Visual Monitoring Task Research Articles

Visual Process Monitoring by Data-Dependent Kernel Discriminant Analysis with t-Distributed Similarities.

Visual process monitoring would provide more directly appreciable and more easily comprehensible information about the process operating status as well as clear depictions of the occurrence path of faults; however, as a more challenging task, it has been sporadically discussed in the research literature on conventional process monitoring. In this paper, the Data-Dependent Kernel Discriminant Analysis (D2K-DA) model is proposed. A special data-dependent kernel function is constructed and learned from the measured data, so that the low-dimensional visualizations are guaranteed, combined with intraclass compactness, interclass separability, local geometry preservation, and global geometry preservation. The new optimization is innovatively designed by exploiting both discriminative information and t-distributed geometric similarities. On the construction of novel indexes for visualization, experiments of visual monitoring tasks on simulated and real-life industrial processes illustrate the merits of the proposed method.

Testing Senders' Visual Occlusion Model: Do Operators (Drivers) Really Predict During Visual Occlusion?

The present study tests the hypothesis that humans are capable of predicting the state of a system during visual occlusion, an assumption often made in models of sampling behaviour, but seldom tested. In 1967, John Senders introduced the visual occlusion paradigm to evaluate attentional demand of tasks such as automobile driving. Despite multiple studies employing this paradigm, the concept of operators actually being able to resolve uncertainty during occlusion by predicting system output has remained unvalidated. A self-paced visual occlusion monitoring task was contrived, involving a randomly rotating basin with a ball at the bottom. Participants were required to detect critical events (ball falling off the edge) while looking only as often as subjectively deemed necessary. Assuming the need to resolve uncertainty imposed by the random rotations, we examined relations between occlusion durations and system states preceding occlusion, for different glance durations, to infer whether predicting may have taken place. Results suggested that glance requests were consistent with the use of simple first order predictions. This pertained not only for longer (300 and 500ms) glances, but even for 100ms glances whenever critical events were imminent. The presumption that human operators are capable, under certain circumstances, of predicting system state in the absence of visual information appears feasible; however, glance duration plays an important role. By providing support for some of its basic premises, the use of Senders' visual occlusion paradigm as a potential tool for evaluating human monitoring performance has been strengthened.

Speech discrimination and word identification with a consumer-level bone-conduction headset and remote microphone for children with normal hearing

Objective This study investigated the use of bone-conduction headsets paired to a wireless, remote microphone on speech discrimination and word identification for children with normal hearing. Design Children were tested with and without the headset, using the McCormick speech discrimination test in quiet and in speech-shaped noise to measure word-discrimination thresholds. Additionally, open-set word identification in noise was assessed while children were simultaneously engaged in a visual-monitoring task. Study sample Twenty normal-hearing children, aged 4–11 years. Results Median word-discrimination threshold in quiet (n = 20) was 20.5 dB(A) without a headset and 11.5 dB(A) with a headset (Z = –3.826, p = 0.0001). In noise, the median word-discrimination threshold (n = 20) was 52 dB(A) without a headset and 40.5 dB(A) with a headset (Z = –3.926, p< 0.0001). For open-set word identification (n = 11), children performed significantly better with a headset than without it, with an average improvement of 23 percentage points (t(10) = −5.227, p = 0.0004, two tailed). Conclusions A bone-conduction headset paired to a Bluetooth microphone improved discrimination of distant speech in quiet and in noise and open-set word identification in noise.

Investigating the Effects of Interruptions and Reliable Cueing on Change Detection within Dynamic Scenes

The goal of the present study was to examine the effects of cuing and task interruptions on change detection within dynamic scenes. Undergraduate students watched 24 brief videos (12 containing interruptions) for anomalous feature changes appearing in 8 videos. Half of the object changes occurred during a visual occlusion, while the others contained no interruption. All videos were unique and depicted various dynamic scenes. Participants were assigned at random to one of three conditions containing cues to the changes (reliable, unreliable, or no cue). The results showed that more object changes were detected during uninterrupted vs. interrupted trials. More object changes were detected with reliable vs. unreliable cues for uninterrupted trials. Providing reliable cues had no benefit over the other conditions when interruptions were present. Overall, these results suggest that visual interruptions may degrade information stored in memory, which could compromise visual monitoring tasks.

