Biomedical subjects

B Tuller

Publications and source records attributed to B Tuller.

13 recordsLinked to original sources

PubMed1991

The production and perception of syllable structure.

Much research on speech over the years has focused on uncovering examples of the nonlinear relationship between acoustics and perception (e.g., so-called "categorical perception") and between articulation and acoustics [as described by Stevens's (1972) quantal theory]. In the present experiment we demonstrate that naturally occurring linear changes in articulation may also be perceived discontinuously. Specifically, linear changes in relative phase of glottal and oral movements are perceived as categorical changes in the location of syllable juncture. Thus, phase transitions observed during speech demarcate a change in syllabic organization.

Glottis↗

PubMed1990

An evaluation of an alternating magnetic field device for monitoring tongue movements.

Alternating magnetic field devices hold much promise for tracking movements of multiple articulators, including the tongue, in the midsagittal plane. Here, the accuracy, repeatability, and linearity of one such device, the Articulograph AG-100 (Carstens Medizinelektronik GmbH, Göttingen, West Germany), are evaluated. The results indicate that with proper precautions in transducer calibration and placement, the Articulograph can be a useful tool in speech production research.

Adult↗

PubMed1989

Environmentally-specified patterns of movement coordination in normal and split-brain subjects.

Rhythmic movement patterns between the hands in response to environmental signals are studied in normal (musicians and nonmusicians) and split-brain subjects. Only two phase-locked states - in-phase and anti-phase - are shown to be stable for all subjects. Split-brain subjects show an even greater attraction to these patterns, thus providing no support for the notion that reduced cortical interaction between the hemispheres allows for independent visuomotor control of the hands in such tasks. Moreover, differences in trajectories produced by normal individuals and those without an intact corpus callosum are remarkable. The resultant patterns of coordination afford 1) a generalization of previous results on intrisincally generated rhythmic behavior to environmentally-specified movement patterns; and 2) a discussion of neural mechanisms underlying stable phase relations.

Adult↗

PubMed1988

Patterns of interarticulator phasing and their relation to linguistic structure.

Work by Tuller and Kelso [J. Acoust. Soc. Am. 76, 1030-1036 (1984)] and Kelso et al. [J. Phon. 14, 29-59 (1986)] has demonstrated stable relations between jaw and lip movements in (bV#CVb) utterances across rate and stress conditions. Specifically, the onset of lip movement toward the intervocalic consonant was found to be constant with respect to the vowel-to-vowel jaw cycle in both time and relative phasing. An attempt was made to replicate and extend this work by investigating interarticulator phase relations for utterances having a broader range of linguistic organization: In addition to rate and stress, syllable structure (open versus closed syllables) and identity of the intervocalic consonant (/p/ vs /m/) were manipulated. Results showed that the upper lip's lowering onset varied systematically with respect to the jaw vowel cycle as a function of both rate and stress. In addition, syllable structure and consonant identity influenced the relation of lip and jaw gestures. There was a general tendency for any condition that shortened the first vowel to produce earlier onsets of the upper lip relative to the jaw. However, the within-condition jaw cycle duration variability did not correlate with the within-condition variability in phase. Thus it seems that stable interarticulator phase relations maintain not only the integrity of phonological structure, as suggested by Kelso et al., but structural integrity at other levels of linguistic organization as well.

Female↗

PubMed1984

On categorizing aphasic speech errors.

Acoustic studies of voice-onset-time in aphasics' speech suggest that fluent aphasics' errors are misselected phonemic targets whereas nonfluent aphasics' errors are of articulatory origin. However, we must be cautious when extrapolating a theory from only one measure of articulation. In this experiment, I examined utterances produced by five fluent aphasics, five nonfluent aphasics and two controls. First, the voice-onset-time findings were replicated. Second, I examined the duration of vowels preceding word-final stop consonants as an index of the consonant's voicing category. The pattern of voice-onset-times produced did not predict the pattern of vowel durations. Thus, voice-onset-time cannot be used to characterize more generally the output of the speaker.

Adult↗

PubMed1984

Functionally specific articulatory cooperation following jaw perturbations during speech: evidence for coordinative structures.

In three experiments we show that articulatory patterns in response to jaw perturbations are specific to the utterance produced. In Experiments 1 and 2, an unexpected constant force load (5.88 N) applied during upward jaw motion for final /b/ closure in the utterance /baeb/ revealed nearly immediate compensation in upper and lower lips, but not the tongue, on the first perturbation trial. The same perturbation applied during the utterance /baez/ evoked rapid and increased tongue-muscle activity for /z/ frication, but no active lip compensation. Although jaw perturbation represented a threat to both utterances, no perceptible distortion of speech occurred. In Experiment 3, the phase of the jaw perturbation was varied during the production of bilabial consonants. Remote reactions in the upper lip were observed only when the jaw was perturbed during the closing phase of motion. These findings provide evidence for flexibly assembled coordinative structures in speech production.

Adult↗

PubMed1984

The timing of articulatory gestures: evidence for relational invariants.

In this article, we examine the effects of changing speaking rate and syllable stress on the space-time structure of articulatory gestures. Lip and jaw movements of four subjects were monitored during production of selected bisyllabic utterances in which stress and rate were orthogonally varied. Analysis of the relative timing of articulatory movements revealed that the time of onset of gestures specific to consonant articulation was tightly linked to the timing of gestures specific to the flanking vowels. The observed temporal stability was independent of large variations in displacement, duration, and velocity of individual gestures. The kinematic results are in close agreement with our previously reported EMG findings [B. Tuller et al., J. Exp. Psychol. 8, 460-472 (1982)] and together provide evidence for relational invariants in articulation.

