Auditory Channels Research Articles

Primate Communication and the Gestural Origin of Language

Wallace, Tylor, Wundt, Johannesson, and others have proposed that human language had its basis in hand and arm gestures. The Gardners' work with the chimpanzee Washoe, Premack's study of the chimpanzee Sarah, and continuing experiments along these lines indicate that neural restructuring would not have been necessary for the protohominid acquisition of a simple propositional gesture or sign language which did not involve cross-modal transfer at a high level from the visual to the auditory channel or vice versa. Evidence from primate studies, early tool-using, the continuing functions of gesture in human communication, lateral dominance in its relation to speech and tool manipulation, and other sources is presented to support a model of glottogenesis. It is argued that a preexisting gestural language system would have provided an easier pathway to vocal language than a direct outgrowth of the "emotional" use of vocalization characteristic of nonhuman primates.

A Study of Information Acquirement by Visual and Auditory Channels

A Study of Information Acquirement by Visual and Auditory Channels

Gap detection in multiple narrow bands of noise as a function of spectral configuration

This study sought to differentiate between the effect of stimulus bandwidth and the effect of number of activated auditory channels on gap detection in narrow bands of noise. The aim was to clarify the role of across-frequency analysis in temporal processing. Experiment 1 established that when total noise bandwidth is held constant at 100 Hz, gap detection improves as stimulus energy is distributed to both lower and higher frequencies. Experiment 2a showed that the effect was smaller, or was absent, when the cumulative stimulus bandwidth was increased from 100 to 200 Hz. Experiment 2b confirmed that the benefit of spectral dispersion for the narrower cumulative bandwidth also held for a higher frequency region. The results suggest that in conditions where the cumulative stimulus bandwidth is relatively narrow and, concomitantly, gap detection is relatively poor, there is an advantage in dispersing the stimulus across a number of auditory channels. The advantage for the distribution of energy across a range of auditory channels may be offset when the spectral spacing of bands exceeds a critical value.

Effects of Auditory Disruption of Lingual Tactile Sensitivity in Skilled and Unskilled Speaking Conditions

The purpose of this study was to investigate the effect of disruption of the auditory feedback channel on lingual vibrotactile thresholds obtained under skilled and unskilled speaking conditions. Each of 22 adults was asked to read an English (skilled) and French (unskilled) passage under conditions of normal and altered auditory feedback. Bilateral presentation of masking noise was utilized to disrupt auditory feedback. Before each of the experimental sessions and immediately following a reading, lingual vibrotactile thresholds were obtained. Analysis indicated that the mean differences in the pre- and postvibrotactile threshold measurements of the skilled auditory disrupted condition varied significantly from the mean differences in the pre- and postvibrotactile threshold measurements of the three other conditions. The role of feedback in the speech production of skilled and unskilled speakers is discussed.

Voice as interface: An overview

Speech, as a medium for communicating with computers, has several potential advantages, and its introduction may have far‐reaching implications for the evolution of information technology. Yet, despite the availability of speech I/O devices over the past few years, their introduction into day‐today use has been relatively slow. A human factors perspective helps to explain the predominance of the visual/manual interface, and the reasons for its preference over speech. This view reflects fundamental differences between the two modes of communication. However, human factors also suggest that much can be done to improve the usability of speech systems. Broad guidelines for the use of speech‐output devices are detailed, and include criteria for the assignment of output either to the visual or auditory channel. The human factors of synthetic speech are discussed, in terms of enhancing both its intelligibility and its acceptability to users. Performance measures of automatic speech recognition (ASR) technology m...

Measuring Verbal Behaviour and Social Competence with the Verbal Interaction Analysis System: Further Validation

Abstract The Verbal Interaction Analysis System (VIAS) is a recently developed measure of social competence which also enables target behaviour to be selected and treatment gains assessed. A brief description of the VIAS is followed by a further investigation of its validity, three high competent and three low competent male adults were selected from a larger sample on the basis of the combined global competency ratings of a participant and an independent observer of conversations with two unknown female confederates. Extracts from these conversations were randomly presented by means of videotape to 36 undergraduate psychology students who were randomly assigned to one of four experimental conditions. Conditions were designed to manipulate the information presented by varying the auditory and visual channels on the videotape recordings. Thus some subjects saw and heard the target males in both conversations, whereas others did not receive visual information for one or both of the conversations. Results st...

