Language Evolution and Computation Bibliography

Hauser, Chomsky, and Fitch (HCF) proposed that recursion is the only thing that distinguishes language (a) from other human capacities, and (b) from the capacities of animals. These factors are independent. The narrow faculty of language might include more than recursion, falsifying (a). Or it might consist only of recursion, although parts of the broad faculty might be uniquely human as well, falsifying (b). This chapter presents a view that is contrasted with HCF's above. It shows that there is considerably more of language that is special, though still a plausible product of the processes of evolution. It assesses the key bodies of evidence, coming to a different reading from HCF's. The chapter organizes the discussion by distinguishing the conceptual, sensorimotor, and specifically linguistic aspects of the broad language faculty in turn.

What roles do syntax and semantics have in the grammar of a language? What are the consequences of these roles for syntactic structure, and why does it matter? We sketch the Simpler Syntax Hypothesis, which holds that much of the explanatory role attributed to syntax in contemporary linguistics is properly the responsibility of semantics. This rebalancing permits broader coverage of empirical linguistic phenomena and promises a tighter integration of linguistic theory into the cognitive scientific enterprise. We suggest that the general perspective of the Simpler Syntax Hypothesis is well suited to approaching language processing and language evolution, and to computational applications that draw upon linguistic insights.

In a continuation of the conversation with Fitch, Chomsky, and Hauser on the evolution of language, we examine their defense of the claim that the uniquely human, language-specific part of the language faculty (the ``narrow language faculty'') consists only of recursion, and that this part cannot be considered an adaptation to communication. We argue that their characterization of the narrow language faculty is problematic for many reasons, including its dichotomization of cognitive capacities into those that are utterly unique and those that are identical to nonlinguistic or nonhuman capacities, omitting capacities that may have been substantially modified during human evolution. We also question their dichotomy of the current utility versus original function of a trait, which omits traits that are adaptations for current use, and their dichotomy of humans and animals, which conflates similarity due to common function and similarity due to inheritance from a recent common ancestor. We show that recursion, though absent from other animals' communications systems, is found in visual cognition, hence cannot be the sole evolutionary development that granted language to humans. Finally, we note that despite Fitch et al.'s denial, their view of language evolution is tied to Chomsky's conception of language itself, which identifies combinatorial productivity with a core of ``narrow syntax.'' An alternative conception, in which combinatoriality is spread across words and constructions, has both empirical advantages and greater evolutionary plausibility.

We examine the question of which aspects of language are uniquely human and uniquely linguistic in light of recent suggestions by Hauser, Chomsky, and Fitch that the only such aspect is syntactic recursion, the rest of language being either specific to humans but not to language (e.g. words and concepts) or not specific to humans (e.g. speech perception). We find the hypothesis problematic. It ignores the many aspects of grammar that are not recursive, such as phonology, morphology, case, agreement, and many properties of words. It is inconsistent with the anatomy and neural control of the human vocal tract. And it is weakened by experiments suggesting that speech perception cannot be reduced to primate audition, that word learning cannot be reduced to fact learning, and that at least one gene involved in speech and language was evolutionarily selected in the human lineage but is not specific to recursion. The recursion-only claim, we suggest, is motivated by Chomsky's recent approach to syntax, the Minimalist Program, which de-emphasizes the same aspects of language. The approach, however, is sufficiently problematic that it cannot be used to support claims about evolution. We contest related arguments that language is not an adaptation, namely that it is 'perfect,' non-redundant, unusable in any partial form, and badly designed for communication. The hypothesis that language is a complex adaptation for communication which evolved piecemeal avoids all these problems.

Already hailed as a masterpiece, Foundations of Language offers a brilliant overhaul of the last thirty-five years of research in generative linguistics and related fields." Few books really deserve the cliche'this should be read by every researcher in the field,'" writes Steven ...

Much current discussion of the evolution of language has concerned the emergence of a stage in which single vocal or gestural signals were used symbolically. Assuming the existence of such a stage, the present review decomposes the emergence of modern language into nine partially ordered steps, each of which contributes to precision and variety of expression. Bickerton's proposed `protolanguage' falls somewhere in the middle of this succession. In addition to the by-now accepted evidence from language learning, language disorders, and ape language experiments, modern languages provide evidence of these stages of evolution through the presence of detectable `fossils' in vocabulary and grammar.