Instruction’s effect on semantic scale ratings of interior car sounds

The aim of the study presented here is to examine the effects of instructions on the perception of a sequence of interior car sounds in three different conditions. In each condition, participants listened to the same sound sequence, but the type of information given during the instruction phase, prior to the listening test, were different. In the first condition, a group of participants listens to the sound sequence without any external information except that the sound sequence was recorded inside a car. In the second condition, another group of participants was informed by a text of the successive events that are presented in the sound sequence. In the third condition, participants were informed first by the same text as in condition 2, and then by several pictures showing the different steps that could be heard from the beginning to the end of the sound sequence. Each of the three groups of subjects participated in three tasks: an identification task, a recognition task, and a semantic judgment task using twelve verbal attributes. We assessed how listeners’ judgments of the sound sequence were affected by external information. Results show that the effect is dependant on the type of verbal attribute and on the combination of external information. The verbal information, provided without visual information in condition 2, improves the identification and recognition scores, and thus influences positively the comprehension of the sound sequence and the feeling of immersion. The added visual information, in condition 3, does not change the identification scores, but affects judgements on the pleasantness scale. It appears that the perception of the sound sequence was influenced by visual cues. This study reveals that the format of instructions influences perceptive judgments of the sound sequence tested, but globally factors accounting for the participants’ perception across the three conditions are not modified.     

Rapid perceptual learning of noise-vocoded speech requires attention

Humans are able to adapt to unfamiliar forms of speech (such as accented, time-compressed, or noise-vocoded speech) quite rapidly. Can such perceptual learning occur when attention is directed away from the speech signal? Here, participants were simultaneously exposed to noise-vocoded sentences, auditory distractors, and visual distractors. One group attended to the speech, listening to each sentence and reporting what they heard. Two other groups attended to either the auditory or visual distractors, performing a target-detection task. Only the attend-speech group benefited from the exposure when subsequently reporting noise-vocoded sentences. Thus, attention to noise-vocoded speech appears necessary for learning.     

Hemodynamic responses in human multisensory and auditory association cortex to purely visual stimulation

Background  

Recent findings of a tight coupling between visual and auditory association cortices during multisensory perception in monkeys and humans raise the question whether consistent paired presentation of simple visual and auditory stimuli prompts conditioned responses in unimodal auditory regions or multimodal association cortex once visual stimuli are presented in isolation in a post-conditioning run. To address this issue fifteen healthy participants partook in a "silent" sparse temporal event-related fMRI study. In the first (visual control) habituation phase they were presented with briefly red flashing visual stimuli. In the second (auditory control) habituation phase they heard brief telephone ringing. In the third (conditioning) phase we coincidently presented the visual stimulus (CS) paired with the auditory stimulus (UCS). In the fourth phase participants either viewed flashes paired with the auditory stimulus (maintenance, CS-) or viewed the visual stimulus in isolation (extinction, CS+) according to a 5:10 partial reinforcement schedule. The participants had no other task than attending to the stimuli and indicating the end of each trial by pressing a button.     

Influence of vehicle color on loudness judgments

This experiment investigates the effect of images of differently colored sports cars on the loudness of a simultaneously perceived car sound. Still images of a sports car, colored in red, light green, blue, and dark green, were displayed to subjects during a magnitude estimation task. The sound of an accelerating sports car was used as a stimulus. Statistical analysis suggests that the color of the visual stimulus may have a small influence on loudness judgments. The observed loudness differences are generally equivalent to a change in sound level of about 1 dB, with maximum individual differences of up to 3 dB.     

