Machine Impostors Can Avoid Human Detection and Interrupt the Formation of Stable Conventions by Imitating Past Interactions: A Minimal Turing Test

Interactions between humans and bots are increasingly common online, prompting some legislators to pass laws that require bots to disclose their identity. The Turing test is a classic thought experiment testing humans' ability to distinguish a bot impostor from a real human from exchanging text messages. In the current study, we propose a minimal Turing test that avoids natural language, thus allowing us to study the foundations of human communication. In particular, we investigate the relative roles of conventions and reciprocal interaction in determining successful communication. Participants in our task could communicate only by moving an abstract shape in a 2D space. We asked participants to categorize their online social interaction as being with a human partner or a bot impostor. The main hypotheses were that access to the interaction history of a pair would make a bot impostor more deceptive and interrupt the formation of novel conventions between the human participants. Copying their previous interactions prevents humans from successfully communicating through repeating what already worked before. By comparing bots that imitate behavior from the same or a different dyad, we find that impostors are harder to detect when they copy the participants' own partners, leading to less conventional interactions. We also show that reciprocity is beneficial for communicative success when the bot impostor prevents conventionality. We conclude that machine impostors can avoid detection and interrupt the formation of stable conventions by imitating past interactions, and that both reciprocity and conventionality are adaptive strategies under the right circumstances. Our results provide new insights into the emergence of communication and suggest that online bots mining personal information, for example, on social media, might become indistinguishable from humans more easily.

Cultural Evolution of Precise and Agreed-Upon Semantic Conventions in a Multiplayer Gaming App

The amount of information conveyed by linguistic conventions depends on their precision, yet the codes that humans and other animals use to communicate are quite ambiguous: they may map several vague meanings to the same symbol. How does semantic precision evolve, and what are the constraints that limit it? We address this question using a multiplayer gaming app, where individuals communicate with one another in a scaled-up referential game. Here, the goal is for a sender to use black and white symbols to communicate colors. We expected that the players' mappings between symbols and colors would grow more specific over time, through a selection process whereby precise mappings are preferentially copied. We found that players become increasingly more precise in their use of symbols over the course of their interactions. This trend did not, however, result from selective copying of precise mappings. We explore the implications of this result for the study of lexical ambiguity, Zipf's Law of Meaning, and disagreements over semantic conventions.

Noise, Economy, and the Emergence of Information Structure in a Laboratory Language

The acceptability of sentences in natural language is constrained not only grammaticality, but also by the relationship between what is being conveyed and such factors as context and the beliefs of interlocutors. In many languages the critical element in a sentence (its focus) must be given grammatical prominence. There are different accounts of the nature of focus marking. Some researchers treat it as the grammatical realization of a potentially arbitrary feature of universal grammar and do not provide an explicit account of its origins; others have argued, however, that focus marking is a (grammaticalized) functional solution to the problem of efficiently transmitting information via a noisy channel. By adding redundancy to highlight critical elements in particular, focus protects key parts of the message from noise. If this information-theoretic account is true, then we should expect focus-like behavior to emerge even in non-linguistic communication systems given sufficient noise and pressures for efficiency. We tested this in an experiment in which participants played a simple communication game in which they had to click cells on a grid to communicate one of two line figures drawn across the grid. We manipulated the noise, available time, and required effort, and measured patterns of redundancy. Because the lines in many cases overlapped, meaning that only some parts of each line could be used to distinguish it from the other, we were able to compare the extent to which effort was expended on adding redundancy to critical (non-overlapping) and non-critical (overlapping) parts of the message. The results supported the information-theoretic account of focus and shed light on the emergence of information structure in language.

Linguistic Convergence to Observed Versus Expected Behavior in an Alien-Language Map Task

Individuals shift their language to converge with interlocutors. Recent work has suggested that convergence can target not only observed but also expected linguistic behavior, cued by social information. However, it remains uncertain how expectations and observed behavior interact, particularly when they contradict each other. We investigated this using a cooperative map task experiment, in which pairs of participants communicated online by typing messages to each other in a miniature "alien" language that exhibited variation between alien species. The overall task comprised three phases, in each of which participants were told that they would be paired with a different partner. One member of the pair was given explicit linguistic expectations in each phase, while the software controlled whether or not observed behavior from their partner would be consistent or inconsistent with these expectations. The other participant was given no such expectations, allowing us to control for the role of expectation. Participants converged to both observed and expected linguistic behavior, and convergence was boosted when observation and expectation were aligned. When expected and observed behavior were misaligned, participants updated their expectations, though convergence levels did not drop. Furthermore, participants generalized what they learned about one partner to apparent novel partners of the same alien species. We also discuss individual variation in convergence patterns and the lack of a relationship between linguistic convergence and success at the map task. Findings are consistent with observations outside the laboratory that language users converge toward expected linguistic behavior. They also have broader implications for understanding linguistic accommodation and the influence of social information on linguistic processing and production.

