Prediction and control as determinants of behavioural uncertainty: Effects on task performance and heart rate reactivity

Control or control-belief is often viewed as being directly instrumental in facilitating coping mechanisms in aversive situations, and yet the empirical evidence for the beneficial effects of control is inconclusive. In this study we investigated the role of predictability in determining the effects of perceived control during an aversive reaction time task. Fifty-six subjects were allocated to one of four groups; predictable-control, predictable-no control, unpredictable-control, unpredictable-no control. In the predictable conditions, subjects could temporally predict the occurrence of an aversive noise. In the perceived control conditions, duration of the aversive tone was contingent on subject’s performance. All subjects were matched in terms of the nature of the task and in the number and time of receipt of both the warning signal and noise. Heart rate reactivity and two performance parameters were measured, reaction time and performance increase. Both predictability and control-belief led to a reduction in heart rate reactivity, although they appeared to function independently and at different points in the sequence of events. That is, predictability or perceived control was sufficient to mitigate the effects, of an aversive situation. Neither perception of control or predictability led to better task performance. These results are discussed in terms of behavioural uncertainty explanations.     

Prediction and control as determinants of behavioural uncertainty: effects on task performance and heart rate reactivity.

Control or control-belief is often viewed as being directly instrumental in facilitating coping mechanisms in aversive situations, and yet the empirical evidence for the beneficial effects of control is inconclusive. In this study we investigated the role of predictability in determining the effects of perceived control during an aversive reaction time task. Fifty-six subjects were allocated to one of four groups; predictable-control, predictable-no control, unpredictable-control, unpredictable-no control. In the predictable conditions, subjects could temporally predict the occurrence of an aversive noise. In the perceived control conditions, duration of the aversive tone was contingent on subject's performance. All subjects were matched in terms of the nature of the task and in the number and time of receipt of both the warning signal and noise. Heart rate reactivity and two performance parameters were measured, reaction time and performance increase. Both predictability and control-belief led to a reduction in heart rate reactivity, although they appeared to function independently and at different points in the sequence of events. That is, predictability or perceived control was sufficient to mitigate the effects of an aversive situation. Neither perception of control or predictability led to better task performance. These results are discussed in terms of behavioural uncertainty explanations.     

Toward Meaningful Noise Research

The present review considers a series of studies of noise conducted in collaboration with Dr. Michel Loeb. This review attempts to provide a theoretical perspective as well as to summarize the most important findings of those studies. The work reviewed shows that noise effects interact with other variables, such that a noise effect on one sex is reversed for the other, and is also reversed at different times of the day. A second experiment confirmed this finding with a different arithmetic task. Further work indicated parallels between noise and fatigue, with aftereffects depending upon both work and noise. The final experiment repeated some of these findings with a different task battery of information processing tasks while showing that noise effects further depend on the meaningfulness of the noise background.     

Toward meaningful noise research

The present review considers a series of studies of noise conducted in collaboration with Dr. Michel Loeb. This review attempts to provide a theoretical perspective as well as to summarize the most important findings of those studies. The work reviewed shows that noise effects interact with other variables, such that a noise effect on one sex is reversed for the other, and is also reversed at different times of the day. A second experiment confirmed this finding with a different arithmetic task. Further work indicated parallels between noise and fatigue, with aftereffects depending upon both work and noise. The final experiment repeated some of these findings with a different task battery of information processing tasks while showing that noise effects further depend on the meaningfulness of the noise background.     

Speech‐perception‐in‐noise deficits in dyslexia

Speech perception deficits in developmental dyslexia were investigated in quiet and various noise conditions. Dyslexics exhibited clear speech perception deficits in noise but not in silence. Place‐of‐articulation was more affected than voicing or manner‐of‐articulation. Speech‐perception‐in‐noise deficits persisted when performance of dyslexics was compared to that of much younger children matched on reading age, underscoring the fundamental nature of speech‐perception‐in‐noise deficits. The deficits were not due to poor spectral or temporal resolution because dyslexics exhibited normal ‘masking release’ effects (i.e. better performance in fluctuating than in stationary noise). Moreover, speech‐perception‐in‐noise predicted significant unique variance in reading even after controlling for low‐level auditory, attentional, speech output, short‐term memory and phonological awareness processes. Finally, the presence of external noise did not seem to be a necessary condition for speech perception deficits to occur because similar deficits were obtained when speech was degraded by eliminating temporal fine‐structure cues without using external noise. In conclusion, the core deficit of dyslexics seems to be a lack of speech robustness in the presence of external or internal noise.     