Adult↗

PubMed1984

Converging evidence in support of common dynamical principles for speech and movement coordination.

We suggest that a principled analysis of language and action should begin with an understanding of the rate-dependent, dynamical processes that underlie their implementation. Here we present a summary of our ongoing speech production research, which reveals some striking similarities with other work on limb movements. Four design themes emerge for articulatory systems: 1) they are functionally rather than anatomically specific in the way they work; 2) they exhibit equifinality and in doing so fall under the generic category of a dynamical system called point attractor; 3) across transformations they preserve a relationally invariant topology; and 4) this, combined with their stable cyclic nature, suggests that they can function as nonlinear, limit cycle oscillators (periodic attractors). This brief inventory of regularities, though not mean to be inclusive, hints strongly that speech and other movements share a common, dynamical mode of operation.

Animals↗

PubMed1983

Converging evidence for the role of relative timing in speech.

In an earlier article (Tuller, Kelso, & Harris, 1982a) we suggested that the timing of consonant-related muscle activity was constrained relative to the period between onsets of muscle activity for successive vowels. Here, we reexamine those data based on reservations posed by Barry (1983). Next, we present a kinematic study of articulation that extends and strongly supports our original observations. Finally, we very briefly survey some converging lines of evidence for a functionally significant vowel-to-vowel period in speech and how this may relate to the role of temporal invariance in motor skills in general.

Electromyography↗

PubMed1983

"Compensatory articulation" under conditions of reduced afferent information: a dynamic formulation.

A well-established feature of speech production is that talkers, faced with either anticipated or unanticipated perturbations, can spontaneously adjust the movement patterns of articulators such that the acoustic output remains relatively undistorted. Less clear is the nature of the underlying processes involved. In this study we examined five subjects' productions of the point vowels /i, a, u/ in isolation and of the same vowels embedded in a dynamic speech context under normal conditions and under a combined condition, in which (a) the mandible was fixed by means of a bite block; (b) proprioceptive information was reduced through bilateral anesthetization of the temporomandibular joint; (c) tactile information from the oral mucosa was reduced by application of a topical anesthetic; and (d) auditory information was masked by white noise. Minimal distortion of the formant patterns was found in the combined condition. These findings are unfavorable for central (e.g., predictive simulation) or peripheral closed-loop models, both of which require reliable peripheral information; they are more in line with recent work suggesting that movement goals may be achieved by muscle collectives that behave in a way that is qualitatively similar to a nonlinear vibratory system.

Acoustic Stimulation↗

PubMed1982

Stress and rate: differential transformations of articulation.

Early theorizing in speech production considered variations in syllable stress and speaking rate to be identical transformations of motor activity [e.g., Lindblom, J. Acoust. Soc. Am. 35, 1773-1781 (1963)]. More recent work, however, suggests that modulation of stress and rate have different acoustic and perceptual effects, and thus may have independent "signatures" in production. The experiments reported here examined these hypotheses. In the first experiment, electromyographic activity from two muscles, one primarily related to vowel production and the other to consonant production, was examined during utterances whose stress and rate characteristics were systematically varied. The results support the hypothesis that stress and rate modulations have differential effects on muscle activity. The second experiment addressed the same basic question but examined a broader set of muscles. In all cases, the changes in duration and peak amplitude of muscle activity for altered stress were not equivalent to the changes for altered rate. Decreases in stress produced decreases in peak amplitude and duration of vowel-related muscle activity that were consistent across speakers. In contrast, activity patterns associated with rate contrasts varied considerably across muscles and speakers.

Adult↗

PubMed1977

Some aspects of the psychological representation of speech sounds.

If one listens to a meaningless syllable that is repeated over and over, he will hear it undergo a variety of changes that can be described systematically in terms of reorganization of the phones constituting the syllable and changes in a restricted set of phonetic distinctive features. When the repeated syllable is followed by a different syllable but in the same voice, the new (test) syllable will be misperceived in a manner related to the perceptual misrepresentation of the repeated syllable. In the present experiment subjects (N = 24) listened to 72 different experimental sequences of repeated syllables in a male voice followed by test syllables in a female voice. Identification of penultimate and test syllables was independent and in no instance were the phone constituting the syllables reorganized. These results are interpreted as evidence against both auditory and phonetic feature detector theories of speech perception.

Auditory Perception↗

PubMed1977

Some factors affecting the perceived ordering of natural speech stimuli.

Primary auditory stream segregation--the perceptual segregation of acoustically related elements of a continuous auditory sequence into spatially distinct streams--disrupts recovery of the relative temporal order of repeated sequences of consonant and vowel syllables. Three experiments were performed to determine why the apparent temporal order of natural speech is not similarly disrupted. Exp. 1 (N =24) showed that the disruption is not dependent on repetition of the 32 experimental sequences of consonant and vowel syllables. Exps. 2 (N = 48) and 3 (N = 20) showed that when 4 English monosyllables are used as stimuli and syntactic and intonational structure is present then the temporal integrity of the acoustic signal is preserved perceptually. Despite accurate resolution of order for the 40 experimental sequences, errors of words were common. These errors often imposed a syntactic organization on the resulting sequence.

Auditory Perception↗