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Previous studies have shown that for high-rate click trains and low-frequency pure tones, interaural time differences (ITDs) at the onset of stimulus contribute most strongly to the overall lateralization percept (receive the largest perceptual weight). Previous studies have also shown that when these stimuli are modulated, ITDs during the rising portion of the modulation cycle receive increased perceptual weight. Baltzell, Cho, Swaminathan, and Best [(2020). J. Acoust. Soc. Am. 147, 3883–3894] measured perceptual weights for a pair of spoken words (“two” and “eight”), and found that word-initial phonemes receive larger weight than word-final phonemes, suggesting a “word-onset dominance” for speech. Generalizability of this conclusion was limited by a coarse temporal resolution and limited stimulus set. In the present study, temporal weighting functions (TWFs) were measured for four spoken words (“two,” “eight,” “six,” and “nine”). Stimuli were partitioned into 30-ms bins, ITDs were applied independently to each bin, and lateralization judgements were obtained. TWFs were derived using a hierarchical regression model. Results suggest that “word-initial” onset dominance does not generalize across words and that TWFs depend in part on acoustic changes throughout the stimulus. Two model-based predictions were generated to account for observed TWFs, but neither could fully account for the perceptual data.

The accent advantage effect in phoneme monitoring-faster responses to a target phoneme at the beginning of an L + H*-accented word than to a target phoneme at the beginning of an unaccented word-is viewed as a product of listeners' predictive capabilities [Cutler (1976). Percept. Psychophys. 20(1), 55-60]. However, previous studies have not established what information listeners use to form these predictions [Cutler (1987). Proceedings of the International Congress of Phonetic Sciences, pp. 84-87; Cutler and Darwin (1981). Percept. Psychophys. 29(3), 217-224]. This article presents evidence that at least the information in the syllable immediately preceding a target phoneme is necessary to cue the predictive attention allocation that underlies the accent advantage effect.

Speech-on-speech informational masking arises because the interferer disrupts target processing (e.g., capacity limitations) or corrupts it (e.g., intrusions into the target percept); the latter should produce predictable errors. Listeners identified the consonant in monaural buzz-excited three-formant analogues of approximant-vowel syllables, forming a place of articulation series (/w/-/l/-/j/). There were two 11-member series; the vowel was either high-front or low-back. Series members shared formant-amplitude contours, fundamental frequency, and F1+F3 frequency contours; they were distinguished solely by the F2 frequency contour before the steady portion. Targets were always presented in the left ear. For each series, F2 frequency and amplitude contours were also used to generate interferers with altered source properties—sine-wave analogues of F2 (sine bleats) matched to their buzz-excited counterparts. Accompanying each series member with a fixed mismatched sine bleat in the contralateral ear produced systematic and predictable effects on category judgments; these effects were usually largest for bleats involving the fastest rate or greatest extent of frequency change. Judgments of isolated sine bleats using the three place labels were often unsystematic or arbitrary. These results indicate that informational masking by interferers involved corruption of target processing as a result of mandatory dichotic integration of F2 information, despite the grouping cues disfavoring this integration.

Integration of auditory and aero-tactile information during speech perception has been documented during two-way closed-choice syllable classification tasks [Gick and Derrick (2009). Nature 462, 502–504], but not during an open-choice task using continuous speech perception [Derrick, O'Beirne, Gorden, De Rybel, Fiasson, and Hay (2016). J. Acoust. Soc. Am. 140(4), 3225]. This study was designed to compare audio-tactile integration during open-choice perception of individual syllables. In addition, this study aimed to compare the effects of place and manner of articulation. Thirty-four untrained participants identified syllables in both auditory-only and audio-tactile conditions in an open-choice paradigm. In addition, forty participants performed a closed-choice perception experiment to allow direct comparison between these two response-type paradigms. Adaptive staircases, as noted by Watson [(1983). Percept. Psychophys. 33(2), 113–120] were used to identify the signal-to-noise ratio for identification accuracy thresholds. The results showed no significant effect of air flow on syllable identification accuracy during the open-choice task, but found a bias towards voiceless identification of labials, and towards voiced identification of velars. Comparison of the open-choice results to those of the closed-choice task show a significant difference between both response types, with audio-tactile integration shown in the closed-choice task, but not in the open-choice task. These results suggest that aero-tactile enhancement of speech perception is dependent on response type demands.Integration of auditory and aero-tactile information during speech perception has been documented during two-way closed-choice syllable classification tasks [Gick and Derrick (2009). Nature 462, 502–504], but not during an open-choice task using continuous speech perception [Derrick, O'Beirne, Gorden, De Rybel, Fiasson, and Hay (2016). J. Acoust. Soc. Am. 140(4), 3225]. This study was designed to compare audio-tactile integration during open-choice perception of individual syllables. In addition, this study aimed to compare the effects of place and manner of articulation. Thirty-four untrained participants identified syllables in both auditory-only and audio-tactile conditions in an open-choice paradigm. In addition, forty participants performed a closed-choice perception experiment to allow direct comparison between these two response-type paradigms. Adaptive staircases, as noted by Watson [(1983). Percept. Psychophys. 33(2), 113–120] were used to identify the signal-to-noise ratio for identification acc...

Humans possess mechanisms to suppress distracting early sound reflections, summarized as the precedence effect. Recent work shows that precedence is affected by visual stimulation. This paper investigates possible effects of visual stimulation on the perception of later reflections, i.e., reverberation. In a highly immersive audio-visual virtual reality environment, subjects were asked to quantify reverberation in conditions where simultaneously presented auditory and visual stimuli either match in room identity, sound source azimuth, and sound source distance, or diverge in one of these aspects. While subjects reliably judged reverberation across acoustic environments, the visual room impression did not affect reverberation estimates.