The emergence of systematicity: How environmental and communicative factors shape a novel communication system

Where does linguistic structure come from? We suggest that systematicity in language evolves adaptively in response to environmental and contextual affordances associated with the practice of communication itself. In two experiments, we used a silent gesture referential game paradigm to investigate environmental and social factors promoting the propagation of systematicity in a novel communication system. We found that structure in the emerging communication systems evolve contingent on structural properties of the environment. More specifically, interlocutors spontaneously relied on structural features of the referent stimuli they communicated about to motivate systematic aspects of the evolving communication system even when idiosyncratic iconic strategies were equally afforded. Furthermore, we found systematicity to be promoted by the nature of the referent environment. When the referent environment was open and unstable, analytic systematic strategies were more likely to emerge compared to stimulus environments with a closed set of referents. Lastly, we found that displacement of communication promoted systematicity. That is, when interlocutors had to communicate about items not immediately present in the moment of communication, they were more likely to evolve systematic solutions, supposedly due to working memory advantages. Together, our findings provide experimental evidence for the idea that linguistic structure evolves adaptively from contextually situated language use.

Universal Principles of Human Communication: Preliminary Evidence From a Cross-cultural Communication Game

The present study points to several potentially universal principles of human communication. Pairs of participants, sampled from culturally and linguistically distinct societies (Western and Japanese, N = 108: 16 Western-Western, 15 Japanese-Japanese and 23 Western-Japanese dyads), played a dyadic communication game in which they tried to communicate a range of experimenter-specified items to a partner by drawing, but without speaking or using letters or numbers. This paradigm forced participants to create a novel communication system. A range of similar communication behaviors were observed among the within-culture groups (Western-Western and Japanese-Japanese) and the across-culture group (Western-Japanese): They (a) used iconic signs to bootstrap successful communication, (b) addressed breakdowns in communication using other-initiated repairs, (c) simplified their communication behavior over repeated social interactions, and (d) aligned their communication behavior over repeated social interactions. While the across-culture Western-Japanese dyads found the task more challenging, and cultural differences in communication behavior were observed, the same basic findings applied across all groups. Our findings, which rely on two distinct cultural and linguistic groups, offer preliminary evidence for several universal principles of human communication.

When Height Carries Weight: Communicating Hidden Object Properties for Joint Action

In the absence of pre-established communicative conventions, people create novel communication systems to successfully coordinate their actions toward a joint goal. In this study, we address two types of such novel communication systems: sensorimotor communication, where the kinematics of instrumental actions are systematically modulated, versus symbolic communication. We ask which of the two systems co-actors preferentially create when aiming to communicate about hidden object properties such as weight. The results of three experiments consistently show that actors who knew the weight of an object transmitted this weight information to their uninformed co-actors by systematically modulating their instrumental actions, grasping objects of particular weights at particular heights. This preference for sensorimotor communication was reduced in a fourth experiment where co-actors could communicate with weight-related symbols. Our findings demonstrate that the use of sensorimotor communication extends beyond the communication of spatial locations to non-spatial, hidden object properties.

Rethinking foundations of language from a multidisciplinary perspective

The issue of language foundations has been of great controversy ever since it was first raised in Lenneberg's (1967) monograph Biological Foundations of Language. Based on a survey of recent findings relevant to the study of language acquisition and evolution, we propose that: (i) the biological predispositions for language are largely domain-general, not necessarily language-specific or human-unique; (ii) the socio-cultural environment of language serves as another important foundation of language, which helps shape language components, induce and drive language shift; and (iii) language must have coevolved with the cognitive mechanisms associated with it through intertwined biological and cultural evolution. In addition to theoretical issues, this paper also evaluates the primary approaches recently joining the endeavor of studying language foundations and evolution, including human experiments and computer simulations. Most of the evidence surveyed in this paper comes from a variety of disciplines, and methodology therein complements each other to form a global picture of language foundations. These reflect the complexity of the issue of language foundations and the necessity of taking a multidisciplinary perspective to address it.

Experimental semiotics: a new approach for studying communication as a form of joint action

In the last few years, researchers have begun to investigate the emergence of novel forms of human communication in the laboratory. I survey this growing line of research, which may be called experimental semiotics, from three distinct angles. First, I situate the new approach in its theoretical and historical context. Second, I review a sample of studies that exemplify experimental semiotics. Third, I present an empirical study that illustrates how the new approach can help us understand the socio-cognitive underpinnings of human communication. The main conclusion of the paper will be that, by reproducing micro samples of historical processes in the laboratory, experimental semiotics offers new powerful tools for investigating human communication as a form of joint action.