The dynamical hypothesis is the claim that cognitive agents are dynamical systems. It stands opposed to the dominant computational hypothesis, the claim that cognitive agents are digital computers. This target article articulates the dynamical hypothesis and defends it as an open empirical alternative to the computational hypothesis. Carrying out these objectives requires extensive clarification of the conceptual terrain, with particular focus on the relation of dynamical systems to computers. Key words cognition, systems, dynamical systems, computers, computational systems, computability, modeling, time. Long Abstract The heart of the dominant computational approach in cognitive science is the hypothesis that cognitive agents are digital computers; the heart of the alternative dynamical approach is the hypothesis that cognitive agents are dynamical systems. This target article attempts to articulate the dynamical hypothesis and to defend it as an empirical alternative to the compu...

Chomsky and Halle (1968) and many formal linguists rely on the notion of a universally available phonetic space defined in discrete time. This assumption plays a central role in phonological theory. Discreteness at the phonetic level guarantees the discreteness of all other levels of language. But decades of phonetics research demonstrate that there exists no universal inventory of phonetic objects. We discuss three kinds of evidence: first, phonologies differ incommensurably. Second, some phonetic characteristics of languages depend on intrinsically temporal patterns, and, third, some linguistic sound categories within a language are different from each other despite a high degree of overlap that precludes distinctness. Linguistics has mistakenly presumed that speech can always be spelled with letter-like tokens. A variety of implications of these conclusions for research in phonology are discussed.* The generative paradigm of language description (Chomsky 1964, 1965, Chomsky & Halle 1968) has dominated linguistic thinking in the United States for many years. Its specific claims about the phonetic basis of linguistic analysis still provide the cornerstone of most linguistic research. Many criticisms have been raised against the phonetic claims of the Sound pattern of English (Chomsky & Halle 1968), some from early on

This study investigates the contribution of the temporal patterning of speech to the reduced intelligibility of foreign-accented utterances. Short English phrases spoken by a native Chinese speaker were instrumentally modified, using LPC resynthesis and dynamic time warping, so as to align the duration of acoustic segments with tokens of the same phrases spoken by a native English speaker, while retaining the spectral and source characteristics of the Chinese speaker. Similarly, the native speaker's productions were distorted to match the durational patterns of the nonnative speaker. Intelligibility of these stimuli was measured based on native English listeners' performance in a forced-choice identification test with four alternatives: the correct phrase plus three phonetically similar distractor phrases suggested by listening to the Chinese productions. Intelligibility of the unmodified Chinese-accented phrases was poor (39% correct), but improved significantly (to 58%) after tempora...

Introduction We are interested in modeling an aspect of human rhythm perception and production called beat induction. Roughly, beat induction consists of nding the downbeats in a metrical signal. The most common example of beat induction in human performance is foot tapping to music, and one way to state our goal is that we want to build feet which can tap to the radio as well as people do. However, we are interested in more than the end-state of adult rhythmical behavior; we also focus on the path that people take in perfecting this skill. We build embodied models, ones with actual robotic components that interact with and constrain computational components. This commitment to a physical model of beat induction might seem wrong-headed. After all, beat induction is a perceptual phenomenon in adults, not necessarily involving motor control at all. But we believe that the interactions between body and brain in developing infants and toddlers cannot

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It is proposed that the theory of dynamical systems offers appropriate tools to model many phonological aspects of both speech production and perception. A dynamic account of speech rhythm is shown to be useful for description of both Japanese mora timing and English timing in a phrase repetition task. This orientation contrasts fundamentally with the more familiar symbolic approach to phonology, in which time is modeled only with sequentially arrayed symbols. It is proposed that an adaptive oscillator offers a useful model for perceptual entrainment (or `locking in') to the temporal patterns of speech production. This helps to explain why speech is often perceived to be more regular than experimental measurements seem to justify. Because dynamic models deal with real time, they also help us understand how languages can differ in their temporal detail---contributing to foreign accents, for example. The fact that languages differ greatly in their temporal detail suggests that these effe...

: This paper is a tutorial on a particular method for designing behavior-based robots, the dual dynamics (DD) scheme. The DD scheme guides the specification of multilevel control architectures in a format of differential equations. DD design is characterized by two principal properties. First, behaviors are construed as dynamical systems, which consist of two subsystems (hence the name, "dual dynamics"). One subsystem generates the behavior's dynamics proper, the other is responsible for activating and de-activating the behavior. The second principal property is that higher levels in the control architecture do not directly "call" lower-level behaviors to execute. Rather, a higher-level behavior can "configure" the entire lower level, which thereafter can operate fully on its own, without ongoing supervision by the higher level. Zusammenfassung: Dies ist ein Tutorial fur das "Dual Dynamics" (DD) Entwurfsschema, eine spezielle Entwurfsmethode fur behavior-basierte Roboter. Das DD-Schema...

A series of arguments is presented showing that words are not stored in memory in a way that resembles the abstract, phonological code used by alphabetical orthographies or by linguistic analysis. Words are stored in a very concrete, detailed auditory code that includes nonlinguistic information including speaker’s voice properties and other details. Thus, memory for language resembles an exemplar memory and abstract descriptions (using letter-like units and speaker-invariant features) are probably computed on the fly whenever needed. One consequence of this hypothesis is that the study of phonology should be the study of generalizations across the speech of a community and that such a description will employ units (segments, syllable types, prosodic patterns, etc.) that are not necessarily employed as units in speakers’ memory for language. That is, the psychological units of language are not useful for description of linguistic generalizations and linguistic generalizations across a community are not useful for storing the language for speaker use.

Animals and humans exhibit many kinds of behavior where the frequencies of gestures are related by small integer ratios (like 1:1, 2:1 or 3:1). We show that speakers who repeat a short phrase to a metronome have a strong tendency to place the onsets of stressed syllables at temporal harmonic fractions of the metronome cycle (like 1/2, 1/3 and 2/3). Studies of errors by early language learners also show that some metrical patterns are easier than others. All these effects support a view of meter as an abstract dynamical system on the state space of two or more oscillators. 1 Introduction It is a common observation that human speech is often rhythmically produced. One thinks of worksongs, nursery rhymes, auctioneer calls, group recitation of prayers and chants, marching songs, cheers at sport events, chants by train conductors and so forth. It is worth our time to wonder where such rhythmic performance comes from. It appears that typical speech rhythms vary from language to language, es...

The dynamical hypothesis in cognition identifies various research paradigms applying the mathematics of dynamical systems to understanding cognitive function. The approach is allied with and partly inspired by research in neural science over the past fifty years for which dynamical equations have been found to provide excellent models for the behavior of single neurons (Hodgkins and Huxley, 1952). It also derives inspiration from work on gross motor activity by the limbs (e.g., Bernstein, 1967, Fel’dman, 1966). In the early 1950s, Ashby made the startling proposal that all of cognition might be accounted for with dynamical system models (1952), but little work directly followed from his speculation due to a lack of appropriate mathematical methods and computational tools to implement practical models. More recently, the connectionist movement (Rumelhart and McClelland, 1986) provided insights and mathematical implementations of perception and learning, for example, that have helped restore interest in dynamical modeling. The dynamical approach to cognition is also closely related to ideas about the embodiment of mind and the environmental situatedness of human cognition, since it