why children are better (or at least more open-minded) scientists than adults are: search,...
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Why children are better (or at least more open-minded) scientists than adults are: Search,
temperature and the origins of human cognition.
Alison GopnikDept. of Psychology
UC Berkeley
The Probabilistic Models Approach to Causal Learning
Abstract structured representations of causal knowledge with systematic relations to data
Intuitive theories –Gopnik & Meltzoff, 1997
Causal Bayes nets- Spirtes, Glymour and Scheines, 1993, Pearl 2000, Woodward 2003, Gopnik et al. 2004
Hierarchical causal Bayes nets and probabilistic logic-
Griffiths and Tenebaum 2007, Goodman 2010
Probabilistic Models and Cognitive Development
• Gopnik 2012 Science• Gopnik & Wellman 2012
Psychological Bulletin
Unanswered Questions
• How do children search through all the possible hypotheses?
• Do children learn higher-order causal principles as well as specific causal relationships?
• Why do children sometimes appear so irrational?
• Are there developmental differences ?
The Sampling Hypothesis
Denison, Bonawitz, Gopnik, & Griffiths, Cognition, 2013
Why Childhood?: Longer Childhood, Bigger Brain, Smarter
Animal
Quokka vs. OpposumWeisbecker & Goswami, PNAS
2010
Regression of predicted versus actual age for eight fossil juveniles and 36 recent (living) humans.
Smith T M et al. PNAS 2010;107:20923-20928
©2010 by National Academy of Sciences
Fossil Dental Evidence For Immaturity
Exploration vs. Exploitation
• Search and temperature
• Childhood is evolution’s way of performing simulated annealing
Inferring Abstract Laws:Lucas, Gopnik & Griffiths
• Framework theories• Hierarchical Bayes-nets (Griffiths &
Tenenbaum)• The blessing of abstraction
(Goodman)
Which objects are blickets?
Is D a blicket? Is E a blicket? Is F a blicket?
What if you also saw these events?
“Or“ Training
“And” Training
Test
Functional Form Procedure: “OR” and “AND” Test Trial
D D D E
D + F D + E + F D + F
Functional Form Procedure: “OR” and “AND” Conditions
Do think the circle is a blicket or not a blicket?
CIRCLE DIAMOND BALL
Functional Form Procedure: “OR” and “AND” Conditions
Which of these should we use to make the
machine turn on?
CIRCLE DIAMOND BALL
Intervention Question
“BASELINE” Test Trial 1 Results:Percentage of Participants who think D and F are
Blickets
Children Adults0
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DF
N = 24 N = 26
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“OR” Test Trial Results:Percentage of Participants who think D and F are
Blickets**
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N = 25 N = 28
Children Adults0
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DF
“AND” Test Trial Results:Percentage of Participants who think D and F are
Blickets**
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N = 25 N = 24
Children Adults0
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DF
“BASELINE” Intervention 1 Results:Percentage of Single vs. Multiple Object
Interventions
Children Adults0
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SingleMultiple
N = 22 N = 26
“OR” Intervention Results:Percentage of Single vs. Multiple Object
Interventions
Children Adults0
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SingleMultiple
N = 25 N = 28
“AND” Intervention Results:Percentage of Single vs. Multiple Object
Interventions
N = 25 N = 24Children Adults
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“BASELINE” Intervention 1 Results:F v. DF v. DEF Interventions
Children Adults0
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FDFDEF
N = 22 N = 26
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“OR” Intervention Results:F v. DF v. DEF Interventions
Children Adults0
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FDFDEF
N = 25 N = 28
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“AND” Intervention Results:F v. DF v. DEF Interventions
Children Adults0
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FDFDEF
N = 25 N = 24
***_______________________________
*__________________
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Tulver Flowers
Tulver “AND” Test Trial Results:Percentage of Adults who think D and F are
