摘要:

Binaural adaptation was combined with a dichotic ear‐monitoring task to estimate the output function of the voiceless detector sensitive to VOT and to determine how this function is modified by selective adaptation. On each test trial, a voiced stop was paired with one of a set of voiceless stops, which spanned a range of VOT values. The percentage of voiceless responses per pair, which reflects both the number of correct voicing judgments on voiceless targets and the number of voiceless intrusions on voiced targets, was measured before and after adaptation with a voiced stimulus and a variety of voiceless stimuli. Before adaptation, the percentage of voiceless responses per pair systematically increased with an increase in the VOT value of the voiceless stimulus of the pair. Adaptation resulted in a shift in the percentage of voiceless responses per pair in the predicted direction, with progressively larger shifts occurring for voiceless adapting stimuli with higher VOT values. These results indicate (1) that the output of the detector is graded signal whose magnitude is an increasing function of VOT value and (2) that adaptation depresses the entire output function from its preadaptation level, with the amount of depression determined by the extent to which the adapting stimulus excites the detector.

ISSN:0001-4966    

DOI:10.1121/1.381577

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

We have investigated the way in which stimulus variability will affects the attenuation characteristic or auditory filter shape inferred from masking experiments. Stimulus variability was found to have a pronounced effect on filter shapes derived from bandlimiting experiments in which the signal is a tone, the masker is a band of noise centered on the tone, and the independent variable is the width of the noise band. But stimulus variability had virtually no effect on filters obtained from notched noise masking experiments. In an attempt to extend the utility of the filter‐shape concept we have replicated an earlier experiment in which the masker is two tones rather than noise. The tones, each 57 dB SPL, were used to mask a narrow band of noise centered midway between them and threshold for the noise signal was measured as a function of the frequency separation of the tonal maskers. The form of the data is in good agreement with the auditory filter shape derived using a notched‐noise masker and a tonal signal. In order to predict the absolute levels obtained in the noise‐masking experiments, it was necessary to assume that internal noise adds to the variability of the stimuli. The resulting model, which incorporates the filter shape from the notched noise experiment and the energy detection model, predicts not only the form but also the absolute levels obtained in the bandlimiting and notched noise experiments. In addition, it predicts the shape of the data from the two‐tone masking experiment but it does not predict the overall level.

ISSN:0001-4966    

DOI:10.1121/1.381578

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

Electronic models that process signals to simulate omissions and distortions in perception by the deaf are useful analytical tools. These models can help in determining the degree to which the represented loss and/or distortion of acoustic speech cues, isolated from any central pathology, affects speech intelligibility. They can also help in evaluating the potential effectiveness of different modes of compensatory signal processing. Three examples of such models, designed on the basis of measured characteristics of the deaf subjects’ residual hearing, are described. A model of recruitment combined with accentuated high‐frequency loss is used to study speech perception in noise. It suggests an explanation for the previously reported ability of sensorineurals to tolerate the masking of speech by white noise at least as well as normals do, and for the special vulnerability of the speech perception of such deaf subjects to masking signals that have the spectral distribution of speech. A second model, that simulates the severely restricted dynamic range of hearing in profound deafness, predicts that this one factor can destroy the intelligibilty of amplified speech by making the perceived sound drop out at frequent intervals. Finally, a model that simulates reduced frequency‐discriminating ability is described, as an example of a model that deals with aspects of perception other than loudness.

ISSN:0001-4966    

DOI:10.1121/1.381579

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

Data on loundness comparisons are complemented by additional measurements. Thus, temporal effects in loudness with respect to four parameters can be summarized: (a) phase effects of complex tones and the influence of physiological noise, both in the low‐frequency range, (b) effects of amplitude modulation, (c) frequency modulation, and (d) bandwidth in the high‐frequency range. Additionally, transient masking patterns and the corresponding specific loudness patterns produced by strongly time‐varying sounds are discussed. A model for the loudness development of such sounds is designed and realized electronically as a loudness measuring device. The usefulness of this equipment is demonstrated for measuring loudness of the following six types of sounds that vary both temporally and spectrally: (a) single tone bursts as a function of duration, (b) sinusoidally amplitude modulated tones as a function of repetition rate, (c) bandpass noise with constant rms value as a function of bandwidth within the critical band, (d) strongly frequency modulated tones as a function of modulation frequency, (e) temporally partially masked tone bursts, and (f) continuous speech.

