Auditory Background Research Articles

The incongruency advantage for environmental sounds presented in natural auditory scenes.

The effect of context on the identification of common environmental sounds (e.g., dogs barking or cars honking) was tested by embedding them in familiar auditory background scenes (street ambience, restaurants). Initial results with subjects trained on both the scenes and the sounds to be identified showed a significant advantage of about five percentage points better accuracy for sounds that were contextually incongruous with the background scene (e.g., a rooster crowing in a hospital). Further studies with naive (untrained) listeners showed that this incongruency advantage (IA) is level-dependent: there is no advantage for incongruent sounds lower than a Sound/Scene ratio (So/Sc) of -7.5 dB, but there is about five percentage points better accuracy for sounds with greater So/Sc. Testing a new group of trained listeners on a larger corpus of sounds and scenes showed that the effect is robust and not confined to a specific stimulus set. Modeling using spectral-temporal measures showed that neither analyses based on acoustic features, nor semantic assessments of sound-scene congruency can account for this difference, indicating the IA is a complex effect, possibly arising from the sensitivity of the auditory system to new and unexpected events, under particular listening conditions.

The relationship between multisensory integration and IQ in children.

It is well accepted that multisensory integration has a facilitative effect on perceptual and motor processes, evolutionarily enhancing the chance of survival of many species, including humans. Yet, there is limited understanding of the relationship between multisensory processes, environmental noise, and children's cognitive abilities. Thus, this study investigated the relationship between multisensory integration, auditory background noise, and the general intellectual abilities of school-age children (N = 88, mean age = 9 years, 7 months) using a simple audiovisual detection paradigm. We provide evidence that children with enhanced multisensory integration in quiet and noisy conditions are likely to score above average on the Full-Scale IQ of the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV). Conversely, approximately 45% of tested children, with relatively low verbal and nonverbal intellectual abilities, showed reduced multisensory integration in either quiet or noise. Interestingly, approximately 20% of children showed improved multisensory integration abilities in the presence of auditory background noise. The findings of the present study suggest that stable and consistent multisensory integration in quiet and noisy environments is associated with the development of optimal general intellectual abilities. Further theoretical implications are discussed.

Effect of background noise on food perception

We investigated the effects of auditory background noise on the perception of gustatory food properties (sugar level, salt level), food crunchiness and food liking. Participants blindly consumed different foods whilst passively listening to either no sound, or quiet or loud background white noise. The foods were then rated in terms of sweetness, saltiness and liking (Experiment 1) or in terms of overall flavour, crunchiness and liking (Experiment 2). Reported sweetness and saltiness was significantly lower in the loud compared to the quiet sound conditions (Experiment 1), but crunchiness was reported to be more intense (Experiment 2). This suggests that food properties unrelated to sound (sweetness, saltiness) and those conveyed via auditory channels (crunchiness) are differentially affected by background noise. A relationship between ratings of the liking of background noise and ratings of the liking of the food was also found (Experiment 2). We conclude that background sound unrelated to food diminishes gustatory food properties (saltiness, sweetness) which is suggestive of a cross-modal contrasting or attentional effect, whilst enhancing food crunchiness.

Hippocampus responds to auditory change in rabbits

Any change or novelty in the auditory environment is potentially important for survival. The cortex has been implicated in the detection of auditory change whereas the hippocampus has been associated with the detection of auditory novelty. Local field potentials (LFPs) were recorded from the CA1 area of the hippocampus in waking rabbits. In the oddball condition, a rare tone of one frequency (deviant) randomly replaced a repeated tone of another frequency (standard). In the equal-probability condition, the standard was replaced by a set of tones of nine different frequencies in order to remove the repetitive auditory background of the deviant (now labelled as control-deviant) while preserving its temporal probability. In the oddball condition, evoked potentials at 36–80 ms post-stimulus were found to have greater amplitude towards negative polarity for the deviant relative to the standard. No significant differences in response amplitudes were observed between the control-deviant and the standard. These findings suggest that the hippocampus plays a role in auditory change detection.

