Transcript Color Term Typology and Evolution

A Computational Evolutionary Approach to Colour Term Typology
Mike Dowman, Ph.D. Student, School of Information Technologies,
Smart Internet Technology Research Group
Networks and Systems Research Laboratory
Supervised by Judy Kay
Introduction
Explaining Language Typology
Colour Terms vary between languages.
What causes this kind of typological pattern?
Some languages have only 2 basic colour terms – others 11.
Individual psychology?
But the variation is far from random – so what causes these patterns?
Properties of the mind/brain constrain the range of possible human languages.
Berlin and Kay (1969) – languages evolve from simple to complex, and gradually add colour terms over
time.
The best examples of each colour term fall into clusters, both for different speakers of the same
language, and for speakers of different languages.
The World Colour Survey looked at 110 languages – and found that most languages lie somewhere
along the evolutionary trajectory shown below (Kay and Maffi, 1999). The top of the hierarchy represents
a language with only two color terms such as Dani. From this starting point, colour term systems can
evolve until each unique hue is represented by a separate colour term.
Or an interaction of psychological and social processes?
Purple, pink and brown are less predictable. Purple usually but not always emerges before orange.
We never see Turquoise or Lime basic terms.
0.4
0.2
0
Simulated Languages Show the Same
Patterns seen in Real Languages
Most of the colour terms which emerge in the simulations are of the same type as those in Kay and Maffi’s
(1999) evolutionary trajectory.
Individual's
Knowledge
of Language
Primary
Linguistic
Data
The correlation between the results of the World Colour Survey and the evolutionary model is 0.959
(Pearson’s product moment coefficient, P≪0.01).
The emergent colour term systems as a whole tend to be of the same types as those found in the World
Colour Survey.
This research is sponsored by the University of
Sydney and the Australian Government through
IPA and IPRS scholarships.
WCS
Model
10
G-B-R
Y-G-B
B-R
0
R-Y-G
5
G-B
Kay, P. & Maffi, L. (1999). Colour Appearance and the Emergence and Evolution of Basic Colour
Lexicons. American Anthropologist, Volume 101, pages 743-760.
15
R-Y
Hurford, J. R. (1987). Language and Number The Emergence of a Cognitive System. New York,
NY: Basil Blackwell.
20
Y-G
Chomsky, N. (1972). Language and Mind. New York, NY: Harcourt Brace Jovanovich Inc.
25
Blue
Berlin, B. & Kay, P. (1969). Basic Colour Terms. Berkeley, CA: University of California Press.
30
Green
Arena of
Language
Use
Red
white + red + yellow-green +
blue + black
0.6
Hue (red at left to purple at right) + mark unique hues
Language
Acquisition
Device
References
white + red +
yellow-green-blue + black
1
0.8
On Example of an Emergent Colour Term System
Hurford’s Diachronic Spiral (Hurford, 1987)
white + red + yellow +
green + black-blue
Conversations consisting only of naming colours were simulated over twenty generations of speakers,
in 425 separate simulations.
Colour terms systems may have developed as the result of a process of cultural evolution.
white + red + yellow +
black + green + blue
white + red + yellow +
black-green-blue
The learning mechanism was a form of Bayesian inference, and the red, yellow, green and blue unique
hues were made especially salient.
Yellow
white + red + yellow +
black + green-blue
Individual's
Knowledge of
Language
Chomsky’s Language Acquisition Device
(Chomsky, 1972)
white + red-yellow +
black-green-blue
white + red-yellow +
black + green-blue
They could learn colour word denotations by observing other artificial people talking.
Percent of terms of this type
white-red-yellow +
black-green-blue
Language
Acquisition
Device
Ten artificial people were created.
Degreeo of
m em bership in color
category
Cross-Linguistic Evidence
Primary
Linguistic Data
An Expression-Induction Model
Type of colour term
Frequency of Types of Colour Term in the
Simulations and in the World Colour Survey