Pitch is a fundamental attribute in auditory perception involved in source identification and segregation, music, and speech understanding. Pitch percepts are intimately related to harmonic resolvability of sound. When harmonics are well-resolved, the induced pitch is usually salient and precise, and several models relying on autocorrelations or harmonic spectral templates can account for these percepts. However, when harmonics are not completely resolved, the pitch percept becomes less salient, poorly discriminated, with upper range limited to a few hundred hertz, and spectral templates fail to convey percept since only temporal cues are available. Here, a biologically-motivated model is presented that combines spectral and temporal cues to account for both percepts. The model explains how temporal analysis to estimate the pitch of the unresolved harmonics is performed by bandpass filters implemented by resonances in dendritic trees of neurons in the early auditory pathway. It is demonstrated that organizing and exploiting such dendritic tuning can occur spontaneously in response to white noise. This paper then shows how temporal cues of unresolved harmonics may be integrated with spectrally resolved harmonics, creating spectro-temporal harmonic templates for all pitch percepts. Finally, the model extends its account of monaural pitch percepts to pitches evoked by dichotic binaural stimuli.

Results of the first formal perceptual study of jet crackle are presented. Prior studies examined noise waveform properties believed to be linked to the jet crackle percept from a physics perspective or using signal processing and informal subjective evaluation. This investigation involves 31 listeners that rated 15 jet noise waveforms with a category subdivision scaling test. Results reveal a strong log-linear correlation between the pressure waveform time derivative's skewness and crackle rating. A regression analysis establishes practical derivative skewness bounds for a five-point categorical crackle scale and results in the suggested definition of the crepit as the unit of crackliness.

Bilateral cochlear implant users often have difficulty fusing sounds from the two ears into a single percept. However, measuring fusion can be difficult, particularly with cochlear implant users who may have no reference for a fully fused percept. As a first step to address this, this study examined how localization performance of normal hearing subjects relates to binaural fusion. The stimuli were vocoded speech tokens with various interaural mismatches. The results reveal that the percentage of stimuli perceived as fused was correlated with localization performance, suggesting that changes in localization performance can serve as an indicator for binaural fusion changes.

This study adopted the Musical Ear Test [Wallentin, Nielsen, Friis-Olivarius, Vuust, and Vuust (2010). Learn. Indiv. Diff. 20, 188–196] to compare musical competence of sighted and congenitally blind Mandarin speakers. On the rhythm subtest, the blind participants outperformed the sighted. On the melody subtest, however, the two groups performed equally well. Compared with sighted speakers of non-tonal languages reported in previous studies [Wallentin, Nielsen, Friis-Olivarius, Vuust, and Vuust (2010). Learn. Indiv. Diff. 20, 188–196; Bhatara, Yeung, and Nazzi (2015). J. Exp. Psychol. Hum. Percept. Perform. 41(2), 277–282], sighted Mandarin speakers performed better only on the melody subtest. These results indicate that tonal language experience and congenital blindness exert differential influences on musical aptitudes with rhythm perception reflecting a cross-modal compensation effect and melody perception dominated by a cross-domain language-to-music transfer effect.

Voice actors are an interesting population for linguistic study because their professional field requires them to perform complex vocal tract manipulations in order to consistently and believably convey many different character types. Previous investigations have looked at how voice actors manipulate laryngeal setting and voice quality, to portray specific types of characters in animation (Teshigawara and Murano, 2004; Starr, 2015), but investigations of articulatory manipulations employed by voice actors are rare. This study uses 3-D ultrasound and acoustic analyses to compare the different kinds of articulatory and phonatory strategies that different actors use in order to approximate a smaller vocal tract and achieve a similar ‘childlike’ percept. Preliminary analysis shows that one amateur actor relies on manipulation of articulatory setting by implementing hyoid bone raising, gesture fronting, and tongue grooving, whereas one professional actor relies more on manipulation of laryngeal structures and prosody. Despite these differences in approach, the two actors still achieve similar child-like percepts. This poster will compare strategies from two female and two male subjects as well as describe within-subject variation across each actor’s adult and imitated child voices.Voice actors are an interesting population for linguistic study because their professional field requires them to perform complex vocal tract manipulations in order to consistently and believably convey many different character types. Previous investigations have looked at how voice actors manipulate laryngeal setting and voice quality, to portray specific types of characters in animation (Teshigawara and Murano, 2004; Starr, 2015), but investigations of articulatory manipulations employed by voice actors are rare. This study uses 3-D ultrasound and acoustic analyses to compare the different kinds of articulatory and phonatory strategies that different actors use in order to approximate a smaller vocal tract and achieve a similar ‘childlike’ percept. Preliminary analysis shows that one amateur actor relies on manipulation of articulatory setting by implementing hyoid bone raising, gesture fronting, and tongue grooving, whereas one professional actor relies more on manipulation of laryngeal structures and ...

Visual speech cues play an important role in speech recognition, and the McGurk effect is a classic demonstration of this. In the original McGurk and MacDonald (1976) experiment, 98% of participants reported an illusory “fusion” percept of /d/ when listening to the spoken syllable /b/ and watching the visual speech movements for /g/. However, recent work (e.g., Mallick et al., 2015) shows that subject and task differences influence the proportion of fusion responses. In the current study, we varied task (forced-choice versus open-ended), stimuli (synthetic versus naturally produced), design (mixed versus blocked audio-visual and single-modality trials), and data collection environment (lab versus Mechanical Turk) to investigate the robustness of the McGurk effect. Across all conditions, we found a low number of fusion responses. Rather than a robust perceptual illusion, we therefore argue that the McGurk effect is a product of individual differences and task demands.

Freeman et al. (J. Exp. Psych.: Hum. Percept. Perform., 2017) demonstrated an auditory analog to the visual Filehne Illusion. For the auditory Filehne Illusion, a stationary sound source is often perceived as rotating in the opposite direction of head rotation, i.e., in a head-centric direction based on the changing auditory-spatial cues due to head rotation. We investigated conditions like the auditory Filehne Illusion for a variety of stimulus and rotation conditions to gain additional insights into how head-position information might compensate for head-centric information (derived from the auditory-spatial cues) to form world-centric, sound-source localization estimates.