Sample discrimination of frequency by hearing-impaired and normal-hearing listeners

In a multiple observation, sample discrimination experiment normal-hearing (NH) and hearing-impaired (HI) listeners heard two multitone complexes each consisting of six simultaneous tones with nominal frequencies spaced evenly on an ERB(N) logarithmic scale between 257 and 6930 Hz. On every trial, the frequency of each tone was sampled from a normal distribution centered near its nominal frequency. In one interval of a 2IFC task, all tones were sampled from distributions lower in mean frequency and in the other interval from distributions higher in mean frequency. Listeners had to identify the latter interval. Decision weights were obtained from multiple regression analysis of the between- interval frequency differences for each tone and listeners' responses. Frequency difference limens (an index of sensorineural resolution) and decision weights for each tone were used to predict the sensitivity of different decision-theoretic models. Results indicate that low-frequency tones were given much greater perceptual weight than high-frequency tones by both groups of listeners. This tendency increased as hearing loss increased and as sensorineural resolution decreased, resulting in significantly less efficient weighting strategies for the HI listeners. Overall, results indicate that HI listeners integrated frequency information less optimally than NH listeners, even after accounting for differences in sensorineural resolution.     

Effects of acoustical noise on annoyance, performance and fatigue during mental memory task

This paper describes the effects of meaningful and meaningless external acoustical noise, at various sound pressure level values, on participants during a mental task. That is, the authors focused on the psychological impression of `annoyance' caused by noise, and `performance' indicated by factors such as percentage of correct answers and reaction time. More specifically, the authors discussed how these two items depend on the sound pressure level value of noise, and how they change due to meaningful or meaningless noise. Moreover, the difference between subjective feelings of `fatigue' before and after the task, both with and without noise was considered. Furthermore, an investigation was made into how the above items change in the case of aural or visual task presentations. The task was the probe digit, which is a short-term memory task. As a result, the importance of reducing meaningful external noise at low sound pressure level values was shown.     

Noise within the social context: annoyance reduction through fair procedures

The social context of noise exposure is a codeterminant of noise annoyance. The present study shows that fairness of the exposure procedure (sound management) can be used as an instrument to reduce noise annoyance. In a laboratory experiment (N = 117) participants are exposed to aircraft sound of different sound pressure level (SPL: 50 vs 70 dB A)--which is experienced as noise--while they work on a reading task. The exposure procedure (fair versus neutral) is modeled in line with findings from social justice theory. In the fair condition, participants can voice their preference for a certain sound sample, although they cannot deduce whether their preference is granted. In the neutral condition, participants are not asked to voice their preference. Results show the predicted interaction effect of sound pressure level and procedure on annoyance: Annoyance ratings are significantly lower in the fair condition than in the neutral condition, but this effect is found only in the 70 dB condition. When the SPL is considerably disturbing, fair procedures reduce noise annoyance. Consequences of the reported findings for both theory and practice are discussed.     

Effect of masking noise on cognitive performance and annoyance in open plan offices

Even for low noise levels, employees working in open-plan offices declare they are disturbed by different sound sources and especially by intelligible speech. This paper presents two experiments that aim at studying the effects of sound sources on task performance and cognitive load. In the first experiment, thirty-five individuals were assigned a serial memory task in four noise conditions: printers, intelligible speech, non-intelligible speech and phone rings. Noise annoyance was assessed by measuring task performance and cognitive workload (NASA-TLX). Although there was no significant difference between intelligible speech, unintelligible speech and phone ring tone signals in terms of annoyance, the performance in a memory task decreased in the presence of intelligible speech. In the second experiment, the relevance of a new intelligibility index was evaluated. This index was derived from eSII as defined by Rhebergen et al. (2006) to deal with fluctuating noise as speech babble. Fifty-five subjects performed a serial memory task in four STIt (time varying Speech Transmission Index calculated for every 12.5 ms in dynamic environment) conditions (from 0.38 to 0.69) while STI values were kept constant (around 0.36). No significant difference appeared between the decreases in performance observed with multiple levels of intelligibility. However, a significant difference between two groups of individuals appeared in performance measurements. The group of better performers seemed to be less affected by the high level of intelligibility condition than the other ones.     

