Irrelevant Speech Effect Research Articles

Cognitive disruption by noise-vocoded speech stimuli: Effects of spectral variation.

The effect of irrelevant sounds on short-term memory was investigated in two experiments using noise-vocoded speech stimuli (NVSS). Speech samples were systematically modified by a noise-vocoder and a set of stimuli varying from amplitude-modulated white noise to intelligible speech was created. Eight NVSS conditions, composed of 1-, 2-, 4-, 6-, 9-, 12-, 15-, and 18-bands, were used as the distracting stimuli in a digit-recall task next to the speech and silence conditions. The results showed that performance decreased with the number of frequency bands up to the 6-bands condition, but there was no influence of number of bands on performance beyond six bands. The results were analyzed using four acoustic metrics proposed in the literature: the frequency domain correlation coefficient (FDCC), the fluctuation strength, the speech transmission index (STI), and the normalized covariance measure (NCM). None of the metrics successfully predicted the results. However, the parameter values of the FDCC, the STI, and the NCM indicated that a prediction model for irrelevant sound effect should account for both temporal and spectral features of the irrelevant sounds.

The irrelevant speech effect among younger and older adults: The influence of background noises on reading comprehension

ABSTRACTBackground: Aging could exacerbate the decreases in cognitive functioning already caused by noise pollution. According to the inhibitory deficit hypothesis, older adults have more difficulty than do younger adults keeping irrelevant information from interfering with processing of relevant information. However, irrelevant speech studies typically fail to support this hypothesis. The present study aimed to quantify the effects of age and noise pollution on reading comprehension.Methods: Seventeen younger (age 21–29) and 15 older (age 62–77) adults completed a reading task (reading discourse material for a follow-up comprehension test) in the presence of six irrelevant background noise conditions. Repeated measures ANOVAs and t tests were used to analyze participant accuracy on the follow-up comprehension tests.Results: Contrary to the inhibitory deficit hypothesis, but congruent with previous irrelevant speech studies, younger and older adults did not have significantly different reading comprehension scores, and both groups’ accuracy was greatest when asked to read in silence. Noise conditions that contained English speech, regardless of whether this background noise was spoken or sung, were most disruptive.Conclusion: Younger and older adults appear to be equally influenced by irrelevant background material when reading. Regardless of age, reading in a distraction-free environment whenever possible is the best way to maximize reading comprehension.

The role of speech fidelity in the irrelevant sound effect: Insights from noise-vocoded speech backgrounds.

The Irrelevant Sound Effect (ISE) is the finding that background sound impairs accuracy for visually presented serial recall tasks. Among various auditory backgrounds, speech typically acts as the strongest distractor. Based on the changing-state hypothesis, speech is a disruptive background because it is more complex than other nonspeech backgrounds. In the current study, we evaluate an alternative explanation by examining whether the speech-likeness of the background (speech fidelity) contributes, beyond signal complexity, to the ISE. We did this by using noise-vocoded speech as a background. In Experiment 1, we varied the complexity of the background by manipulating the number of vocoding channels. Results indicate that the ISE increases with the number of channels, suggesting that more complex signals produce greater ISEs. In Experiment 2, we varied complexity and speech fidelity independently. At each channel level, we selectively reversed a subset of channels to design a low-fidelity signal that was equated in overall complexity. Experiment 2 results indicated that speech-like noise-vocoded speech produces a larger ISE than selectively reversed noise-vocoded speech. Finally, in Experiment 3, we evaluated the locus of the speech-fidelity effect by assessing the distraction produced by these stimuli in a missing-item task. In this task, even though noise-vocoded speech disrupted task performance relative to silence, neither its complexity nor speech fidelity contributed to this effect. Together, these findings indicate a clear role for speech fidelity of the background beyond its changing-state quality and its attention capture potential.

Effects of irrelevant background speech on eye movements during reading.

