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Annoyance and Performance Effects of Nearby Speech
Abstract
Twenty-four subjects were engaged in three different tasks in a laboratory experiment: a difficult proof reading task and a logic test both with high demands on concentration and a simpler letter sorting task. The subjects were told to perform at their maximum in all tasks. Each task was performed during four 15 min periods while exposed to different types of noise, a broadband noise at 40 or 50 dB(A), or a background speech at 40 or 50 dB(A). A 5 minutes pause was inserted between the work periods. Subjects rated their performance, annoyance and effort during each period. Annoyance and effort ratings were higher and performance ratings lower in the speech than in the broadband noise condition and this effect was more pronounced during the two verbal tests. Annoyance and effort but not rated performance were affected by noise level. In contrast, actual performance was only impaired by the speech during the simple manual sorting test.
... Several different types of tasks (proof reading, logic test and letter sorting task) have been used during assessments of noise annoyance. In a study using moderate noise levels, it was found that both annoyance and the effort people needed to perform the task were negatively affected by noise level (Landström, Söderberg, Kjellberg, & Nordström, 2002). ...
... Furthermore, the amount of annoyance seemed to be dependent partly on the task that was performed while being exposed to noise: annoyance was higher due to speech than to broadband noise and this effect was stronger during verbal tasks (Landström et al., 2002). ...
PhD thesis on subjective and physiological responses (aircraft) noise. Important topics are for instance, noise sensitivity, identifiability, order effects, CDA's, heart rate variability, mismatch negativity
... Previous behavioral studies on the effect of background sounds on reading have painted a mixed picture (for a review, see Vasilev, Kirkby, & Angele, 2018). For example, while some of them have found that intelligible speech is detrimental to reading and proofreading performance (Jones, Miles, & Page, 1990;Martin et al., 1988;Sörqvist, Halin, & Hygge, 2010), others have failed to find such an effect (Haka et al., 2009;Landström, Söderberg, Kjellberg, & Nordström, 2002;Ljung, Sörqvist, & Hygge, 2009;Venetjoki, Kaarlela-Tuomaala, Keskinen, & Hongisto, 2006). Similarly, studies on the effect of acoustical noise on reading in adults have also resulted in mixed findings. ...
... This is especially because a facilitation effect of acoustical noise has generally not been reported in previous studies (e.g. Johansson, 1983;Landström et al., 2002;Martin et al., 1988). Overall, the present results are largely consistent with Hyönä and Ekholm's (2016) Experiment 1, in the sense that the authors did not find any evidence to support the phonological disruption account. ...
It is not well understood whether background speech affects the initial processing of words during reading or only the later processes of sentence integration. Additionally, it is not clear how eye-movements support text comprehension in the face of distraction by background speech and noise. In the present research, participants read single sentences (Experiment 1) and short paragraphs (Experiments 2-3) in four sound conditions: silence, speech-spectrum Gaussian noise, English speech (intelligible to participants), and Mandarin speech (unintelligible to participants). Intelligible speech did not affect the lexical access of words and had a limited effect on the first-pass fixations of words. However, it led to more regressions and more re-reading fixations compared to both unintelligible speech and silence. The results suggested that the distraction is mostly semantic in nature, and there was only limited evidence for a contribution of phonology. Finally, intelligible speech disrupted comprehension only when participants were prevented from re-reading previous words. These findings suggest that the semantic properties of irrelevant speech can disrupt the ongoing reading process, but that this disruption occurs in the post-lexical stages of reading when participants need to integrate words to form the sentence context and to construct a coherent discourse of the text.
... Additionally, if the background speech is intelligible, it also carries semantic meaning (completely unintelligible background speech might also occur, but it is not very frequently encountered unless one is in a foreign country and does not understand the language). Perhaps owing to its semantic content, background speech is often rated as more distracting and more annoying than acoustical noise (Haapakangas et al., 2011;Haka et al., 2009;Landström, Söderberg, Kjellberg, & Nordström, 2002). Consistent with this subjective perception, intelligible background speech has been found to disrupt reading comprehension in a number of experiments (Armstrong et al., 1991;Baker & Madell, 1965;Martin et al., 1988;Sörqvist, Halin, & Hygge, 2010; however, see Venetjoki, Kaarlela-Tuomaala, Keskinen, & Hongisto, 2006). ...
