Current laboratory tests of speech understanding that are in common use in audiology do not incor... more Current laboratory tests of speech understanding that are in common use in audiology do not incorporate important elements of daily listening that engage the cognitive elements of listening (e.g., attention, working memory). Given that cognitive processing takes on a particularly important role in sub-optimal listening scenarios, it is not surprising that traditional speech tests have had limited success in accounting for the complexities of daily listening caused by complex acoustic environments, listening goals that may change from moment to moment, hearing impairment, distortions caused by signal processing, and the auditory processing effects of aging. With the goal of developing better tools for assessing the impact of hearing impairment and sensory and cognitive interventions (hearing technology, auditory and cognitive training) on speech communication, we are developing a new speech test and measurement paradigm that incorporates important elements of daily listening that engage cognitive aspects of auditory processing. The new test focuses on understanding the meaning of speech rather than just hearing and reporting the phonetic elements of speech. It also incorporates important demands of daily listening such as the need for listeners to operate within the context of a continuous flow of speech information and with the presence of competing speech. This presentation will review how the test is constructed to achieve these elements of listening, and what impact these elements have on performance when compared to traditional tests of speech reception. Such research should lead to tests that are better than traditional tests at predicting the effects of treatments on real-life experiences of listening-instrument users. As such, they may form a part of a toolkit that clinicians deploy for determining intervention plans for their patients.
A common complaint of hearing-impaired listeners is dif culty understanding speech in the presenc... more A common complaint of hearing-impaired listeners is dif culty understanding speech in the presence of noise. Digital hearing aids have opened the door to complex signal processing algorithms that attempt to improve the quality, ease of listening, and/or intelligibility of speech in noisy environments. In reality, however, hearing aid users show no intelligibility improvements from single-microphone noise reduction (NR) algorithms, even though they sometimes report that speech sounds easier to understand. A possible explanation for this dichotomy is that NR algorithms replace a function that the human auditory system would otherwise perform. This redundancy means that there is no improvement in intelligibility, but a reduction in listening effort, since fewer cognitive resources would be necessary. We investigated this hypothesis using a dual-task paradigm with normal-hearing and hearing-impaired listeners. They were asked to repeat sentences or words presented in noise while perform...
The Journal of the Acoustical Society of America, 1973
The lateralization model of Masking-Level Differences (MLDs) asserts that detection in those bina... more The lateralization model of Masking-Level Differences (MLDs) asserts that detection in those binaural conditions that produce an MLD is directly related to the perception of lateral space. The model was tested here by obtaining subjective reports of the lateral place of dichotic and diotic signals in noise which were in turn used by an “ideal observer” to determine the discriminability of the two classes of stimuli. The results support the model, showing that an observer using no information other than the lateralization judgments could detect NOSM in the dichotic condition as well as a subject who hear the acoustic stimuli.
The Journal of the Acoustical Society of America, 1970
An earlier paper demonstrated a direct relation between lateralization and the binaural-masking c... more An earlier paper demonstrated a direct relation between lateralization and the binaural-masking condition N0Sπ. This work extends the technique to the binaural condition N0SM. Signals were monaurally presented (500 Hz, 100-msec tones; the masker was a diotically presented (continuous wide-band noise). Test intervals were marked by a 100-msec light; signals were randomly presented on half of the test trials. Subjects were instructed to lateralize the acoustic image occurring simultaneously with the test light and to indicate the laterality on a 12-in. rating scale. The scale was designated to represent intracranial auditory space. Trials that contained signals produced responses more toward the periphery of the scale than those that contained noise alone; for more intense signals, subjects showed a lateral bias toward the side receiving the signal. Receiver Operating Characteristics (ROCs) were drawn for each signal-level tested by computing likelihood ratios across the rating space,...
The Journal of the Acoustical Society of America, 1971
The binaural trading ratio (Δt/ΔI) is traditionally measured by opposing an interaural time diffe... more The binaural trading ratio (Δt/ΔI) is traditionally measured by opposing an interaural time difference (Δt) with an interaural intensity difference (ΔI) in proportions sufficient for apparent cancellation of the perceptual effects of the two cues. In a previous paper [E. R. Hafter and S. C. Carrier, J. Acoust. Sac. Amer. 46, 125 (A) (1969)], we showed that no combination of Δt and ΔI produces a dichotic tone which cannot be detected as different from an otherwise comparable diotic. In that paper we proposed a “dual-threshold” model in which intensive and temporal information are encoded by peripheral dual-threshold devices. The two sets of information are then weighted and recombined by a central processor. An important test of the model is the response to signals of levels sufficiently low as to render the high threshold device functionless. In this study, we measured the tradability of Δt and ΔI at overall levels of 20 and 40 dB SPL. At these levels, Δt and ΔI apparently do cancel...
