Are other animals as smart as great apes? Do others provide better models for the evolution of speech or language?
Kathleen R. Gibson
This article reviews recent evidence for advanced, language-pertinent, cognitive capacities in birds and mammals and evaluates the potential suitability of song and other animal vocal behaviors as models for the evolution of speech. Dolphins are extremely vocal, exhibit intelligence across a number of behavioral domains, are highly social, and often cooperate to herd schools of fish. Dolphins can also recognize themselves in mirrors, coordinate body postures and swimming patterns with those of other dolphins, and imitate each other's vocalizations, including unique signature whistles which serve for individual recognition among adults and in the mother-infant dyad. The only other non-primate mammals whose “language” capacities appear to have been investigated are domestic dogs. Some have also claimed that domestic dogs equal or exceed great apes in social intelligence. It is reported that both elephants and spotted hyenas are unusually intelligent. Elephants remember and recognize by olfactory and visual means numerous conspecifics and classify them into social groups. They also sometimes cooperate to achieve joint goals and seem to understand others' intentions and emotions. Elephants have highly manipulative trunks, use tools for varied purposes, may recognize themselves in mirrors, and may have a stronger numerical sense than non-human primates. They have elaborate vocal, olfactory, tactile, and gestural communication systems and can imitate some sounds.
This article provides an overview of bird song and language. There are several reasons why bird song might be of interest to those who are studying human language. First, and most obviously, it is a system of communication. Birds use sounds to communicate with one another. The most elaborate sounds are referred to as songs; males largely use songs in the breeding season to attract mates and keep rivals out of their territories. But there are other simpler sounds, usually labeled as calls, which fulfill other functions and are often used by both sexes throughout the year. Sounds can go round corners and are as useful by night as they are by day, both features that give them an advantage over visual signals. The third main modality, that of smell, has the advantage of persistence, as when the scent marks of one dog are sensed by another days later, but is certainly not appropriate for the transfer of a complex and changing stream of information. Beyond these two basic similarities comes a fourth, superficially more important, one: birds, like human beings, often have a huge repertoire of different sounds. To conclude, it is clear that vocal communication is of prime importance in many birds as it is in humans. Some of the similarities, such as that between our vocabulary and the large song repertoires found in many birds, are superficial. But the fact that learning plays a role in the song development of many birds, as it does in language development, may help us to look back in time and think about the reasons why this crucial evolutionary step took place on the way of language development.
Frederick L. Coolidge and Thomas Wynn
This article proposes the important prerequisites for indirect speech that includes at least four major cognitive factors, adequate phonological storage capacity, recursion, a full theory of mind, and executive functions. The phonological store subsystem is considered to play a critical role in language production and comprehension. Adults who have greater phonological storage capacity have also been found to score higher on verbal tests of intelligence and higher on measures of verbal fluency and they also do better on retroactive and proactive interference tasks. The phonological storage capacity represents a short-term memory ensemble that can be phylogenetically tracked to earlier homologues in hominin evolution and to current primate brain systems. The recursion is highly dependent upon the phonological storage capacity. The theory of mind refers to the ability to infer the thoughts, emotions, and intentions of others. The theory of mind also consists of four independent skills that include detection of the intentions of others, detection of eye-direction, shared attention, and the final component called the theory of mind module. The final component, whose onset in humans is thought to develop by the age of four, contains a complex set of social-cognitive rules, and combined with the other three components, creates the full-fledged, adult-like theory of mind. The specific executive function might be involved in the theory of mind.
Michael A. Arbib
This article mentions that a formal view of compositional semantics is helpful both for what it reveals about the structure of language and also for what it deletes, including context, the use of compositionality to index rather than define meaning, and the role of idioms. It also discusses how Construction Grammar (CG) allows one to incorporate idioms into a framework in which compositionality may sometimes use familiar sequences of words as atoms when the meanings of single words do not themselves contribute to the meaning of the whole. Schema Theory shows what is meant by embodied meaning, and the way it is embedded in social experience. Linguists working within CG, with its close relations to Cognitive Grammar, have teased out the rule-governed and productive linguistic behaviors specific to each family of constructions.
Kenny Smith and Simon Kirby
The productivity of language is subserved by two structural properties: language is recursive, which allows the creation of an infinite number of utterances, and language is compositional, which makes the interpretation of novel utterances possible. A potential explanation for the linkage between the functional properties of compositionality and the compositional structure of language is that this fit arose through cultural, rather than biological, evolution. In order to argue that the compositional structure of language is a product of cultural evolution, it is assumed that language is compositional, socially learned, and therefore culturally transmitted. A well-established solution to the problem of linkage in biological systems is that of evolution by natural selection: adaptation. Compositionality can be explained as a cultural adaptation by language to the problem of transmission through a learning bottleneck.