Assessment of mental workload based on multi-physiological signals.

BACKGROUND: Mental workload is one of the contributing factors to human errors in road accidents or other potentially adverse incidents.OBJECTIVE: This research probes the effects of mental workload on the electroencephalographic (EEG) and electrocardiogram (ECG) of subjects in visual monitoring tasks, based on which a comprehensive evaluation model for mental workload is established effectively.METHODS: Three degrees of mental workload were obtained by monitoring tasks with different levels of difficulty. 20 healthy subjects were selected to take part in the research.RESULTS: The subjective scores showed a significant increase with the increase of task difficulty, meanwhile the reaction time (RT) increased and the accuracy decreased significantly, which proved the validity of three degrees of mental workload induced. For the EEG parameters, a significant decrease of energy was found in Frontal, Parietal and Occipital with the increase of level of mental workload, as well as a significant decrease of energy in Frontal, Central and Occipital, meanwhile a significant increase of energy occurred in Frontal and Occipital. There was a significant decrease of / in Occipital, and significant increases of / and ( in Frontal, Central and Occipital, meanwhile ( and WPE decreased significantly in Frontal and Occipital. Among the ECG parameters, it was shown that Mean RR, RMSSD, HF_norm and SampEn decreased significantly with the increase of task difficulty, while LF_norm and LF/HF showed significant increases. These EEG indictors in Occipital and ECG indictors were chosen and constituted a multidimensional original sample. Principal Component Analysis (PCA) was used to extract the principal elements and decreased the dimension of sample space in order to simplify the calculation, based on which an effective classification model with accuracy of 80% was achieved by support vector machine (SVM).CONCLUSION: This study demonstrates that the proposed algorithm can be applied to mental workload monitoring.

Listening Effort in Native and Nonnative English-Speaking Children Using Low Linguistic Single- and Dual-Task Paradigms.

Purpose It is not clear if behavioral indices of listening effort are sensitive to changes in signal-to-noise ratio (SNR) for young children (7-12 years old) from multilingual backgrounds. The purpose of this study was to explore the effects of SNR on listening effort in multilingual school-aged children (native English, nonnative English) as measured with a single- and a dual-task paradigm with low-linguistic speech stimuli (digits). The study also aimed to explore age effects on digit triplet recognition and response times (RTs). Method Sixty children with normal hearing participated, 30 per language group. Participants completed single and dual tasks in three SNRs (quiet, -10 dB, and -15 dB). Speech stimuli for both tasks were digit triplets. Verbal RTs were the listening effort measure during the single-task paradigm. A visual monitoring task was the secondary task during the dual-task paradigm. Results Significant effects of SNR on RTs were evident during both single- and dual-task paradigms. As expected, language background did not affect the pattern of RTs. The data also demonstrate a maturation effect for triplet recognition during both tasks and for RTs during the dual-task only. Conclusions Both single- and dual-task paradigms were sensitive to changes in SNR for school-aged children between 7 and 12 years of age. Language background (English as native language vs. English as nonnative language) had no significant effect on triplet recognition or RTs, demonstrating practical utility of low-linguistic stimuli for testing children from multilingual backgrounds.