... However, even though the task included both contextual and non-contextual errors, there was no significant effect of background speech on either error type in isolation. In a similar study, Landström et al. (2002) found that background speech, compared to broadband noise (i.e., noise consisting of a wide range of frequencies), did not affect proofreading performance for either contextual or non-contextual errors. The auditory stimuli were presented at a comparable sound intensity level to Venetjoki et al. (2006), although the speech consisted of random spoken statements. ...
Everyday reading occurs in different settings, such as on the train to work, in a busy cafeteria, or at home, while listening to music. In these situations, readers are exposed to external auditory stimulation from nearby noise, speech, or music that may distract them from their task and reduce their comprehension. Although many studies have investigated auditory distraction effects during reading, the results have proved to be inconsistent and sometimes even contradictory. Additionally, the broader theoretical implications of the findings have not always been explicitly considered. In the present study, we report a Bayesian meta-analysis of 65 studies on auditory distraction effects during reading and use meta-regression models to test predictions derived from existing theories. The results showed that background noise, speech, and music all have a small, but reliably detrimental effect on reading performance. The degree of disruption in reading comprehension did not generally differ between adults and children. Intelligible speech and lyrical music resulted in the biggest distraction. While this last result is consistent with theories of semantic distraction, there was also reliable distraction by noise. It is argued that new theoretical models are needed that can account for distraction by both background speech and noise.
... 1 Noise may also interfere with cognitive activities and may increase aggressive behavior. A number of studies have investigated the effects of noise exposure on cognitive performance in laboratory settings [2][3][4][5][6] . There have also several been in situ studies examining the relationship between noise exposure and task performance of adult workers. ...
... 10,11,14 Train noise and road traffic noise have also been associated with harmful cognitive effects 2,10,15,16 , and recent studies have included meaningful irrelevant speech and background conversation. [2][3][4] Because they are one of most common noise sources in everyday life, there is large body of work directly relating office background noises such as ventilation and low frequency noise to work performance. [17][18][19][20][21][22] It was found that the low-frequency noise made the subjects less attentive, which negatively affected monotonous tasks. ...
The present study investigates the cognitive performance and subjective perceptions in the context of road traffic noise alone and multiple noises, including construction and ventilation noises. A total of 20 university students were exposed to seven noise conditions. Laboratory experiments employed semantic and episodic memory tasks. Self-reports of perception were collected from the participants. It was found that multiple noise sources impaired the free recall of words, and free recall scores were affected by noise type. Significant differences in free recall scores were found when the noise level difference between the individual noise and multiple noise sources was more than 5 dB. In contrast, word comprehension did not mediate the effects of noise on semantic memory. Annoyance caused by multiple noise sources correlated highly with the results of the free recall and word comprehension tasks. Moreover, loudness and roughness were found to account for the annoyance ratings of combinations of road traffic noise with construction or ventilation noises.
... Single-talker background speech is also a common source of auditory distraction in daily life situations and may be particularly difficult to ignore given its salience for human listeners. In fact, for adults, speech is typically observed to have a more deleterious effect on reading comprehension than non-verbal acoustic noise (Landström, Söderberg, Kjellberg, & Nordström, 2002;Vasilev et al., 2018) with comparable but less well-studied effects on reading speed (Cauchard, Cane, & Weger, 2012;Hyönä & Ekholm, 2016;Vasilev et al., 2018;Vasilev, Liversedge, Rowan, Kirkby, & Angele, 2019). Typically, our understanding of the potential causal mechanisms underlying auditory distraction has relied on measuring its effect on serial recall or other working memory tasks-but these factors may also affect complex tasks such as reading (Jones, 1995). ...
Reading skills are usually assessed in silent conditions, but children often experience noisy educational settings. Effects of auditory distraction on children's reading skills remain relatively unexplored. The present study investigates the influence of two features of background speech—intelligibility and loudness—on children's reading speed and comprehension. Sixty‐three 8‐to‐10‐year‐old elementary school children performed a reading task in the context of single‐talker background speech. Background speech was either intelligible or unintelligible and presented at low (45–50 dB SPL) or moderate (65–72 dB SPL) sound intensity (here termed “loudness”). Results showed a differential effect of intelligibility and loudness, respectively affecting children's comprehension and reading speed. In addition, the intelligibility effect was larger in children with lower interference control, as assessed with an auditory Stroop task. Our findings provide evidence for the influence of different properties of background speech on children's text reading with implications for reading in everyday classroom environments.