Coherence masking protection (CMP) is the phenomenon in which a low-frequency target (typically a first formant) is labeled accurately in poorer signal-to-noise levels when combined with a high-frequency cosignal, rather than presented alone. An earlier study by the authors revealed greater CMP for children than adults, with more resistance to disruptions in harmonicity across spectral components [Nittrouer and Tarr (2011). Atten. Percept. Psychophys. 73, 2606-2623]. That finding was interpreted as demonstrating that children are obliged to process speech signals as broad spectral patterns, regardless of the harmonic structure of the spectral components. The current study tested three alternative, auditory explanations for the observed coherence of target + cosignal: (1) unique spectral shapes of target + cosignal support labeling, (2) periodicity of target + cosignal promotes coherence, and (3) temporal synchrony across target + cosignal reinforces temporal expectancies. Adults, eight-year-olds, and five-year-olds labeled stimuli in five conditions: F1 only and F1 + a constant cosignal (both used previously) were benchmarks for comparing thresholds for F1 + 3 new cosignals. Children again showed greater CMP than adults, but none of the three hypotheses could explain their CMP. It was again concluded that children are obliged to recognize speech signals as broad spectral patterns.

This study investigates the importance of source spectrum slopes in the perception of phonation by White Hmong listeners. In White Hmong, nonmodal phonation (breathy or creaky voice) accompanies certain lexical tones, but its importance in tonal contrasts is unclear. In this study, native listeners participated in two perceptual tasks, in which they were asked to identify the word they heard. In the first task, participants heard natural stimuli with manipulated F0 and duration (phonation unchanged). Results indicate that phonation is important in identifying the breathy tone, but not the creaky tone. Thus, breathiness can be viewed as contrastive in White Hmong. Next, to understand which parts of the source spectrum listeners use to perceive contrastive breathy phonation, source spectrum slopes were manipulated in the second task to create stimuli ranging from modal to breathy sounding, with F0 held constant. Results indicate that changes in H1-H2 (difference in amplitude between the first and second harmonics) and H2-H4 (difference in amplitude between the second and fourth harmonics) are independently important for distinguishing breathy from modal phonation, consistent with the view that the percept of breathiness is influenced by a steep drop in harmonic energy in the lower frequencies.

International audience; Subjects presented with coherent auditory and visual streams generally fuse them into a single per- cept. This results in enhanced intelligibility in noise, or in visual modification of the auditory per- cept in the McGurk effect. It is classically considered that processing is done independently in the auditory and visual systems before interaction occurs at a certain representational stage, resulting in an integrated percept. However, some behavioral and neurophysiological data suggest the existence of a two-stage process. A first stage would involve binding together the appropriate pieces of audio and video information before fusion per se in a second stage. Then it should be possible to design experiments leading to unbinding . It is shown here that if a given McGurk stimulus is preceded by an incoherent audiovisual context, the amount of McGurk effect is largely reduced. Various kinds of incoherent contexts (acoustic syllables dubbed on video sentences or phonetic or temporal modi- fications of the acoustic content of a regular sequence of audiovisual syllables) can significantly reduce the McGurk effect even when they are short (less than 4s). The data are interpreted in the framework of a two-stage "binding and fusion" model for audiovisual speech perception.

Users of bilateral cochlear implants and a cochlear implant combined with a contralateral hearing aid are sensitive to interaural time differences (ITDs). The way cochlear implant speech processors work and differences between modalities may result in interaural differences in shape of the temporal envelope presented to the binaural system. The effect of interaural differences in envelope shape on ITD sensitivity was investigated with normal-hearing listeners using a 4 kHz pure tone modulated with a periodic envelope with a trapezoid shape in each cycle. In one ear the onset segment of the trapezoid was transformed by a power function. No effect on the just noticeable difference in ITD was found with an interaural difference in envelope shape, but the ITD for a centered percept was significantly different across envelope shape conditions.

Natural auditory scenes typically include some motion. When this motion is the result of a moving listener, as is often the case, an accurate spatial percept requires that the listener be able to: 1) determine sound source location over time, 2) determine the extent and characteristics of his/her own motion, and 3) integrate these two pieces of information together. We assembled a battery of tests to evaluate these three criteria in normal, hearing-impaired, and balance-impaired listeners. The battery consists of a dynamic visual acuity test to estimate the listener’s self-motion processing, a measure of the minimum audible movement angle to determine source-motion acuity, and an adapted version of a previously published dynamic front/back illusion to examine the ability to combine self and sound-source motion. We found that listeners with potential vestibular impairment were more likely to have larger differences between source-motion acuity and self-motion integration acuity. This finding and the observ...

How are laminar circuits of neocortex organized to generate conscious speech and language percepts? How does the brain restore information that is occluded by noise, or absent from an acoustic signal, by integrating contextual information over many milliseconds to disambiguate noise-occluded acoustical signals? How are speech and language heard in the correct temporal order, despite the influence of contexts that may occur many milliseconds before or after each perceived word? A neural model describes key mechanisms in forming conscious speech percepts, and quantitatively simulates a critical example of contextual disambiguation of speech and language; namely, phonemic restoration. Here, a phoneme deleted from a speech stream is perceptually restored when it is replaced by broadband noise, even when the disambiguating context occurs after the phoneme was presented. The model describes how the laminar circuits within a hierarchy of cortical processing stages may interact to generate a conscious speech percept that is embodied by a resonant wave of activation that occurs between acoustic features, acoustic item chunks, and list chunks. Chunk-mediated gating allows speech to be heard in the correct temporal order, even when what is heard depends upon future context.

Tonal music is characterized by a hierarchical structuring of pitch, whereby certain tones appear stable and others unstable within their musical context. Despite its prevalence, the cortical mechanisms supporting such a percept remain poorly understood. We examined the neural processing dynamics underlying pitch-structure in Western Tonal Music. Listeners were presented with tones embedded within a musical context whilst their magnetoencephalographic (MEG) activity was recorded. Using multivariate pattern analysis, decoders attempted to classify the identity of tones from their corresponding MEG activity at each peristimulus time-sample, providing a dynamic measure of their cortical dissimilarity. Time-evolving neural distinctions were then compared with the predictions of several acoustic and perceptual models. Following the onset, a temporal evolution was witnessed in the representational structure in cortex. While MEG dissimilarities between tones initially corresponded to their fundamental frequency separation, distinctions beyond 200 ms reflected their status within the hierarchy of perceived stability. Transposing dissimilarities corresponding to this latter period into different keys, neural relations between keys correlated with the well-known circle of fifths. Convergent with fundamental principles of music-theory and perception, results detail the dynamics with which the complex perceptual structure of Western tonal music emerges in human cortex within the timescale of an individual tone.Tonal music is characterized by a hierarchical structuring of pitch, whereby certain tones appear stable and others unstable within their musical context. Despite its prevalence, the cortical mechanisms supporting such a percept remain poorly understood. We examined the neural processing dynamics underlying pitch-structure in Western Tonal Music. Listeners were presented with tones embedded within a musical context whilst their magnetoencephalographic (MEG) activity was recorded. Using multivariate pattern analysis, decoders attempted to classify the identity of tones from their corresponding MEG activity at each peristimulus time-sample, providing a dynamic measure of their cortical dissimilarity. Time-evolving neural distinctions were then compared with the predictions of several acoustic and perceptual models. Following the onset, a temporal evolution was witnessed in the representational structure in cortex. While MEG dissimilarities between tones initially corresponded to their fundamental frequency ...