Tulvers
N = 28 N = 27
Adult “AND” Intervention Results:Percentage of Single vs. Multiple Object
Interventions
Adult “AND” Intervention Results:F v. DF v. DEF Interventions
N = 28 N = 27
Learning Higher-Order Causal Relations: Walker & Gopnik,
Psychological Science In press• ,• Learn causal properties of objects between
19- and 24-months(Gopnik, 2012; Sobel & Kirkham, 2006; Meltzoff, Waismeyer & Gopnik, 2012)
• Determine whether effects were caused by their own actions at 16-months(Gweon & Shchulz, 2011)
Relational Reasoning in Non-Human Primates
• Failure as evidence for key difference in human cognition (Penn, Holyoke, & Povinelli, 2008)
• Depends on culture/language (Gentner, 2010)
• Not a qualitative difference (Premack, 1988)
• Primates can learn– Hundreds of trials
(Premack, 1988)
– Learning to use words for “same” and “different” (Premack, 1983)
• 46 participants• 18- to 24-month-olds (mean 20.9 mos.)------------------------------------------------------------• Created a causal version of Premack’s
(1983) match-to-sample task– Observe an abstract relational pattern (AA’,
BB’, CC’ lead to a reward)– Select between AB (object match) and DD
(relational match)
Experiment 1Match-to-Sample
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Match-to-Sample Trial 1a
Match-to-Sample Trial 1b
Match-to-Sample Trial 2a
Match-to-Sample Trial 2b
Match-to-Sample Trial 3a
Match-to-Sample Trial 3b
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Novel Distractor
Familiar Novel Paired
Test Blocks
Match-to-Sample Test Trial 1
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Novel Distractor
Familiar Novel Paired
Test Blocks
Match-to-Sample Test Trial 2
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18-20 months 21-24 months0
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18- to 24-month-olds, t(45) = 2.47, p<.02**18-20 month olds: p=.72 21-23 month olds: p<.02**Significant difference between age groups: p<.05**
Results: Match-to-Sample
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Experiment 1a: Control• Due to “matching” the experimenter’s
selection or a baseline preference for pairs?• 21 participants total • 21- to 24-month-olds (mean = 22.4 mos.)---------------------------------------------------------------• Occlude the 2nd object in the pair• No evidence for relational property “same”• Prediction: random selection on test items
Control Trial 1a
Control Trial 1b
Control Trial 2a
Control Trial 2b
Control Trial 3a
Control Trial 3b
Novel Distractor
Familiar Novel Paired
Test Blocks
Control Test Trial
21- to 24-month-olds in Experiment 1: p<.0221- to 24-month-olds in Experiment 2: p=.65 (ns)Significant diff. between infants in Exp 1 and Exp 2: p<.05
Results: Control ExperimentPe
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21-24 mos EXP 1 21-24 mos EXP 20
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Experiment 2: Relational Match-to-Sample
• 2 conditions: “same” and “different”• 38 participants, 19 per condition• Age: 18- to 30-months (mean 25.8 mos.)-----------------------------------------------------------• Present + and - evidence for the relation
“same” or “different”• Evidence presented as pairs of objects• Single test trial
“Same” Trial 1
“Same” Trial 2
“Same” Trial 3
“Same” Trial 4
“Same” Condition Test Trial
“Different” Trial 1
“Different” Trial 2
“Different” Trial 3
“Different” Trial 4
“Different” Condition Test Trial
18- to 24-month-olds 25- to 30-month-olds0
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Results: RMTSPe
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Median split (younger: mean = 22.8; older: mean = 28.7) 18-24 month olds: p=.08 (one-tail); p=.16 (two-tail)25-30 month olds: p<.001 (two-tail exact binomial test)No significant diff between age groups, p=.58
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Summary and Discussion• Infants can learn abstract relational
causal principles (same/different) and use them to guide action
• Appears very early in development• May help explain how children
acquire abstract causal knowledge
U-Shaped Curve?• Piloting: older children pass the
“same” condition, but fail the “different” condition
• Older children doing WORSE than younger children?