Lay Summary
Children often read in noisy environments, but we know little about how background chatter might affect their reading. Here, we found that 8–10‐year‐old children read stories more slowly with louder background speech. The children also understood less about a story if the background voice was speaking in their own language—especially those who, in a different task, were less able to ignore irrelevant but attention‐grabbing information. This suggests background speech differentially affects beginning readers.
... Irrelevant background sounds can also impair more complextasks (e.g. [12,13,14,15,16]). ...
In Germany, the rating level is an important parameter to assess noise immissions in occupied offices. The rating level denotes the energy-equivalent sound pressure level during a measurement period with speech sounds and considers penalties for tonal, informational and impulsive constituents. There is little evidence that the rating level correlates with the performance and perceived annoyance of office workers. This study evaluates 89 different sound conditions under which subjects have to complete a short-term memory task and a questionnaire in laboratory conditions with respect to their relationships with the rating level. The relationships of the penalty for impulsiveness and the penalty for tonality or informational constituents with the rating level are analyzed separately. In addition, the penalty for tonality or informational constituents is substituted by percentile level statistics, namely the difference between the 10 th and 90 th percentile levels. In contrast to the penalty for tonality or informational constituents, this metric is objectively measurable. Using the rating level to assess the noise at office workplaces could be improved by using percentile level statistics to account for informational constituents. To improve the predictive validity, it is suggested to report the penalties separately.
... Most individuals showthe effect and the average impairment of performance can be as high as 30% [16]. Irrelevant background speech has also been found to disturb more complextasks, such as proofreading [17,18], reading comprehension [19], activation of prior knowledge in long-term memory [20] and logical reasoning [21]. ...
The purpose of this study was to find out what kind of features should be preferred and avoided when using speech masking sound in open-plan offices. Fifty-four subjects were tested in seven sound conditions: speech, silence and five masked speech conditions. The five masking sounds were filtered pink noise, ventilation noise, instrumental music, vocal music and the sound of spring water. They were superimposed on speech. The masked speech conditions corresponded to an acoustically excellent open-plan office in respect of the Speech Transmission Index (STI 0.38). The speech condition (STI 0.62) corresponded to an STI obtained between nearby workstations in an acoustically poor open-plan office. Silent condition (STI 0.00) corresponded to the STI measured between two nearby private office rooms. In each of the seven sound conditions, the subjects performed a short-term memory task, a proofreading task and a creative thinking task and completed a questionnaire on acoustic comfort. Compared to the silent condition, short-term memory performance deteriorated in speech condition and in most masked speech conditions. Compared to the speech condition, performance improved when speech was masked with spring water sound. Ratings of acoustic satisfaction and subjective workload showed that the masked speech conditions subjectively improved the working conditions compared to the speech condition. Overall, the performance results and subjective perceptions showed that the spring water sound was the most optimal speech masker whereas vocal music produced negative effects similar to those of speech.
... Most individuals showthe effect and the average impairment of performance can be as high as 30% [16]. Irrelevant background speech has also been found to disturb more complextasks, such as proofreading [17,18], reading comprehension [19], activation of prior knowledge in long-term memory [20] and logical reasoning [21]. ...
The purpose of this study was to find out what kind of masking sound is most optimal to be used to mask distracting speech in open-plan offices. Fifty-four subjects were tested in seven sound conditions: speech, silence and five masked speech conditions. The five masking sounds were filtered pink noise, ventilation noise, instrumental music, vocal music and the sound of spring water. They were superimposed on speech. The masked speech conditions corresponded to an acoustically excellent open-plan office in respect to the Speech Transmission Index (STI 0.38). The speech condition (STI 0.62) corresponded to the STI obtained between nearby workstations in an acoustically poor open-plan office. Silent condition (STI 0.00) corresponded to the STI measured between two nearby private office rooms. In each of the seven sound conditions, the subjects performed a short-term memory task, a proofreading task and a creative thinking task and completed a questionnaire on acoustic comfort. Compared to silence condition, short-term memory performance deteriorated in speech condition and in most masked speech conditions. Compared to speech condition, performance improved when speech was masked with spring water sound. Ratings of acoustic satisfaction and subjective workload showed that masked speech conditions subjectively improved the working conditions compared to speech condition. Overall, the performance results and subjective perceptions showed that the spring water sound was the most optimal speech masker whereas vocal music produced negative effects similar to those of speech. The use of constant masking sounds should be preferred in open-plan offices instead of instrumental or vocal music.