Ideational and pragmatic markers of discourse structure

This paper presents an integrative approach to the study of discourse coherence which follows the observation of Bühler (1934) and others that language use always involves both the representation of propositional content and the expression of attitudes and intentions. Consideration of only one of these functions is shown to be insufficient for an adequate account of discourse coherence. Coherence is regarded as arising from semantic relations between the ideas states and pragmatic relations between the actions performed in speaking or writing. Empirical evidence for this view is provided by the use of pragmatic and ideational structuring devices in film descriptions. Speakers who were describing a film to a friend used more markers of pragmatic structure than those whose listener was a stranger. At the same time, they were less explicit in indicating the ideational structure of their discourse. This trade-off between pragmatic and ideational structuring occurred not only in dialogues (two-way auditory channel where the friends gave more feedback, but also in monologues (one-way channel), where the two conditions differed only in the speaker's knowledge that the listener was a friend or a stranger.

Within- and cross-channel mechanisms in the detection of frequency modulation coherence and incoherence

Mechanisms involved in the detection of frequency modulation coherence and incoherence in harmonic sounds were studied. In a 14-component harmonic series, subsets of one or more components were modulated coherently among themselves, but independently of the rest. The locus of target harmonics in the series was varied, as was their disposition: adjacent or interleaved with the background. Subjects were presented a test tone containing a target subset and a comparison tone with no target. The modulation coherence of the comparison was the same as that of the test tone background. The task was to detect which of two 500-ms intervals contained the target tone. Threshold was measured as function of frequency modulation width. For coherent backgrounds, thresholds generally decreased as a function of the relative proximity of target and background components. However, results from stimuli with incoherent backgrounds indicate that detection thresholds were closely related to the distribution of regions of relative coherence and incoherence across auditory channels, implying a mechanism of cross-channel comparison.

Differential auditory ERP negativities in focussed, divided and passive attention and inattention to two auditory channels

Differential auditory ERP negativities in focussed, divided and passive attention and inattention to two auditory channels

Effects of temporal position on the detectability of interaurally uncorrelated noise

Listeners' ability to detect an interaurally uncorrelated segment of noise within binaural broadband noise bursts was measured as a function of the temporal position of the uncorrelated noise. Psychometric functions were obtained by varying the duration of uncorrelated noise. The results indicate that detectability improves as the duration of uncorrelated noise is increased. Temporal position affected detectability only at the shortest durations of uncorrelated noise tested; a segment positioned either at the end or at the beginning of the burst is more detectable than one in the middle. This result is not easily accounted for by models of binaural processing. For example, the EC model [N. I. Durlach, J. Acoust. Soc. Am. 35, 1206–1218 (1963)] assumes that performance is determined by the power of the difference in the waveforms in the two auditory channels. Since power is computed over the total stimulus duration, it is independent of the temporal position of the uncorrelated noise. The relationship of the current findings to those for the discriminability of diotic noise stimuli will be discussed. [Work supported by AFOSR.]

A comparison of comodulation masking release and profile analysis

Large reductions in signal thresholds may be observed under stimulus conditions in which there is common information in a number of auditory channels or critical bands. In comodulation masking release (CMR) tasks, a reduction in the threshold of a signal in a narrow‐band noise occurs when a flanking or cue band of noise is also present, provided that the flanking band has an amplitude envelope which is correlated with that of the masker band. This reduction in threshold occurs in dichotic conditions, where the flanking band is presented in the opposite ear to the signal‐plus‐masker. In profile analysis (PA), the overall level is randomized from one stimulus to the next. The threshold for detecting an increment in level of a single component is reduced when flanking components equal in amplitude to the pedestal are added. In general, this effect has not been found when the flanking components are presented dichotically. The present work examines the extent of the similarity, and divergence, between CMR and PA. For the PA conditions, a five‐component sinusoidal complex was used; its level was varied randomly over a 40‐dB range. For the CMR conditions, each of the five components was 100% sinusoidally amplitude modulated at a 10‐Hz rate. Two intermediate conditions of PA without the level variation, and CMR with the level variation, were also run. All four conditions were run monaurally and dichotically. A reference condition in which only one masking component was present was also used. For PA conditions when the stimulus level was randomized, thresholds in the monaural and dichotic conditions were 16 and 11 dB lower than in the reference condition, respectively. By contrast, for the CMR conditions, whether the stimulus level was randomized or not, thresholds in the reference, monaural and dichotic conditions differed by little more than 3 dB; i.e., no CMR was observed. Further experiments are now in progress to determine why a CMR was not observed in these conditions.

