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.     

The effects of meaningful irrelevant speech and road traffic noise on teachers' attention, episodic and semantic memory

The aim of the present experiment was to examine the effects of meaningful irrelevant speech and road traffic noise on attention, episodic and semantic memory, and also to examine whether the noise effects were age-dependent. A total of 96 male and female teachers in the age range of 35-45 and 55-65 years were randomly assigned to a silent or the two noise conditions. Noise effects found in episodic memory were limited to a meaningful text, where cued recall contrary to expectations was equally impaired by the two types of noise. However, meaningful irrelevant speech also deteriorated recognition of the text, whereas road traffic noise caused no decrement. Retrieval from two word fluency tests in semantic memory showed strong effects of noise exposure, one affected by meaningful irrelevant speech and the other by road traffic noise. The results implied that both acoustic variation and the semantic interference could be of importance for noise impairments. The expected age-dependent noise effects did not show up.     

The effects of noise and gender on children's episodic and semantic memory

The main objectives in the present study were to examine meaningful irrelevant speech and road traffic noise effects on episodic and semantic memory, and to evaluate whether gender differences in memory performance interact with noise. A total of 96 subjects, aged 13-14 years (n = 16 boys and 16 girls in each of three groups), were randomly assigned to a silent or two noise conditions. Noise effects found were restricted to impairments from meaningful irrelevant speech on recognition and cued recall of a text in episodic memory and of word comprehension in semantic memory. The obtained noise effect suggests that the meaning of the speech were processed semantically by the pupils, which reduced their ability to comprehend a text that also involved processing of meaning. Meaningful irrelevant speech was also assumed to cause a poorer access to the knowledge base in semantic memory. Girls outperformed boys in episodic and semantic memory materials, but these differences did not interact with noise.     

The effects of road traffic noise and meaningful irrelevant speech on different memory systems

To explore why noise has reliable effects on delayed recall in a certain text-reading task, this episodic memory task was employed with other memory tests in a study of road traffic noise and meaningful but irrelevant speech. Context-dependent memory was tested and self-reports of affect were taken. Participants were 96 high school students. The results showed that both road traffic noise and meaningful irrelevant speech impaired recall of the text. Retrieval in noise from semantic memory was also impaired. Attention was impaired by both noise sources, but attention did not mediate the noise effects on episodic memory. Recognition was not affected by noise. Context-dependent memory was not shown. The lack of mediation by attention, and road traffic noise being as harmful as meaningful irrelevant speech, are discussed in relation to where in the input/storing/output sequence noise has its effect and what the distinctive feature of the disturbing noise is.     

The effect of forced recall on illusory recollection in younger and older adults

The effect of an initial forced recall test on later recall and recognition tests was examined in younger and older adults. Subjects were presented with categorized word lists and given an initial test under standard cued recall instructions (with a warning against guessing) or forced recall instructions (that required guessing); subjects were later given a cued recall test for the original list items. In 2 experiments, initial forced recall resulted in higher levels of illusory memories on subsequent tests (relative to initial cued recall), especially for older adults. Older adults were more likely to say they remembered rather than knew that forced guesses had occurred in the original study episode. The effect persisted despite a strong warning against making errors in Experiment 2. When a source monitoring test was given, older adults had more difficulty than younger adults in identifying the source of items they had originally produced as guesses. If conditions encourage subjects to guess on a first memory test, they are likely to recollect these guesses as actual memories on later tests. This effect is exaggerated in older adults, probably because of their greater source monitoring difficulties. Both dual process and source monitoring theories provide insight into these findings.     

Recall of words heard in noise

The aim of the study was to explore if recall of words and recognition of sentences orally presented was affected by a background noise. A further aim was to investigate the role of working memory capacity in performance in these conditions. Thirty‐two subjects performed a word recall and a sentence recognition test. They repeated each word to ensure that they had heard them. A reading span test measured their working memory capacity. Performance on the word recall task was impaired by the background noise. A high reading span score was associated with a smaller noise effect, especially on recall of the last part of the word list. Copyright © 2007 John Wiley & Sons, Ltd.     