... Lorsque l'activité ne nécessite pas de faire appel à un processus de mémoire sérielle de façon intensive, la sensibilité de la performance à l'intelligibilité du bruit de parole environnant est fondamentalement modifiée. Ainsi, le raisonnement grammatical (Schlittmeier et al., 2008b ;Liebl et al., 2011), le calcul mental (Banbury et Berry, 1998), la compréhension écrite (Venetjoki et al., 2006) ou encore la correction de texte (Landström et al., 2002 ;Haka et al., 2009) ...
Speech noise is a major cause of annoyance in open-plan offices. The purpose of this research was to assess the quality of existing tools for predicting the nuisance potential of speech and highlight possibilities for improvement. The ways in which speech sounds influence noise annoyance were thus investigated. To this end, experiments were carried out based on classical mental tasks, with concurrent objective and subjective measurements of the increase in mental workload caused by ambient speech. First, the effect of speech intelligibility was studied. Indeed, some argue for the use of a speech intelligibility measure, the Speech Transmission Index (STI), to predict noise annoyance in open-plan offices. Results confirmed the increase in disruption caused by speech made more intelligible. However, the STI was incapable of predicting noise annoyance for fluctuating background sounds, which are usual in open-plan offices. An alternative was then provided that accounted for the temporal variability seen in actual office sound environments. The predictive ability of this measure was assessed for varied tasks. The resulting effects were small when compared with individual differences in susceptibility to speech noise. However, they indicated that allowing for level fluctuations in the sound environment is essential to quantifying the induced noise annoyance. Moreover, it appeared that subjective measurements of noise annoyance were a critical complement to objective measurements for identifying certain causes of noise annoyance.
... De nombreuses tâches cognitives peuventêtre utilisées pourévaluer l'impact du type de source sonore sur la gêne ou la performance. Des tâches de verbalisation, de calcul mental, de lecture ou encore de recherche d'informations se retrouvent régulièrement dans la littérature [11,12,13]. Une tache de mémorisation sérielleà court terme estégalement souvent utilisée. ...
Désormais de plus en plus courant au sein des entreprises, le bureau ouvert est une forme déspace de travail qui permet un gain de place tout en facilitant l'échange verbal entre collègues. Cependant, il apparait que le manque d'intimité et l'augmentation du niveau sonore sont parmi les principaux inconvénients de ce type déspace de travail. Le projet GABO (Gêne Acoustique dans les Bureaux Ouverts) s’intéresse à l’évaluation de la nuisance sonore pour les travailleurs dans les bureaux ouverts et a pour but de définir des indicateurs de gêne qui tiennent compte notamment du type de la nuisance sonore. Dans la première partie du projet, il a été montré à partir d’enquêtes in-situ [1] que les conversations intelligibles et non intelligibles, les sonneries de téléphone et le bruit de machines (imprimantes) étaient parmi les sources sonores qui contribuaient le plus à la gêne totale ressentie par les utilisateurs. En s’appuyant sur ces résultats, la suite de l’étude a pour but d’évaluer en laboratoire la gêne occasionnée par ces différents types de source. Ainsi, trente cinq sujets ont réalisé une tâche de mémorisation à court terme dans cinq contextes sonores différents, à savoir quatre types de sources (imprimante, parole intelligible, parole non intelligible et sonnerie de téléphone) et un bruit de fond (ventilation), sans aucune source sonore supplémentaire (situation de contrôle). Ainsi, la gêne due au bruit a pu être évaluée de façon subjective, mais il a également été possible de mesurer la dégradation de la performance (sur la tache de mémorisation) suivant le type de source sonore subie par l’individu. Si les conversations intelligibles impactent significativement la performance, il n’y a en revanche pas de différence significative de la gêne ressentie entre les paroles intelligibles, les paroles non intelligibles et les sonneries de téléphones. Seules les imprimantes sont moins gênantes.
... Beside, most studies have shown that this presentation level has very little influence on performance, as measured by various tasks. As an example, Landström et al. [28] measured performance of subjects submitted to random noise or speech at two levels (40 and 50 dB(A)). While the kind of background noise modified the performance, its level did not. ...