The irrelevant speech effect (ISE) refers to the impairment of visual information processing by background speech. Prior research on the ISE has focused on short-term memory for visually presented word lists. The present research extends this work by using measurements of eye movements to examine effects of irrelevant background speech during Chinese reading. This enabled an examination of the ISE for a language in which access to semantic representations is not strongly mediated by phonology. Participants read sentences while exposed to meaningful irrelevant speech, meaningless speech (scrambled meaningful speech) or silence. A target word of high or low lexical frequency was embedded in each sentence. The results show that meaningful, but not meaningless, background speech produced increased re-reading. In addition, the appearance of a normal word frequency effect, characterised by longer fixation times on low- compared to high-frequency words, was delayed when meaningful or meaningless speech was present in the background. These findings show that irrelevant background speech can disrupt normal processes of reading comprehension and, in addition, that background noise can interfere with the early processing of words. The findings add to evidence showing that normal reading processes can be disrupted by environmental noise such as irrelevant background speech.

Mechanism of the irrelevant speech effect in reading: Is the interference determined by content, or process?

Mechanism of the irrelevant speech effect in reading: Is the interference determined by content, or process?

Metacognition in Auditory Distraction: How Expectations about Distractibility Influence the Irrelevant Sound Effect.

Task-irrelevant, to-be-ignored sound disrupts serial short-term memory for visually presented items compared to a quiet control condition. We tested whether disruption by changing state irrelevant sound is modulated by expectations about the degree to which distractors would disrupt serial recall performance. The participants’ expectations were manipulated by providing the (bogus) information that the irrelevant sound would be either easy or difficult to ignore. In Experiment 1, piano melodies were used as auditory distractors. Participants who expected the degree of disruption to be low made more errors in serial recall than participants who expected the degree of disruption to be high, independent of whether distractors were present or not. Although expectation had no effect on the magnitude of disruption, participants in the easy-to-ignore group reported after the experiment that they were less disrupted by the irrelevant sound than participants in the difficult-to-ignore group. In Experiment 2, spoken texts were used as auditory distractors. Expectations about the degree of disruption did not affect serial recall performance. Moreover, the subjective and objective distraction by irrelevant speech was similar in the easy-to-ignore group and in the difficult-to-ignore group. Thus, while metacognitive beliefs about whether the auditory distractors would be easy or difficult to ignore can have an effect on task engagement and subjective distractibility ratings, they do not seem to have an effect on the actual degree to which the auditory distractors disrupt serial recall performance.

Sound masking in office environments—Trade-off between masking effect and user acceptance

Solving cognitive tasks is adversely affected by speech sound (Irrelevant Speech Effect). In particular, the interfering potential of speech sound is high in open-plan office environments. Sound masking is one of the most effective methods to reduce the disturbing speech sound by covering certain fractions of it with a masking signal. Since the most effective masking signals are subjectively perceived as annoying themselves, the goal of this work was to develop a masking signal which fulfills both, a good masking effect and a high user acceptance. To achieve this goal, qualitatively different masking signals with varying structural properties were developed. The efficacy of these signals was tested in a laboratory experiment using a cognitive task (serial recall). In addition, a subjective evaluation of the signals (loudness, annoyance, etc.) was carried out. In the second part of this work, a questionnaire was developed, which can be used to evaluate the acceptance and the subjectively assessed effectiveness of newly developed masking signals by their potential users. Using this questionnaire, the newly developed masking signals were evaluated by persons working in open-plan offices. Findings and implications for practical usage are presented.

A simple sound metric for evaluating sound annoyance in open-plan offices

Noise in open-plan offices has become a major health issue. Intelligible speech is considered as the most annoying noise sources by the occupants of such offices. Speech level fluctuations prevent people from achieving some high-demanding tasks, thus inducing annoyance and tiredness. Many studies were conducted in order to identify a sound metric closely related to this Irrelevant Speech Effect. Hongisto et al. have shown that Speech Transmission Effect is appropriate for evaluating the annoyance due to a neighbor in the office. More recently, Schlittmeier et al. suggested that the Fluctuation Strength can be used to evaluate the effect of the fluctuations of the ambient noise on task performance. This paper intends to present a new metric. It is based on the measurement of short-term temporal modulation of sound level. Results indicate that it seems to be as efficient as STI or FS, while being more suitable for in-situ experiments and usable by practitioners.

