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

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

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

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

N = 24 N = 26

*______

***______

“OR” Test Trial Results:Percentage of Participants who think D and F are

Blickets**

***______

N = 25 N = 28

Children Adults0

“AND” Test Trial Results:Percentage of Participants who think D and F are

Blickets**

N = 25 N = 24

Children Adults0

“BASELINE” Intervention 1 Results:Percentage of Single vs. Multiple Object

Interventions

Children Adults0

SingleMultiple

N = 22 N = 26

“OR” Intervention Results:Percentage of Single vs. Multiple Object

Interventions

Children Adults0

SingleMultiple

N = 25 N = 28

“AND” Intervention Results:Percentage of Single vs. Multiple Object

Interventions

N = 25 N = 24Children Adults

SingleMultiple

**_______________________________________

“BASELINE” Intervention 1 Results:F v. DF v. DEF Interventions

Children Adults0

FDFDEF

N = 22 N = 26

**___________________

***___________________

“OR” Intervention Results:F v. DF v. DEF Interventions

Children Adults0

FDFDEF

N = 25 N = 28

***___________________

“AND” Intervention Results:F v. DF v. DEF Interventions

Children Adults0

FDFDEF

N = 25 N = 24

***_______________________________

*__________________

**________

**_______________

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

Match-to-Sample Trial 1a

Match-to-Sample Trial 1b

Novel Distractor

Familiar Novel Paired

Test Blocks

Match-to-Sample Test Trial 1

Novel Distractor

Test Blocks

Match-to-Sample Test Trial 2

18-20 months 21-24 months0

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

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

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

21-24 mos EXP 1 21-24 mos EXP 20

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” Condition Test Trial

18- to 24-month-olds 25- to 30-month-olds0

Results: RMTSPe

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

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

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

Expt. 2: Mean Correct on Counterfactual and Pretense Questions

Mean C

No Music Partial Correlation Counterfactuals and Pretense accounting for age, conservation, executive function: p < 0.05*, r = 0.38

Zando Non-Zando

Exp 2: Average Score for Pretense Questions

Counterfactuals Incorrect

Counterfactuals Correct

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

Ladybugs

Butterflies

Wrestle

Scared

Reasoning about Complex Causal Structures in Pretense:

Backtracking vs Surgery

Preliminary Results

Proportion "Forward" Answers Consistent with Story Structure

Preliminary Results

Proportion "Backtracking” Answers

Learning Higher-Order Causal Relations, Walker &

Gopnik 2012

Novel Distractor

Test Blocks

Novel Distractor

Test Blocks

18-20 months 21-24 months0

18-20 month olds: p=.72 21-23 month olds: p<.02Sig diff between age groups: p<.05

Results: Experiment 1Pe

Novel Distractor

Test Blocks

21-24 mos EXP 1 21-24 mos EXP 20

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

Results: Experiment 1 vs. 2

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

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