Sean Roberts

Composite beings (“monsters”) are those mythical creatures composed of a mix of different anatomical forms. There are several scholarly claims for why these appear in the imagery and lore of many societies, including claims that they are found near-universally as well as those arguments that they co-occur with particular sociocultural arrangements. In order to evaluate these claims, we identify the presence of composite monsters cross-culturally in a global sample of societies, the Standard Cross-Cultural Sample. We find that composite beings are not universal, and that their presence or absence co-varies most significantly with social stratification and transportation technology. This supports hypotheses that the cultural evolution of composite monsters is driven by human concerns with social distinctions within societies as well as increased contact with distant peoples.

This is the final paper in a four-part series which addresses the methodology of research studies under ethical review. The focus is on study conduct, governance and peer review. The nature and adequacy of peer review as a mechanism for assessing the study design and analysis are discussed. The paper argues that a properly constituted and functioning research team is crucial to the ethical conduct of a study and that an ethical review of methodology should extend beyond study design and analysis to a concern with data collection, storage and availability, and publication. While ethical review committees cannot monitor study conduct, they can ensure that the protocol pays sufficient attention to appropriate monitoring structures and personnel.

Previous research on linguistic relativity and economic decisions hypothesized that speakers of languages with obligatory tense marking of future time reference (FTR) should value future rewards less than speakers of languages which permit present tense FTR. This was hypothesized on the basis of obligatory linguistic marking (e.g., will) causing speakers to construe future events as more temporally distal and thereby to exhibit increased “temporal discounting”: the subjective devaluation of outcomes as the delay until they will occur increases. However, several aspects of this hypothesis are incomplete. First, it overlooks the role of “modal” FTR structures which encode notions about the likelihood of future outcomes (e.g., might). This may influence “probability discounting”: the subjective devaluation of outcomes as the probability of their occurrence decreases. Second, the extent to which linguistic structures are subjectively related to temporal or probability discounting differences is currently unknown. To address these, we elicited FTR language and subjective ratings of temporal distance and probability from speakers of English, which exhibits strongly grammaticized FTR, and Dutch, which does not. Several findings went against the predictions of the previous hypothesis: Framing an FTR statement in the present (“Ellie arrives later on”) versus the future tense (“…will arrive…”) did not affect ratings of temporal distance; English speakers rated future statements as relatively more temporally proximal than Dutch speakers; and English and Dutch speakers rated future tenses as encoding high certainty, which suggests that obligatory future tense marking might result in less discounting. Additionally, compared with Dutch speakers, English speakers used more low-certainty terms in general (e.g., may) and as a function of various experimental factors. We conclude that the prior cross-linguistic observations of the link between FTR and psychological discounting may be caused by the connection between low-certainty modal structures and probability discounting, rather than future tense and temporality.

Iconicity, the resemblance between the form of a word and its meaning, has effects on behavior in both communicative symbol development and language learning experiments. These results have invited speculation about iconicity being a key feature of the origins of language, yet the presence of iconicity in natural languages seems limited. In a diachronic study of language change, we investigated the extent to which iconicity is a stable property of vocabulary, alongside previously investigated psycholinguistic predictors of change. Analyzing 784 English words with data on their historical forms, we found that stable words are higher in iconicity, longer in length, and earlier acquired during development, but that the role of frequency and grammatical category may be less important than previously suggested. Iconicity is revealed as a feature of ultra-conserved words and potentially also as a property of vocabulary early in the history of language origins.

This paper outlines a first attempt to model the special constraints that arise in language processing in conversation, and to explore the implications such functional considerations may have on language typology and language change. In particular, we focus on processing pressures imposed by conversational turn-taking and their consequences for the cultural evolution of the structural properties of language. We present an agent-based model of cultural evolution where agents take turns at talk in conversation. When the start of planning for the next turn is constrained by the position of the verb, the stable distribution of dominant word orders across languages evolves to match the actual distribution reasonably well. We suggest that the interface of cognition and interaction should be a more central part of the story of language evolution.

We investigate the emergence of iconicity, specifically a bouba-kiki effect in miniature artificial languages under different functional constraints: when the languages are reproduced and when they are used communicatively. We ran transmission chains of participant dyads who played an interactive communicative game and individual participants who played a matched learning game. An analysis of the languages over six generations in an iterated learning experiment revealed that in the Communication condition, but not in the Reproduction condition, words for spiky shapes tend to be rated by naive judges as more spiky than the words for round shapes. This suggests that iconicity may not only be the outcome of innovations introduced by individuals, but, crucially, the result of interlocutor negotiation of new communicative conventions. We interpret our results as an illustration of cultural evolution by random mutation and selection.