The impact of background speech varying in intelligibility: Effects on cognitive performance and perceived disturbance

Noise abatement in office environments often focuses on the reduction of background speech intelligibility and noise level, as attainable with frequency-specific insulation. However, only limited empirical evidence exists regarding the effects of reducing speech intelligibility on cognitive performance and subjectively perceived disturbance. Three experiments tested the impact of low background speech (35 dB(A)) of both good and poor intelligibility, in comparison to silence and highly intelligible speech not lowered in level (55 dB(A)). The disturbance impact of the latter speech condition on verbal short-term memory (n = 20) and mental arithmetic (n = 24) was significantly reduced during soft and poorly intelligible speech, but not during soft and highly intelligible speech. No effect of background speech on verbal-logical reasoning performance (n = 28) was found. Subjective disturbance ratings, however, were consistent over all three experiments with, for example, soft and poorly intelligible speech rated as the least disturbing speech condition but still disturbing in comparison to silence. It is concluded, therefore, that a combination of objective performance tests and subjective ratings is desirable for the comprehensive evaluation of acoustic office environments and their alterations.     

The effect of speech and speech intelligibility on task performance

The aim of this study was to find out what are the effects of three different sound environments on performance of cognitive tasks of varying complexity. These three sound environments were ‘speech’, ‘masked speech’ and ‘continuous noise’. They corresponded to poor, acceptable and perfect acoustical privacy in an open-plan office, respectively. The speech transmission indices were 0.00, 0.30 and 0.80, respectively. Sounds environments were presented at 48 dBA. The laboratory experiment on 36 subjects lasted for 4 h for each subject. Proofreading performance deteriorated in the ‘speech’ (p < 0.05) compared to the other two sound environments. Reading comprehension and computer-based tasks (simple and complex reaction time, subtraction, proposition, Stroop and vigilance) remained unaffected. Subjects assessed the ‘speech’ as the most disturbing, most disadvantageous and least pleasant environment (p < 0.01). ‘Continuous noise’ annoyed the least. Subjective arousal was highest in ‘masked speech’ and lowest in ‘continuous noise’ (p < 0.05). Performance in real open-plan offices could be improved by reducing speech intelligibility, e.g. by attenuating speech level and using an appropriate masking environment.     

The effect of speech and speech intelligibility on task performance

The aim of this study was to find out what are the effects of three different sound environments on performance of cognitive tasks of varying complexity. These three sound environments were 'speech', 'masked speech' and 'continuous noise'. They corresponded to poor, acceptable and perfect acoustical privacy in an open-plan office, respectively. The speech transmission indices were 0.00, 0.30 and 0.80, respectively. Sounds environments were presented at 48 dBA. The laboratory experiment on 36 subjects lasted for 4 h for each subject. Proofreading performance deteriorated in the 'speech' (p < 0.05) compared to the other two sound environments. Reading comprehension and computer-based tasks (simple and complex reaction time, subtraction, proposition, Stroop and vigilance) remained unaffected. Subjects assessed the 'speech' as the most disturbing, most disadvantageous and least pleasant environment (p < 0.01). 'Continuous noise' annoyed the least. Subjective arousal was highest in 'masked speech' and lowest in 'continuous noise' (p < 0.05). Performance in real open-plan offices could be improved by reducing speech intelligibility, e.g. by attenuating speech level and using an appropriate masking environment.     

The impact of perceived ease of use on Internet service adoption: The moderating effects of temporal distance and perceived risk

Perceived ease of use is found to affect consumer’s intention toward using an Internet-based service. However, to protect online transaction security, more security verification mechanisms are established which in turn increase the complexity and difficulty of using online services. This study proposed that the importance of perceived ease of use is depending on short- vs. long-term transaction expectation, product type, and whether security concern information is presented. In certain situations buyers or sellers of an Internet service may tolerate the inconvenience of using the Internet-based service. A 2 (verification requirement) × 2 (network externality) × 2 (short vs. long term) between-subject design was conducted on sellers of an auction site and a 2 (verification requirement) × 2 (product type) × 2 (with vs. without security concern information) between-subject design was conducted on buyers of an auction site. The results of two studies suggest that perceived ease of use increases the intention toward using online service when sellers expect that the Internet service usage is only for a short-term transaction or when buyers have no access of the security concern information on the website. In contrast, sellers prefer using an online service which requires a relatively high verification requirement when the purpose of using Internet service is for long-term transaction or when buyers have access of security concern information. The results also showed that perceived network externality positively affect sellers’ intention toward using an auction website.     