Auditory perception depends on more than just the processing of acoustic stimuli. Visual stimuli can also have a profound influence on listening. Salient examples of such effects include spatial ventriloquism—in which the location percept of an auditory stimulus is “captured” by that of a simultaneous visual stimulus—as well as drastically improved understanding of speech in noise when the talker's face is visible to the listener. These phenomena are typically described as “audio-visual integration,” and are often well modeled, as in the case of the ventriloquist effect, by ideal Bayesian causal inference. However, there is an over-reliance in these studies on single pairs of stimuli (i.e., one auditory and one visual stimulus) and the nature in which cross-modal discrepancies are resolved. This talk will first discuss two problems resulting from that: first, there is ambiguity about whether the integration occurs from weighing two independent sensory estimates or a single bound percept, and second, the design is less useful for studying integration when the stimuli are congruent. The talk will then describe recent work from our lab focused on new designs using multiple stimuli in an attempt to alleviate these issues and inform better models of integration.

The binaural beat has been used for over one hundred years as a stimulus for generating the percept of motion. Classically the beat consists of a pure tone at one ear (e.g. 500 Hz) and the same pure tone at the other ear but shifted upwards or downwards in frequency (e.g., 501 Hz). An experiment and binaural computational analysis are reported which demonstrate that a more powerful motion percept can be obtained by applying the concept of the frequency shift to a noise, via an upwards or downwards shift in the frequency of the Fourier components of its spectrum.

Exposing one ear to a series of brief 80 dB sound pressure level (SPL) inducing tones reduces the tendency to lateralize subsequent target tones to that ear and shifts the point of subjective equality (PSE) toward the unexposed ear. Furthermore, targets with average SPLs of 60 and 80 dB at the two ears showed similar changes in PSE. These results support and extend earlier findings of Arieh and Marks (2007). Percept. Psychophys. 69, 523-528 and suggest the presence of a mechanism, located at least partially before the site of binaural integration, that depresses the magnitude of intensity information from the ear in response to moderately intense transient stimuli. Assuming that lateralization depends on the ratio of the magnitude of intensity information from the two ears that reach the central integrator, the results imply that the inducer reduced the representations of magnitude of 60 and 80 dB test tones in equal proportion.

Phonemic restoration occurs when speech is perceived to be continuous through noisy interruptions, even when the speech signal is artificially removed from the interrupted epochs. This temporal filling-in illusion helps maintain robust comprehension in adverse environments and illustrates how contextual knowledge through the auditory modality (e.g., lexical) can improve perception. This study investigated how one important form of context, visual speech, affects phonemic restoration. The hypothesis was that audio-visual integration of speech should improve phonemic restoration, allowing the perceived continuity to span longer temporal gaps. Subjects listened to tri-syllabic words with a portion of each word replaced by white noise while watching lip-movement that was either congruent, temporally reversed (incongruent), or static. For each word, subjects judged whether the utterance sounded continuous or interrupted, where a “continuous” response indicated an illusory percept. Results showed that illusory filling-in of longer white noise durations (longer missing segments) occurred when the mouth movement was congruent with the spoken word compared to the other conditions, with no differences occurring between the static and incongruent conditions. Thus, phonemic restoration is enhanced when applying contextual knowledge through multisensory integration.

Prior investigations, using isolated words as stimuli, have shown that older listeners tend to require longer temporal cues than younger listeners to switch their percept from one word to its phonetically contrasting counterpart. The extent to which this age effect occurs in sentence contexts is investigated in the present study. The hypothesis was that perception of temporal cues differs for words presented in isolation and a sentence context and that this effect may vary between younger and older listeners. Younger and older listeners with normal-hearing and older listeners with hearing loss identified phonetically contrasting word pairs in natural speech continua that varied by a single temporal cue: voice-onset time, vowel duration, transition duration, and silent interval duration. The words were presented in isolation and in sentences. A context effect was shown for most continua, in which listeners required longer temporal cues in sentences than in isolated words. Additionally, older listeners required longer cues at the crossover points than younger listeners for most but not all continua. In general, the findings support the conclusion that older listeners tend to require longer target temporal cues than younger normal-hearing listeners in identifying phonetically contrasting word pairs in isolation and sentence contexts.

Tongue shape can vary greatly for allophones of /r/ produced in different phonetic contexts but the primary acoustic cue used by listeners, lowered F3, remains stable. For the current study, it was hypothesized that auditory feedback maintains the speech motor control mechanisms that are constraining acoustic variability of F3 in /r/; thus the listener’s percept remains /r/ despite the range of articulatory configurations employed by the speaker. Given the potential importance of auditory feedback, postlingually deafened speakers should show larger acoustic variation in /r/ allophones than hearing controls, and auditory feedback from a cochlear implant could reduce that variation over time. To test these hypotheses, measures were made of phoneme perception and of production of tokens containing /r/, stop consonants, and /r/+stop clusters in hearing controls and in eight postlingually deafened adults pre- and postimplant. Postimplant, seven of the eight implant speakers did not differ from the control mean. It was also found that implant users’ production of stop and stop+/r/ blend improved with time but the measured acoustic contrast between these was still better in the control speakers than for the implant group even after the implant users had experienced a year of improved auditory feedback.