Interference from audio distracters during speechreading

Although many audio-visual speech experiments have focused on situations where the presence of an incongruent visual speech signal influences the perceived utterance heard by an observer, there are also documented examples of a related effect in which the presence of an incongruent audio speech signal influences the perceived utterance seen by an observer. This study examined the effects that different distracting audio signals had on performance in a color and number keyword speechreading task. When the distracting sound was noise, time-reversed speech, or continuous speech, it had no effect on speechreading. However, when the distracting audio signal consisted of speech that started at the same time as the visual stimulus, speechreading performance was substantially degraded. This degradation did not depend on the semantic similarity between the target and masker speech, but it was substantially reduced when the onset of the audio speech was shifted relative to that of the visual stimulus. Overall, these results suggest that visual speech perception is impaired by the presence of a simultaneous mismatched audio speech signal, but that other types of audio distracters have little effect on speechreading performance.     

Long-term memory for unfamiliar voices

From a sample of young male Californians, ten speakers were selected whose voices were approximately normally distributed with respect to the "easy-to-remember" versus "hard-to-remember" judgments of a group of raters. A separate group of listeners each heard one of the voices, and, after delays of 1, 2, or 4 weeks, tried to identify the voice they had heard, using an open-set, independent-judgment task. Distributions of the results did not differ from the distributions expected under the hypothesis of independent judgments. For both "heard previously" and "not heard previously" responses, there was a trend toward increasing accuracy as a function of increasing listener certainty. Overall, heard previously responses were less accurate than not heard previously responses. For heard previously responses, there was a trend toward decreasing accuracy as a function of delay between hearing a voice and trying to identify it. Information-theoretic analysis showed loss of information as a function of delay and provided means to quantify the effects of patterns of voice confusability. Signal-detection analysis revealed the similarity of results from diverse experimental paradigms. A "prototype" model is advanced to explain the fact that certain voices are preferentially selected as having been heard previously. The model also unites several previously unconnected findings in the literature on voice recognition and makes testable predictions.     

The effect of intermittent noise on vigilance performance

An experiment was conducted to determine the effect of the level of predictability of intermittent noise on performance on a visual vigilance task. Under a quiet condition and three intermittent noise conditions, subjects (Ss) carried out a 55-min task where they were required to detect a change in the brightness of one element of a visual display. The results indicated that Ss were less sensitive, less accurate, and more prone to response failures during intermittent noise, although responses were faster under noise conditions. Measures of response bias and response certainty were not significantly affected by the presentation of noise. Variation in the level of predictability of the noise affected only the accuracy of response measure during the final quarter of the vigilance task, with the group receiving the least predictable noise performing significantly worse than the other three groups. The results are discussed in relation to theories of noise and performance.     

Auditory externalization in hearing-impaired listeners: the effect of pinna cues and number of talkers

Hearing-aid wearers have reported sound source locations as being perceptually internalized (i.e., inside their head). The contribution of hearing-aid design to internalization has, however, received little attention. This experiment compared the sensitivity of hearing-impaired (HI) and normal-hearing listeners to externalization cues when listening with their own ears and simulated behind-the-ear hearing-aids in increasingly complex listening situations and reduced pinna cues. Participants rated the degree of externalization using a multiple-stimulus listening test for mixes of internalized and externalized speech stimuli presented over headphones. The results showed that HI listeners had a contracted perception of externalization correlated with high-frequency hearing loss.     

Acoustic comparison of voice use in solo and choir singing

An experiment was carried out in which eight bass/baritone singers were recorded while singing in both choral and solo modes. Together with their own voice, they heard the sound of the rest of the choir and a piano accompaniment, respectively. The recordings were analyzed in several ways, including computation of long-time-average spectra for each passage, analysis of the sound levels in the frequency ranges corresponding to the fundamental and the "singer's formant," and a comparison of the sung levels with the levels heard by the singers. Matching pairs of vowels in the two modes were inverse filtered to determine the voice source spectra and formant frequencies for comparison. Differences in both phonation and articulation between the two modes were observed. Subjects generally sang with more power in the singer's formant region in the solo mode and with more power in the fundamental region in the choral mode. Most singers used a reduced frequency distance between the third and fifth formants for increasing the power in the singer's formant range, while the difference in the fundamental was mostly a voice source effect. In a choral singing mode, subjects usually adjusted their voice levels to the levels they heard from the other singers, whereas in a solo singing mode the level sung depended much less on the level of an accompaniment.     