The impact of cognitive absorption on perceived usefulness and perceived ease of use in on-line learning: an extension of the technology acceptance model

Internet-based learning systems are being used in many universities and firms but their adoption requires a solid understanding of the user acceptance processes. Our effort used an extended version of the technology acceptance model (TAM), including cognitive absorption, in a formal empirical study to explain the acceptance of such systems. It was intended to provide insight for improving the assessment of on-line learning systems and for enhancing the underlying system itself. The work involved the examination of the proposed model variables for Internet-based learning systems acceptance. Using an on-line learning system as the target technology, assessment of the psychometric properties of the scales proved acceptable and confirmatory factor analysis supported the proposed model structure. A partial-least-squares structural modeling approach was used to evaluate the explanatory power and causal links of the model. Overall, the results provided support for the model as explaining acceptance of an on-line learning system and for cognitive absorption as a variable that influences TAM variables.     

The effect of bone conduction microphone locations on speech intelligibility and sound quality

This paper presents the results of three studies of intelligibility and quality of speech recorded through a bone conduction microphone (BCM). All speech signals were captured and recorded using a Temco HG-17 BCM. Twelve locations on or close to the skull were selected for the BCM placement. In the first study, listeners evaluated the intelligibility and quality of the bone conducted speech signals presented through traditional earphones. Listeners in the second study evaluated the intelligibility and quality of signals presented through a loudspeaker. In the third study the signals were reproduced through a bone conduction headset; however, signal evaluation was limited to speech intelligibility only. In all three studies, the Forehead and Temple BCM locations yielded the highest intelligibility and quality rating scores. The Collarbone location produced the least intelligible and lowest quality signals across all tested BCM locations.     

基于语音起始段检测语音可懂度客观评价方法

传统的语音评价算法,如SNR,存在语音的可懂度相关性不高的问题.有研究表明,语音的不同部分对可懂度的贡献不同,语音的浊音起始段对可懂度的影响较大.提出一种可懂度相关性相对较高的语音评价算法.在计算分段SNR之前,对语音段进行选择,选出起始段.所提出方法的可懂度计算结果与主观得分进行比较,实验结果表明,结合语音起始段(speech onset)检测算法,能够将可懂度与主观评价的相关值分别提高0.11(辅音)和0.06(句子),这也从一个侧面验证了语音的起始段对可懂度有较大影响这一研究结论.     

The perceived urgency of speech warnings: semantics versus acoustics

The relationship between the semantics of words and the acoustics of the way they are spoken is explored. Actors spoke warning signal words in an urgent, nonurgent and monotone style, and participants rated the urgency of the words. Results showed effects for signal word and style of presentation. Acoustic analysis showed that the urgent words were spoken at higher frequency with a broader pitch range and were louder than the nonurgent or monotone words. These acoustic differences were used to synthesize artificial versions of signal words in urgent and nonurgent formats. The urgent words were rated as more urgent than the nonurgent words, a finding attributable to their differing acoustics. Within each speaking style the words were acoustically the same, yet effects for signal word were found, suggesting that semantics is also important in urgency perception. This research has implications for the design and implementation of speech warning systems, particularly those in which urgency mapping is required.     

Team experiential cognitive style and team performance: The moderating impact of workplace setting

With an increasing need in organizations to come up with novel and useful ideas to renew and survive, team creativity has grown in importance to managers and researchers. As the cognitive resources of team members are the core input for team creativity, researchers increasingly look at team cognition in general and team cognitive styles in particular. In this research stream, the environmental context in which team members are embedded has received limited attention. We therefore experimentally test variation in the physical workplace environment and how it influences the relationship between team experiential cognitive styles and team creativity. Manipulating the nature of architectural elements in the room, we distinguish between a physical workplace with (i) experiential cues and (ii) rational cues. We also use a control condition where architectural elements are absent in the workplace environment. We rely on resource‐matching theory to build our hypotheses. Using data of 75 student teams of a Dutch university, we find that the relationship between teams' experiential cognitive style and team creativity was positive in the control condition. This positive relationship became insignificant in the two conditions where experiential or rational cues were introduced. Theoretical and practical implications are discussed.     