Primates communicate not only because they are biologically hardwired to do so, but also because they pursue specific goals during social interactions. This is well documented in the context of ape gestural signals, which have revealed a considerable degree of flexibility in interesting ways. In terms of vocal behavior, however, both monkeys and apes appear to be much less flexible, which raises important questions about how and why vocal flexibility evolved in the human lineage. The emerging picture is that, across the primate order, flexibility is widespread in call comprehension but largely restricted to humans in call production. Non-human primates, including the great apes, are curiously constrained by weak motor control over their vocal apparatus, resulting in limited vocal repertoires. A key transition in the evolutionary origins of language may have been when early humans began to interact with each other collaboratively. Another prediction is that, the species in which infants are exposed to competition over non-maternal caregivers should be more likely to exhibit elaborate vocal behavior than species in which their mothers raise infants only. Research on the communicative skills of other cooperative breeders, particularly communal breeders, may provide interesting empirical data to test this hypothesis.
John L. Locke
This article presents several factors related to the evolution of vocal and phonetic behaviors thus discussing the emergence of symbolization and reference. Evolutionary theories must identify the environmental changes that produced phenotypic variation and the modes of selection that reinforced certain of the variants, thereby increasing reproductive success, and they must specify the developmental stages in which these actions took place. The primary task of evolutionary theorists is to identify the environmental changes, and the responses to those changes, that edged our ancestors closer to the linguistic capacity possessed by modern humans. A new paradigm, evolutionary developmental linguistics (EDL), a naturalization of human language, is concerned with the evolution of developmental properties, processes, and stages that independently, or in concert with other environmental changes, facilitated the emergence of language in the species. Modern humans have four developmental stages that include infancy, childhood, juvenility, and adolescence. Much of the linguistically relevant phenotypic variation originated in ancestral infancies, with selection by parents occurring in this stage, and, with persistence of selected behaviors, in later stages by peers and others. Juvenility provides additional time for the brain growth and learning required for reproductive success in various species of mammals. The modification of juvenility would naturally increase phenotypic variability and offer new bases for selection at a time when greater independence and sexual maturity were rapidly approaching.
Joan L. Bybee
The article demonstrates many aspects of grammar that can be derived from domain-general cognitive processes, especially those of neuromotor automation, chunking, categorization, inference-making, and cross-modal association. Construction grammar posits a direct connection between the conventionalized constructions of a language and their meanings. All constructions have some specific lexical or grammatical material in them. Construction grammar emphasizes the interaction of the lexicon with the syntax. The domain-general processes involved in construction formation and use are sequential processing and categorization. Sequential processing or chunking is the process by which repeated sequences of experience (words or other events) come to be grouped together in memory as units that can be accessed directly. Categorization is necessary to the cognitive representations of constructions in several ways. First, categorization is necessary for the recognition that an element or sequence is the same as one previously experienced. Second, categorization is used to develop the schematic slots of constructions. Constructions are created through the repetition and thus conventionalization of useful sequences of elements and their meanings arise from associations with the context and implications that are present. The most pervasive process by which new constructions are created is grammaticalization, in which a new construction is created along with a new grammatical morpheme and the latter evolves from a lexical morpheme or combinations of grammatical and lexical morphemes.
Biolinguistics is a fairly broad research program that allow for the exploration of many avenues of research, including the formalist, functionalist, and nativist, and it insists on the uniqueness of the language faculty or alternatively, nativist about general (human) cognition, but not about language per se. It is assumed that the language faculty arose in Homo sapiens, and fairly recently, that is, within the last 200,000 years. The recent emergence of the language faculty is most compatible with the idea that at most one or two evolutionary innovations, combined with the cognitive resources available before the emergence of language, delivers the linguistic capacity much as it is known today. Biolinguists, especially those of a minimalist persuasion, have explored the possibility that some of the properties of language faculty may have emerged spontaneously, by the sheer force of biophysics. The type of principles by which minimalists seek to reanalyze the data captured by previous models are, quite plausibly, reflexes of computational laws that go well beyond the linguistic domain. All the linguistic models, no matter how minimalist, rely on the existence of lexical items. Numerous comparative studies in psychology reveal that mature linguistic creatures transcend many cognitive limits seen in animals and prelinguistic infants. Such limits are the signature limits of core knowledge systems, which correspond to primitive knowledge modules. Such systems suffer from informational encapsulation and quickly reach combinatorial limits.
The human hands, face, and vocal machinery have evolved as finely differentiated parts as compared to other primates due to the two phenomena that includes child development and computational modeling. Infants imitate face and hand action as well as speech. All three modalities may share a common evolutionary path to organ differentiation through imitation. Facial imitation is unique among the three because infants can neither see the face they feel nor feel the face they see, so that imitation must be mediated by an intermodal representation. Language, spoken or signed, evidently requires an integral anatomical system of discrete, independently activated parts that can be coordinated to effect rapid sequences of expressive global action. Consonants are specified by acoustic trajectories, formed by gestural combinations of varying degrees of complexity. Lindblom's proposed a modified dispersal algorithm to predict consonant-vowel (CV) syllable trajectories by means of a cost/benefit ratio (articulatory cost/perceptual discriminability) summed and minimized over a system of syllable trajectories such as might appear in a small lexicon. Lindblom's work offers the most comprehensive computational model so far available of how systems of discrete gestures, phonemes, and syllables may have emerged by self-organization under perceptuomotor constraints from an evolved vocal tract.