Shared Gaze Fails to Improve Team Visual Monitoring

The aim was to test the value of shared gaze as a way to improve team performance in a visual monitoring task. Teams outperform individuals in monitoring tasks, but fall short of achievable levels. Shared-gaze displays offer a potential method of improving team efficiency. Within a shared-gaze arrangement, operators collaborate on a visual task, and each team member's display includes a cursor to represent the other teammates' point of regard. Past work has suggested that shared gaze allows operators to better communicate and coordinate their attentional scanning in a visual search task. The current experiments sought to replicate and extend earlier findings of inefficient team performance in a visual monitoring task, and asked whether shared gaze would improve team efficiency. Participants performed a visual monitoring task framed as a sonar operation. Displays were matrices of luminance patches varying in intensity. The participants' task was to monitor for occasional critical signals, patches of high luminance. In Experiment 1, pairs of participants performed the task independently, or working as teams. In Experiment 2, teams of two participants performed the task with or without shared-gaze displays. In Experiment 1, teams detected more critical signals than individuals, but were statistically inefficient; detection rates were lower than predicted by a control model that assumed pairs of operators searching in isolation. In Experiment 2, shared gaze failed to increase target detection rates. Operators collaborate inefficiently in visual monitoring tasks, and shared gaze does not improve their performance.

Behavioral Measures of Listening Effort in School-Age Children: Examining the Effects of Signal-to-Noise Ratio, Hearing Loss, and Amplification.

Increased listening effort in school-age children with hearing loss (CHL) could compromise learning and academic achievement. Identifying a sensitive behavioral measure of listening effort for this group could have both clinical and research value. This study examined the effects of signal-to-noise ratio (SNR), hearing loss, and personal amplification on 2 commonly used behavioral measures of listening effort: dual-task visual response times (visual RTs) and verbal response times (verbal RTs). A total of 82 children (aged 6-13 years) took part in this study; 37 children with normal hearing (CNH) and 45 CHL. All children performed a dual-task paradigm from which both measures of listening effort (dual-task visual RT and verbal RT) were derived. The primary task was word recognition in multi-talker babble in three individually selected SNR conditions: Easy, Moderate, and Hard. The secondary task was a visual monitoring task. Listening effort during the dual-task was quantified as the change in secondary task RT from baseline (single-task visual RT) to the dual-task condition. Listening effort based on verbal RT was quantified as the time elapsed from the onset of the auditory stimulus to the onset of the verbal response when performing the primary (word recognition) task in isolation. CHL completed the task aided and/or unaided to examine the effect of amplification on listening effort. Verbal RTs were generally slower in the more challenging SNR conditions. However, there was no effect of SNR on dual-task visual RT. Overall, verbal RTs were significantly slower in CHL versus CNH. No group difference in dual-task visual RTs was found between CNH and CHL. No effect of amplification was found on either dual-task visual RTs or verbal RTs. This study compared dual-task visual RT and verbal RT measures of listening effort in the child population. Overall, verbal RTs appear more sensitive than dual-task visual RTs to the negative effects of SNR and hearing loss. The current findings extend the literature on listening effort in the pediatric population by demonstrating that, even for speech that is accurately recognized, school-age CHL show a greater processing speed decrement than their normal-hearing counterparts, a decrement that could have a negative impact on learning and academic achievement in the classroom.

Multitasking During Degraded Speech Recognition in School-Age Children.

Multitasking requires individuals to allocate their cognitive resources across different tasks. The purpose of the current study was to assess school-age children’s multitasking abilities during degraded speech recognition. Children (8 to 12 years old) completed a dual-task paradigm including a sentence recognition (primary) task containing speech that was either unprocessed or noise-band vocoded with 8, 6, or 4 spectral channels and a visual monitoring (secondary) task. Children’s accuracy and reaction time on the visual monitoring task was quantified during the dual-task paradigm in each condition of the primary task and compared with single-task performance. Children experienced dual-task costs in the 6- and 4-channel conditions of the primary speech recognition task with decreased accuracy on the visual monitoring task relative to baseline performance. In all conditions, children’s dual-task performance on the visual monitoring task was strongly predicted by their single-task (baseline) performance on the task. Results suggest that children’s proficiency with the secondary task contributes to the magnitude of dual-task costs while multitasking during degraded speech recognition.

Age-Related Differences in Listening Effort During Degraded Speech Recognition.