In open-plan offices, employees often have to work despite being distracted by multiple sources of speech close to them. This disturbance is even more severe when the surrounding conversations are intelligible. For this reason the disruptive power of such babble-like noises can be quantified by measuring speech intelligibility. As such, the Speech Transmission Index is usually used to assess the quality of open-plan offices. In this article, the STI is used to evaluate the nuisance potential of sound environments in an open-plan office. 57 subjects were confronted with a serial memory task in four STI conditions (from 0.25 to 0.65). Noise annoyance was assessed objectively by measuring performance, and subjectively using the NASA-TLX questionnaire for measuring cognitive load. A very strong inter-individual variability appeared in performance measurements. Approximately half of the panel was made of high performing subjects, who proved to be insensitive to speech intelligibility. For the other half, performance was reduced when STI increased, as shown in previous studies, with a plateau for STI greater than 0.45. This strong inter-individual variability can explain the discrepancy between results observed in previously published studies. The NASA-TLX questionnaire proved to give useful complementary results. For example, high-performing subjects related a higher workload in the condition of maximum speech intelligibility.
... Most individuals showthe effect and the average impairment of performance can be as high as 30% [16]. Irrelevant background speech has also been found to disturb more complextasks, such as proofreading [17,18], reading comprehension [19], activation of prior knowledge in long-term memory [20] and logical reasoning [21]. ...
The aim of this study was to compare different sounds which can be used in open-plan offices to mask distracting speech. Fifty-four subjects were tested in seven sound conditions: speech, silence and five masked speech conditions. The five masking sounds were filtered pink noise, ventilation noise, instrumental music, vocal music and the sound of spring water. They were superimposed on speech. The masked speech conditions corresponded to an acoustically excellent open-plan office in respect to the Speech Transmission Index (STI 0.38). The speech condition (STI 0.62) corresponded to the STI obtained between nearby workstations in an acoustically poor open-plan office. Silent condition (STI 0.00) corresponded to the STI measured between two nearby private office rooms. In each of the seven sound conditions, the subjects performed a short-term memory task, a proofreading task and a creative thinking task and completed a questionnaire on acoustic comfort. Compared to silence condition, short-term memory performance deteriorated in speech condition and in most masked speech conditions. Compared to speech condition, performance improved when speech was masked with spring water sound. Ratings of acoustic satisfaction and subjective workload showed that masked speech conditions subjectively improved the working conditions compared to speech condition. Overall, the performance results and subjective perceptions showed that the spring water sound was the most optimal speech masker whereas vocal music produced negative effects similar to those of speech. The use of constant masking sounds should be preferred in open-plan offices instead of instrumental or vocal music.
... This relationship is in line with previous studies involving simple reaction time paradigms , instead of an attention capture task, and requiring participants to attend to the auditory stimuli (e.g., Arrabito, 2009; Haas & Casali, 1995; Suied et al., 2008). From a methodological point of view, the convergence between the subjective rating of urgency and behavioral measures is encouraging in the face of studies failing to find correlations between subjective ratings and objective measures (e.g., Kjellberg & Sköldström, 1991; Landström, Söderberg, Kjellberg, & Nordström, 2002; Ljungberg & Neely, 2007a, 2007b Ljungberg, Neely, & Lundström, 2004 ). Behavioral performance and subjective ratings did not converge for the valence manipulation, however. ...
The objective was to study the involuntary capture of attention by spoken words varying in intonation and valence. In studies of verbal alarms, the propensity of alarms to capture attention has been primarily assessed with the use of subjective ratings of their perceived urgency. Past studies suggest that such ratings vary with the alarms' spoken urgency and content.
We measured attention capture by spoken words varying in valence (negative vs. neutral) and intonation (urgently vs. nonurgently spoken) through subjective ratings and behavioral measures. The key behavioral measure was the response latency to visual stimuli in the presence of spoken words breaking away from the periodical repetition of a tone.
The results showed that all words captured attention relative to a baseline standard tone but that this effect was partly counteracted by a relative speeding of responses for urgently compared with nonurgently spoken words. Word valence did not affect behavioral performance. Rating data showed that both intonation and valence increased significantly perceived urgency and attention grabbing without any interaction. The data suggest a congruency between subjective ratings and behavioral performance with respect to spoken intonation but not valence. This study demonstrates the usefulness and feasibility of objective measures of attention capture to help design efficient alarm systems.