Cochlear implant subjects continue to experience difficulty understanding speech in noise and performing pitch-based musical tasks. Acoustic model studies have suggested that transmitting additional fine structure via multiple stimulation rates is a potential mechanism for addressing these issues [Nie et al., IEEE Trans. Biomed. Eng. 52, 64-73 (2005); Throckmorton et al., Hear. Res. 218, 30-42 (2006)]; however, results from preliminary cochlear implant studies have been less compelling. Multirate speech processing algorithms previously assumed a place-dependent pitch structure in that a basal electrode would always elicit a higher pitch percept than an apical electrode, independent of stimulation rate. Some subjective evidence contradicts this assumption [H. J. McDermott and C. M. McKay, J. Acoust. Soc. Am. 101, 1622-1630 (1997); R. V. Shannon, Hear. Res. 11, 157-189 (1983)]. The purpose of this study is to test the hypothesis that the introduction of multiple rates may invalidate the tonotopic pitch structure resulting from place-pitch alone. The SPEAR3 developmental speech processor was used to collect psychophysical data from five cochlear implant users to assess the tonotopic structure for stimuli presented at two rates on all active electrodes. Pitch ranking data indicated many cases where pitch percepts overlapped across electrodes and rates. Thus, the results from this study suggest that pitch-based tuning across rate and electrode may be necessary to optimize performance of a multirate sound processing strategy in cochlear implant subjects.

It is commonly assumed that one can always assign a direction-upward or downward-to a percept of pitch change. The present study shows that this is true for some, but not all, listeners. Frequency difference limens (FDLs, in cents) for pure tones roved in frequency were measured in two conditions. In one condition, the task was to detect frequency changes; in the other condition, the task was to identify the direction of frequency changes. For three listeners, the identification FDL was about 1.5 times smaller than the detection FDL, as predicted (counterintuitively) by signal detection theory under the assumption that performance in the two conditions was limited by one and the same internal noise. For three other listeners, however, the identification FDL was much larger than the detection FDL. The latter listeners had relatively high detection FDLs. They had no difficulty in identifying the direction of just-detectable changes in intensity, or in the frequency of amplitude modulation. Their difficulty in perceiving the direction of small frequency/pitch changes showed up not only when the task required absolute judgments of direction, but also when the directions of two successive frequency changes had to be judged as identical or different.

Some theorists claim that cues that contribute to the same acoustic percept are naturally coupled in category learning. In contrast, others claim that no pairs of cues are privileged in this way, and listeners simply learn cue correlations from language input. We compared the cue weighting and cue-shifting between pitch and breathiness, which are enhancing but do not signal a phonemic contrast in English (Experiment I), and pitch and closure duration, which are not enhancing but are correlated in signaling the English voicing contrast (Experiment II). When the cues were enhancing but not contrastive, English listeners successfully learned to weight the more informative cue higher. In contrast, preliminary results show that listeners have difficulty weighting the informative cue higher when the two cues are not enhancing but only contrastive. Results suggest that language experience outweighs auditory enhancement relationships in the perceptual coupling of cues.

Binaural synthesis of spatial audio for virtual and augmented environments is typically performed by convolving an anechoic signal with impulse responses measured at the listener's ears using a source at a fixed distance. This method is accurate for sounds presented at the measured impulse response's distance, and for more distant sources, decreasing intensity provides a reasonable approximation. However, sources nearer than 1 m provide additional distance cues. The head-shadow effect becomes markedly stronger and exponential sound intensity falloff comes into play, exaggerating inter-aural level differences. Also, the angle to each ear diverges, changing the directionally dependent spectral filtering of the pinnae. Changes in inter-aural level differences can be approximated across listeners, but changes in pinna cues with changes in distance are highly individual, and thus less easily approximated. Reproducing some or all of these cues for each individual may be necessary to create a convincing percept ...

Pitch is a salient perceptual quality that underlies our musical experience, interpretation of speech, and ability to attend to one of multiple speakers. Yet the brain mechanisms that support this key percept remain unclear. We have measured the pitch discrimination of humans, ferrets, and mice on a 2-alternative forced choice task. These experiments show that species differ in their weighting of harmonic and temporal envelope cues for pitch judgments. By applying existing computational models, we demonstrate how cochlear filter properties can explain some of these species differences. We have also used microelectrode recordings in behaving ferrets to understand how individual cortical neurons represent pitch. We find that: (1) cortical activity correlates better with ferrets’ pitch judgements than stimulus f0; and (2) inhibition can shape neural representations of f0 when animals are actively engaged in a pitch discrimination task, compared to when they are passively listening to the same sounds. We are ...

Alignment of human vocal behavior is a well-documented phenomenon, however, the factors which influence its direction and magnitude are not firmly established. Components of speech which are subject to alignment include—but are not limited to—word choice, syntax, and rate of speech. In the present study, Speakers completed a puzzle task which required them to communicate with a Model whose fundamental frequency (F0) changed during the interaction. Additionally, naive subjects (Listeners) assessed the overall similarity between the Speaker’s speech over time and the Model using an AXB paradigm. Speakers were found to deviate from the Model in F0, however, were perceived by Listeners to mimic the Model in a holistic measure. Speakers were rated as becoming more like the Model when this partner diverged as opposed to converged. A personality factor survey showed that greater Openness predicted less perceived similarity. The discrepancy between divergence in the acoustic measure and convergence in the percept...

Three methods of altering a waveform that exhibits the crackle percept in high-amplitude noise were previously considered [Swift, Gee, Neilsen, 2014]. Two alterations—expanding shocks and transforming the derivative of the waveform to a Gaussian distribution—were found to eliminate crackle, while a third modification—transforming the waveform pressure to exhibit a Gaussian distribution—did not eliminate the crackle percept. In this paper, a fourth alteration, altering the phase of a crackling signal in the frequency domain in the manner of an all-pass filter in selected frequency bands, is considered and its effects on the crackle percept is compared to the previous methods. In addition to waveform playback, metrics such as skewness of the pressure waveform derivative and loudness and sharpness, along with their time-varying forms, are used in the comparison. [Work supported by AF SBIR.]

