Pinker, S. & Bloom, P. (1990). Natural language and natural selection. Behavioral and Brain Sciences 13

A motor theory of speech perception, initially proposed to account for results of early experiments with synthetic speech, is now extensively revised to accommodate recent findings, and to relate the assumptions of the theory to those that might be made about other perceptual modes. According to the revised theory, phonetic information is perceived in a biologically distinct system, a ‘module ’ specialized to detect the intended gestures of the speaker that are the basis for phonetic categories. Built into the structure of this module is the unique but lawful relationship between the gestures and the acoustic patterns in which they are variously overlapped. In consequence, the module causes perception of phonetic structure without translation from preliminary auditory impressions. Thus, it is comparable to such other modules as the one that enables an animal to localize sound. Peculiar to the phonetic module are the relation between perception and production it incorporates and the fact that it must compete with other modules for the same stimulus variations.

Abstract not found

Running title: Speech reference frames Does the speech motor control system utilize invariant vocal tract shape targets of any kind when producing phonemes? We present a four-part theoretical treatment favoring models whose only invariant targets are auditory perceptual targets over models that posit invariant constriction targets. When combined with earlier theoretical and experimental results (Guenther, 1995a,b; Perkell et al., 1993; Savariaux et al., 1995a,b), our hypothesis is that, for vowels and semi-vowels at least, the only invariant targets of the speech production process are multidimensional regions in auditory perceptual space. These auditory perceptual target regions are hypothesized to arise during development as an emergent property of neural map formation in the auditory system. Furthermore, speech movements are planned as trajectories in auditory perceptual space. These trajectories are then mapped into articulator movements through a neural mapping that allows motor equivalent variability in constriction locations and degrees when needed, but maintains approximate constriction invariance for a given sound in most instances. These hypotheses are illustrated and substantiated using computer simulations of the DIVA model of speech acquisition and production. Finally, we pose several difficult challenges to proponents of constriction theories based on this theoretical treatment.

Data and models about recognition and recall of words and non words are unified using a real-time network processing theory. Lexical decision and word frequency effect data are analyzed in terms of theoretical concepts that have unified data about development of circular reactions, imitation of novel sounds, the matching of phonetic to articulatory requirements, serial and paired associate verbal learning, free recall, unitization, categorical perception, selective adaptation, auditory contrast, and word superiority effects. The theory, called adaptive resonance theory, arose from an analysis of how a language system self-organizes in real time in response to its complex input environment. Such an approach emphasizes the moment-by-moment dynamical interactions that control language development, learning, and stability. Properties of language performance emerge from an analysis of the system constraints that govern stable language learning. Concepts such as logogens, verification, automatic activation, interactive activation, limited-capacity processing, conscious attention, serial search, processing stages, speed-accuracy trade-off, situational frequency, familiarity, and encoding specificity are revised and developed using this analysis. Concepts such as adaptive resonance, resonant equilibration of short-term memory, bottom-up adaptive filtering, tQp-down adaptiveteml'late matching, competitive masking field, unitized list representation, temporal order information over item representations,

Ever since Helmholtz, the perceptual basis of speech has been associated with the energy distribution across frequency. However, there is now accumulating evidence that speech understanding does not require a detailed spectral portraiture of the signal. As a consequence, a new theoretical perspective, focused on time, is beginning to emerge. This framework emphasizes the temporal evolution of coarse spectral patterns as the primary carrier of information within the speech signal, and provides an efficient and effective means of shielding linguistic information against the potentially hostile forces of the natural soundscape, such as reverberation and background acoustic interference. The auditory system may extract this relational information through computation of the low-frequency modulation spectrum in the auditory cortex, and this representation provides a principled basis for segmentation of the speech signal into syllabic units. Because of the systematic relationship between the syllable and higher-level lexicogrammatical organization it is possible, in principle, to gain direct access to the lexicon and grammar through such an auditory analysis of speech.

The authors report a series of studies designed to determine whether effects similar to those observed in the innate categorical perception of color and phonemes are induced during the learning of simple unidimensional categories and more complex multidimensional ones. In Experiment 1 no evidence was found for such effects when stimuli varied on 1 dimension. Experiments 2 and 3 demonstrated a within-category compression effect but no between-category expansion effect for stimuli varying in 2 dimensions. Compression only was also shown in Experiment 4, which used pictures of actual objects. Multidimensional scaling analyses illustrate how within-category compression without expansion was sut~cient to produce categorical clustering of items in the similarity space. These analyses also show that learning changed the dimensional structure of similarity space. Results are compared with those from other studies exploring similar phenomena and with neural network simulations. Most contemporary models of category learning rely to

The precise neural mechanisms underlying speech perception are still to a large extent unknown. The most accepted view is that speech perception depends on auditory-cognitive mechanisms specifically devoted to the analysis of speech sounds. An alternative view is that, crucial for speech perception, it is the activation of the articulatory (motor) gestures that generate these sounds. The listener understands the speaker when his/her articulatory gestures are activated (motor theory of speech perception). Here, by using transcranial magnetic stimulation (TMS), we demonstrate that, during speech listening, there is an increase of motor-evoked potentials recorded from the listeners' tongue muscles when the presented words strongly involve, when pronounced, tongue movements. Although these data do not prove the motor theory of speech perception, they demonstrate for the first time that word listening produces a phoneme specific activation of speech motor centres.

We examine the question of which aspects of language are uniquely human and uniquely linguistic in light of recent arguments 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 this argument problematic. It ignores the many aspects of grammar that are not recursive, such as phonology, morphology, case, and agreement. It is inconsistent with the anatomy and neural control of the human vocal tract. And it is weakened by experiments showing 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 other arguments from Chomsky that language is not an adaptation, namely that it is “perfect, ” nonredundant, 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.

In everyday tasks, selecting actions in the proper sequence requires a continuously updated representation of temporal context. Many existing models address this problem by positing a hierarchy of processing units, mirroring the roughly hierarchical structure of naturalistic tasks themselves. Such an approach has led to a number of difficulties, including a reliance on overly rigid sequencing mechanisms, an inability to account for context sensitivity in behavior, and a failure to address learning. We consider here an alternative framework, according to which the representation of temporal context is facilitated by recurrent connections within a network mapping from environmental inputs to actions. Applying this approach to a specific, and in many ways prototypical, everyday task (coffee-making), we examine its ability to account for several central characteristics of normal and impaired human performance. The model we consider learns to deal flexibly with a complex set of sequencing constraints, encoding contextual information at multiple time-scales within a single, distributed internal representation. Mildly degrading this context representation leads