Use of autocorrelation analysis to characterize audibility of low-frequency tonal signals

Autocorrelation function (ACF) parameters were used to identify low-frequency tonal sound detected in actual living environments. Five houses whose residents had made complaints for unidentified noise were selected as measurement sites. The sounds and the residents' detection responses were recorded simultaneously inside a room in each house. When they heard the suspected noise, the participants pushed a response button on a portable recording device as the sound was recorded. Results showed that tonal components in the low-frequency range were highly correlated with the sound detection. This study suggests that autocorrelation analysis can reveal the human detection of low-frequency tonal signals. Low-frequency tonal components were identified and quantified using ACF parameters: the delay time and amplitude of the ACF's first dominant peak. The amplitude was useful to describe the detection and prominence of low-frequency tonal components in noise.     

s] and [sh] as a function of linguapalatal contact place and sibilant groove width

Sibilant groove place and width were initially examined during [s] [s] in isolation and in CV and VC syllables. The [s] was found to be produced through a 6- to 8-mm-wide groove near the front of the alveolar ridge by one talker and near the back of the ridge by the other. [s] was produced through a 10- to 12-mm groove behind the posterior border of the alveolar ridge by both. In the second experiment three subjects used visual articulatory feedback to vary sibilant groove width and place systematically. One subject was able to do this with comparatively few retrials; one had difficulty with certain targeted grooves; one had difficulty with many targeted grooves. The noises generated were replayed to 14 listeners who labeled them as "s," "probably s," "probably sh," or "sh." They usually heard the sound as [s] when the grooves were narrow and near the front of the alveolar process, [s] when the groove was wider and behind the alveolar process. Noise through grooves that matched natural speech places and widths usually produced higher listener recognition scores. Exceptions were found when the subjects had unusual difficulty in achieving stipulated groove widths and places.     

Neural activity associated with distinguishing concurrent auditory objects

The neural processes underlying concurrent sound segregation were examined by using event-related brain potentials. Participants were presented with complex sounds comprised of multiple harmonics, one of which could be mistuned so that it was no longer an integer multiple of the fundamental. In separate blocks of trials, short-, middle-, and long-duration sounds were presented and participants indicated whether they heard one sound (i.e., buzz) or two sounds (i.e., buzz plus another sound with a pure-tone quality). The auditory stimuli were also presented while participants watched a silent movie in order to evaluate the extent to which the mistuned harmonic could be automatically detected. The perception of the mistuned harmonic as a separate sound was associated with a biphasic negative-positive potential that peaked at about 150 and 350 ms after sound onset, respectively. Long duration sounds also elicited a sustained potential that was greater in amplitude when the mistuned harmonic was perceptually segregated from the complex sound. The early negative wave, referred to as the object-related negativity (ORN), was present during both active and passive listening, whereas the positive wave and the mistuning-related changes in sustained potentials were present only when participants attended to the stimuli. These results are consistent with a two-stage model of auditory scene analysis in which the acoustic wave is automatically decomposed into perceptual groups that can be identified by higher executive functions. The ORN and the positive waves were little affected by sound duration, indicating that concurrent sound segregation depends on transient neural responses elicited by the discrepancy between the mistuned harmonic and the harmonic frequency expected based on the fundamental frequency of the incoming stimulus.     

The effect of hearing impairment on localization dominance for single-word stimuli

Localization dominance (one of the phenomena of the "precedence effect") was measured in a large number of normal-hearing and hearing-impaired individuals and related to self-reported difficulties in everyday listening. The stimuli (single words) were made-up of a "lead" followed 4 ms later by a equal-level "lag" from a different direction. The stimuli were presented from a circular ring of loudspeakers, either in quiet or in a background of spatially diffuse babble. Listeners were required to identify the loudspeaker from which they heard the sound. Localization dominance was quantified by the weighting factor c [B.G. Shinn-Cunningham et al., J. Acoust. Soc. Am. 93, 2923-2932 (1993)]. The results demonstrated large individual differences: Some listeners showed near-perfect localization dominance (c near 1) but many showed a much reduced effect. Two-thirds (64/93) of the listeners gave a value of c of at least 0.75. There was a significant correlation with hearing loss, such that better hearing listeners showed better localization dominance. One of the items of the self-report questionnaire ("Do you have the impression of sounds being exactly where you would expect them to be?") showed a significant correlation with the experimental results. This suggests that reductions in localization dominance may affect everyday auditory perception.     