Age-related cognitive decline as a function of daytime testing

ABSTRACTThe current study investigates the effects of age, cognitive load, optimal time-of-day testing, and irrelevant background noise suppression on mental processing. One hundred and seventy-eight young (M = 22.97 years) and 114 old adults (M = 56.38 years) were assessed for implicit learning and speed of information processing under irrelevant sound interference early during daytime (7AM–2.30PM) or in the afternoons (3PM–midnight). No direct effect of irrelevant speech effect was found on implicit learning. An optimal time of testing per age group was identified according to the ability to suppress irrelevant auditory information. If no semantic meaning was derived from the sound conditions, irrelevant sound was easily inhibited leaving no room for declined cognitive performance. This suggests an intact phonological inhibition in older adults and a further circumvention of the phonological loop. However, when difficulty was increased, a widened performance gap between young and old people could be observed. Education modulated difficult performance irrespective of age. With increasing age, task demand fulfillment becomes a function of a limited time mechanism. If extraneous time is not adapted to cognitive skills and performance, higher order processing cannot be reached, rendering older adults slower than their younger counterparts.

Memory disruption by irrelevant noise-vocoded speech: Effects of native language and the number of frequency bands.

To investigate the mechanisms by which unattended speech impairs short-term memory performance, speech samples were systematically degraded by means of a noise vocoder. For experiment 1, recordings of German and Japanese sentences were passed through a filter bank dividing the spectrum between 50 and 7000 Hz into 20 critical-band channels or combinations of those, yielding 20, 4, 2, or just 1 channel(s) of noise-vocoded speech. Listening tests conducted with native speakers of both languages showed a monotonic decrease in speech intelligibility as the number of frequency channels was reduced. For experiment 2, 40 native German and 40 native Japanese participants were exposed to speech processed in the same manner while trying to memorize visually presented sequences of digits in the correct order. Half of each sample received the German, the other half received the Japanese speech samples. The results show large irrelevant-speech effects increasing in magnitude with the number of frequency channels. The effects are slightly larger when subjects are exposed to their own native language. The results are neither predicted very well by the speech transmission index, nor by psychoacoustical fluctuation strength, most likely, since both metrics fail to disentangle amplitude and frequency modulations in the signals.

Simultaneous effects of irrelevant speech, temperature and ventilation rate on performance and satisfaction in open-plan offices

The aim of this study was to investigate how irrelevant speech, temperature and ventilation rate together affect cognitive performance and environmental satisfaction in open-plan offices. In Condition A, neutral temperature (23.5 °C), low intelligibility of speech (high absorption and low masking sound level) and high fresh air supply rate (30 l/s per person) were applied. This was contrasted to Condition B with high room temperature (29.5 °C), highly intelligible speech (low absorption and high masking sound level) and a negligible fresh air supply rate (2 l/s per person). Sixty-five participants were tested. In Condition B, performance decrement was observed especially in working memory tasks. Based on subjective assessments, mental workload, cognitive fatigue and symptoms were higher and environmental satisfaction was lower in Condition B. It was concluded that special attention should be paid to the design of whole indoor environment in open-plan offices to increase subjective comfort and improve performance.

The impact of road traffic noise on cognitive performance in attention-based tasks depends on noise level even within moderate-level ranges.

