Simplicity and informativeness in the cultural evolution of language - PowerPoint PPT Presentation

Simplicity and informativeness in the cultural evolution of language Jon W. Carr, Kenny Smith, Jennifer Culbertson, Simon Kirby Centre for Language Evolution School of Philosophy, Psychology and Language Sciences University of Edinburgh

Pressures shaping language Language

Pressures shaping language e l p m i S Language Learning

Pressures shaping language e l p m i S Language Learning Communication e v i t a m r o f n I

Kinship terms are simple and informative English Northern Paiute 4 3 ⬅ Informative 2 1 0 0 50 100 ⬅ Simple Kemp & Regier (2012)

Kinship terms are simple and informative English Northern Paiute 4 3 ⬅ Informative 2 1 0 0 50 100 ⬅ Simple Kemp & Regier (2012)

Lab experiments Learning-only

Lab experiments Learning-only Communication-only

Lab experiments Learning-only Learning + Communication

Learning and communication pressures 4 3 2 ⬅ Informative 1 0 0 50 100 ⬅ Simple

Learning and communication pressures 4 3 2 learning ⬅ Informative 1 0 0 50 100 ⬅ Simple

Learning and communication pressures 4 3 2 learning ⬅ Informative 1 communication 0 0 50 100 ⬅ Simple

Learning and communication pressures 4 3 2 learning ⬅ Informative 1 l c e o a m r n m i n communication u g n + i c a t i o n 0 0 50 100 ⬅ Simple

Learning and communication pressures 4 tuge tuge tuge tuge tuge tuge tuge tuge tuge tupim tupim tupim 3 pihino nemone piga kawake miniku miniku miniku tupin tupin tupin poi poi poi poi poi poi poi poi poi kapa gakho wuwele nepi Kirby, Cornish, & Smith (2008) 2 learning newhomo kamone gaku hokako ⬅ Informative Kirby, Tamariz, Cornish, & Smith (2015) 1 l c e o a m r n m egewawu egewawa egewuwu ege i n communication u g n + i c a t i o n mega megawawa megawuwu wulagi 0 0 50 100 gamenewawu gamenewawa gamenewuwu gamene ⬅ Simple Kirby, Tamariz, Cornish, & Smith (2015)

Iterated learning can give rise to informative languages Carstensen, Xu, Smith, Regier (2015)

Iterated learning can give rise to informative languages Carstensen, Xu, Smith, Regier (2015)

Experiment 1

Training phase

Test phase

Stimuli Angle Size

Stimuli Angle Size

Stimuli Angle Size

Stimuli Angle Size

Which is easiest to learn? Angle-only Size-only Angle & Size

Results Angle-only

Results Size-only

Results Angle & Size

Result: Learnability advantage for the less informative systems

Experiment 2

Iterated learning

Results 1 category 2 categories 3 categories 4 categories

Measuring simplicity

Measuring simplicity 1×1 3×3 1×1 3×4 4×8 1×1 1×8 1×2 2×6 4×8 1×4 1×2 2×3 1×6

Simplicity

Simplicity Informativeness

Simplicity Informativeness

Two ways of achieving simplicity Category reorganization

Two ways of achieving simplicity Category reorganization Loss of expressivity

Two ways of achieving simplicity Category reorganization increases informativeness Loss of expressivity decreases informativeness

Conclusions The pressure from learning has two consequences: Loss of Expressivity: Loss of words/categories to aid learning Simpler categories: Reorganization of the space to aid learning Iterated learning favours semantic category systems that are simple Some informativeness comes along for the ride, potentially obscuring the causal mechanism

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