An agent-based model of the emergence and evolution of a language system for boolean coordination

This paper presents an agent-based model of the emergence and evolution of a language system for Boolean coordination. The model assumes the agents have cognitive capacities for invention, adoption, abstraction, repair and adaptation, a common lexicon for basic concepts, and the ability to construct complex concepts using recursive combinations of basic concepts and logical operations such as negation, conjunction or disjunction. It also supposes the agents initially have neither a lexicon for logical operations nor the ability to express logical combinations of basic concepts through language. The results of the experiments we have performed show that a language system for Boolean coordination emerges as a result of a process of self-organisation of the agents' linguistic interactions when these agents adapt their preferences for vocabulary, syntactic categories and word order to those they observe are used more often by other agents. Such a language system allows the unambiguous communication of higher-order logic terms representing logical combinations of basic properties with non-trivial recursive structure, and it can be reliably transmitted across generations according to the results of our experiments. Furthermore, the conceptual and linguistic systems, and simplification and repair operations of the agent-based model proposed are more general than those defined in previous works, because they not only allow the simulation of the emergence and evolution of a language system for the Boolean coordination of basic properties, but also for the Boolean coordination of higher-order logic terms of any Boolean type which can represent the meaning of nouns, sentences, verbs, adjectives, adverbs, prepositions, prepositional phrases and subexpressions not traditionally analysed as forming constituents, using linguistic devices such as syntactic categories, word order and function words.Peer ReviewedPostprint (author's final draft

A multi-agent experiment on the acquisition of a language system of logical constructions

This paper analyses an experiment which studies the acquisition of the linguistic competence required to communicate logical combinations of categories from the wisdom of the crowds perspective. The acquisition of such competence encompasses both the construction of a set of logical categories by each individual agent and of a shared language by the population. The processes of conceptualisation and language acquisition in each individual agent are based on general purpose cognitive capacities such as discrimination, invention, adoption and induction. The construction of a shared language by the population is achieved using a particular type of linguistic interaction, known as the evaluation game, which gives rise to a shared language system of logical constructions as a result of a process of self-organisation of the individual agents’ interactions, when these agents adapt their languages to the expressions they observe are used more often by other agents.Peer ReviewedPostprint (author’s final draft

An agent-based model studying the acquisition of a language system of logical constructions

This paper presents an agent-based model that studies the emergence and evolution of a language system of logical constructions, i.e. a vocabulary and a set of grammatical constructions that allows the expression of logical combinations of categories. The model assumes the agents have a common vocabulary for basic categories, the ability to construct logical combinations of categories using Boolean functions, and some general purpose cognitive capacities for invention, adoption, induction and adaptation. But it does not assume the agents have a vocabulary for Boolean functions nor grammatical constructions for expressing such logical combinations of categories through language. The results of the experiments we have performed show that a language system of logical constructions emerges as a result of a process of selforganisation of the individual agents’ interactions when these agents adapt their preferences for vocabulary and grammatical constructions to those they observe are used more often by the rest of the population, and that such a language system is transmitted from one generation to the next.Peer ReviewedPostprint (published version

Horn query learning with multiple refinement

In this paper we try to understand the heuristics that underlie the decisions made by the Horn query learning algorithm proposed in [1]. We take advantage of our explicit representation of such heuristics in order to present an alternative termination proof for the algorithm, as well as to justify its decisions by showing that they always guarantee that the negative examples in the sequence maintained by the algorithm violate different clauses in the target formula. Finally, we propose a new algorithm that allows multiple refinement when we can prove that such a refinement does not affect the independence of the negative examples in the sequence maintained by the algorithm.Postprint (published version

Experiments on the acquisition of the semantics and grammatical constructions required for communicating propositional logic sentences

We describe some experiments which simulate a grounded approach to language acquisition in which a population of autonomous agents without prior linguistic knowledge tries to construct at the same time a conceptualisation of its environment and a shared language. The conceptualisation and language acquisition processes in each individual agent are based on general purpose cognitive capacities, such as categorisation, discrimination, evaluation and induction. The emergence of a shared language in the population results from a process of selforganisation of a particular type of linguistic interaction which takes place among the agents in the population. The experiments, which extend previous work by addressing the problem of the acquisition of both the semantics and the syntax of propositional logic, show that at the end of the simulation runs the agents build different conceptualisations and different grammars. However, these conceptualisations and grammars are compatible enough to guarantee the unambiguous communication of propositional logic sentences. Furthermore the categorisers of the perceptually grounded and logical categories built during the conceptualisation and language acquisition processes can be used for some forms of common sense reasoning, such as determining whether a sentence is a tautology, a contradiction, a common sense axiom or a merely satisfiable formula.Peer Reviewe

Horn query learning with multiple refinement

In this paper we try to understand the heuristics that underlie the decisions made by the Horn query learning algorithm proposed in [1]. We take advantage of our explicit representation of such heuristics in order to present an alternative termination proof for the algorithm, as well as to justify its decisions by showing that they always guarantee that the negative examples in the sequence maintained by the algorithm violate different clauses in the target formula. Finally, we propose a new algorithm that allows multiple refinement when we can prove that such a refinement does not affect the independence of the negative examples in the sequence maintained by the algorithm

Propositional logic syntax acquisition using induction and self-organisation

This paper addresses the problem of the acquisition of the syntax of propositional logic. An approach based on general purpose cognitive capacities such as invention, adoption, parsing, generation and induction is proposed. Self-organisation principles are used to show how a shared set of preferred lexical entries and grammatical constructions, i.e., a language, can emerge in a population of autonomous agents which do not have any initial linguistic knowledge. Experiments in which a population of autonomous agents constructs a grammar that allows communicating the formulas of a propositional logic language are presented. These experiments extend previous work by considering a larger population and a much larger search space of grammar rules. In particular the agents are allowed to order the expressions associated with the constituents of a logical formula in arbitrary order. Previous work assumed that the expressions associated with the connectives should be placed in the first position of the sentence.Peer Reviewe

The Acquisition of Linguistic Competence for Communicating Propositional Logic Sentences

Abstract. We describe some experiments which show how a language expressive enough to allow the communication of meanings of the same complexity as propositional logic formulas can emerge in a population of autonomous agents which have no prior linguistic knowledge. We take an approach based on general purpose cognitive capacities, such as invention, adoption and induction, and on self-organisation principles applied to a particular type of linguistic interaction known as a language game. These experiments extend previous work by considering a larger population and a much larger search space of grammar rules. In particular the agents are allowed to order the expressions associated with the constituents of a logical formula in arbitrary order in the sentence. Previous work assumed that the expressions associated with the connectives should be always placed in the first position of the sentence. Another difference is that communication is considered successful in a language game if the meaning interpreted by the hearer is logically equivalent to the meaning the speaker had in mind. In previous experiments the meanings of speaker and hearer were required to be syntactically equal. This allows us to observe how a less strict grammar in terms of word order emerges through the self-organisation process, which minimizes the learning effort of the agents by imposing only those order relations among the components of a sentence that are necessary for language understanding.

An agent-based model of the emergence and evolution of a language system for boolean coordination

This paper presents an agent-based model for studying the emergence and evolution of a language system for Boolean coordination. The model has been implemented and tested by conducting a series of experiments that show that a language system for Boolean coordination emerges as a result of a process of self-organisation of the agents’ linguistic interactions when these agents adapt their preferences for vocabulary, syntactic categories and word order to those they observe are used more often by other agents, and that such a language system is reliably transmitted across generations.Peer Reviewe