Noise effects on human performance: a meta-analytic synthesis

Noise is a pervasive and influential source of stress. Whether through the acute effects of impulse noise or the chronic influence of prolonged exposure, the challenge of noise confronts many who must accomplish vital performance duties in its presence. Although noise has diffuse effects, which are shared in common with many other chronic forms of stress, it also exerts its own specific influences on various forms of cognitive and motor response. We present a quantitative evaluation of these influences so that their harmful effects can be mitigated, their beneficial effects exploited, and any residual effects incorporated and synthesized into selection, training, and design strategies to facilitate human performance capacities. Predictions of single and joint moderator effects were made on the basis of major theories of noise and performance, specifically those explanations based on arousal, masking, or cognitive-resource mechanisms. These predictions were tested through moderator analyses of effects as a function of task type, performance measure, noise type and schedule, and the intensity and duration of exposure. Observed outcome effects (797 effect sizes derived from 242 studies) varied as a function of each of these moderators. Collective findings identified continuous versus intermittent noise, noise type, and type of task as the major distinguishing characteristics that moderated response. Mixed evidence was obtained for the traditional arousal and masking explanations for noise effects. The overall pattern of findings was most consistent with the maximal adaptability theory, a mental-resource-based explanation of stress and performance variation.     

Sources of auditory masking in infants: Distraction effects

Previous work has demonstrated that infants’ thresholds for a pure tone are elevated by a masker more than would be predicted from their critical bandwidths. The present studies explored the nature of this additional masking. In Experiment 1, detection thresholds of 6-month-old infants and of adults for a 1-kHz tone were estimated under three conditions: in quiet, in the presence of a 4- to 10-kHz bandpa] noise at 40 dB SPL, and in the presence of the same noise at 50 dB SPL. The noise was gated on at the beginning of each trial. Adult thresholds were the same in all three conditions, indicating that little or no sensory masking took place in the presence of the noise. Infant thresholds were about 10 dB higher in the presence of the noise. We term this effectdistraction masking. In Experiment 2, the effect of gating the noise on at trial onset was examined. Thresholds for the same tone were estimated in quiet and in the presence of the bandpass noise at 40 dB SPL, but the noise was presented continuously during the session. Under these conditions, distraction masking was still observed for infants. These findings suggest that a masker can have nonsensory effects on infants’ performance in a psychoacoustic task.     

Sources of auditory masking in infants: distraction effects.

Previous work has demonstrated that infants' thresholds for a pure tone are elevated by a masker more than would be predicted from their critical bandwidths. The present studies explored the nature of this additional masking. In Experiment 1, detection thresholds of 6-month-old infants and of adults for a 1-kHz tone were estimated under three conditions: in quiet, in the presence of a 4- to 10-kHz bandpass noise at 40 dB SPL, and in the presence of the same noise at 50 dB SPL. The noise was gated on at the beginning of each trial. Adult thresholds were the same in all three conditions, indicating that little or no sensory masking took place in the presence of the noise. Infant thresholds were about 10 dB higher in the presence of the noise. We term this effect distraction masking. In Experiment 2, the effect of gating the noise on at trial onset was examined. Thresholds for the same tone were estimated in quiet and in the presence of the band-pass noise at 40 dB SPL, but the noise was presented continuously during the session. Under these conditions, distraction masking was still observed for infants. These findings suggest that a masker can have nonsensory effects on infants' performance in a psychoacoustic task.     

Effects of jet engine noise and performance feedback on perceived workload in a monitoring task

This study examined the effects of exposure to intermittent jet aircraft noise (70 dBA or 95 dBA maximum intensity) and knowledge of results concerning signal detections (hit-KR) on performance efficiency and perceived workload in a 40-min visual vigilance task. The noise featured a Doppler-like quality in which planes seemed to approach from the monitor's left and recede to the right. Perceptual sensitivity (d') was poorer in the context of noise than in quiet but only in the presence of hit-KR. The lack of noise-related performance differences in the absence of hit-KR most likely reflected a "floor effect" rather than some special relation between noise and feedback. When compared to subjects performing in quiet, those who operated in noise were less able to profit from hit-KR, a result that may reflect the effects of noise on information processing. In addition to its negative effects on signal detectability, noise elevated the perceived workload, as measured by the NASA-TLX. This effect was robust; it was independent of the presence of hit-KR, even though hit-KR generally lowered the overall level of perceived workload. The results provide the initial experimental demonstration that perceived workload is a sensitive measure of the effects of aircraft noise in monitoring tasks.     