Gap detection in narrow bands of noise as a function of the number and proximity of the bands

The minimum detectable gap in a noise decreases both as the bandwidth of the noise increases and as the number of independent noise bands carrying the gap increases. The present study attempted to relate these two observations by differentiating between the parameters of bandwidth and number of active channels. The stimuli consisted of either one band or five independent bands of noise, each 20 Hz wide. In all conditions, one of the bands was centered on 1000 Hz. The multiple bands were either juxtaposed to give a single band of noise centered on 1000 Hz or were spaced in various configurations, resulting in a set of conditions ranging from all bands passing through a single auditory channel to each band passing through an independent channel. The stimuli were presented at a spectrum level equal to that of a 15‐dB SL, 20‐Hz‐wide band of noise centered on 1000 Hz. The gap was imposed with a 10‐ms rise‐fall time. Gap thresholds improved with an increased cumulative bandwidth, but more so for the spaced band...

Visual primacy in social attitude judgement: a qualification.

Previous research has suggested that visual information has primacy over verbal and vocal information in the judgement of social attitude. However, this could be because the contextual inappropriateness of the verbal information switched attention away from the auditory channel and on to the visual. The experiment reported in this paper assesses this possibility by considering the contribution made by visual information when the verbal is appropriate. Focusing on the expression of superior and inferior attitude, it finds that visual information does not simply fail to achieve primacy. It is markedly less important than either vocal or verbal information, which both play more or less equal roles.

Neurophysiological evidence of auditory channel anomalies in developmental dysphasia.

Steady-state auditory evoked responses to frequency-modulated tones were obtained from normal children and two groups of children with developmental language disorders (developmental dysphasia). Children with predominantly expressive language impairment produced responses not different from normal children, while children with primary receptive language impairment produced responses that were markedly diminished, even absent. This occurred in recordings from either cerebral hemisphere and at mean frequency-modulation depths ranging from +/- 20 to +/- 100 Hz. Pathophysiology of auditory mechanisms concerned with frequency-modulation analysis are particularly associated with receptive developmental language impairment and may underlie associated difficulties in speech perception.

Interference of modulation rate discrimination of pure tones

Modulation rate discrimination (Δfm) thresholds were obtained for sinusoidally amplitude modulated (SAM) pure tones. The carrier frequencies were 1000 and 4000 Hz and the modulation rates were 5, 10, 20, and 50 Hz. The Δfm thresholds of one carrier (the probe) were also obtained when the other carrier (the masker) was presented simultaneously. The masker was either SAM or was unmodulated. In all conditions the depth of SAM was 100%. This experiment was designed to determine how much the modulated masker interferes with the discrimination of modulation rate and how this interference changes as a function of the difference in modulation rate between the masker and probe. It has been shown previously [Yost and Sheft, J. Acoust. Soc. Am. Suppl. 1 83, S35 (1988)] that a modulated masker interfered significantly with a listener's ability to detect SAM of the probe when the masker and probe were modulated at the same rate. This modulated detection interference (MDI) was reduced when the masker was modulated at a different rate than the probe. These earlier results suggested that there might be auditory channels “tuned” to different rates of amplitude modulation. The present experiment was designed to further test the concept of AM tuned channels. [This research was supported by the NINCDS.]

The ear as a speech analyzer

The representation of speech in the auditory periphery is evaluated from the perspectives of physiology and psychoacoustics. Current models fall into one of four broad classes: rate/place, synchrony/place, synchrony/quasi-place and synchrony/place-independent. Each representational type is evaluated in terms of its ability to account for the perceptual features of speech and on the basis of physiological plausibility. The optimum representational form may vary as a function of the acoustic environment. It is suggested that the rate/place representation operates primarily at low sound-pressure levels and for encoding the gross spectral characteristics of the high-frequency portion of aperiodic signals, such as stops and fricatives. The synchrony/place and synchrony/quasi-place representations may also play an important role, primarily at low sound-pressure levels and under conditions of low signal-to-noise ratio in the high-frequency auditory channels. The place-independent synchrony pattern may provide the basis for the representation of voiced sounds (particularly vowels) at moderate-to-high sound-pressure levels and for conditions where the signal-to-noise ratio in the low-frequency channels is particularly poor. The “onset” units of the posteroventral cochlear nucleus may act to integrate such across-channel synchronous activity to provide a stable of representation of the signal spectrum in terms of both rate and temporal activity.

