*Complete with the obligatory unnecessary primate pictures

*The Emergence of Simple Languages in an Experimental Communication Game- Reinhard Selten and Massimo Warglien (2007)

(Plus – Iteration Experiments)

The Paper

This bears some similarities to the Galantucci and Garrod et al papers but is more concerned with the emergence of linguistic systems than the emergence of symbols

Uses a economic game to apply pressures to the emergence of a communication system Presents language as the product of the competing forces of

communicative needs and personal expenditure The experiment explores the relationship between communication

costs/benefits and the emergence of language Participants are encouraged to look at communication as an economic

game Design aims to filter out other socio-linguistic reasons for

communication to focus on how economy and self interest act as a selective pressure on emergent codes and grammars

The Experiment

Subjects are on separate computer terminals The rules of the game are explained to them in advance (in most cases) The subjects are playing for money There is no communication except the limited communication allowed

by the experiment Communication is limited and the goal of the game is to

harmonise the two separate individual codes into one shared code

Co-operation to produce the code is the only way of making individual money No specific target or goal but personal accumulation No overt way to lose, but you can fail to accumulate Strategies are required to make the communicative limitations work

•In each round..

Player 1 Player 2

Subjects are presented with a

list of geometrical

shapes with a range of features

Player 1 Player 2

Subjects then assign each

symbol a message

constructed from a string of

permissible letters

RS ZSR RZR SZS R

RR SS RZS SRS ZS

SR ZSR SR Z S

RSR Z RRS SS R

R SS RZZ SS ZS

SRZ ZSR RS ZR SR

Player 1 Player 2

One subject and one figure are randomly chosen

Player 1 Player 2

RS

The message specified by the sender’s code is then transmitted to the other player

Player 1 Player 2

RS RS

Currency +10 Currency +10

Payoffs: Players receive a payoff of 10 units of currency each if the communication is ‘successful’ i.e. if the two codes match

Player 1 Player 2

RS RZ

Zero Zero

No payoff is received if the codes do not match

X

Player 1

•In addition to the rewards for a successful communication, the sender of the message bears a cost for the message

•The cost is two units per letter used, so longer messages carry a greater cost to the sender

RS

Currency -4

R=2, S=2, Cost = 4

Player 1 Player 2

After each period both players find out whether the communication was successful

RS RS

Success!

Player 1 Player 2

If the communication was not successful…

RS

Subjects receive feedback on the hidden aspects of the gameSender – the receiver's codeReceiver – the symbol that was chosen

Player 1 Player 2

RS ZSR RZR SZS R

RR SS RZS SRS ZS

SR ZSR SR Z S

RSR Z RRS SS R

R SS RZ SS ZS

SRZ ZSR RS ZR SR

Subjects then have a chance to

change their codes before the

next period

Player 1 Player 2

RR ZR RZR SZS R

RR SS RZ RS ZS

S ZSR SR Z S

RSR Z RS SS R

RZZ SS RZZ SS ZRS

SZ ZR RZ SR SSS

Versions of the Experiment

There were four versions of the experiment:

Version I Limited letter set 1 session

Version II Medium letter set 1 session

Version III Medium letter set 2 sessions

Version IV Medium letter set +

Larger letter set (second session)

2 sessions, second session had different symbol set

All of the letter and symbol sets became progressively larger over the course of the game

Results: Impact of the size of the repertoire

• In Experiment I they experienced an unexpectedly low amount of common code correlations

• This was significantly reduced in the subsequent experiments with larger sets of letters

• They concluded that a large repertoire of possible signs/meanings was necessary for the emergence of a common code

The Influence of Differentiation and Efficiency on Payoffs

• Simpler codes result in larger payoffs• A high degree of asymmetry causes low changes and

high agreement– Low changes and high agreement lead to high payoffs– Solving the task requires teaching/leading by one player

• What are the implications if asymmetry is an important factor in the emergence of code systems?

Grammatical Effects

The experiment looked at the effect of grammaticality effects on the efficiency of the game

Levels of grammaticality: Ungrammatical: No grammatical structure, 1-to-1 mapping of

symbols to individual letter sequences Noncompositional Grammar: Features are expressed by

individual graphemes, association or order, but not in a compositional framework.

Compositional Grammar: A grammar formed by the mapping of features to individual graphemes and then arranging them in a fixed order

Graphemes ‘R’ and ‘S’ represent Circle and Triangle respectively

The number of letters indicates the presence or lack of inserts

The type of insert is determined by the presence or lack of matching final letters

A Noncompositional Grammar

Graphemes ‘R’ and ‘S’ represent Circle and Triangle respectively

The type of insert is determined by the final letters

A Compositional Grammar

Communication and Compositionality

• Under consistent environments, most grammars did not become compositional

• More compositional grammars were formed in the second session Experiment IV than Experiment III

– Novelty forced compositional grammars to emerge

• Compositional grammars were more persistent– 100% persistent, as opposed to uncompositional grammars which were 0%

persistent• In Experiment IV few compositional grammars were formed, but those that

did were highly successful– With grammar, average payout 635 Talers– Without grammar, average payout 211 Talers

Summary of Key Results

1. The size of the linguistic repertoire seems important for linguistic coordination

2. In a repetitive environment, cost efficiency and role asymmetry enhance communicative success

3. In stable environments noncompositional grammars are simpler and easier, but in a changing environment compositional grammars have the advantage

4. Compositional grammars appear to not be an automatic communicative strategy. In stable environments there is little pressure to form a compositional grammar

Issues with the Experiment

Lots of overlapping versions of the experiment and some unclear design

Measurement of ‘common code’ Weights of the experiment and the methods of reward Defining compositional and non-compositional

grammars It does away with sociolinguistic reasons for

communication The expansion of the symbolic repertoire is unnatural

Experimental Tests of Communication: Iteration meets Game Playing

We are seeing a new paradigm in which the experimental techniques of psychology, iteration and evolutionary game theory are used to explore the emergence of communication systems

How does this paradigm build on existing research methods?

• Unconscious and conscious formation of systems

• The line between passive and active cultural transmission

• Use of evolutionary pressures

• Linear and horizontal models

What are the natural limits of this paradigm? How does it relate to evidence from computer

modelling?

Conducting Research in Light of these Experiments

Ecological validity – does it matter that these experiments might not replicate an authentic evolutionary environment?

Exploring alternative explanations for results We need to account for the psychological complexity of

communicative interactions

Integration of the horizontal and vertical dimensions of iteration Experimenting with genuine ontogeny is difficult Defining ‘generations’ in an experiment

Scale and participation

Potential New Designs

Amalgamations of some of the individual designs

Some iteration/communication experiments are essentially a combined sequence of input-output experiments Using information

technology to link individual results

Community based experiments

Combine code experiments and symbol experiments