The purpose of the present study was to quantify age-related differences in executive control as it relates to dual-task performance, which is thought to represent listening effort, during degraded speech recognition. Twenty-five younger adults (YA; 18-24 years) and 21 older adults (OA; 56-82 years) completed a dual-task paradigm that consisted of a primary speech recognition task and a secondary visual monitoring task. Sentence material in the primary task was either unprocessed or spectrally degraded into 8, 6, or 4 spectral channels using noise-band vocoding. Performance on the visual monitoring task was assessed by the accuracy and reaction time of participants' responses. Performance on the primary and secondary task was quantified in isolation (i.e., single task) and during the dual-task paradigm. Participants also completed a standardized psychometric measure of executive control, including attention and inhibition. Statistical analyses were implemented to evaluate changes in listeners' performance on the primary and secondary tasks (1) per condition (unprocessed vs. vocoded conditions); (2) per task (single task vs. dual task); and (3) per group (YA vs. OA). Speech recognition declined with increasing spectral degradation for both YA and OA when they performed the task in isolation or concurrently with the visual monitoring task. OA were slower and less accurate than YA on the visual monitoring task when performed in isolation, which paralleled age-related differences in standardized scores of executive control. When compared with single-task performance, OA experienced greater declines in secondary-task accuracy, but not reaction time, than YA. Furthermore, results revealed that age-related differences in executive control significantly contributed to age-related differences on the visual monitoring task during the dual-task paradigm. OA experienced significantly greater declines in secondary-task accuracy during degraded speech recognition than YA. These findings are interpreted as suggesting that OA expended greater listening effort than YA, which may be partially attributed to age-related differences in executive control.

The influence of positive vs. negative affect on multitasking

Considerable research has investigated how affect influences performance on a single task; however, little is known about the role of affect in complex multitasking environments. In this paper, 178 participants multitasked in a synthetic work environment (SYNWORK) consisting of memory, visual monitoring, auditory monitoring, and math tasks. Participants multitasked for a 3-min baseline phase (MT1), following which they were randomly assigned to watch one of three affect-induction videos: positive, neutral, or negative. Participants then resumed multitasking for two additional critical phases (MT2, MT3; 3min each). In MT2, performance of the positive and neutral conditions was statistically equivalent and higher than the negative condition. In MT3, the positive condition performed better than the negative condition, with the neutral condition not significantly different from the other two. The differences in overall multitasking scores were largely driven by errors in the Math task (the most cognitively demanding task) in MT2 and the Memory task in MT3. These findings have implications for how positive and negative affective states influence processing in a cognitively demanding multitasking environment.

PyVDT: A PsychoPy-Based Visual Sequence Detection Task

PyVDT is a computerized test consisting of two brief visual sequence detection tasks in which participants watch single digits displayed on screen and respond whenever target digit sequences (even – odd – even) are displayed. The total duration of the test is around five minutes. PyVDT is a reimplementation of the Visual Monitoring Task (VMT), a task thought to measure working memory. PyVDT uses the PsychoPy API to display digits, to plot diagnostic information, and to output log files and results. It is available for download on Figshare and GitHub. PyVDT is free software and has minimal software and hardware requirements. Thus, PyVDT provides a readily available visual monitoring task for use in experiments within cognitive science and related fields.

Sustained Attention in Auditory and Visual Monitoring Tasks: Evaluation of the Administration of a Rest Break or Exogenous Vibrotactile Signals.