Noise and the "rehearsal-masking hypothesis"

This study examines the proposal that continuous loud noise impairs short-term recall by masking the inner speech necessary to rehearse material in memory (Poulton, 1976 a, 1977 b). The "masking hypothesis" contrasts with previous theories which relate recall impairment in noise to the latter's action in over-arousing the individual or inducing changes in attentional deployment. Separate groups performed a visual, serial eight-consonant recall task in either 92 dBA "noise" or 75 dBA "quiet" and in "normal" or "suppressed" rehearsal conditions. The masking hypothesis predicted that noise would impair recall relative to quiet in normal rehearsal conditions. But where the rehearsal of both groups was already suppressed by a concurrent articulatory task, recall would not differ between the groups through noise-masking then being irrelevant. Total correct recall scores appeared to confirm the masking hypothesis but the pattern of serial order recall showed differences between noise and quiet in suppressed rehearsal conditions which seemed better explained by an attentional influence of noise. Further, reduced commission and acoustic confusion errors in noise were not consistent with the predictions of the masking hypothesis. It was concluded that noise-masking could not be refuted but that attentional changes due to the arousing action of noise might also be active determinants of recall.     

The Relative Importance of Anticipated Test Format and Anticipated Test Difficulty on Performance

In this investigation, the relative importance of the effects of anticipated test format and anticipated test difficulty on performance was examined by simultaneously manipulating both. Experiments 1 and 2 showed that test performance was affected more by anticipated test format than by anticipated test difficulty. This suggests that the superior performance of subjects who had anticipated a recall test versus those who had anticipated a recognition test, reported here and in previous studies, is more likely to be due to anticipating a recall format than to anticipating a more difficult test. Experiment 2 showed that subjects who had anticipated a recall test studied longer than subjects who had anticipated a recognition test, even when recall tests were less difficult than recognition tests. One explanation for this finding is that subjects inaccurately monitor the relative difficulty of tests across test formats. Subjects rated recall items as more difficult than recognition items, even when recall items are actually less difficult (Experiment 3). These findings suggest that a priori metacognitive knowledge may reduce the accuracy of on-line metacognitive monitoring.     

Age differences in collaborative memory: the role of retrieval manipulations

In two experiments, we examined age differences in collaborative inhibition (reduced recall in pairs of people, relative to pooled individuals) across repeated retrieval attempts. Younger and older adults studied categorized word lists and were then given two consecutive recall tests and a recognition test. On the first recall test, the subjects were given free-report cued recall or forced-report cued recall instructions (Experiment 1) or free recall instructions (Experiment 2) and recalled the lists either alone or in collaboration with another subject of the same age group. Free-report cued recall and free recall instructions warned the subjects not to guess, whereas forcedreport cued recall instructions required them to guess. Collaborative inhibition was obtained for both younger and older adults on initial tests of free-report cued recall, forced-report cued recall, and free recall, showing that the effect generalizes across several tests for both younger and older adults. Collaborative inhibition did not persist on subsequent individual recall or recognition tests for list items. Older adults consistently falsely recalled and recognized items more than did younger adults, as had been found in previous studies. In addition, prior collaboration may exaggerate older adults’ tendency toward higher false alarms on a subsequent recognition test, but only after a free recall test. The results provide generality to the phenomenon of collaborative inhibition and can be explained by invoking concepts of strategy disruption and source monitoring.     

Time-varied noise effects on color-word test performance

The effects of continuous and time-varied 85 dBA broadband noise on the performance of a Stroop-type color-word test and a related word-reading task were investigated. 10 subjects served in one of three groups receiving either continuous, periodic, or aperiodic noise. All subjects performed in both low noise (65 dBA) and high noise (85 dBA) conditions on 80 trials of both word reading and color naming. Median reaction times in the word-reading task were unaffected by either noise intensity or the time-varied aspects of the noise. However, median reaction times in the color-naming task were significantly elevated in the 85-dBA noise condition. Also, reaction times in the high aperiodic noise condition were significantly elevated relative to the continuous and periodic noise conditions. Results are discussed within the framework of arousal, filter, and information theories.     

Channel-capacity, intelligibility and immediate memory

When subjects try to remember lists of digits played to them through pulse-modulated white noise the number of errors they make is greater than would be expected if digitrecognition errors and immediate memory errors were independent (Exp. 1).