ISSN:0001-4966    

DOI:10.1121/1.381580

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

A series of experiments was conducted to determine the extent to which speakers’ syntactic coding influences fundamental frequency (F0) contours in the region of syntactic boundaries.F0measurements were obtained for groups of nine and ten speakers by computer using a parallel processing algorithm. Measurements were obtained for key word segments at syntactic boundaries in sentences matched for surrounding phonetic environment and stress pattern. In experiment I, statistically significant fall–rise patterns ofF0were obtained at the boundaries between main conjoined clauses and at the boundaries between main and embedded clauses. The fall–rise pattern was somewhat more pronounced at the boundaries between two conjoined clauses. The results with main‐embedded clause boundaries provided the basis for experiment II, in which contours were studied at the boundaries between main and embedded clauses for which the location of the boundaries is controversial on linguistic grounds. In experiment III, the study of fall–rise patterns was extended to major phrase boundaries in sentences having subject‐verb‐object word order and in sentences for which such order was violated by the fronting of a constituent to the beginning of the sentence. The results showed more pronounced postboundary rises inF0after the fronted constituents. The results for experiments I and III suggested that the fall–rise patterns observed at clause and phrase boundaries typically represented local effects rather than the resetting of the speakers’ declination line. Finally, separate analyses of data for male and female speakers showed thatF0values for females were approximately 1.8 times those of males at each measured point in theF0contours for all three experiments, suggesting the presence of a single male–female scaling factor forF0.

ISSN:0001-4966    

DOI:10.1121/1.381556

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

A new analytic procedure PARAFAC has been applied to the description of the shape of the tongue in English vowels. The procedure models the data in terms of a unique set of possibly explanatory factors. It solves in parallel for factors in several data sets, simultaneously describing the differences among data sets in terms of different relative involvement of these common factors. Tracings were made of x‐rays taken during the pronunciation of 10 English vowels by five speakers. The positions of the tongue in these 50 vowels were quantized in terms of 13 superimposed grid lines. PARAFAC analysis shows that the data can be described in terms of two factors. One factor generates a forward movement of the root of the tongue accompanied by an upward movement of the front of the tongue. The second factor generates an upward and backward movement of the tongue. Movements from front to back vowels involve decreasing amounts of factor one. Movements from high to low vowels involve decreasing amounts of factor two. Different speakers use the two factors to different degrees which may be associated with their individual anatomy. The correlation between the observed data and that predicted by the model is greater than 0.96.

ISSN:0001-4966    

DOI:10.1121/1.381581

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

A procedure is described for possible use in automatic identification of the language being spoken. The method is to assume that the gross linguistic classes of a language are characterized by certain statistical constraints, namely, they are probabilistic functions of a Markov chain; and that these gross classes can be identified automatically with usable accuracy. The present discussion is in the form of a feasibility experiment and deals only with artificial data (data not derived from acoustic signals). The results indicate that statistical models, as described, can discriminate amongst languages.

ISSN:0001-4966    

DOI:10.1121/1.381582

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

Listening experiments with spliced speech showed that cues for the perception of word juncture occurred always at word onset, at word offset only for /l/ and /r/, and never word medially. Spectrograms showed the cues to be bursts, aspiration, glottal stops, laryngealization, and distinct syllable‐initial allophones of /l/ and /r/.

ISSN:0001-4966    

DOI:10.1121/1.381583

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

This paper discusses methodological issues and problems related to measuring laterality effects in dichotic listening. Section I describes the standard dichotic two‐response paradigm, as well as a number of indices of the degree of ear advantage proposed in the literature. The numerical range of most of these indices is constrained by performance level; only one particular index avoids these constraints. However, this does not make this index necessarily the optimal one. First, a correction for guessing is proposed. Then, analogies to signal‐detection theory are discussed, as well as theoretical and empirical criteria for choosing the correct index of laterality. While this index is still unknown, the index called hereegis proposed as the best solution at the present state of knowledge. Section II discusses the phenomenon of dichotic fusion and the dichotic single‐response paradigm, which offers many methodological advantages over the two‐response paradigm. Section III discusses the factors of ear dominance and stimulus dominance in the perception of fused stimuli. An index of ear dominance is derived by again taking advantage of analogies to signal‐detection theory. In Sec. IV, a number of remaining problems are discussed: stimulus intelligibility, guessing and selective attention, blend responses, test reliability, validity, and homogeneity.

ISSN:0001-4966    

DOI:10.1121/1.381584

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP

摘要:

Recent accounts of selective adaptation in speech perceptin have proposed that either one or two leves of processing are adapted. Most of the previous experimental results can, however, be accounted for by either type of model. In the present experiments, two aspects of the selective adaptation paradigm were manipulated. The spectral (frequency) overlap between adapting and test syllables was manipulated along with differences in interaural presentation (adapting in one ear, testing in the other). The results indicated that the adapting syllables drawn from the test series and adaptors with no spectral overlap with the test series both produced significant changes in subjects ratings of the test stimuli. However, the identical adaptors caused significantly more adaptation than the nonoverlapping adaptors. Moreover, the nonoverlapping adaptors produced 100% interaural transfer of adaptation, indicating a central locus of this effect. The identical adaptors drawn from the test series showed approximately 50% interaural transfer. Taken together, these results strongly suggest that two levels of processing are involved in selective adaptation to place of articulation in stop consonants. One is a peripheral level that is relatively frequency specific and the other is a central level that integrates information over a wider frequency (spectral) range.

ISSN:0001-4966    

DOI:10.1121/1.381545

出版商:Acoustical Society of America    

年代:1977

数据来源: AIP