Little empirical evidence is available regarding the effects of road traffic noise on cognitive performance in adults, although traffic noise can be heard at many offices and home office workplaces. Our study tested the impact of road traffic noise at different levels (50 dB(A), 60 dB(A), 70 dB(A)) on performance in three tasks that differed with respect to their dependency on attentional and storage functions, as follows: The Stroop task, in which performance relied predominantly on attentional functions (e.g., inhibition of automated responses; Experiment 1: n = 24); a non-automated multistage mental arithmetic task calling for both attentional and storage functions (Exp. 2: n = 18); and verbal serial recall, which placed a burden predominantly on storage functions (Experiment 3: n = 18). Better performance was observed during moderate road traffic noise at 50 dB(A) compared to loud traffic noise at 70 dB(A) in attention-based tasks (Experiments 1-2). This contrasted with the effects of irrelevant speech (60 dB(A)), which was included in the experiments as a well-explored and common noise source in office settings. A disturbance impact of background speech was only given in the two tasks that called for storage functions (Experiments 2-3). In addition to the performance data, subjective annoyance ratings were collected. Consistent with the level effect of road traffic noise found in the performance data, a moderate road traffic noise at 50 dB(A) was perceived as significantly less annoying than a loud road traffic noise at 70 dB(A), which was found, however, independently of the task at hand. Furthermore, the background sound condition with the highest detrimental performance effect in a task was also rated as most annoying in this task, i.e., traffic noise at 70 dB(A) in the Stroop task, and background speech in the mental arithmetic and serial recall tasks.

Age differences in the irrelevant sound effect: A serial recognition paradigm

In adults, the disrupting effect of irrelevant background sounds with distinct temporalspectral variations (changing-state sounds) on short-term memory performance was found to be robust. In the present study, a verbal serial recognition task was used to investigate this so-called Irrelevant Sound Effect (ISE) in adults and 8- to 10-year-old children. An essential part of the short-term memory impairment during changing-state speech is due to interference processes (changing-state effect) which can be differentiated from the deviation effect of auditory distraction. In line with recent findings (Hughes et al., 2013), our study demonstrates that the changing-state effect is not modulated by task difficulty. Moreover, our results show that the changing-state effect remains stable for children and adults. This suggests that the differences in the magnitude of the ISE as reported by Elliott (2002) and Klatte et al. (2010) are most likely related to the increase in attentional control during childhood.

Specific foreknowledge reduces auditory distraction by irrelevant speech.

In a series of experiments, it was tested whether distraction by changing-state irrelevant speech is inevitable or can be modulated by foreknowledge of an imminent to-be-ignored distractor sequence. Participants were required to remember visually presented digits while ignoring background speech. In the foreknowledge condition of Experiment 1, the upcoming to-be-ignored sentence was presented auditorily and visually before each trial. With specific foreknowledge, the changing-state irrelevant sound effect (here, increased disruption by sentences compared with repeated words) was significantly attenuated relative to a condition without foreknowledge. This finding was replicated in Experiment 2, in which the information about the upcoming auditory distractor speech was presented only in the visual modality. Experiment 3 showed that only specific foreknowledge of the auditory distractor material has beneficial effects on the ability to ignore distraction. The mere notification that an unspecified distractor sentence would be presented next had no effect on distraction. In Experiment 4, there was only a small and not statistically significant reduction of the irrelevant speech effect when lists of randomly selected words were used as distractor material, suggesting that foreknowledge effects are more pronounced for highly variable, meaningful distractor material. We conclude that the disruption of short-term memory by irrelevant speech is not purely a stimulus-driven process that is immune to top-down control. A significant proportion of the effect can be modulated by specific knowledge about an imminent distractor sequence.

Auditory Distraction by Meaningless Irrelevant Speech: A Developmental Study

SummaryThe irrelevant sound effect (ISE) typically refers to a disruptive effect of a to‐be‐ignored sound in serial recall tasks, where lists of visually presented items (digits and letters) must be recalled in serial order. Although extensively studied in adults, studies on developmental aspects of the ISE are scarce. The present study aims to increase our understanding of developmental changes of auditory distraction in children beyond serial recall. Two tasks (i.e., word categorization and evaluation of simple mathematical equations) were designed to test retrieval from semantic memory. Proportion correct and reaction times (adjusted for speed–accuracy tradeoff) were measured in 8–9 and 12–13‐year‐olds. Results revealed a developmental change in the susceptibility to auditory distraction. Whereas older children were not affected by background sounds, younger children showed impairment in both proportion correct and adjusted reaction times. Overall, results suggest that attention distraction and immature attention control mechanisms contribute to ISEs in young children. Copyright © 2014 John Wiley & Sons, Ltd.