... Note that, while this study clearly demonstrates a link between annoyance and interference, the effects observed are likely to be due to pure acoustical masking, and therefore not indicative of the cognitive interference effects encountered at moderate noise levels. These were the focus of a recent study by Landstro¨m et al. [10] who investigated proofreading, a logicalreasoning task, and physical letter sorting while their participants were exposed to broadband noise or background speech of moderate levels. Surprisingly though, this study showed a performance decrement only in the letter sorting task (under speech), and no systematic relationship between actual performance and annoyance. ...
To determine whether the amount of performance disruption by a noise has an effect on the annoyance that noise evokes, a laboratory situation was created in which the participants rated a number of sounds before, after, and while performing a cognitively demanding memory task. The task consisted of memorizing, and later reproducing, a visually presented sequence of digits while being exposed to irrelevant sound chosen to produce different degrees of disruption. In two experiments, participants assessed these background sounds (frequency-modulated tones, broadband noise and speech) on a rating scale consisting of thirteen categories ranging from ‘not annoying at all’ to ‘extremely annoying.’ The judgments were collected immediately before, after, and concomitant to, the memory task. The results of the first experiment (N=24) showed that the annoyance assessments were indeed altered by the experience of disruption, most strongly during, and to a lesser extent after task completion, whereas ratings of the non-disruptive sounds remained largely unaffected. In the second experiment (N=25), participants were exposed to the same sounds, but for longer intervals at a time: 10 min as opposed to 14 s in the first experiment. The longer exposure resulted in increased annoyance in all noise conditions, but did not alter the differential effect of disruption on annoyance, which was replicated. The results of these laboratory experiments support the notion that annoyance cannot be conceived of as a purely perceptual sound property; rather, it is influenced by the degree of interference with the task at hand.
Previous studies have shown that identifiability of sound sources influence noise annoyance levels. The aim of the present experiment was to additionally study the effects of actively performing a task versus a less active pastime on noise annoyance. This was done by asking participants to perform a task (task condition) or read a magazine of their choice (no-task condition), while listening to identifiable and unidentifiable samples of transportation noise at varying sound exposure levels (55−85 ASEL). Annoyance was higher for identifiable samples (recordings) than for unidentifiable transformed samples (with equal spectral energy and envelope). Although there was no main effect of activity type on noise annoyance, for the transformed samples, an interaction was found between activity type and sound exposure levels: annoyance started lower in the no-task condition, but rose more steeply with ascending exposure levels than was the case during task performance (large effect). When assessing order effects, it was found that annoyance was higher when the task condition came first, especially for lower sound exposure levels (large effects). It is therefore concluded that the type of activity and the condition order do influence noise annoyance but in interaction with exposure levels, the type of noise and habituation.
This article aimed to investigate whether auditory stimuli disrupt the performance of a text recognition task (Experiment 1) and a text recall task (Experiment 2). In Experiment 1, Spanish speech sounds that disrupted the serial recall task (Miyahara & Goshiki, 2004) were presented during the learning phase of the task. The Spanish speech had a reduced d', which indicates that the text recognition task was also disrupted. In Experiment 2, Japanese speech sounds or office noise were presented during either the learning only phase, recall only phase, or during both the phases. The results were that both types of auditory stimuli could disrupt the text recall task, and this effect was independent of the meaning of the speech sounds and the presenting phase. Our results could be interpreted by Cowan's model (1995, 1999) with the inclusion of two modifications.
This paper summarizes results from an experiment designed to investigate the combined effects of noise and temperature on human thermal comfort and task performance. Thirty subjects (16 females, 14 males) were exposed to all combinations of five thermal conditions (PMV +1 [79.6°F:26.4°C], PMV +0.5 [75.8°F:24.3°C], PMV 0 [72.1°F:22.3°C], PMV -0.5 [68.3°F:20.2°C], and PMV -1 [64.6°F:18.1°C]), three RC noise levels (RC-30, RC-40, and RC-50), and two sound qualities (neutral and rumbly): all sounds mimickednoisefrombuildingventilationsystems. After a one-hour adaptation period at each condition, subjects rated their thermal comfort using the ASHRAE Thermal Comfort Scale and the Tenant Survey Questionnaire, and then completed typing and number-checking tasks. There were no statistically significant effects of thermal condition, RC level, or sound quality on performance of the typing or number-checking tasks. Statistical analyses showed that thermal comfort was affected by RC noise level, while ratings of building or office noise were not affected by the ambient temperature. There were also differences in the way males and females experienced the thermal and acoustical environments. Females rated lower temperatures colder than males, and higher temperatures more pleasant than males: thermal comfort composite ratings from males and females converged at about 72°F (22°C).