The traditional approach to the study of sound sources emphasized bottom-up analysis of acoustic ... more The traditional approach to the study of sound sources emphasized bottom-up analysis of acoustic stimuli, whether they were more primitive features such as frequency, sound level, and source direction, or complexes made by combinations of primitives. However, a simple scan of the table of contents of this volume shows that the field has evolved considerably toward a realization of important
The Journal of the Acoustical Society of America, 2017
To better understand issues of hearing-aid benefit during natural listening, this study examined ... more To better understand issues of hearing-aid benefit during natural listening, this study examined the added demand placed by the goal of understanding speech over the more typically studied goal of simply recognizing speech sounds. The study compared hearing-aid benefit in two conditions, and examined factors that might account for the observed benefits. In the phonetic condition, listeners needed only identify the correct sound to make a correct response. In the semantic condition, listeners had to understand what they had heard to respond correctly, because the answer did not include any keywords from the spoken speech. Hearing aids provided significant benefit for listeners in the phonetic condition. In the semantic condition on the other hand, there were large inter-individual differences, with many listeners not experiencing any benefit of aiding. Neither a set of cognitive and linguistic tests, nor age, could explain this variability. Furthermore, analysis of psychometric funct...
Here we report the methods and output of a workshop examining possible futures of speech and hear... more Here we report the methods and output of a workshop examining possible futures of speech and hearing science out to 2030. Using a design thinking approach, a range of human-centered problems in communication were identified that could provide the motivation for a wide range of research. Nine main research programs were distilled and are summarized: (a) measuring brain and other physiological parameters, (b) auditory and multimodal displays of information, (c) auditory scene analysis, (d) enabling and understanding shared auditory virtual spaces, (e) holistic approaches to health management and hearing impairment, (f) universal access to evolving and individualized technologies, (g) biological intervention for hearing dysfunction, (h) understanding the psychosocial interactions with technology and other humans as mediated by technology, and (i) the impact of changing models of security and privacy. The design thinking approach attempted to link the judged level of importance of diffe...
Among my best experiences during a half century in Berkeley was the opportunity to interact as fr... more Among my best experiences during a half century in Berkeley was the opportunity to interact as friend and colleague of Professor David Wessel. A remarkable blend of scientific brilliance and creativity allowed him to look deeply into questions, figure out their good bits, and come up with new and exciting approaches to an answer. This connection between theory and solution defined his role as a Professor and comments from both students and their advisors showed gratitude for the clarity of his advice. Memories gathered here are from people in many areas who had the good fortune to know and work with Professor Wessel.
Current laboratory tests of speech understanding that are in common use in audiology do not incor... more Current laboratory tests of speech understanding that are in common use in audiology do not incorporate important elements of daily listening that engage the cognitive elements of listening (e.g., attention, working memory). Given that cognitive processing takes on a particularly important role in sub-optimal listening scenarios, it is not surprising that traditional speech tests have had limited success in accounting for the complexities of daily listening caused by complex acoustic environments, listening goals that may change from moment to moment, hearing impairment, distortions caused by signal processing, and the auditory processing effects of aging. With the goal of developing better tools for assessing the impact of hearing impairment and sensory and cognitive interventions (hearing technology, auditory and cognitive training) on speech communication, we are developing a new speech test and measurement paradigm that incorporates important elements of daily listening that engage cognitive aspects of auditory processing. The new test focuses on understanding the meaning of speech rather than just hearing and reporting the phonetic elements of speech. It also incorporates important demands of daily listening such as the need for listeners to operate within the context of a continuous flow of speech information and with the presence of competing speech. This presentation will review how the test is constructed to achieve these elements of listening, and what impact these elements have on performance when compared to traditional tests of speech reception. Such research should lead to tests that are better than traditional tests at predicting the effects of treatments on real-life experiences of listening-instrument users. As such, they may form a part of a toolkit that clinicians deploy for determining intervention plans for their patients.
A common complaint of hearing-impaired listeners is dif culty understanding speech in the presenc... more A common complaint of hearing-impaired listeners is dif culty understanding speech in the presence of noise. Digital hearing aids have opened the door to complex signal processing algorithms that attempt to improve the quality, ease of listening, and/or intelligibility of speech in noisy environments. In reality, however, hearing aid users show no intelligibility improvements from single-microphone noise reduction (NR) algorithms, even though they sometimes report that speech sounds easier to understand. A possible explanation for this dichotomy is that NR algorithms replace a function that the human auditory system would otherwise perform. This redundancy means that there is no improvement in intelligibility, but a reduction in listening effort, since fewer cognitive resources would be necessary. We investigated this hypothesis using a dual-task paradigm with normal-hearing and hearing-impaired listeners. They were asked to repeat sentences or words presented in noise while perform...