Irrelevant speech does not interfere with serial recall in early blind listeners.

Phonological working memory is known be (a) inversely related to the duration of the items to be learned (word-length effect), and (b) impaired by the presence of irrelevant speech-like sounds (irrelevant-speech effect). As it is discussed controversially whether these memory disruptions are subject to attentional control, both effects were studied in sighted participants and in a sample of early blind individuals who are expected to be superior in selectively attending to auditory stimuli. Results show that, while performance depended on word length in both groups, irrelevant speech interfered with recall only in the sighted group, but not in blind participants. This suggests that blind listeners may be able to effectively prevent irrelevant sound from being encoded in the phonological store, presumably due to superior auditory processing. The occurrence of a word-length effect, however, implies that blind and sighted listeners are utilizing the same phonological rehearsal mechanism in order to maintain information in the phonological store.

A bilingual advantage in the irrelevant speech effect

The bilingual advantage refers to superior performance by multilingual over monolingual individuals on a variety of linguistic, and non-linguistic cognitive tasks. Tasks that include the bilingual advantage are ones that involve attention control, such as the Simon or Stroop tasks, but not tasks that involve short-term memory (Bialyskok, 2009). The Irrelevant Speech Effect (ISE) is the finding that serial recall accuracy of visual list items declines when task irrelevant speech backgrounds are present (relative to the disruption of white noise backgrounds: Colle and Welsh, 1976; Jones and Macken, 1993). The theories that have been offered to account for ISE are of two kinds, those that assume recall disruption is a function of limited memory, and those that assume it is the result of diffused attention (Elliot, 2002). As the bilingual advantage is found in tasks of attention, but not those concerning memory, a bilingual advantage in the ISE would support an attention based theory. In order to test this prediction, bilingual and monolingual subjects performed serial recall tests against speech and white noise backgrounds. Preliminary results suggest that the size of ISE is substantially smaller in bilingual, than it is in monolingual participants supporting attention-based theories of the ISE.

The Role of Speech-Specific Properties of the Background in the Irrelevant Sound Effect

The irrelevant sound effect (ISE) is the finding that serial recall performance is impaired under complex auditory backgrounds such as speech as compared to white noise or silence. Several findings have demonstrated that ISE occurs with nonspeech backgrounds and that the changing-state complexity of the background stimuli is critical to ISE. In a pair of experiments, we investigate whether speech-like qualities of the irrelevant background have an effect beyond their changing-state complexity. We do so by using two kinds of transformations of speech with identical changing-state complexity: one kind that preserved speech-like information (sinewave speech and fully reversed sinewave speech) and others in which this information was distorted (two selectively reversed sinewave speech conditions). Our results indicate that even when changing-state complexity is held constant, sinewave speech conditions in which speech-like interformant relationships are disrupted, produce less ISE than those in which these relationships are preserved. This indicates that speech-like properties of the background are important beyond their changing-state complexity for ISE.

The psychoacoustics of the irrelevant sound effect

Acoustical science and technology 35 (2014) 1, S. 10-16 Padagogische Teildisziplin: Empirische Bildungsforschung;

Self-relevance increases the irrelevant sound effect: Attentional disruption by one's own name

Memory performance is severely disrupted when task-irrelevant sound is played during item presentation or in a retention interval. Working memory models make contrasting assumptions on whether the semantic content of the auditory distractors modulates the irrelevant sound effect. In the present study, participants made more errors in serial recall when they had to ignore sentences containing their own name as opposed to that of a yoked-control partner. These results are only consistent with working memory models that allow for attentional processes to play a role in the explanation of the irrelevant sound effect. With repeated presentation the disruptive effect of one's own name decreased, whereas the disruptive effect of the auditory distractors in the control condition remained constant. The latter finding is most consistent with the duplex model of auditory attention, which assumes that the irrelevant sound effect is primarily caused by automatic interference of acoustic distractor features, but at the same time allows for a disruption of encoding due to attentional capture by unexpected deviants. However, to explain the present results, the mechanism responsible for the attentional capture has to be extended to highly (self-)relevant auditory distractors.