Abstract This study examined how the intelligibility of irrelevant speech, determined with the Speech Transmission Index (STI), affects demanding cognitive task performance. Experiment was carried out in a laboratory that resembled an open-plan office. Three speech conditions were tested corresponding to a private office (STI = 0.10), an acoustically excellent open office (STI = 0.35) and an acoustically poor open office (STI = 0.65). All conditions were presented at equal level, 48 dBA. The STI was adjusted by the relative levels of speech and masking sound. Thirty-seven students participated in the experiment that lasted for 4 h. All participants performed five tasks in each of the three speech conditions. Questionnaires were used to assess subjective perceptions of the speech conditions. Performance in the operation span task, the serial recall and the activation of prior knowledge from long-term memory were deteriorated in the speech condition with the highest speech intelligibility (STI = 0.65) in comparison with the other two conditions (STI = 0.10 and STI = 0.35). Unlike performance measures, questionnaire results showed consistent differences among all three speech conditions, i.e. subjective disturbance increased with ascending speech intelligibility. Thus, subjective comfort was disturbed more easily than performance. The results support the use of STI as an essential room acoustic design measure in open-plan offices.
Reduction of speech intelligibility in office environments by proper acoustic design would be beneficial in terms of both work performance and subjective comfort. Proper acoustic design requires both the use of high acoustic absorption and an appropriate masking sound.
Irrelevant speech markedly impairs serial recall of visually presented lists, even though the person is asked to ignore the speech. In this, the first major review of the phenomenon, we conclude that (i) the effect occurs in memory rather than at encoding; (ii) within memory, the disruption occurs as a result of a confluence of information at the phonological rather than at the articulatory stage of coding; (iii) speech does not have privileged access to memory, since its disruptive effects may be attenuated by habituation; and (iv) disruption occurs as a result of the changing state of the auditory channel, not as had previously been thought the phonological similarity of visual and auditory streams, and is particularly sensitive to pitch changes in both speech and non-speech stimuli. These conclusions are discussed in the light of two complementary theoretical constructs: a cascading filter system responsible for the access of speech to memory and a system of coding within memory sensitive to changing state of the stream responsible for disruption of serial order. Recommendations are made also for empirical work to refine these constructs.
Three experiments were performed to study the effects of an ongoing task on the annoyance response to noise. In the first two experiments a total of five tasks were used: three versions of a proofreading task, a finger-dexterity task, and a complex reaction time (RT) task. Subjects performed the tasks during exposure to two levels of a continuous broadband noise. Task was of no consequence for rated annoyance. Four tasks were used in Experiment 3: proofreading, complex RT, grammatical reasoning, and simple RT. A third type of noise, irrelevant speech, was added to the broadband noises. Rated annoyance was lower during simple RT than during the reasoning and proofreading tasks, especially in the irrelevant speech condition. The difference corresponded to a 6-dB difference in noise level. It was concluded that task differences probably only explain a small part of the widely differing noise tolerance levels at different work places.
Three groups of 24 subjects were exposed to a 1000-Hz tone or broad band noise in a sound chamber. During the exposures subjects were engaged in an easy reaction time test or a difficult grammatical reasoning test. For each exposure and work subjects adjusted the noise to a tolerance level defined by its interference with task performance. During the simple reaction-time task significantly higher sound-pressure levels were accepted than during the reasoning test. At the tonal exposure, much lower levels were accepted than during the exposure to broad-band noise. For continuous sound exposures much higher levels were accepted than for noncontinuous exposures. For tonal exposures the difference was approximately 5 dB, for the broad-band exposures approximately 9 dB. In a separate study the effects of the noncontinuity of the noise and pauses were analysed. The raised annoying effect of the noncontinuous noise was not more affected by the noncontinuity of the noise periods than by the noncontinuity of the pauses. The results imply that the annoying reactions to the sound will be increased for repetitive noise and that the reaction is highly influenced by the over-all noncontinuity of the exposure.