The Journal of the Acoustical Society of America, 1973
The lateralization model of Masking-Level Differences (MLDs) asserts that detection in those bina... more The lateralization model of Masking-Level Differences (MLDs) asserts that detection in those binaural conditions that produce an MLD is directly related to the perception of lateral space. The model was tested here by obtaining subjective reports of the lateral place of dichotic and diotic signals in noise which were in turn used by an “ideal observer” to determine the discriminability of the two classes of stimuli. The results support the model, showing that an observer using no information other than the lateralization judgments could detect NOSM in the dichotic condition as well as a subject who hear the acoustic stimuli.
The Journal of the Acoustical Society of America, 1970
An earlier paper demonstrated a direct relation between lateralization and the binaural-masking c... more An earlier paper demonstrated a direct relation between lateralization and the binaural-masking condition N0Sπ. This work extends the technique to the binaural condition N0SM. Signals were monaurally presented (500 Hz, 100-msec tones; the masker was a diotically presented (continuous wide-band noise). Test intervals were marked by a 100-msec light; signals were randomly presented on half of the test trials. Subjects were instructed to lateralize the acoustic image occurring simultaneously with the test light and to indicate the laterality on a 12-in. rating scale. The scale was designated to represent intracranial auditory space. Trials that contained signals produced responses more toward the periphery of the scale than those that contained noise alone; for more intense signals, subjects showed a lateral bias toward the side receiving the signal. Receiver Operating Characteristics (ROCs) were drawn for each signal-level tested by computing likelihood ratios across the rating space,...
The Journal of the Acoustical Society of America, 1971
The binaural trading ratio (Δt/ΔI) is traditionally measured by opposing an interaural time diffe... more The binaural trading ratio (Δt/ΔI) is traditionally measured by opposing an interaural time difference (Δt) with an interaural intensity difference (ΔI) in proportions sufficient for apparent cancellation of the perceptual effects of the two cues. In a previous paper [E. R. Hafter and S. C. Carrier, J. Acoust. Sac. Amer. 46, 125 (A) (1969)], we showed that no combination of Δt and ΔI produces a dichotic tone which cannot be detected as different from an otherwise comparable diotic. In that paper we proposed a “dual-threshold” model in which intensive and temporal information are encoded by peripheral dual-threshold devices. The two sets of information are then weighted and recombined by a central processor. An important test of the model is the response to signals of levels sufficiently low as to render the high threshold device functionless. In this study, we measured the tradability of Δt and ΔI at overall levels of 20 and 40 dB SPL. At these levels, Δt and ΔI apparently do cancel...
The traditional approach to the study of sound sources emphasized bottom-up analysis of acoustic ... more The traditional approach to the study of sound sources emphasized bottom-up analysis of acoustic stimuli, whether they were more primitive features such as frequency, sound level, and source direction, or complexes made by combinations of primitives. However, a simple scan of the table of contents of this volume shows that the field has evolved considerably toward a realization of important
The Journal of the Acoustical Society of America, 2017
To better understand issues of hearing-aid benefit during natural listening, this study examined ... more To better understand issues of hearing-aid benefit during natural listening, this study examined the added demand placed by the goal of understanding speech over the more typically studied goal of simply recognizing speech sounds. The study compared hearing-aid benefit in two conditions, and examined factors that might account for the observed benefits. In the phonetic condition, listeners needed only identify the correct sound to make a correct response. In the semantic condition, listeners had to understand what they had heard to respond correctly, because the answer did not include any keywords from the spoken speech. Hearing aids provided significant benefit for listeners in the phonetic condition. In the semantic condition on the other hand, there were large inter-individual differences, with many listeners not experiencing any benefit of aiding. Neither a set of cognitive and linguistic tests, nor age, could explain this variability. Furthermore, analysis of psychometric funct...
Here we report the methods and output of a workshop examining possible futures of speech and hear... more Here we report the methods and output of a workshop examining possible futures of speech and hearing science out to 2030. Using a design thinking approach, a range of human-centered problems in communication were identified that could provide the motivation for a wide range of research. Nine main research programs were distilled and are summarized: (a) measuring brain and other physiological parameters, (b) auditory and multimodal displays of information, (c) auditory scene analysis, (d) enabling and understanding shared auditory virtual spaces, (e) holistic approaches to health management and hearing impairment, (f) universal access to evolving and individualized technologies, (g) biological intervention for hearing dysfunction, (h) understanding the psychosocial interactions with technology and other humans as mediated by technology, and (i) the impact of changing models of security and privacy. The design thinking approach attempted to link the judged level of importance of diffe...
Among my best experiences during a half century in Berkeley was the opportunity to interact as fr... more Among my best experiences during a half century in Berkeley was the opportunity to interact as friend and colleague of Professor David Wessel. A remarkable blend of scientific brilliance and creativity allowed him to look deeply into questions, figure out their good bits, and come up with new and exciting approaches to an answer. This connection between theory and solution defined his role as a Professor and comments from both students and their advisors showed gratitude for the clarity of his advice. Memories gathered here are from people in many areas who had the good fortune to know and work with Professor Wessel.
Uploads
Papers by Ervin Hafter