A second experiment compared recall of digits in early list positions, when digits in subsequent list positions were presented through noise, and in clear. Digits in early positions were less well remembered when digits in later list positions had to be discriminated through noise.

In a third experiment prose passages were played to subjects who subsequently answered questions about their factual content. Judged by this technique recall of the first half of a prose passage is less accurate if the second half must be heard through noise than if the entire passage is heard through a good fidelity system. These results together are interpreted as demonstrations that increased difficulty of recognition of speech through noise may interfere with other activities, (conveniently termed “rehearsal”) which may be necessary to efficiently retain data in memory.     

The effects of initial testing on false recall and false recognition in the social contagion of memory paradigm

In three experiments, participants studied photographs of common household scenes. Following study, participants completed a category-cued recall test without feedback (Exps. 1 and 3), a category-cued recall test with feedback (Exp. 2), or a filler task (no-test condition). Participants then viewed recall tests from fictitious previous participants that contained erroneous items presented either one or four times, and then completed final recall and source recognition tests. The participants in all conditions reported incorrect items during final testing (a social contagion effect), and across experiments, initial testing had no impact on false recall of erroneous items. However, on the final source-monitoring recognition test, initial testing had a protective effect against false source recognition: Participants who were initially tested with and without feedback on category-cued initial tests attributed fewer incorrect items to the original event on the final source-monitoring recognition test than did participants who were not initially tested. These data demonstrate that initial testing may protect individuals’ memories from erroneous suggestions.     

Qualitative and quantitative considerations in encoding difficulty effects

We hypothesized that the effects of encoding difficulty on the memorability of verbal material would depend on both the type of processing induced by the difficulty manipulation and the type of processing afforded by the material. We predicted that if the processing induced by encoding difficulty were complementary to the processing afforded by the material, then difficulty would enhance recall more so than if the processing induced by the two sources were redundant. These expectations were tested by requiring subjects to process either a structured or an unstructured word list with either a sorting task or a pleasantness rating task; the difficulty of each orienting task was also manipulated. We assumed that sorting and pleasantness rating required primarily relational and individual-item processing, respectively, and that the structured and unstructured word lists afforded relational and individual-item processing, respectively. These assumptions were supported by clustering in free recall and by recognition performance. The primary finding was that difficult sorting increased recall only for the unrelated list, whereas difficult pleasantness judgments increased recall most robustly for the related list. These results support the present framework and help illuminate the boundary conditions of the “difficulty effect.”     

Differences in encoding for free recall vs. recognition

Three experiments examined effects of test expectancy on memory for relatively unrelated words. In Experiment I, where preliminary recall or recognition practice was given, both recall and recognition were superior when the subjects expected and had practiced for recall. Free study led to better recall and recognition than paced presentation, but did not interact with test expectancy. Experiment II demonstrated that recall was better for subjects expecting a recall vs. a recognition test in the absence of preliminary practice. In Experiment III all subjects practiced both recall and recognition prior to presentation of the critical list. Study time also was varied. With longer study, recall was better when a recall test was expected, with no test expectancy effect on recognition. There were no appreciable expectancy effects with the short study period. Self-reports and other data suggested that the critical encoding differences produced by test expectancy manipulation were quantitative in nature.     

Stimulus structure, discrimination, and interference.

Subjects learned lists of consonant trigram word pairs varying in intralist formal stimulus similarity. On test trials, subjects were tested with all but one stimulus, then presented either the missing stimulus or one previously tested. Subjects had to correctly identify this stimulus, then recall its associated word. Both recall and recognition performance varied with the difficulty of discovering and utilizing a discriminated element. However, when subjects were instructed as to list structure, recall was improved without improvement in recognition in one condition, and recognition was improved without recall in another. This indicates that stimulus discrimination is neither necessary nor sufficient to reduce intralist interference.     