The effects of background white noise on memory performance in inattentive school children

BackgroundNoise is typically conceived of as being detrimental for cognitive performance; however, a recent computational model based on the concepts of stochastic resonance and dopamine related internal noise postulates that a moderate amount of auditive noise benefit individuals in hypodopaminergic states. On the basis of this model we predicted that inattentive children would be enhanced by adding background white noise while attentive children's performance would deteriorate.MethodsFifty-one secondary school pupils carried out an episodic verbal free recall test in two noise conditions. In the high noise condition, verb-noun sentences were presented during auditory background noise (white noise, 78 dB), and in the low noise condition sentences were presented without noise.ResultsExposure to background noise improved performance for inattentive children and worsened performance for attentive children and eliminated episodic memory differences between attentive and inattentive school children.ConclusionsConsistent with the model, our data show that cognitive performance can be moderated by external background white noise stimulation in a non-clinical group of inattentive participants. This finding needs replicating in a larger sample using more noise levels but if replicated has great practical applications by offering a non-invasive way to improve school results in children with attentional problems.

Short article: Irrelevant speech effects and statistical learning

Immediate serial recall of visually presented verbal stimuli is impaired by the presence of irrelevant auditory background speech, the so-called irrelevant speech effect. Two of the three main accounts of this effect place restrictions on when it will be observed, limiting its occurrence either to items processed by the phonological loop (the phonological loop hypothesis) or to items that are not too dissimilar from the irrelevant speech (the feature model). A third, the object-oriented episodic record (O-OER) model, requires only that the memory task involves seriation. The present studies test these three accounts by examining whether irrelevant auditory speech will interfere with a task that does not involve the phonological loop, does not use stimuli that are compatible with those to be remembered, but does require seriation. Two experiments found that irrelevant speech led to lower levels of performance in a visual statistical learning task, offering more support for the O-OER model and posing a challenge for the other two accounts.

Age-Related Increase in Cross-Sensory Noise in Resting and Steady-State Cerebral Perfusion

Behavioral research indicates that healthy aging is accompanied by maintenance of voluntary attentional function in many situations, suggesting older adults are able to use attention to enhance and suppress neural activity. However, other experiments show increased distractibility with age, suggesting a failure of attention. One hypothesis for these apparently conflicting findings is that older adults experience a greater sensory processing load at baseline compared to younger adults. In this situation, older adults might successfully modulate sensory cortical activity relative to a baseline referent condition, but the increased baseline load results in more activity than younger adults after attentional modulation. This hypothesis was tested by comparing average functional brain activity in auditory cortex using quantitative perfusion imaging during resting state and steady-state visual conditions. It was observed that older adults demonstrated greater processing of task-irrelevant auditory background noise than younger adults in both conditions. As expected, auditory activity was attenuated relative to rest during a visually engaging task for both older and younger participants. However, older adults continued to show greater auditory processing than their younger counterparts even after this task modulation. Furthermore, auditory activity during the visual task was predictive of cross-sensory distraction on a behavioral task in older adults. Together, these findings suggest that older adults are more distractible than younger, and the cause of this increased distractibility may lie in baseline brain functioning.

Intact Spectral but Abnormal Temporal Processing of Auditory Stimuli in Autism

The perceptual pattern in autism has been related to either a specific localized processing deficit or a pathway-independent, complexity-specific anomaly. We examined auditory perception in autism using an auditory disembedding task that required spectral and temporal integration. 23 children with high-functioning-autism and 23 matched controls participated. Participants were presented with two-syllable words embedded in various auditory backgrounds (pink noise, moving ripple, amplitude-modulated pink noise, amplitude-modulated moving ripple) to assess speech-in-noise-reception thresholds. The gain in signal perception of pink noise with temporal dips relative to pink noise without temporal dips was smaller in children with autism (p = 0.008). Thus, the autism group was less able to integrate auditory information present in temporal dips in background sound, supporting the complexity-specific perceptual account.

Marking Time in <em>Doctor Faustus</em> 5.2

Doctor Faustus 5.2, the scene in which Faustus confronts the prospect of damnation against the auditory background of the striking clock, directs our attention to time and mortality in a number of ways. Not only does Marlowe manipulate audience response to make short periods of time seem long and long periods of time seem short (the latter phenomenon mocking Faustus’s bargain with the devil), he also ingeniously deploys the twenty-four separate strikings of the clock to make them recall, with deep irony, the fleeting twenty-four years of Faustus’s ill-fated contract. The scene thus collapses the ‘long’ space of twenty-four years into the ‘short’ space of sixty minutes (the time from eleven to midnight), rendering these separate spans of time symbolically as a single moment and, moreover, one that elapses in only a few minutes of stage action.

