Over the past decade and a half, several lines of research have investigated aspects of the smooth signalling redundancy hypothesis. This hypothesis proposes that speakers distribute the information in linguistic utterances as evenly as possible, in order to make the utterance more robust against noise for the hearer. Several studies have shown evidence for this hypothesis in limited linguistic domains, showing that speakers manipulate acoustic and syntactic features to avoid drastic spikes or troughs in information content. In theory, the mechanism behind this is that these spikes would make utterances more vulnerable to noise events, and thus, communicative failure. However, this previous work doesn't consider information density across entire utterances, and only rarely has this mechanism been directly explored. Here, we introduce a new descriptive statistic that quantifies the uniformity of information across an entire utterance, alongside an algorithm that can measure the uniformity of actual utterances against an optimized distribution. Using a simple simulation, we show that utterances optimized for more uniform distributions of information are, in fact, more robust against noise.

A large body of recent work argues that considerations of information density predict various phenomena in linguistic planning and production. However, the usefulness of an information theoretic account for explaining diachronic phenomena has remained under-explored. Here, we test the idea that speakers prefer informationally uniform utterances on diachronic data from historical English and Icelandic. Our results show that: (i) the information density approach allows us to predict that Subject and Object type will affect the frequencies of OV and VO in specific ways, creating a complex Constant Rate Effect, (ii) the bias towards information uniformity explains this CRE and may help to explain others, and (iii) communities of speakers are constant in their average target level of information uniformity over long periods of historical time. This finding is consistent with an understanding of this bias which places it deep in the human language faculty and the human faculty for communication.

We observe that approaches to intersubjectivity, involving mirror neurons and involving emulationand prediction, have eclipsed discussion of those same mechanisms for achieving coordination between the two hemispheres of the human brain. We explore some of the implications of the suggestion that the mutual modelling of the two situated hemispheres (each hemisphere ‘second guessing’ the other) is a productive place to start in understanding the phylogenetic and ontogenetic development of cognition and of intersubjectivity.

Language is one of only a handful of human cultural systems that is both unique to our species, and universal. This chapter will focus on the cultural evolution of language, situating this alongside the phylogenetic and developmental timescales which also feed into the evolution of language. The chapter begins by outlining the relationship between the emergence of human language and the language faculty and the more rapid, ongoing processes of language change, which are often framed as predominantly cultural. In particular, previous work has emphasized how these timescales interact, and how cultural factors in particular shape which aspects of language exhibit broad cross-cultural variation or stability. This is followed by detailed evidence for this relationship from three domains, focusing on the role of cultural evolution in language as observed in natural language (both historical corpora and cross-linguistic data), the cultural evolution of language in agent-based models, and finally, experimental studies of the cultural evolution of language. The chapter concludes that the study of the cultural evolution of language forms an important data-rich model for the study of the evolution of cultural systems more generally, while also providing key insights into the specific dynamics of this uniquely human behaviour.

Language is one of only a handful of human cultural systems that is both unique to our species, and universal. This chapter will focus on the cultural evolution of language, situating this alongside the phylogenetic and developmental timescales which also feed into the evolution of language. The chapter begins by outlining the relationship between the emergence of human language and the language faculty and the more rapid, ongoing processes of language change, which are often framed as predominantly cultural. In particular, previous work has emphasised how these timescales interact, and how cultural factors in particular shape which aspects of language exhibit broad cross-cultural variation or stability. This is followed by detailed evidence for this relationship from three domains, focusing on the role of cultural evolution in language as observed in natural language (both historical corpora and cross linguistic data), the cultural evolution of language in agent-based models, and finally, experimental studies of the cultural evolution of language. We conclude that the study of the cultural evolution of language forms an important data-rich model for the study of the evolution of cultural systems more generally, while also providing key insights into the specific dynamics of this uniquely human behaviour.