The primary function of language is communication. We use the tools of situation theory and game theory to develop a definition and model of communication between rational agents using a shared situated language. ;A central thesis of this dissertation is that the key feature of situated communication that enables agents to derive content from meaning is a special type of logical inference called a strategic inference. ;The model we develop, called the Strategic Discourse Model, looks at a single strategic inference. (...) An essential element of a strategic inference is that the content depends on the sentence uttered and on the embedding circumstances. This includes the private and public information and beliefs of the agents, their goals and intentions, and crucially, the other sentences the speaker might have uttered but chose not to. A complete model of communication involves a system of simultaneous strategic inferences. ;When the strategic interaction between two agents is common knowledge between them, that is, when it is a game, the information transfer is a communication. The content communicated is given by the solution to the game. This analysis formalizes Grice's ideas on nonnatural meaning within a situation-theoretic framework. A consequence of our situated analysis is that agents do not need to have the complex and infinite set of nested intentions postulated by the Gricean approach. A simple intention to communicate is all that is required, the ambient game doing the rest of the work. ;This model has many applications. Problems like resolving ambiguity, determining reference, inferring implicatures and indirect speech acts fall within its scope. As one application, we outline a new theory of names and definite descriptions. This account builds upon Russell and Strawson, and Barwise and Perry. The basic idea is that names and descriptions can both be used in various ways circumscribed by an ontological and a communicative constraint. This offers a new solution to the puzzle of informative identity statements and clarifies the referential-attributive distinction. It suggests an approach to the concept of representation. ;An underlying theme is to synthesize situation theory and game theory. (shrink)

An important finding of the game theoretic research on signaling games is the insight that under many circumstances, a signal obtains credibility by incurring costs to the sender. Therefore it seems questionable whether or not cheap talk—signals that are not payoff relevant—can serve to transmit information among rational agents. This issue is non-trivial in strategic interactions where the preferences of the players are not aligned. Researchers like Crawford & Sobel, Rabin, and Farrell demonstrated, however, that even in the case of (...) partially divergent interests, cheap talk may be informative. They assume that signals have an exogenously given meaning that is common knowledge between the players, and they explore the conditions under which such a signal is credible. This discussion has obvious relevance to the program of Gricean pragmatics in linguistics. According to Grice’s "Cooperative Principle”, this research tradition only considers scenarios where the interests of the players are aligned. Nevertheless, the assumption of differential signaling costs introduces an element of non-aligned interests. The present paper proposes a framework that combines these two research strands. Using an inference protocol of iterated best response, it gives a recipe for how the interlocutors derive rationalizable strategies from exogeneously given "literal” meanings of signals. No special assumptions about the alignment of interests or signaling costs are made. After introducing the formal model, the paper sketches several applications of this model to problems in linguistic pragmatics, like scalar implicatures, the division of pragmatic labor, and the interpretation of measure terms. (shrink)

Is language understanding a special case of social cognition? To help evaluate this view, we can formalize it as the rational speech-act theory: Listeners assume that speakers choose their utterances approximately optimally, and listeners interpret an utterance by using Bayesian inference to “invert” this model of the speaker. We apply this framework to model scalar implicature (“some” implies “not all,” and “N” implies “not more than N”). This model predicts an interaction between the speaker's knowledge state and the listener's interpretation. (...) We test these predictions in two experiments and find good fit between model predictions and human judgments. (shrink)

To determine what the speaker in a cooperative dialog meant with his assertion, on top of what he explicitly said, it is crucial that we assume that the assertion he gave was optimal. In determining optimal assertions we assume that dialogs are embedded in decision problems (van Rooij 2003) and use backwards induction for calculating them (Benz 2006). In this paper, we show that in terms of our framework we can account for several types of implicatures in a uniform way, (...) suggesting that there is no need for an independent linguistic theory of generalized implicatures. In the final section, we show how we can embed our theory in the framework of signaling games, and how it relates with other game theoretic analyses of implicatures. (shrink)