Performance and mental workload were observed for the administration of a rest break or exogenous vibrotactile signals in auditory and visual monitoring tasks. Sustained attention is mentally demanding. Techniques are required to improve observer performance in vigilance tasks. Participants (N = 150) monitored an auditory or a visual display for changes in signal duration in a 40-min watch. During the watch, participants were administered a rest break or exogenous vibrotactile signals. Detection accuracy was significantly greater in the auditory than in the visual modality. A short rest break restored detection accuracy in both sensory modalities following deterioration in performance. Participants experienced significantly lower mental workload when monitoring auditory than visual signals, and a rest break significantly reduced mental workload in both sensory modalities. Exogenous vibrotactile signals had no beneficial effects on performance, or mental workload. A rest break can restore performance in auditory and visual vigilance tasks. Although sensory differences in vigilance tasks have been studied, this study is the initial effort to investigate the effects of a rest break countermeasure in both auditory and visual vigilance tasks, and it is also the initial effort to explore the effects of the intervention of a rest break on the perceived mental workload of auditory and visual vigilance tasks. Further research is warranted to determine exact characteristics of effective exogenous vibrotactile signals in vigilance tasks. Potential applications of this research include procedures for decreasing the temporal decline in observer performance and the high mental workload imposed by vigilance tasks.

Neural Mechanisms of Temporal Resolution of Attention

The dynamic nature of the world requires that our visual representations are continuously updated. These representations are more precise if there is a narrow time window over which information is averaged. We assess the neural processes of visual updating by testing patients with lesions including inferior parietal cortex, control patients and healthy adults on a continuous visual monitoring task. In Experiment 1, observers kept track of the changing spatial period of a luminance grating and identified the final spatial period after the stimulus disappeared. Healthy older adults and neurological controls were able to perform better than simulated guesses, but only 3 of 11 patients with damage including parietal cortex were able to reach performance that differed from simulated guesses. The effects were unrelated to lesion size. Poor performance on this task is consistent with an inability to selectively attend to the final moment at which the stimulus was seen. To investigate the temporal limits of attention, we varied the rate of stimulus change in Experiment 2. Performance remained poor for some patients even with slow 2.5 Hz change rates. The performance of 4 patients with parietal damage displayed poor temporal precision, namely recovery of performance with slower rates of change.

Measuring cognitive load during simulation-based psychomotor skills training: sensitivity of secondary-task performance and subjective ratings.

As interest in applying cognitive load theory (CLT) to the study and design of pedagogic and technological approaches in healthcare simulation grows, suitable measures of cognitive load (CL) are needed. Here, we report a two-phased study investigating the sensitivity of subjective ratings of mental effort (SRME) and secondary-task performance (signal detection rate, SDR and recognition reaction time, RRT) as measures of CL. In phase 1 of the study, novice learners and expert surgeons attempted a visual-monitoring task under two conditions: single-task (monitoring a virtual patient's heart-rate) and dual-task (tying surgical knots on a bench-top simulator while monitoring the virtual patient's heart-rate). Novices demonstrated higher mental effort and inferior secondary-task performance on the dual-task compared to experts (RRT 1.76 vs. 0.73, p=0.012; SDR 0.27 vs. 0.97, p<0.001; SRME 7.75 vs. 2.80, p<0.001). Similarly, secondary task performance deteriorated from baseline to dual-task among novices (RRT 0.63 vs. 1.76s, p<0.006 and SDR 1.00 vs. 0.27, p<0.001), but not experts (RRT 0.63 vs. 0.73s, p=0.124 and SDR 1.00 vs. 0.97, p=0.178). In phase 2, novices practiced surgical knot-tying on the bench top simulator during consecutive dual-task trials. A significant increase in SDR (F(9,63)=6.63, p<0.001, f=0.97) and decrease in SRME (F(9,63)=9.39, p<0.001, f=1.04) was observed during simulation training, while RRT did not change significantly (F(9,63)=1.18, p<0.32, f=0.41). The results suggest subjective ratings and dual-task performance can be used to track changes in CL among novices, particularly in early phases of simulation-based skills training. The implications for measuring CL in simulation instructional design research are discussed.