图像序列的显著性目标区域检测方法

针对传统视觉显著性模型在自顶向下的任务指导和动态信息处理方面的不足,设计并实现了融入运动特征的视觉显著性模型。利用该模型提取了图像的静态特征和动态特征,静态特征的提取在图像的亮度、颜色和方向通道进行,运动特征的提取采用基于多尺度差分的特征提取方法实现,然后各通道分别通过滤波、差分得到显著图,在生成全局显著图时,提出多通道参数估计方法,计算图像感兴趣区域与眼动感兴趣区域的相似度,从而可在图像上准确定位目标位置。针对20组视频图像序列(每组50帧)进行了实验,结果表明:本文算法提取注意焦点即目标区域的平均相似度为0.87,使用本文算法能够根据不同任务情境,选择各特征通道的权重参数,从而可有效提高目标搜索的效率。     

Segregation of concurrent sounds. II: Effects of spectral envelope tracing, frequency modulation coherence, and frequency modulation width

The research presented here concerns the simultaneous grouping of the components of a vocal sound source. McAdams [J. Acoust. Soc. Am. 86, 2148-2159 (1989)] found that when three simultaneous vowels at different pitches were presented with subaudio frequency modulation, subjects judged them as being more prominent than when no vibrato was present. In a normal voice, when the harmonics of a vowel undergo frequency modulation they also undergo an amplitude modulation that traces the spectral envelope. Hypothetically, this spectral tracing could be one of the criteria used by the ear to group components of each vowel, which may help explain the lack of effect of frequency modulation coherence among different vowels in the previous study. In this experiment, two types of vowel synthesis were used in which the component amplitudes of each vowel either remained constant with frequency modulation or traced the spectral envelope. The stimuli for the experiment were chords of three different vowels at pitch intervals of five semitones (ratio 1.33). All the vowels of a given stimulus were produced by the same synthesis method. The subjects' task involved rating the prominence of each vowel in the stimulus. It was assumed that subjects would judge this prominence to be lower when they were not able to distinguish the vowel from the background sound. Also included as stimulus parameters were the different permutations of the three vowels at three pitches and a number of modulation conditions in which vowels were unmodulated, modulated alone, and modulated either coherently with, or independently of, the other vowels. Spectral tracing did not result in increased ratings of vowel prominence compared to stimuli where no spectral tracing was present. It would therefore seem that it has no effect on grouping components of sound sources. Modulated vowels received higher prominence ratings than unmodulated vowels. Vowels modulated alone were judged to be more prominent than vowels modulated with other vowels. There was, however, no significant difference between coherent and independent modulation of the three vowels. Differences among modulation conditions were more marked when the modulation width was 6% than when it was 3%.     

Aging, spatial cues, and single- versus dual-task performance in competing speech perception

Older individuals often report difficulty coping in situations with multiple conversations in which they at times need to "tune out" the background speech and at other times seek to monitor competing messages. The present study was designed to simulate this type of interaction by examining the cost of requiring listeners to perform a secondary task in conjunction with understanding a target talker in the presence of competing speech. The ability of younger and older adults to understand a target utterance was measured with and without requiring the listener to also determine how many masking voices were presented time-reversed. Also of interest was how spatial separation affected the ability to perform these two tasks. Older adults demonstrated slightly reduced overall speech recognition and obtained less spatial release from masking, as compared to younger listeners. For both younger and older listeners, spatial separation increased the costs associated with performing both tasks together. The meaningfulness of the masker had a greater detrimental effect on speech understanding for older participants than for younger participants. However, the results suggest that the problems experienced by older adults in complex listening situations are not necessarily due to a deficit in the ability to switch and/or divide attention among talkers.