Are Auditory-Evoked Frequency and Duration Mismatch Negativity Deficits Endophenotypic for Schizophrenia? High-Density Electrical Mapping in Clinically Unaffected First-Degree Relatives and First-Episode and Chronic Schizophrenia

Mismatch negativity (MMN) is a negative-going event-related potential (ERP) component that occurs in response to intermittent changes in constant auditory backgrounds. A consistent finding across a large number of studies has been impaired MMN generation in schizophrenia, which has been interpreted as evidence for fundamental deficits in automatic auditory sensory processing. The aim of this study was to investigate the extent to which dysfunction in MMN generation might represent an endophenotypic marker for schizophrenia. We measured MMN to deviants in duration (25 msec, 1000 Hz) and deviants in pitch (50 msec, 1200 Hz) relative to standard tones (50 msec, 1000 Hz) in 45 chronic schizophrenia patients, 25 of their first-degree unaffected biological relatives, 12 first-episode patients, and 27 healthy control subjects. In line with previous work, MMN amplitudes to duration deviants (but not to pitch deviants) were significantly reduced in patients with chronic schizophrenia compared with control subjects. However, both duration and pitch MMNs were completely unaffected in the first-degree biological relatives and this was also the case for the first-episode patients. Furthermore, length of illness did not predict the extent of MMN deficit. These findings suggest that the MMN deficit seen in schizophrenia patients is most likely a consequence of the disease and that MMN, at least to basic auditory feature deviants, is at best only weakly endophenotypic for schizophrenia.

263 EFFECTS OF EXPECTATION ON SOMATOSENSORY EVENT-RELATED POTENTIALS (SEPS) ELICITED BY PAINFUL ELECTRIC STIMULI

Background and Aims: Pain perception is typically measured by questionnaires and behavioural responses. Somatosensory Evoked Potentials (SEPs) however provide a direct measure of stimulus processing in the brain. To investigate whether expectancy influences SEPs we applied a cross‐modal oddball paradigm. The P3 EP component is modulated by expectancy, anticipation and novelty. We hypothesize that the number of background stimuli preceding the painful target determines the expectancy of the target and consequently the amplitude of the P3. Methods: A multi‐channel EEG was recorded (band pass 0.1–100 Hz, sample frequency 1000Hz) from 11 volunteers. Trials commenced with 3, to 11 auditory stimuli, followed by a painful electric target stimulus (ring finger, 1ms duration, individually set to a subjective pain intensity level of 9; 0 = no pain; 10 = maximum pain). Inter‐stimulus intervals were 800 ms. After target presentation the participants rated the stimulus painfulness (0–9). Results and Discussion: An increase in the number of auditory background stimuli preceding the painful stimulus was accompanied with a larger lateralised N130, possibly due to an increase in attention. The centrally localized P350 decreased, as hypothesized, as did the late N450. SEP changes were observed up to 7 preceding background stimuli, after which the effect levelled off. No effects of number of backgrounds was found with respect to the perceived intensity. We propose that SEP P350 components elicited by oddball paradigm behave similarly to P3 EP components observed in other modalities. It will be interesting to study whether cognitive SEP modulation differs between chronic pain patients and healthy volunteers.

The influence of auditory background stimulation (Mozart's sonata K. 448) on visual brain activity

Twenty individuals solved a visual oddball task in two response conditions: while listening to the Mozart's sonata K. 448, and while listening to nothing. The recorded event-related potentials (ERP) were analyzed in the time and frequency domains. In the music response condition the ERP peak latencies on the left hemisphere increased, whereas on the right hemisphere a decrease of peak latencies as compared with the silence response condition was observed. In the theta, lower-1 alpha and gamma band increases in induced event-related coherences were observed while respondents solved the oddball task and listened to music, whereas a decoupling of brain areas in the gamma band was observed in the silence response condition. It is suggested that auditory background stimulation can influence visual brain activity, even if both stimuli are unrelated.

Effect of manipulation and irrelevant noise on working memory capacity of patients with Alzheimer's dementia.