False recall and false recognition induced by presentation of associated words: Effects of retention interval and level of processing

The effects of retention interval and level of processing on false recall and false recognition of associates were examined. False recall and false recognition were induced by presenting subjects with words closely associated with a non-studied word. Both level of processing and retention interval affected false recall (Experiment 1) and false recognition (Experiment 2) in the same direction with which they affected accurate recall and accurate recognition. That is, semantically processed lists exhibited higher levels of later false recall and false recognition than did superficially processed lists. Furthermore, a decline in false recall and false recognition occurred across retention intervals of 0, 2, and 7 days. However, the decline in false recall and false recognition was less pronounced than the decline in accurate recall and accurate recognition. Results are consistent with source monitoring and fuzzy trace explanations of false recall and false recognition.     

Perceptions of Singles and Single Parents: A Laboratory Experiment1

Two hundred forty undergraduates rated their perceptions of an individual for a job requiring relocation using a 2 × 3 (Gender: Single Male, Single Female × Child: No Child, 3‐Year‐Old, 6‐Year‐Old) between‐subjects experimental design. Findings indicate that single parents are perceived as having a more difficult time adjusting to a move but are also perceived to be more mature than childless singles. Single parents are also more likely to be offered a job that did not require relocation and are more likely to be awarded a merit‐based stipend than childless singles. Support was also found for the hypothesized mediating role of perceptions of adjustment and maturity in understanding actions taken toward single parents. The results are discussed in terms of implications for future research and applied practice.     

On the development of encoding in anticipation of various tests of retention

Abstract.— Seven, 9, 12–13, and 18–21-year-old subjects learned a pictorial material in anticipation of free recall (FR), serial recall (SR), or recognition tests. Type of anticipated test and test actually given were factorially combined, retention being tested after 2 min or after 2 weeks. Recall performance improved with age but recognition performance did not improve after CA 9. Differential anticipation had little effect on the performance of the youngest children. For older subjects the effects were clear-cut and similar at all age levels and at both retention intervals. SR and recognition performance was best when subjects anticipated these tests, respectively; anticipation of recognition interfered with recall performance, and vice versa. The main age-related improvement occurred between age levels 7 and 9.     

Intoxicated Witnesses: Testing the Validity of the Alcohol Myopia Theory

In an assessment of the Alcohol Myopia Theory (AMT), the effects of alcohol on an eyewitness's recall of high‐salience and low‐salience details were investigated. In a laboratory, Study 1 participants watched a staged videoed theft whilst either sober (control or placebo), above (M_BAC = 0.09%) or below (M_BAC = 0.06%) the UK drink‐drive limit. A week later, a free recall and recognition tests were completed. Intoxication was not found to reduce recall accuracy using either recall task. In Study 2, whilst on a night out, participants watched the videoed theft with high (M_BAC = 0.14%) or low (M_BAC = 0.05%) blood alcohol concentrations (BACs). A week later, the free recall and recognition tests were attempted. High BACs were seen to impair recall when memory was assessed through free recall but not with the recognition test. Neither study found the attention narrowing predicted by AMT using either recall technique, although poor recall for low‐salience details in all groups may have contributed to this result. Copyright © 2016 John Wiley & Sons, Ltd.     

Predictors of perceived road collision/incident risk among horse users: A survey study from Norway

Although horse users in traffic are a vulnerable road user group, traffic safety problems among them are scantly examined by previous research. The main aim of the present study was to examine the role of some demographic variables, traffic safety attitudes, and level of knowledge about rules and regulations applying to horse use in traffic for predicting perceived road collision/incident risk in a sample of horse users in Norway. An online survey was conducted to collect data from a total of 1733 horse users including horse riders and drivers of horse-drawn sulky, wagon or sled. The respondents accessed the survey via a link put to the website of the Norwegian Horse Centre, which is in contact with many different horse user environments in Norway. The majority of the respondents were female and between the ages of 18–30. A multiple regression analysis was conducted to examine the predictors of the perceived collision/incident risk involving other motor vehicles. Results showed that traffic safety attitudes among horse users were the strongest predictor of the perceived collision/incident risk. In particular, horse users reported a negative attitude towards the other road users (e.g. drivers) indicating that they perceive the other road users’ actions and approaches as the biggest source of risk in road traffic. The level of knowledge about the rules and regulations applying to horse use, especially in walking and cycling lane, was relatively low among the respondents. However, knowledge about rules and regulations did not appear as a strong predictor of the perceived collision/incident risk. Results indicate the need to increase road users, especially drivers’, awareness about the problems and needs of horse users in traffic.