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Centre for Language Evolution School of Philosophy, Psychology and Language Sciences University of Edinburgh
Simplicity and informativeness in the cultural evolution of language
Jon W. Carr, Kenny Smith, Jennifer Culbertson, Simon Kirby
Language
Pressures shaping language
LanguageLearning
Pressures shaping language
Simple
Language CommunicationLearning
Pressures shaping language
Simple
Informative
English Northern Paiute
0 50 1000
1
2
3
4
⬅ In
form
ativ
e
⬅ Simple
Kinship terms are simple and informative
Kemp & Regier (2012)
English Northern Paiute
0 50 1000
1
2
3
4
⬅ In
form
ativ
e
⬅ Simple
Kinship terms are simple and informative
Kemp & Regier (2012)
Lab experiments
Learning-only
Lab experiments
Learning-only
Communication-only
Lab experiments
Learning-only
Learning + Communication
English Northern Paiute
0 50 1000
1
2
3
4
⬅ In
form
ativ
e
⬅ Simple
Kinship terms are simple and informative
Kemp & Regier (2012)
0 50 1000
1
2
3
4
Learning and communication pressures
⬅ In
form
ativ
e
⬅ Simple
0 50 1000
1
2
3
4
Learning and communication pressures
⬅ In
form
ativ
e
⬅ Simple
Learning-only
0 50 1000
1
2
3
4
Learning and communication pressures
⬅ In
form
ativ
e
⬅ Simple
Communication-only
Learning-only
0 50 1000
1
2
3
4
Learning and communication pressures
⬅ In
form
ativ
e
⬅ Simple
Learning + communication Communication-only
Learning-only
0 50 1000
1
2
3
4
Learning and communication pressures
⬅ In
form
ativ
e
⬅ Simple
Learning + communication Communication-only
Learning-only
newhomo kamone gaku hokako
kapa gakho wuwele nepi
pihino nemone piga kawake
gamenewawu gamenewawa gamenewuwu gamene
mega megawawa megawuwu wulagi
egewawu egewawa egewuwu ege
tuge tuge tugetuge tuge tugetuge tuge tuge
tupim tupim tupimminiku miniku minikutupin tupin tupin
poi poi poipoi poi poipoi poi poi
Kirby, Cornish, & Smith (2008)
Kirby, Tamariz, Cornish, & Smith (2015)
Kirby, Tamariz, Cornish, & Smith (2015)
Iterated learning gives rise to informative spatial terms
Carstensen, Xu, Smith, Regier (2015)
Iterated learning gives rise to informative spatial terms
Carstensen, Xu, Smith, Regier (2015)
Experiment 1
Stimuli
Ang
le
Size
Stimuli
Ang
le
Size
Stimuli
Ang
le
Size
Stimuli
Ang
le
Size
Conditions
Angle-only Size-only Angle & Size
Easy to learn but low informativeness Informative but hard to learn
Training phase
Test phase
Results
Angle-only
Results
Size-only
Results
Angle & Size
Result: Learnability advantage for the less informative systems
Experiment 2
Iterated learning
1 category 2 categories 4 categories3 categories
Results
Simplicity
Simplicity Informativeness
Simplicity Informativeness
Simplicity Informativeness
Measuring simplicity
Measuring simplicity
Measuring simplicity
4×8
4×8
Measuring simplicity
3×3 1×1
1×8
1×2
1×4
1×6
1×1
3×4
1×1
2×6
2×31×2
4×8
4×8
What makes language informative?
Expressivity A system of many categories is more informative than a system of few categories
Convexity A system of convex categories is more informative than a system of nonconvex categories
Learning Pressure for simplicity
Communication Pressure for informativeness
>
>
Property Example
What makes language informative?
Expressivity A system of many categories is more informative than a system of few categories
Convexity A system of convex categories is more informative than a system of nonconvex categories
Learning Pressure for simplicity
Communication Pressure for informativeness
>
>
Property Example
What makes language informative?
Expressivity A system of many categories is more informative than a system of few categories
Convexity A system of convex categories is more informative than a system of nonconvex categories
Learning Pressure for simplicity
Communication Pressure for informativeness
>
>
Property Example
What makes language informative?
Expressivity A system of many categories is more informative than a system of few categories
Convexity A system of convex categories is more informative than a system of nonconvex categories
Learning Pressure for simplicity
Communication Pressure for informativeness
>
>
Property Example
What makes language informative?
Expressivity A system of many categories is more informative than a system of few categories
Convexity A system of convex categories is more informative than a system of nonconvex categories
Learning Pressure for simplicity
Communication Pressure for informativeness
>
>
Property Example
What makes language informative?
Expressivity A system of many categories is more informative than a system of few categories
Convexity A system of convex categories is more informative than a system of nonconvex categories
Learning Pressure for simplicity
Communication Pressure for informativeness
>
>
Property Example
What makes language informative?
Expressivity A system of many categories is more informative than a system of few categories
Convexity A system of convex categories is more informative than a system of nonconvex categories
Learning Pressure for simplicity
Communication Pressure for informativeness
Our experiments
>
>
Property Example
What makes language informative?
Expressivity A system of many categories is more informative than a system of few categories
Convexity A system of convex categories is more informative than a system of nonconvex categories
Learning Pressure for simplicity
Communication Pressure for informativeness
Carstensen et al.
>
>
Property Example
Conclusions
The pressure from learning yields simple languages, but this can manifest itself through multiple semantic properties:
Expressivity Loss of words/categories to aid learning
Convexity Reorganization of the meaning space to aid learning
The pressure from communication has the same effect on convexity as learning does, making it difficult to identify the causal mechanism.
In iterated learning, the pressure for simplicity favours semantic category systems that are convex – informativeness comes along for the ride.
Vielen Dank!