The effect of manipulation and distracting noise on immediate serial recall was measured in patients with dementia of the Alzheimer type (DAT), neurologically healthy elderly individuals, and young adults. In Experiment 1, the authors compared serial word recall with word recall in alphabetical order. Alphabetical recall requires the active manipulation of the contents of working memory. Findings indicated that DAT patients were severely impaired in the alphabetical recall task, whereas the performance of neurologically healthy elderly participants was comparable with the performance of young adult participants. In Experiment 2, the authors investigated the effect of different irrelevant auditory backgrounds on immediate digit recall. In this task, both elderly participants and DAT patients performed similarly to the group of young adult participants, indicating comparable efficacy to resist auditory distraction.

Auditory noise can prevent increased extracellular acetylcholine levels in the hippocampus in response to aversive stimulation

The intent of this study was to investigate neurochemical and behavioural effects of aversive stimulation and the impact of auditory background noise. Using in vivo microdialysis, hippocampal acetylcholine was extracted and subjected to HPLC analysis while male Wistar rats were exposed to aversive stimulation similar to that used in conventional procedures for aversive conditioning. Three groups of animals were used. Animals in the first group were exposed to a single tone/footshock pairing followed by a tone alone 2 h later. Animals in the second group served as controls and were only exposed to the tone without shock. A third group was exposed to the same tone/shock pairing and tone as the first group while being exposed to constant background noise during the whole experiment. The results showed, that the tone/shock combination led to pronounced behavioral and cholinergic activation. In contrast, exposure to background noise prevented the increase in hippocampal ACh levels to tone/shock stimulation. The unconditioned behavioural response, however, was not prevented suggesting that hippocampal ACh is not a necessary correlate of behavioural activation or arousal. A second experiment intended to investigate the effects of background noise in a shuttle box avoidance learning paradigm where rats were trained to avoid an aversive footshock, which was signalled by a tone. There, one group of rats was exposed to background noise during avoidance learning, and the other group was not exposed to noise. Whereas both groups learned to avoid the shock to some degree over training, the noise exposed animals did not show improvement in escape performance over the course of training, indicating that the noise hindered development of an adaptive response to the shock. In summary, our data indicate that background noise can prevent increased extracellular hippocampal ACh levels in response to an aversive stimulus, and can also lead to deficits in learning to escape from shock.

The Sense of Presence for the Suddenly Deafened Adult:Implications for Virtual Environments

Reports from adventitiously deafened individuals of a sense of unconnectedness with their surroundings, of a sense that the world seems “dead,” offer a compelling rationale for the argument that auditory cues are a crucial determinant of the sense of presence. Moreover, the crucial element of auditory stimulation for creating a sense of presence may be the auditory background, comprising the incidental sounds made by objects in the environment, rather than the communication and warning signals that typically capture our attention. Although designers of virtual environments have most often tried to maximize the sense of presence in the user by attempting to improve the fidelity of visual displays, the arguments presented here suggest that background auditory stimulation may be useful or even critical for achieving a full sense of presence.

Different rates of functional development in the two visual systems of the chicken revealed by [formula omitted

Age-dependent changes in neuronal metabolic activity in the visual systems of the male chicken were assessed using [ 14 C]2- deoxyglucose (2-DG) autoradiography. Groups of 3 and 4 chicks aged either 2 or 23 days posthatching were injected with 2-DG and exposed for 30 min to a variety of visual stimuli in either the monocular or binocular condition. Control birds had both eyes occluded. All groups were subjected to the same auditory background. In the 2-day-old chicks high levels of metabolic activity occurred in the rotundal-ectostriatal system in a manner consistent with eye use and known neuro-anatomical connections, but very low levels of activity occurred in the thalamo-hyperstriatal visual system. In the 23-day-old chicks eye use resulted in high levels of metabolic activity in both visual systems. The distribution of higher activity within the rostral regions of the anterior hyperstriatum at this age was consistent with eye use and the known distribution of ipsilateral and contralateral projections to the region. Different rates of functional development in the hyperstriatal and ectostriatal systems may reflect a requirement for different visual information processing in young versus older chickens. This study indicates that the ectostriatal system subserves the majority of early visual behavior. Age-dependent changes in the regional arrangement of activity in the Field L auditory region were also noted.