Pitch is a percept of the mind that correlates to, but not solely with, acoustical periodicities. Simply stated, it relates different acoustic signals that share the same repetition rate into one percept. In contrast, various stimuli entering the acoustical periphery are expressed differently in the auditory nerves population response. Thus, there is a difference between the input activity and the percept of the brain. Broadly, two leading opponent approaches exist, temporal models and spatial models, but these models can explain partly disjoint features of the pitch. We propose a novel approach to bridge the gap between these two extremities. It is based on optimality constraints that assume parsimonious representation of the sensory auditory input. A recurrent neural network is trained to extract spatiotemporal patterns—pitch cues—from the auditory nerves population activities. These pitch cues are then linearly related to the stimulus' pitch. The model can explain different stimuli from psychoacoustic ...

Sharpness as defined in DIN 45692 and in Fastl and Zwicker [2007] is a measure of the scaled center of frequency of a sound, i.e., sounds with relatively greater high-frequency content have a greater sharpness than those with proportionally greater low-frequency content. The sharpness percept also influences the overall “pleasantness” of a sound and is thus important to sound acceptability. Measures of sharpness have been predominantly constructed to work with Zwicker’s loudness model [DIN 45631/ISO 532B], with less attention to the standardized model given in “Procedure for the Computation of Loudness of Steady Sounds” [ANSI S3.4-2007]. In this paper, a mathematical method for adapting the standardized sharpness measure for use with the ANSI S3.4-2007 loudness standard (and other loudness metrics producing a specific loudness distribution) is discussed. Benchmarking results for the resultant ANSI-based metric implementations and potential limitations of this approach are also addressed.

In the design process of concerts halls, it is the task of the architects—preferably with the aid of experience acoustical consultants— to transform their concept on how the hall should sound into built form. To this end, a profound knowledge of the psychoacoustics of listening in concert halls is mandatory. Psychoacoustics relates auditory perception to the physical attribute of the sound field in the hall. While the sound field can be assessed by physical measurement, the measurement of auditory percept requires human assessors. However, to avoid costly listening test, algorithms been developed for estimating certain features of auditory percepts in concert halls. These estimators are useful for computer simulations of halls. In our talk, basic psychoacoustic phenomena and relevant instrumental estimators for psychoacoustic features will be evaluated. Finally, the concept of the “Quality of the Acoustics” of a concert hall will be considered in a broader context, thereby including aspects like the “Qual...

Pitch is generally defined as the percept corresponding to a sound’s fundamental frequency (F0). However, there is surprisingly little evidence for the importance of F0-specific mechanisms in pitch perception. To investigate the extent to which pitch perception involves estimating F0, we conducted a battery of pitch-related music and speech tasks using harmonic and inharmonic stimuli, the rationale being that inharmonic stimuli lack a clear F0 and should impair F0-dependent mechanisms. Inharmonic speech was generated with a variant of STRAIGHT analysis/synthesis. We found no difference in performance between harmonic and inharmonic stimuli for basic pitch discrimination, melodic contour discrimination, and speech contour discrimination, but substantial inharmonicity-induced deficits for sour-note detection, interval recognition and discrimination, melody recognition, and voice recognition. Collectively, the results indicate that F0 estimation is not necessary to extract pitch contours in speech or music, ...

Musicianship confers enhancements to hearing at nearly all levels of the auditory system from periphery to percept. Musicians' superior psychophysical abilities are particularly evident in spectral discrimination and noise-degraded listening tasks, achieving higher perceptual sensitivity than their nonmusician peers. Greater spectral acuity implies that musicianship may increase auditory filter selectivity. This hypothesis was directly tested by measuring both forward- and simultaneous-masked psychophysical tuning curves. Sharper filter tuning (i.e., higher Q10) was observed in musicians compared to nonmusicians. Findings suggest musicians' pervasive listening benefits may be facilitated, in part, by superior spectral processing/decomposition as early as the auditory periphery.

Studies with adults have demonstrated that acoustic cues cohere in speech perception such that two stimuli cannot be discriminated if separate cues bias responses equally, but oppositely, in each. This study examined whether this kind of coherence exists for children's perception of speech signals, a test that first required that a contrast be found for which adults and children show similar cue weightings. Accordingly, experiment 1 demonstrated that adults, 7-, and 5-year-olds weight F2-onset frequency and gap duration similarly in "spa" versus "sa" decisions. In experiment 2, listeners of these same ages made "same" or "not-the-same" judgments for pairs of stimuli in an AX paradigm when only one cue differed, when the two cues were set within a stimulus to bias the phonetic percept towards the same category (relative to the other stimulus in the pair), and when the two cues were set within a stimulus to bias the phonetic percept towards different categories. Unexpectedly, adults' results contradicted earlier studies: They were able to discriminate stimuli when the two cues conflicted in how they biased phonetic percepts. Results for 7-year-olds replicated those of adults, but were not as strong. Only the results of 5-year-olds revealed the kind of perceptual coherence reported by earlier studies for adults. Thus, it is concluded that perceptual coherence for speech signals is present from an early age, and in fact listeners learn to overcome it under certain conditions.

To achieve the most effective speech processing for individuals with cochlear implants, it is important to understand the perceptual features associated with the stimulation parameters. In general, when electrodes are stimulated in order from apex to base, the pitch of the perceived sound changes in an orderly fashion from low to high. Some deviations from this assumed order have been documented. Also, pitch is the dominant perceptual attribute of a sound when the stimuli associated with different electrodes have been accurately loudness balanced. In this study, the results of a multidimensional scaling (MDS) paradigm were compared to the results of a pitch-ranking procedure for six subjects implanted with multichannel cochlear prostheses. Results indicate that there may be multiple percepts that change with electrode location. Not surprisingly, the dominant percept is strongly correlated with pitch. The results also indicate that the structure of the second percept is consistent across subjects, although not interpretable using the data measured in this study. Furthermore, results indicate that MDS data can be used to pinpoint indiscriminable electrodes more accurately than pitch data. The results of this study may have importance for the design of the next generation of speech processors.