Effects of white noise and irrelevant information on speeded classification: A developmental study

The study examined how well subjects were able to ignore the presence of irrelevant stimulus information in noise and in silence, as a function of age. Children aged six and nine, and adults, performed speeded card-sorting tasks with one binary dimension relevant and zero or two dimensions irrelevant. The presence of irrelevant information interfered with performance, the magnitude of interference declining with age. The interfering effects of irrelevant information were greater when it was (relatively) more salient than when it was less salient, but there was no interaction between relative salience and the effects of noise. Noise (95 dB(A)) slowed down sorting performance of adult subjects in all conditions, it slightly improved the performance of nine-year-old children, and it improved the performance of six-year-old children significantly when irrelevant information was present. The effects of noise on attentional control are discussed, mainly with reference to inhibitory effects of noise on subvocal activity.     

Temporal grouping in auditory spatial serial memory

Grouping effects in serial recall have been widely studied with verbal stimuli, but hardly ever with spatial stimuli and not at all with auditory spatial stimuli. In Experiment 1, we examined the influence of combined temporal and pitch grouping on recall of the locations from which bursts of white noise were presented. Similar to findings in verbal studies, effects of the grouping manipulation were found in performance accuracy, in the nature of order errors, and in the timing of responses. Experiment 2 was designed to distinguish the role played by pitch grouping from that played by temporal grouping, through independent manipulation of the presence of a shift in pitch and that of a temporal gap. The results showed that the temporal grouping manipulation determined performance and the pitch grouping manipulation did not. Similarities between our findings and those of verbal studies, and implications for the understanding of serial memory are discussed.     

The Effects of Street Noise and Field Independency on Police Officers' Shooting Behavior

Two studies examining the effects of street noise on police officers' emotion, perception, and performance in simulated shooting events are discussed. Compared to previous research, our studies had a higher ecological validity. In our studies, "relevant" noise was introduced, the subjects were police officers instead of students, and the behavior we examined was police behavior in simulated firearms incidents. Results revealed that noise resulted in increased emotion, a narrowed perception, and an impairment in performance on secondary tasks. In Study 2, the effects of field independency on emotion, perception, and performance were examined. The outcomes showed that high field-independent subjects compared to low field independent subjects obtained better results regarding perception and performance. Finally, some implications are discussed.     

An Exploration of a Possible Physiological Explanation for Stressor Aftereffects1

The present study examined the relationship between performance deficits that occur following exposure to uncontrollable stressors and activation of the endogenous opioid system. Subjects were given an injection of saline or naloxone, an opioid antagonist, prior to exposure to 23 min of unpredictable intermittent bursts of noise or silence. Changes in mood were assessed following the injection and the stressor. Performance was measured during and after stressor exposure. Measures of performance following the stressor included a proofreading, an encoding, and a puzzle task. Results replicated previous work on the effects of noise on performance; exposure to noise was associated with performance deficits during and after the stressor. Although naloxone had no effect on performance following the noise, it was associated with greater performance deficits during exposure to the stressor. Further, although all subjects became more hostile, anxious, and depressed following exposure to noise or silence, naloxone improved mood before the stressor began.     

On the use of discrimination to assess memory

A number of studies have made use of sensory discrimination to assess memory. These experiments have typically employed a temporal two-alternative forced choice paradigm in which the interstimulus interval (ISI) is varied. Many of these tests have shown that ISI has little or no effect on discrimination performance. This has been taken as evidence for perfect or very good memory. An alternative interpretation would be that discrimination tests lack sufficient sensitivity to reveal memory effects. In the present study, computer simulations based on signal detection theory were used to estimate the relative effects of memory noise and direct noise (i.e., noise inherent in the discrimination task) on discrimination performance. These simulations indicate that the amount of memory noise has to be quite large to cause a marked elevation in discrimination thresholds and that sensory discrimination is a relatively insensitive test of memory.     

Some effects of noise on visual performance

A group of ten subjects showed impaired performance, when watch-keeping on a display made up of steam-pressure gauges, in 100 db. noise as compared with 70 db. On the easier task of watch-keeping on a display made up of small lights, another group of twenty subjects showed no overall effect of noise. Individual subjects who showed a practice effect on the latter task comparable to that shown by all subjects on the former one, however, also showed a similar effect of noise.