Event-related potentials to deviant visual stimuli: Awareness and discrimination

Occasional shifts of loudness in a repetitive train of clicks elicited a late-positive wave (P3a) in nonattending subjects which peaked at a mean latency of 258 msec and had a fronto-central scalp distribution; and P3a was typically preceded by an “N2” component at 196 msec. The P3a wave was distinguishable from the longer-latency (378 msec) parieto-centrally distributed “P3b” wave, that was evoked by the same stimulus in an actively attending subject, thus confirming the findings of Squires et al. Infrequently presented single sounds did not produce large or consistent N2-P3a components; the critical condition for the generation of an N2-P3a wave seemed to be that the infrequent sounds represent a deviation (intensity increment or decrement) from a repetitive background. Furthermore, increasing the repetition rate of the background clicks drastically reduced Nl-P2 amplitude but had little effect on the amplitude of N2-P3a. This suggests that N2-P3a is not simply a delayed N1-P2 “vertex potential”, but rather reflects the operation of a “mismatch” detector, which registers deviations from an ongoing auditory background.

Contextual effects and speaker quality in vowel perception

Studies utilizing an anchoring paradigm have suggested that vowel identification can be explained on the basis of the acoustic nature of the vowel, the immediate phonetic context, and in terms of contrast with an “auditory ground” or adaptation level [J. R. Sawusch and H. C. Nusbaum, Percept. Psychophys. 25, 292–302 (1979); H. J. Simon and M. Studdert-Kennedy, J. Acoust. Soc. Am. 64, 1338–1357 (1978)]. A study was designed to investigate the nature of this auditory ground, in particular, to determine whether the relevant acoustic information is represented in a veridical fashion or has undergone specific types of auditory processing (e.g., speaker normalization). A series of experiments utilizing the anchoring paradigm was conducted. Ss identified synethetic vowels from a [hɪd]-[hεd] continuum under two conditions: an equiprobable control and an anchoring condition (with one continuum endpoint token occurring at least three times more often than any other). Three different stimulus continuua were constructed to represent vowels from a low F0 male, a high F0 male, and a high F0 female. Ss were run under each of 18 different control/anchor combinations. Contrast effects were found such that phoneme boundaries shifted toward the anchoring category and differential shifts of the boundaries were found as a function of both F0 and relative F-pattern height. Neither feature detector fatigue nor response bias can account for such results, and they suggest that information in the postulated auditory background has already undergone formant normalization and its characteristics are consistent with Massaro's synthesized auditory memory.

The Effects of Extraneous Speech on Visual Vigilance Performance of Children

First-grade males performed a 30-min visual vigilance task under 5 conditions of auditory background stimulation. The 5 conditions consisted of (1) continuous conversation, in which subjects listened to a tape of conversation spliced so that there were no intervals of silence lasting longer than 3 sec; (2) continuous reverse, in which subjects heard the continuous conversation tape played in reverse; (3) intermittent conversation, in which subjects heard alternating segments of conversation and silence; (4) intermittent reverse, in which subjects heard alternating segments of reverse conversation and silence; and (5) silence control. Compared with silence or continuous stimulation, intermittent stimulation produced better detection regardless of whether or not it was meaningful. High achievers made more correct detections than low achievers, but only in the second and third time periods. Few subjects made errors of commission.

Long-latency evoked potentials to irrelevant, deviant stimuli

Occasional shifts of loudness in a repetitive train of clicks elicited a late-positive wave (P3a) in nonattending subjects which peaked at a mean latency of 258 msec and had a fronto-central scalp distribution; and P3a was typically preceded by an “N2” component at 196 msec. The P3a wave was distinguishable from the longer-latency (378 msec) parieto-centrally distributed “P3b” wave, that was evoked by the same stimulus in an actively attending subject, thus confirming the findings of Squires et al. Infrequently presented single sounds did not produce large or consistent N2-P3a components; the critical condition for the generation of an N2-P3a wave seemed to be that the infrequent sounds represent a deviation (intensity increment or decrement) from a repetitive background. Furthermore, increasing the repetition rate of the background clicks drastically reduced Nl-P2 amplitude but had little effect on the amplitude of N2-P3a. This suggests that N2-P3a is not simply a delayed N1-P2 “vertex potential”, but rather reflects the operation of a “mismatch” detector, which registers deviations from an ongoing auditory background.