Animated Lombard speech: Motion capture,facial animation and visual intelligibility of speech produced in adverse conditions

In this paper we study the production and perception of speech in diverse conditions for the purposes of accurate, flexible and highly intelligible talking face animation. We recorded audio, video and facial motion capture data of a talker uttering a set of 180 short sentences, under three conditions: normal speech (in quiet), Lombard speech (in noise), and whispering. We then produced an animated 3D avatar with similar shape and appearance as the original talker and used an error minimization procedure to drive the animated version of the talker in a way that matched the original performance as closely as possible. In a perceptual intelligibility study with degraded audio we then compared the animated talker against the real talker and the audio alone, in terms of audio-visual word recognition rate across the three different production conditions. We found that the visual intelligibility of the animated talker was on par with the real talker for the Lombard and whisper conditions. In addition we created two incongruent conditions where normal speech audio was paired with animated Lombard speech or whispering. When compared to the congruent normal speech condition, Lombard animation yields a significant increase in intelligibility, despite the AV-incongruence. In a separate evaluation, we gathered subjective opinions on the different animations, and found that some degree of incongruence was generally accepted.     

基于包络回归的语言清晰度客观评价方法

为了评价不同环境下语言清晰度的恶化程度,提出了一种基于包络回归的语言清晰度客观评价方法。使用普通话语音作为测试信号,使用Gammatone滤波器组对语音进行听觉预处理。利用包络回归模型计算包络的变化特性,从而客观地评价普通话语音清晰度。将实验结果与传统测试方法 STIPA作对比,该方法比STIPA有更好的拟合度。     

Impact of speech presentation level on cognitive task performance: implications for auditory display design

Speech displays and verbal response technologies are increasingly being used in complex, high workload environments that require the simultaneous performance of visual and manual tasks. Examples of such environments include the flight decks of modern aircraft, advanced transport telematics systems providing invehicle route guidance and navigational information and mobile communication equipment in emergency and public safety vehicles. Previous research has established an optimum range for speech intelligibility. However, the potential for variations in presentation levels within this range to affect attentional resources and cognitive processing of speech material has not been examined previously. Results of the current experimental investigation demonstrate that as presentation level increases within this 'optimum' range, participants in high workload situations make fewer sentence-processing errors and generally respond faster. Processing errors were more sensitive to changes in presentation level than were measures of reaction time. Implications of these findings are discussed in terms of their application for the design of speech communications displays in complex multi-task environments.     

Impact of speech presentation level on cognitive task performance: implications for auditory display design

Speech displays and verbal response technologies are increasingly being used in complex, high workload environments that require the simultaneous performance of visual and manual tasks. Examples of such environments include the flight decks of modern aircraft, advanced transport telematics systems providing in-vehicle route guidance and navigational information and mobile communication equipment in emergency and public safety vehicles. Previous research has established an optimum range for speech intelligibility. However, the potential for variations in presentation levels within this range to affect attentional resources and cognitive processing of speech material has not been examined previously. Results of the current experimental investigation demonstrate that as presentation level increases within this ‘optimum’ range, participants in high workload situations make fewer sentence-processing errors and generally respond faster. Processing errors were more sensitive to changes in presentation level than were measures of reaction time. Implications of these findings are discussed in terms of their application for the design of speech communications displays in complex multi-task environments.     

Contribution of display size to speech intelligibility in videophone systems

Widespread use of videophones has been limited due to cost factors and human factors. If demands for image size and quality were relaxed while preserving the communicational value added by visual data, low end videophones may become feasible. After a review of pertinent research, we describe an experiment indicating modest visual augmentation significantly aids speech intelligibility. The results suggest several directions for further research.