The capacity to generate recursive sequences is a marker of rich, algorithmic cognition, and perhaps unique to humans. Yet, the precise processes driving recursive sequence generation remain mysterious. We investigated three potential cognitive mechanisms underlying recursive pattern processing: hierarchical reasoning, ordinal reasoning, and associative chaining. We developed a Bayesian mixture model to quantify the extent to which these three cognitive mechanisms contribute to adult humans’ performance in a sequence generation task. We further tested whether recursive rule discovery depends upon relational (...) information, either perceptual or semantic. We found that the presence of relational information facilitates hierarchical reasoning and drives the generation of recursive sequences across novel depths of center embedding. In the absence of relational information, the use of ordinal reasoning predominates. Our results suggest that hierarchical reasoning is an important cognitive mechanism underlying recursive pattern processing and can be deployed across embedding depths and relational domains. (shrink)

In their recent book, Ladyman and Wiesner (What is a complex system?, Yale University Press, 2020) delineate the bounds of the exciting interdisciplinary field of complexity science. In this work, they provide examples of generally accepted complex systems and common features which these possess to varying degrees. In this paper, I plan to extend their list to include the formal study of natural language, i.e. linguistics. In fact, I will argue that language exhibits many of the hallmarks of a complex (...) system, specifically a complex biological system. Thus, my aim is to advocate contra the the ‘Minimalist Program’ (Chomsky, The minimalist program, MIT Press, Cambridge, 1995), which motivates simple underlying mechanisms (i.e. Merge) in their idealisations, that biolinguistics should embrace a ‘Maximalist Program’ in which multiple subfields contribute component explanations to an emerging whole. (shrink)

The question: are humans the only animals endowed with language? must be preceded by the question: what makes language a unique communication system? The American linguist Charles F. Hockett answers the second question by listing what he considers the criteria that differentiate language from other communication systems. His ‘design-feature’ approach, first presented in 1958, has become a popular tool by which the communication systems of non-human animals are guaranteed a priori exclusion from the notion of language. However, the results of (...) interspecific communication research and the discovery of language–like qualities in the natural communication systems of non-human animals demonstrate that language capabilities have evolved in parallel in many species. Thus Hockett’s approach is thoroughly undermined, and in need of revision. The more fundamental question that must be faced by the design-feature approach is: are its features essential for language as a distinct and vivid phenomenon, or merely applied to language as an object of linguistic investigation? This paper offers a detailed overview of Hockett’s design-features and emphasizes the problematic nature of certain characteristics. Following Slobodchikoff and Segerdahl et al., the paper shows that language cannot be defined as an exclusive quality of a single species. (shrink)

Taking Chomsky’s Syntactic Structures as a starting point, this paper explores the use of recursive techniques in contemporary linguistic theory. Specifically, it is shown that there were profound ambiguities surrounding the notion of recursion in the 1950s, and that this was partly due to the fact that influential texts such as Syntactic Structures neglected to define what exactly constituted a recursive device. As a result, uncertainties concerning the role of recursion in linguistic theory have prevailed until the present day, and (...) some of the most common misunderstandings that have appeared in recent discussions are examined at some length. This article shows that debates about such topics are frequently undermined by fundamental misunderstandings concerning core terminology, and the full extent of the prevailing haziness is revealed. An attempt is made, for instance, to distinguish between such things as iterative constructional devices and self-similar syntactic embedding, despite the fact that these are usually both unhelpfully classified as examples of recursion. Consequently, this article effectively constitutes a plea for much greater accuracy and clarity when such important issues are addressed from a linguistic perspective. (shrink)

Language sciences have long maintained a close and supposedly necessary coupling between the infinite productivity of the human language faculty and recursive grammars. Because of the formal equivalence between recursion and non-recursive iteration; recursion, in the technical sense, is never a necessary component of a generative grammar. Contrary to some assertions this equivalence extends to both center-embedded relative clauses and hierarchical parse trees. Inspection of language usage suggests that recursive rule components in fact contribute very little, and likely nothing significant, (...) to linguistic creativity. Further than this, if the productivity of human language is considered as not rigidly bound, but not infinite, then the need for any sort of iteration in generative grammars vanishes and can be replaced with a Non-iterative Explicit Alternatives Rule grammar. The knock-on effects of dispensing with recursive grammar components are: that language diversity can simply be based on rule and lexicon combinatorics with no potentially infinite dimensions derived from recursive or iterative components of rules; the oddity of a vast, multiply-infinite competence set of ‘grammatical but unacceptable’ productions is gone; and the development of a language faculty based on rules that eschew iterative rule components avoids any need for explaining ‘special’ mechanisms. On the broader front of searching for the mechanisms of mind, our analysis can be similarly applied to the proposals for a recursive basis for mind as an explanation for humanity’s great leap forward. (shrink)