Tone-in-noise detection is severely degraded when only a few spectral components of the noise are presented at random on each trial [Neff and Green, Percept. Psychophys. 41, 409-415 (1987)]. The elevations in threshold are attributed to uncertainty regarding the noise caused by sparse sampling of noise components-informational masking is the term used to describe the result. The present experiment was undertaken to determine how informational masking is affected when sparse sampling is from a set of common everyday sounds instead of noise. On each presentation a different masker waveform of constant total power was synthesized from the magnitude and phase of a fixed number, m, of spectral components (m = 2-921 across blocks of trials). The components were selected at random from 1 of 50 common environmental sounds (e.g., baby crying, door slamming, phone ringing), or 1 of 50 samples of Gaussian noise. Masked thresholds for a 1.0-kHz signal in the presence of both types of maskers were obtained using an adaptive, two-interval, forced-choice procedure. Results with noise replicated earlier, results showing largest elevations in threshold for 10-20 sampled components. Results with everyday sounds showed a similar pattern with thresholds elevated above those for noise by as much as 10 dB at the larger values of m. The differences in masked thresholds were systematically related to differences in the ensemble variance of masker spectra, as predicted by a model previously applied to noise [Lutfi, J. Acoust. Soc. Am. 94, 748-758 (1993)]. Not predicted was the result of a subsequent trial-by-trial analysis in which 9-11 dB less masking was observed for samples from everyday sounds rated as easily recognized by listeners. The results suggest that listeners fail to exploit lawful dependencies among spectral components of everyday sounds to aid detection, unless enough information is available for the sound to be easily recognized.

McFadden [J. Acoust. Soc. Am. 57, 702-704 (1975)] questioned the accuracy and reliability of magnitude estimation for measuring loudness of tones that vary both in duration and level, whereas Stevens and Hall [Percept. Psychophys. 1, 319-327 (1966)] reported reasonable group data. To gain insight into this discrepancy, the present study compares loudness measures for 5- and 200-ms tones using magnitude estimation and equal-loudness matches from the same listeners. Results indicate that both procedures provide rapid and accurate assessments of group loudness functions for brief tones, but may not be reliable enough to reveal specific characteristics of loudness in individual listeners.

The goal of this study was to investigate the relationship between variation in electrode site of stimulation and the perceptual dimensions along which such stimuli vary. This information may allow more effective use of electrode place when encoding speech information. To achieve this goal, two procedures which measure pitch in subjects implanted with the Nucleus/Cochlear Corporation multichannel device were performed. Estimates of electrode discriminability that can be obtained from these procedures were compared to a more direct measure of electrode discriminability that was obtained in a previous study [Collins et al., Assoc. Res. Otolaryng. Abstracts, No. 642 (1994)]. In the first task, subjects performed a pitch ranking procedure similar to that used in previous studies [Townshend et al., J. Acoust. Soc. Am. 82, 106-115 (1987); Nelson et al., J. Acoust. Soc. Am. 98, 1987-1999 (1995)]. Estimates of the pitch percept elicited by stimulation of each electrode as well as the discriminability of the electrodes were generated from the data using two different statistical analyses. In the second task, subjects performed a pitch scaling procedure similar to one used in a previous study [Busby et al., J. Acoust. Soc. Am. 95, 2658-2669 (1994)]. Again, two different statistical analyses were performed to generate estimates of the pitch percept corresponding to stimulation of each electrode and to generate estimates of electrode discriminability. In general, the estimates of the relationships between the pitch percepts obtained from the two procedures were not identical. In addition, the estimates of electrode discriminability were not equivalent to the electrode discrimination measures obtained from the same subjects during the previous study. Signal detection theory has been used to model the decision processes required by each of the procedures described above [e.g., Jesteadt and Bilger, J. Acoust. Soc. Am. 55, 1266-1276 (1974)]. However, these models do not predict the differences that were observed between the data sets obtained during this study. An alternate model is proposed which may explain the data obtained from these subjects. This model is based on the assumption that the percept that is elicited by electrical stimulation of an electrode is multidimensional, as opposed to unidimensional in nature. Therefore, the perceived signal is more appropriately modeled using a multidimensional random vector, where each element of the vector represents the perceived value of one of the dimensions of the signal.

Previous research, using both magnitude-scaling and direct-comparison methods, has shown the perception of loudness to be contingent on the distribution of tonal stimuli varying in sound frequency as well as SPL: When a low-frequency signal, f1, is presented at low SPLs and a high-frequency signal, f2, at high SPLs, loudness at f1 is great relative that at f2; reversing the association of SPL with frequency reverses the loudness relation. These shifts in relative loudness, recently termed "recalibration" [Marks, J. Exp. Psychol: Hum. Percept. Perf. 20, 382-396 (1994)] [corrected], are consistent with the operation of frequency-specific, fatiguelike processes at f1 and f2. Experiment 1 combined both scaling (magnitude estimation) and matching (direct-comparison) methods and showed that exposing one ear to recalibrating stimuli (500 and 2500 Hz) led to substantial shifts not only in the ipsilateral ear but also in the contralateral ear (albeit smaller ones). Experiment 2 used a selective-exposure procedure and gave similar results. Thus the processes underlying recalibration of loudness appear to involve central mediation; consequently, it is possible that processes of auditory fatigue rely on central as well as peripheral mechanisms.

Several theories (e.g., Motor Theory [Liberman and Mattingly, Cognition 21, 1– 36, 1985]) posit a link between perception and production. One way of examining the interrelationship between production and perception is to look at individual differences in both types of tasks. Previous research has yielded somewhat ambiguous results, but many of these studies looked at the boundaries between categories. The current study examined individuals’ prototypes and related data from production. Subjects participated in a perceptual task modeled on that of Miller and Volaitis [Percept. Psychophys. 46, 505–512 1989]. Subjects heard members of a VOT series centered on /pa/, and rated them according to ‘‘p’’ category goodness. These same subjects were recorded producing stop consonant–vowel tokens, and the VOTs of these productions were measured. A correlation was found between the average VOT for subjects’ productions of ‘‘pa’’ and the VOT of the tokens they rated as the best examples. This supports the idea of a perc...