• This would support a U-shape – acquiring prior that “different” is a low probability relation
• 30-48-month-olds (M=36.2 months)
Preliminary Results
Same Different0
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Conclusions
• Yes, damn it, children are little scientists
• They may be better, or at least more open-minded scientists than we are
• Apparent irrationalities may actually be causal inference advantages
• Normative philosophical inquiries and empirical psychological ones can be mutually illuminating
Collaborators and Support• Clark Glymour• Tom Griffiths• Elizabeth Bonawitz• Caren Walker• Chris Lucas• Sophie Bridgers• NSF • The James S. McDonnell Foundation
Causal Learning Collaborative
Reasoning and Learning about Complex Causal Structures:
Backtracking/conditioning vs Surgery/Intervening
Pretense and Causal ReasoningBuchsbaum et al, Philosophical
Transactions of the Royal Society, ’12
• Counterfactuals in causal reasoning and learning
• Intuitive link between causal counterfactuals and pretense – are they related?
Monkey’s Birthday• Two within-subject phases
– Counterfactual phase– Pretense phase
• 52 preschool age children– 26 four year olds– 26 three year olds
• “Birthday machine” for Monkey’s birthday
Counterfactual Phase
• Introduced to “birthday machine” and two objects– Plays happy birthday when “zando” is on top– Does nothing when “not a zando” is on top
• Asked counterfactuals– “if this one was not a zando what would happen if we put it on the machine?”– “if this one was a zando, what would happen if we put it on the machine?”
Pretense Phase• Confederate needs to borrow real machine and objects
• Introduce box + two wood blocks for pretend
• How do we pretend to make the machine go?– What do we pretend whenwe put each block on the machine?– Reverse roles of blocks andrepeat
Counterfactual Pretense0
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Expt. 2: Mean Correct on Counterfactual and Pretense Questions
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Mean C
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Music
No Music Partial Correlation Counterfactuals and Pretense accounting for age, conservation, executive function: p < 0.05*, r = 0.38
Zando Non-Zando
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Exp 2: Average Score for Pretense Questions
Counterfactuals Incorrect
Counterfactuals Correct
Reasoning about Complex Causal Structures in Pretense
Reasoning about Complex Causal Structures in Pretense
• In this book, we are going to learn about my friend Katie’s dog named Sparky and cat named Buster. Sparky and Buster spend a lot of time in Katie’s backyard. Sometimes Sparky barks. When Sparky barks, it makes Buster feel scared. Other times, Sparky wags his tail. When Sparky wags his tail, it makes Buster feel happy. When Buster is scared, his fear makes him run up a tree to hide from Sparky. When Buster is happy, his happiness makes him wrestle with Sparky. When Sparky barks, his barking also makes the birds fly out of the tree. When Sparky wags his tail, the wagging makes the fleas on his tail dizzy. Sometimes there are ladybugs in Katie’s backyard. Other times there are butterflies in Katie’s backyard.
Reasoning about Complex Causal Structures in Pretense
Bark
Wag
Ladybugs
Butterflies
Run
Wrestle
Birds
Fleas
Scared
Happy
Reasoning about Complex Causal Structures in Pretense:
Backtracking vs Surgery
Preliminary Results
Counterfactual Pretense0
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Proportion "Forward" Answers Consistent with Story Structure
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Preliminary Results
Counterfactual Pretense0
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Proportion "Backtracking” Answers
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Learning Higher-Order Causal Relations, Walker &
Gopnik 2012
Novel Distractor
Familiar Novel Paired
Test Blocks
Novel Distractor
Familiar Novel Paired
Test Blocks
18-20 months 21-24 months0
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18-20 month olds: p=.72 21-23 month olds: p<.02Sig diff between age groups: p<.05
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Results: Experiment 1Pe
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Novel Distractor
Familiar Novel Paired
Test Blocks
21-24 mos EXP 1 21-24 mos EXP 20
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21-23 month olds in Exp 1: p<.0221-23 month olds in Exp 2: p=.72Sig diff between infants in Exp 1 and Exp 2: p<.05
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Results: Experiment 1 vs. 2
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Summary and Discussion
• Preschool age children can reason about counterfactuals for a novel causal relationship
• Maintain and intervene on a newly learned causal relationship within a pretend scenario
• Flexibly reassign the causal roles of pretend objects