In addition, performance on the light-watching became relatively less efficient in noise with continued exposure: and although parts of the task were still adequately carried out, others were not. The fact that noise effects are thus functions of individual differences, of visibility of signal, and of length of performance in noise, allows us to explain the negative findings of many previous workers.     

Noise on, voicing off: Speech perception deficits in children with specific language impairment

Speech perception of four phonetic categories (voicing, place, manner, and nasality) was investigated in children with specific language impairment (SLI) (n = 20) and age-matched controls (n = 19) in quiet and various noise conditions using an AXB two-alternative forced-choice paradigm. Children with SLI exhibited robust speech perception deficits in silence, stationary noise, and amplitude-modulated noise. Comparable deficits were obtained for fast, intermediate, and slow modulation rates, and this speaks against the various temporal processing accounts of SLI. Children with SLI exhibited normal “masking release” effects (i.e., better performance in fluctuating noise than in stationary noise), again suggesting relatively spared spectral and temporal auditory resolution. In terms of phonetic categories, voicing was more affected than place, manner, or nasality. The specific nature of this voicing deficit is hard to explain with general processing impairments in attention or memory. Finally, speech perception in noise correlated with an oral language component but not with either a memory or IQ component, and it accounted for unique variance beyond IQ and low-level auditory perception. In sum, poor speech perception seems to be one of the primary deficits in children with SLI that might explain poor phonological development, impaired word production, and poor word comprehension.     

Affect and Performance on Cognitive Task as a Function of Crowding and Noise1

Sixty undergraduate males participated in an experiment with a 2 × 3 factorial design involving two levels of density and three levels of noise to demonstrate effects of the independent variables (density, noise) on cognitive task performance and affect. As predicted, it was found that crowding and noise lead to deterioration of subject's performance on cognitively complex tasks but not on simple (cognitive) task. Also, density and noise generated a negative feeling in the subjects. Significant two-way interaction for complex task, showed variation in performance of Ss of high and low density under low and high noise conditions. In addition, crowded-condition subjects reported more dissatisfaction about their performance and evaluated the presence of the experimenter as significantly less pleasant than their noncrowded-condition counterparts.     

Perceived control in continuous loud noise

The effects of two types of perceived control were assessed for performance during and following exposure to continuous loud noise at 90 dBC. Subjects performed a tracking task during exposure and the Stroop test in the period following exposure. Control could be effected either (1) by attenuating the intensity of the noise or (2) by reducing the difficulty of the tracking task. In both cases subjects were encouraged not to exercise control. Performance in treatments involving loud (90 dBC) and soft (55 dBC) noise served as baseline conditions. Perceived control of task difficulty accentuated the tendency for root-mean-square error to rise during the tracking task. There were no significant effects of noise intensi ty on tracking performance. Loud noise reduced the incidence of errors in the Stroop test but perceived control failed to influence this effect. The results are discussed in terms of the generality of perceived control phenomena.     

The effects of noise and task priority on recall of order and location

Previous studies have suggested that one of the effects of noise is to improve performance on a primary task and impair performance on a secondary task. This was confirmed in the first experiment which used a modified version of Hockey and Hamilton's (1970) task of memory for order and location. A second experiment showed that the effect was due to noise interacting with task priority and not with the identity of the task performed first rather than second. The effect of priority can easily be modified and a third experiment showed that priority instructions have to be effective for there to be an interaction between noise and priority. It is suggested that a major effect of noise is to bias the allocation of effort towards the operation which appears to best repay the investment of more effort. This may take the form of a bias towards the high priority task but the effect of noise is also likely to depend on other factors such as the difficulty of each part of the task and the salience of the stimuli.     

A signal-to-noise theory of the effects of luminance on picture memory: comment on Loftus

In studies of picture memory, subjects typically view a sequence of pictures. Their memory is tested either after each picture is presented (short-term recall) or at the end of the sequence (long-term recall). The increase in performance as a function of picture viewing time defines "the rate of information acquisition." Loftus (1985) found that reducing the luminance of a picture reduces the rate at which information is acquired (for both short-term and long-term tests) and, for long viewing times, reduces the total amount of recall. The theory proposed here assumes that both of these effects are consequences of intrinsic noise in the visual system that becomes relatively more prominent as signal (picture luminance or contrast) is reduced. Noise shares a limited capacity channel with signal, and thus noise reduces the rate of information acquisition; noise, as well as signal, occupies space in memory, and thus noise reduces recall performance.