Multi-Resolution Design for Large-Scale and High-Resolution Monitoring

Large-scale and high-resolution monitoring systems are ideal for many visual surveillance applications. However, existing approaches have insufficient resolution and low frame rate per second, or have high complexity and cost. We take inspiration from the human visual system and propose a multi-resolution design, e-Fovea, which provides peripheral vision with a steerable fovea that is in higher resolution. In this paper, we firstly present two user studies, with a total of 36 participants, to compare e-Fovea to two existing multi-resolution visual monitoring designs. The user study results show that for visual monitoring tasks, our e-Fovea design with steerable focus is significantly faster than existing approaches and preferred by users. We then present our design and implementation of e-Fovea, which combines both multi-resolution camera input and multi-resolution steerable projector output. Finally, we present our deployment of e-Fovea in three installations to demonstrate its feasibility.

Compensatory Strategies for Managing the Workload Demands of a Multimodal Reserve Capacity Task

The purpose of the present study was to use a newly-developed measure of reserve attentional capacity to evaluate unitary versus multiple resource theories of attention. Participants performed a primary visual monitoring task and were presented with visual, auditory, and tactile secondary loading tasks. The data indicate that participants failed to maintain performance on the primary task, as instructed, in order to maximize overall performance. A significant difference was found on the basis of primary task condition, wherein performance on the visual monitoring task was significantly worse when paired with a visual task versus auditory or tactile tasks. Although the data do not preclude interpretation in terms of a unitary resource model, data trends offer potential support for multiple resource models.

Cognitive Load in eCommerce Applications—Measurement and Effects on User Satisfaction

Guidelines for designing usable interfaces recommend reducing short term memory load. Cognitive load, that is, working memory demands during problem solving, reasoning, or thinking, may affect users′ general satisfaction and performance when completing complex tasks. Whereas in design guidelines numerous ways of reducing cognitive load in interactive systems are described, not many attempts have been made to measure cognitive load in Web applications, and few techniques exist. In this study participants′ cognitive load was measured while they were engaged in searching for several products in four different online book stores. NASA‐TLX and dual‐task methodology were used to measure subjective and objective mental workload. The dual‐task methodology involved searching for books as the primary task and a visual monitoring task as the secondary task. NASA‐TLX scores differed significantly among the shops. Secondary task reaction times showed no significant differences between the four shops. Strong correlations between NASA‐TLX, primary task completion time, and general satisfaction suggest that NASA‐TLX can be used as a valuable additional measure of efficiency. Furthermore, strong correlations were found between browse/search preference and NASA‐TLX as well as between search/browse preference and user satisfaction. Thus we suggest browse/search preference as a promising heuristic assessment method of cognitive load.

Effects of Secondary Loading Task Modality on Attentional Reserve Capacity

The purpose of the present study was to use a newly-developed measure of reserve attentional capacity to evaluate unitary versus multiple resource theories of attention. Participants performed a primary visual monitoring task and were presented with visual, auditory, and tactile secondary loading tasks. The data indicate that participants maintained performance on the primary task, as instructed, and performed the secondary task with any remaining attentional reserve capacity. A significant difference was found on the basis of secondary task modality, wherein performance on the visual secondary task was significantly worse than that of secondary auditory and tactile tasks. This result was additionally supported by scores on a subjective workload questionnaire. Although the data do not preclude interpretation in terms of a unitary resource model, data trends offer potential support for a multiple resource model.

A comparison of three measures of cognitive load: Evidence for separable measures of intrinsic, extraneous, and germane load.

Understanding how to measure cognitive load is a fundamental challenge for cognitive load theory. In 2 experiments, 155 college students (ages = 17 to 22; 49 men and 106 women) with low domain knowledge learned from a multimedia lesson on electric motors. At 8 points during learning, their cognitive load was measured via self-report scales (mental effort ratings) and response time to a secondary visual monitoring task, and they completed a difficulty rating scale at the end of the lesson. Correlations among the three measures were generally low. Analyses of variance indicated that the response time measure was most sensitive to manipulations of extraneous processing (created by adding redundant text), effort ratings were most sensitive to manipulations of intrinsic processing (created by sentence complexity), and difficulty ratings were most sensitive to indications of germane processing (reflected by transfer test performance). Results are consistent with a triarchic theory of cognitive load in which different aspects of cognitive load may be tapped by different measures of cognitive load.