Communication and content presents a comprehensive and foundational account of meaning based on new versions of situation theory and game theory. The literal and implied meanings of an utterance are derived from first principles assuming little more than the partial rationality of interacting agents. New analyses of a number of diverse phenomena – a wide notion of ambiguity and content encompassing phonetics, syntax, semantics, pragmatics, and beyond, vagueness, convention and conventional meaning, indeterminacy, universality, the role of truth in communication, semantic (...) change, translation, Frege’s puzzle of informative identities – are developed. Communication, speaker meaning, and reference are defined. Frege’s context and compositional principles are generalized and reconciled in a fixed-point principle, and a detailed critique of Grice, several aspects of Lewis, and some aspects of the Romantic conception of meaning are offered. Connections with other branches of linguistics, especially psycholinguistics, sociolinguistics, historical linguistics, and natural language processing, are explored. -/- The book will be of interest to scholars in philosophy, linguistics, artificial intelligence, and cognitive science. It should also interest readers in related fields like literary and cultural theory and the social sciences. (shrink)

According to standard linguistic theory, the meaning of an utterance is the product of conventional semantic meaning and general pragmatic rules on language use. We investigate how such a division of labor between semantics and pragmatics could evolve under general processes of selection and learning. We present a game‐theoretic model of the competition between types of language users, each endowed with certain lexical representations and a particular pragmatic disposition to act on them. Our model traces two evolutionary forces and their (...) interaction: (i) pressure toward communicative efficiency and (ii) transmission perturbations during the acquisition of linguistic knowledge. We illustrate the model based on a case study on scalar implicatures, which suggests that the relationship between underspecified semantics and pragmatic inference is one of coevolution. (shrink)

When we speak, we mean more than we say. In this book Stephen C. Levinson explains some general processes that underlie presumptions in communication.

In this paper an approach to the exhaustive interpretation of answers is developed. It builds on a proposal brought forward by Groenendijk and Stokhof (1984). We will use the close connection between their approach and McCarthy's (1980, 1986) predicate circumscription and describe exhaustive interpretation as an instance of interpretation in minimal models, well-known from work on counterfactuals (see for instance Lewis (1973)). It is shown that by combining this approach with independent developments in semantics/pragmatics one can overcome certain limitations of (...) Groenenedijk and Stokhof's (1984) proposal. In the last part of the paper we will provide a Gricean motivation for exhaustive interpretation building on work of Schulz (to appear) and van Rooij and Schulz (2004). (shrink)

A systematic, rigorous, comprehensive, and unified overview of evolutionary game theory.

In a recent contribution in this journal, Sascia Pavan proposed a new game theoretic approach to explain generalized conversational implicatures in terms of general principles of rational behavior. His approach is based on refining Nash equilibrium by a procedure called iterated admissibility. I would like to strengthen Pavan’s case by sketching an epistemic interpretation of iterated admissibility, so as to further our understanding of why iterated admissibility might be a good approximation of pragmatic reasoning. But the explicit epistemic view taken (...) here also points to some shortcomings of his approach in comparison to rivaling accounts. (shrink)

This paper combines a survey of existing literature in game-theoretic pragmatics with new models that fill some voids in that literature. We start with an overview of signaling games with a conflict of interest between sender and receiver, and show that the literature on such games can be classified into models with direct, costly, noisy and imprecise signals. We then argue that this same subdivision can be used to classify signaling games with common interests, where we fill some voids in (...) the literature. For each of the signaling games treated, we show how equilibrium-refinement arguments and evolutionary arguments can be interpreted in the light of pragmatic inference. (shrink)

Language use and interpretation is heavily contingent on context. But human interlocutors need not always agree what the actual context is. In game theoretic approaches to language use and interpretation, interlocutors’ beliefs about the context are the players’ beliefs about the game that they are playing. Together this entails that we need to consider cases in which interlocutors have different subjective conceptualizations of the game they are in. This paper therefore extends iterated best response reasoning, as an established model for (...) pragmatic reasoning, to games with unawareness. This extension not only leads to more plausible context models for many communicative situations, but also to improved predictions for otherwise problematic cases and an extension of the scope of pragmatic phenomena that can be captured by game theoretic analysis. (shrink)

