Effects Of Intermittent Noise Research Articles

The effect of intermittent noise on lexically-guided perceptual learning in native and non-native listening

There is ample evidence that both native and non-native listeners deal with speech variation by quickly tuning into a speaker and adjusting their phonetic categories according to the speaker’s ambiguous pronunciation. This process is called lexically-guided perceptual learning. Moreover, the presence of noise in the speech signal has previously been shown to change the word competition process by increasing the number of candidate words competing for recognition and slowing down the recognition process. Given that reliable lexical information should be available quickly to induce lexically-guided perceptual learning and that word recognition is slowed down in the presence of noise, and especially so for non-native listeners, the present study investigated whether noise interferes with lexically-guided perceptual learning in native and non-native listening. Native English and Dutch listeners were exposed to a story in English in clean speech or with stretches of noise. All the /l/ and /ɹ/ sounds in the story were replaced with an ambiguous sound half-way between /l/ and /ɹ/. Although noise altered the pattern of responses for the non-native listeners in a subsequent phonetic categorization task, both native and non-native listeners demonstrated lexically-guided perceptual learning in both clean and noisy listening conditions. We argue that the robustness of perceptual learning in the presence of intermittent noise for both native and non-native listeners is additional evidence for the remarkable flexibility of native and non-native perceptual systems even in adverse listening conditions.

The effect of intermittent noise on cardiovascular functioning during vigilance task performance.

This study was designed to investigate the effect of presentations of intermittent noise differing in predictability on cardiovascular functioning during task performance. Under a quiet condition and three conditions of intermittent noise, measures of blood pressure, heart rate (interbeat interval), and heart rate variability (variance, successive difference mean square, and the 0.1 Hz component of sinus arrhythmia) were obtained while subjects were occupied with a 55-min vigilance task. The results indicated that intermittent noise significantly increased diastolic and mean blood pressure. In addition, 0.1 Hz measures differed between the group working under quiet conditions and the groups working under noise. Although heart rate increased in all groups during the task, it increased significantly more in groups receiving unpredictable noise bursts. For the variables that were significantly affected by the noise presentations there was no evidence of response habituation over the task period. The results are discussed in relation to the effort required to maintain performance levels during noise, and attention is drawn to the implications of the present findings for cardiovascular health under conditions of chronic intermittent noise.

The effect of intermittent noise on vigilance performance.

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

No effect of noise on vigilance performance?

The effects of intermittent noise and its temporal pattern on visual vigilance performance were investigated using a between-subjects design with a multivariate approach. The conventional way of analyzing the data showed a decrement in sensitivity (A′) with time on task, a rise in false alarms, but no significant effect of noise. However, a detailed analysis demonstrated a facilitatory effect of the noise stimuli, which may be explained in terms of orienting reaction theory. It is suggested that the usual way of analyzing data from vigilance experiments may veil the effects of independent variables, such as noise. Some sex differences in performance were also noted. An additional estimation task provided no support for expectancy theory.

The effects of intermittent noise on human serial decoding performance and physiological response.

The effects of continuous, periodic, and aperiodic broad band noise on serial decoding performance and on three physiological response measures were investigated. Performance data were recorded from 16 undergraduate university students using an electronically programmed rapid serial decoding task. The task configuration chosen combined a basic serial reaction function with a mental coding and short-term memory function. To assess activation or arousal effects of noise, three physiological variables were also simultaneously recorded: finger photoplethysmographic blood volume pulse amplitude, pulse rate, and forearm eleetromyogram. In addition, responses to a noise annoyance sensitivity questionnaire were used in an attempt to assign subjects to experimental groups such that noise annoyance sensitivity across groups would be constant. Each subject was isolated in a soundproof chamber while performance data and physiological data were collected under four counterbalanced conditions: work in quiet, continuous...

Target-detection performance as a function of noise intensity and task difficulty.

The purpose of the present investigation was to determine the effects of intermittent white noise with a 30% on-off ratio on target-detection performance under 4 levels of noise intensity and 3 levels of task difficulty. The 2 measures of performance were response latency and detection errors. The results showed that intensity interacts with task difficulty to determine the effect of intermittent noise on target-detection performance with both performance facilitation and decrement obtained.

Noise-induced arousal and breadth of attention.

The effect of intermittent noise upon attention span was investigated in two experiments. In Exp. 1, 4 levels of noise intensity were used (no noise, 75 db, 85 db, and 100 db). The task was a serial anticipation task in which the relevant stimuli were 4-letter words located in the center of a projected slide. 3-letter words were peripherally located; the peripheral words were not mentioned to Ss. Ss in the 85-db and the 100-db conditions learned fewer of the peripheral words as indicated by a free-recall test than Ss in the no-noise and the 75-db conditions, indicating a narrowing of attention due to the higher noise levels. In Exp. 2, Ss operating under noise (85 db) performed significantly better on the Stroop Color-Word Test than did Ss operating under no noise, again indicating a focusing of attention due to noise-induced arousal. The results are consistent with the proposal of several authors that increasing emotional arousal causes a narrowing of attention.

Effects of Intermittent Noise on Visual Search Tasks of Varying Complexity

The present investigation was designed to test the effects of various ratios of intermittent noise on a visual search task varied in complexity. Four noise ratios were utilized: 0, 30, 70, and 100% noise on-time in successive 5-sec. intervals. The task required that Ss search a display for a single letter located among a larger background of letters which were all the same but different from the single letter. Task complexity was varied by changing the number of background letters. Two difficulty levels were utilized: 8-letter and 32-letter displays. Twenty-two Ss were tested under all conditions specified by the task complexity by noise ratio matrix. Detection speeds for the 32-letter task condition were faster for any ratio of noise than in the control condition but for the 8-letter condition only the 30% noise ratio was faster than the control. The speeds for the 70% and 100% ratios were slower for the 8-letter condition. The order of the 30, 70, and 100% ratios, however, without the control comparison indicated that the relative differences between noise effects were the same for both levels of task complexity. The order of conditions beginning with fastest was: 30%, 100%, and 70%.

Effects of Intermittent Noise on Human Target Detection

The purpose of the present investigation was to examine the effects of intermittent noise on target detection performance. Specifically, the present study was designed to test whether the effects of noise presented at a 70% on-off, “neutral” ratio are independent of the noise intensity level. Four levels of noise were used: no noise, and 80, 90, and 100 db. The results revealed that detection time was not significantly affected by the noise level. The total number of errors recorded for each noise condition showed that, in general, as intensity level increased, the total number of errors decreased. These findings are related to the concept of “flexibility of attention.”