicit measure of
  false belief - should correlate with statistical
  learning

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Statistical Learning Task

• 53 preschoolers
• listened to computer-generated syllables taken
  from Saffran, Aslin Newport (1996) for 20
  minutes while coloring (e.g., golabutupirobidaku
  padoti)
• syllables (e.g., bi, da, go, la) were
  spoken by text-reading software one
  syllable/0.36 seconds
• no intonation cues between syllables
• certain syllable pairs repeated in the training
  phase (e.g., bida, gola), whereas others
  (e.g., bigo) never occurred
• later, presented with syllable pairs old (e.g.,
  bida) versus new (e.g., bigo) word, and
  asked which heard previously

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False Belief Tasks

• Two transfer tasks, one misleading container
  task, one appearance-reality task
• Composite score 0 to 8

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Language Task

• PPVT measures receptive vocabulary
• e.g., shown 4 pictures Show me bucket

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Statistical Learning Test Stimuli

• Words and Nonwords used in Familiarization
• and Test Phases
• Words Nonwords
• bida bigo
• gola gobi
• tupi tugo
• Presented in pairs (bida bigo) child
  identified which word they had heard before
• 12 of 53 kids were correct (3/3)

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Descriptive Statistics
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Correlations
p lt 0.05 Stat FB (partialling out language)
pr .26, p lt .05
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Summary

• Children with better false belief understanding
  have better statistical learning ability even
  after accounting for their language ability

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Conclusions

• Several examples of nonverbal understanding
  preceding verbal understanding in normal and
  autistic development
• Nonverbal is core understanding (a) more likely
  to differentiate autistic and MLD children, (b)
  higher correlate of autistic severity
• Eye gaze in false belief task taps implicit
  performance in youngest children
• Verbal but not nonverbal performance correlates
  with language language provides terminology to
  develop explicit knowledge or theories
• Verbal false belief understanding correlates
  positively with statistical learning ability even
  after accounting for language abilty, consistent
  with idea that basis is implicit