Lateralization on the basis of interaural envelope delays: The effect of additional frequency components

A lateralization experiment was performed in which threshold interaural envelope delays were measured as a function of modulation frequency (fm = 25, 50, 100, 200, 300, 400, and 500 Hz) for three‐ and five‐component complexes whose center frequency (fc) was either 2000 or 4000 Hz. A two‐alternative forced‐choice procedure was used in which the envelope lagged to the right ear during one interval and to the left interval during the other. The level of each component was 50 dB SPL, and the signal duration was 200 ms with 10‐ms linear rise‐decay times. Thresholds obtained with three‐ and five‐component complexes were quite similar regardless of fm, a finding that seemed consistent with the notion that the envelope is extracted from components interacting within an auditory filter, with more distal components having no effect. Surprisingly, making the outermost sidebands (fc − 2fm and fc + 2fm) diotic was found to severely impare one's ability to utilize envelope delays even when the fm's were quite high. These findings place in doubt the contention that the binaural auditory system extracts envelopes by monitoring the outputs of narrow‐band auditory channels. [Work supported by NINCDS and AFOSR.]

The effect of signal-frequency uncertainty in a CMR paradigm

The phenomenon of comodulation masking release (CMR) indicates that the auditory system is capable of comparing the outputs of several auditory channels simultaneously. The presence of the signal is presumed to be cued by a dissimilarity in the temporal pattern in that channel, relative to the remaining comodulating channels, due to the addition of the signal. In its simplest form, such a cuing mechanism could operate quite independently of any a priori knowledge of which channel the signal occurs in. To test this possibility, a study was undertaken to compare the effect of signal-frequency uncertainty in a comodulated and a noncomodulated background. It was hypothesized that the detection of a signal whose frequency fluctuated randomly from trial to trial would be less deleteriously affected in a comodulating background than in a noncomodulating background. A novel feature of this study was the use of amplitude-modulated pure-tone components as the background masker. Results to date indicate that the effect of signal-frequency uncertainty is itself small relative to fixed-frequency signals, and no significant difference has emerged between its measurement in comodulated versus uncomodulated backgrounds.

Effects of Rote Versus Note Presentations on Rhythm Learning and Retention

This study examined the effects of aural and visual approaches to rhythm reading and short-term retention. Second- and sixth-grade students were presented with two-measure rhythm patterns in four modes: (1) audio-rhythm, (2) audio-mnemonics, (3) (audio) visual-rhythm, and (4) (audio) visual-mnemonics. Raw data consisted of the number of trials necessary for the correct performance of the rhythms on a woodblock. Results indicated that the simultaneous use of auditory and visual channels facilitates learning and retention of rhythms at both grade levels. Maturation is significant in the acquisition of rhythms, in that older students learned the patterns twice as quickly as the younger children, regardless of presentation mode. Factors concerning the mnemonics, short-term memory, and the development of music literacy were discussed.

Temporal changes in a complex spectral profile.

The spectral properties of a complex stimulus (rippled noise) were varied over time, and listeners were asked to discriminate between this stimulus and a flat-spectrum, stationary noise. The spacing between the spectral peaks of rippled noise was changed sinusoidally as a function of time, or the location of the spectral peaks of rippled noise was moved up and down the spectrum as a sinusoidal function of time. In most conditions, listeners were able to make the discriminations up to rates of temporal modulation of 5-10 cycles per second. Beyond 5-10 cps the rippled noise with the temporally varying peaks was indiscriminable from a flat (nonrippled) noise. The results suggest that for temporal changes in the spectral peaks of rippled noise, listeners cannot monitor the output of a single (or small number of) auditory channel(s) (critical bands), or that the mechanism used to extract the perceptual information from these stimuli is slow. Temporal variations in the spectral properties of rippled noise may relate to temporal changes in the repetition pitch of complex sounds, the temporal properties of the coloration added to sound in a reverberant environment, and the nature of spectral peak changes such as those that occur in speech-formant transitions. The results are relevant to the general issue of the auditory system's ability to extract information from a complex spectral profile.