Ability to lateralize stimuli was measured in eight normally hearing subjects. In experiment 1 auditory or visual stimuli were presented. Subjects responded with an auditory or visual pointer in conditions where stimulus and response modalities were the same (uni‐modal) or different (cross‐modal). A linear relationship was found between the position of the target stimuli and the perceived lateral position, establishing the correspondence between auditorily and visually presented positions, consistent with Yost [J. Acoust. Soc. Am. 70, 397–409 (1981)]. Mean judgments of linear position were independent of stimulus or response modality. In experiment 2 subjects were presented with bi‐modal audio‐visual stimuli with spatially and temporally correspondent modal components and subjects responded with an auditory pointer. Mean judgments of position were similar to those in experiment 1 but standard deviations were significantly smaller for the bi‐modal stimuli relative to uni‐modal stimuli. Experiments 3 and 4 involved manipulations of the spatial or temporal relationship between modal components of bi‐modal stimuli. Whereas the relative importance of the visual modality was confirmed [Colavita, Percept. Psychophys. 15(2), 409–412 (1974)] the results of both experiments indicated that perception of the location of an audio‐visual stimulus is influenced by information conveyed in both modalities. [Work supported by UKBBSRC.]

The McGurk effect—the integration of visual information into speech perception—is well documented for English consonants. However, a recent attempt to extend the effect to musical events (violin plucks and bows) showed only a weak visual influence on perception [Saldana and Rosenblum, Percept. Psychophys. 54, 406–416 (1993)]. Thus the conditions required to produce a strong McGurk effect are unknown. The effect may be specific to perception of native phonological categories; alternatively, it may apply to dynamic vocal‐tract events in general. This study tested for a McGurk effect with click consonants, which are phonological in some African languages, but are treated as nonspeech by English speakers [Best, McRoberts, and Sithole, JEP:HPP 14, 345–360 (1988)]. Audio bilabial, dental, and lateral clicks, spoken in isolation and coarticulated with a vowel, were dubbed onto video presentations of each click. Parallel stimuli were made from English stops in syllables and with their excised bursts only. English...

Previous work [Acker and Pastore, Percept. Psychophys. (in press)] using a discrimination version of the Garner paradigm found the E and G frequencies of a root position C‐major chord to be integral, with both frequencies exhibiting significant redundancy gains in the correlated condition, but with the E exhibiting less interference in the orthogonal condition than the G. This finding raised the question of whether attention was better allocated to the E frequency specifically, or if it was a function of the middle spectral location. The current work addresses this question by evaluating discrimination of chord components in a first inversion chord, where the E is the lowest frequency component instead of the middle component. Subjects completed fixed, correlated, and orthogonal discrimination tasks for each frequency. Replicating the earlier results, both frequencies experienced significant redundancy gains in the correlated condition, and the E frequency again exhibited less interference in the orthogonal condition. These results will be discussed in terms of attention being more easily allocated to the E frequency specifically, regardless of spectral location. [Work supported by AFSOR.]

While young children’s ability to use dynamic acoustic information to categorize speech sounds has been studied in some detail [Nittrouer, J. Phon. 20, 1–32 (1992)], relatively little is known about their ability to use dynamic information for word recognition. This study investigates whether preschool children could use dynamic acoustic information to identify familiar words with missing consonants or vowels. A gated series [Elliot et al., Percept. Psychophys. 42, 150–157 (1987)] was used to examine young children’s identification of familiar CVC words with missing final consonants; similarly, a silent center series [Fox et al., J. Speech Hear. Res. 35, 892–902 (1992)] was used to examine identification of CVC words with missing vowels. Eighteen typically developing children aged three to five were tested. It was found that even the youngest children did remarkably well at recognizing words with missing final consonants, even at the longest gate when the consonant was deleted 40 ms before stop closure. B...

What role does attention play in the perception of components within a melody? A paradigm used by Palmer and Holleran [Percept. Psychophys. 56(3), 301–312] provides a basis for addressing this question. Their study investigated different influences on the perception of pitch alterations in three‐voiced musical passages, where subjects first learned a four‐measure standard, then completed a same/different task. ‘‘Different’’ passages were constructed by altering the original standard, with a harmonically related (HR) or unrelated (HU) frequency change made in the lowest, middle, or upper voices of the musical passage. Results indicated that HR changes were less detectable than HU changes and were the least detectable in the middle voice. The current study uses the same procedures and musical materials as the Palmer and Holleran work, but provides the subjects with cues indicating which frequency region might contain the alteration (low, medium, or high). Results will be discussed in terms of the role direc...

The perceptual dimensions evoked by dual-electrode stimulation were investigated in four cochlear implantees. The dual-electrode stimulation consisted of biphasic current pulse trains, such that two intracochlear electrodes each received one pulse in a 250-Hz cycle. The experiments tested the hypothesis that perceptual qualities would be altered when there was an increased likelihood of interactions occurring between the two electrode places. The parameters of the stimulation which were manipulated to test this hypothesis were the time delay between the pulses on the two electrodes (2 ms and a value between 0.62 and 0.92 ms), the distance between the component electrode rings of each bipolar pair (3.75 mm and either 2.25 or 1.5 mm), and the distance between the two bipolar pairs in the dual-electrode stimuli (from 0.75 to 12.0 mm). Five set of 15 loudness balanced stimuli were created, each set having different stimulation parameters. These stimuli consisted of five single-electrode stimuli (a 250-Hz pulse train on each of five electrodes) and the ten dual-electrode stimuli formed by the combinations of those five electrodes. Two perceptual dissimilarity matrices were obtained for each subject and each set, and were analyzed using repeated nonmetric multidimensional scaling techniques. The resultant "stimulus spaces" were then examined to see how many perceptual dimensions the stimuli were best described by, and to what perceptual or stimulus qualities the dimensions might correspond. The results showed that the percept evoked by dual-electrode stimulation contained two main dimensions. Increasing the width of the current path to create substantially overlapping stimulation areas, or altering the temporal delay between the two electrodes, had very little effect on this percept. The position of the stimuli in the two-dimensional space was related to the distances of the two component electrodes along the electrode array. These results are relevant to speech processing strategies and electrode design for cochlear implants, as they imply that the creation of discrete, nonoverlapping areas of stimulation may not cause the percepts to be more distinct, and therefore may not necessarily lead to better speech perception.