Communication involves a great deal of uncertainty. Prima facie, it is therefore surprising that biological communication systems—from cellular to human—exhibit a high degree of ambiguity and often leave its resolution to contextual cues. This puzzle deepens once we consider that contextual information may diverge between individuals. In the following we lay out a model of ambiguous communication in iterated interactions between subjectively rational agents lacking a common contextual prior. We argue ambiguity’s justification to lie in endowing interlocutors with means to (...) flexibly adapt language use to each other and the context of their interaction to serve their communicative preferences. Linguistic alignment is shown to play an important role in this process; it foments convergence of contextual expectations and thereby leads to agreeing use and interpretation of ambiguous messages. We conclude that ambiguity is ecologically rational when interlocutors’ contextual expectations are generally in line or they interact multiple times in an informative context, enabling for the alignment of their expectations. In light of these results meaning multiplicity can be understood as an opportunistic outcome enabled and shaped by linguistic adaptation and contextual information. (shrink)

In Language and Equilibrium, Prashant Parikh offers a new account of meaning for natural language. He argues that equilibrium, or balance among multiple interacting forces, is a key attribute of language and meaning and shows how to derive the meaning of an utterance from first principles by modeling it as a system of interdependent games.His account results in a novel view of semantics and pragmatics and describes how both may be integrated with syntax. It considers many aspects of meaning--including literal (...) meaning and implicature--and advances a detailed theory of definite descriptions as an application of the framework.Language and Equilibrium is intended for a wide readership in the cognitive sciences, including philosophers, linguists, and artificial intelligence researchers as well as neuroscientists, psychologists, and economists interested in language and communication. (shrink)

This paper provides a game-theoretic analysis of contrastive focus, extending insights from recent work on the role of noisy communication in prosodic accent placement to account for focus within sentences, sub-sentential phrases and words. The shared insight behind these models is that languages with prosodic focus marking assign prosodic prominence only within elements which constitute material critical for successful interpretation. We first take care to distinguish the information-structural notion of focus from an ontologically distinct notion of givenness marking, and then (...) outline the core properties of focus. We then introduce a signaling game between a speaker and hearer in which the goal is to transmit semantic content with the smallest signal possible. We apply the Iterated Best Response method of Franke to find equilibrium strategies in this game, where a unique equilibrium strategy in this case picks out the “critical information” of an utterance, which by hypothesis constitutes its focus. We show that iterating this game at different syntactic levels of a sentence makes correct predictions about the role of contrast in determining stress within words and phrases, and can be extended to account for association and second occurrence focus effects. (shrink)

We reopen the investigation into the formal and conceptual relationship between bidirectional optimality theory (Blutner in J Semant 15(2):115–162, 1998 , J Semant 17(3):189–216, 2000 ) and game theory. Unlike a likeminded previous endeavor by Dekker and van Rooij (J Semant 17:217–242, 2000 ), we consider signaling games not strategic games, and seek to ground bidirectional optimization once in a model of rational step-by-step reasoning and once in a model of reinforcement learning. We give sufficient conditions for equivalence of bidirectional (...) optimality and the former, and show based on numerical simulations that bidirectional optimization may be thought of as a process of reinforcement learning with lateral inhibition. (shrink)

In this paper, we discuss some formal properties of the model ofbidirectional Optimality Theory that was developed inBlutner (2000). We investigate the conditions under whichbidirectional optimization is a well-defined notion, and we give aconceptually simpler reformulation of Blutner's definition. In thesecond part of the paper, we show that bidirectional optimization can bemodeled by means of finite state techniques. There we rely heavily onthe related work of Frank and Satta (1998) about unidirectionaloptimization.