Primary Task Performance Research Articles

The effects of psychosocial and cognitive stress on executive functions and automatic processes in healthy subjects: A pilot study

The main aim of the present study was to examine the effects of psychosocial and cognitive stress on executive functions and automatic processes in healthy subjects. To achieve these purposes, we investigated whether cognitive stress impaired the controlled processing underlying cognitive flexibility, working memory and initial letter fluency performances, and whether social stress impaired both performance of executive processes and of semantic fluency. We employed the psychosocial stress paradigm in which cognitive assessment was superimposed on cognitive and social stressors soon after their introduction and was carried out concurrently while they were present. With reference to cognitive stress, we employed the dual-task paradigm that involves a primary task (performances related to executive functions and automatic task) and a secondary task (focusing attention and memorizing items in another cognitive task). Eighty-eight healthy subjects, between 18 and 30 years, participated in this study. They were randomly divided into three groups: two groups undergoing a stress procedure, respectively a cognitive stress group and a social stress group, and a control group. Results indicated that stress impaired cognitive flexibility, working memory and verbal fluency. Cognitive flexibility was affected to a greater extent by psychosocial stress than cognitive stress. This study suggests that the negative effects of stress on cognitive flexibility may be a consequence of the interplay between controlled and automatic processes.

The invisible breast cancer: Experience does not protect against inattentional blindness to clinically relevant findings in radiology.

Retrospectively obvious events are frequently missed when attention is engaged in another task-a phenomenon known as inattentional blindness. Although the task characteristics that predict inattentional blindness rates are relatively well understood, the observer characteristics that predict inattentional blindness rates are largely unknown. Previously, expert radiologists showed a surprising rate of inattentional blindness to a gorilla photoshopped into a CT scan during lung-cancer screening. However, inattentional blindness rates were higher for a group of naïve observers performing the same task, suggesting that perceptual expertise may provide protection against inattentional blindness. Here, we tested whether expertise in radiology predicts inattentional blindness rates for unexpected abnormalities that were clinically relevant. Fifty radiologists evaluated CT scans for lung cancer. The final case contained a large (9.1 cm) breast mass and lymphadenopathy. When their attention was focused on searching for lung nodules, 66% of radiologists did not detect breast cancer and 30% did not detect lymphadenopathy. In contrast, only 3% and 10% of radiologists (N = 30), respectively, missed these abnormalities in a follow-up study when searching for a broader range of abnormalities. Neither experience, primary task performance, nor search behavior predicted which radiologists missed the unexpected abnormalities. These findings suggest perceptual expertise does not protect against inattentional blindness, even for unexpected stimuli that are within the domain of expertise.

Mid-Air Tactile Feedback Co-Located With Virtual Touchscreen Improves Dual-Task Performance.

The use of haptic technology has recently become essential in Human-Computer Interaction to improve performance and user experience. Mid-air tactile feedback co-located with virtual touchscreen displays have a great potential to improve the performance in dual-task situations, such as when using a phone while walking or driving. The purpose of this article is to investigate the effects of augmenting virtual touchscreen with mid-air tactile feedback to improve dual-task performance where the primary task is driving in a simulation environment and the secondary task involves interacting with a virtual touchscreen. Performance metrics included primary task performance in terms of velocity error, deviation from the middle of the road, number of collisions, and the number of off-road glances, secondary task performance including the interaction time and the reach time, and quality of user experience for perceived difficulty and satisfaction. Results demonstrate that adding mid-air tactile feedback to virtual touchscreen resulted in statistically significant improvement in the primary task performance (the average speed error, spatial deviation, and the number of off-road glances), the secondary task (reach time), and the perceived difficulty. These results provide a great motivation for augmenting virtual touchscreens with mid-air tactile feedback in dual-task human-computer interaction applications.

Adverse Behavioral Adaptation to Adaptive Forward Collision Warning Systems: An Investigation of Primary and Secondary Task Performance

Advanced driver assistance systems can effectively support drivers but can also induce unwanted effects in behavior. The present study investigates this adverse behavioral adaptation in adaptive Forward Collision Warning (FCW) systems. Other than conventional FCW systems that provide warnings based on static Time-To-Collision (TTC) thresholds, adaptive FCW systems consider the driver’s need for support by adjusting warning thresholds according to distraction. A neglected question is how drivers adapt their behavior when they use adaptive FCW systems under realistic conditions, i.e., when warnings occur infrequently but system functionality is anticipated. Forty-eight participants drove with two different FCW systems (adaptive vs. non-adaptive) while working on a secondary in-vehicle task in a driving simulator. During the main part of the experiment, no brake events occurred and hence FCW functioning was largely anticipated. Additionally, visual system feedback about the driver’s distraction state was manipulated between groups. Participants had significantly shorter minimal time-headways and TTCs when driving with the adaptive relative to the non-adaptive system. Participants with system feedback about distraction state spent generally more time with engaging in the secondary task. These results indicate behavioral adaptation which, however, is restricted to the task that is specifically supported by the system, namely longitudinal control.

Towards Intelligent Data Analytics: A Case Study in Driver Cognitive Load Classification.

One debatable issue in traffic safety research is that the cognitive load by secondary tasks reduces primary task performance, i.e., driving. In this paper, the study adopted a version of the n-back task as a cognitively loading secondary task on the primary task, i.e., driving; where drivers drove in three different simulated driving scenarios. This paper has taken a multimodal approach to perform ‘intelligent multivariate data analytics’ based on machine learning (ML). Here, the k-nearest neighbour (k-NN), support vector machine (SVM), and random forest (RF) are used for driver cognitive load classification. Moreover, physiological measures have proven to be sophisticated in cognitive load identification, yet it suffers from confounding factors and noise. Therefore, this work uses multi-component signals, i.e., physiological measures and vehicular features to overcome that problem. Both multiclass and binary classifications have been performed to distinguish normal driving from cognitive load tasks. To identify the optimal feature set, two feature selection algorithms, i.e., sequential forward floating selection (SFFS) and random forest have been applied where out of 323 features, a subset of 42 features has been selected as the best feature subset. For the classification, RF has shown better performance with F1-score of 0.75 and 0.80 than two other algorithms. Moreover, the result shows that using multicomponent features classifiers could classify better than using features from a single source.

Gauging the utility of ambient displays by measuring cognitive load

Ambient Displays, a sub-class of ubiquitous computing, aim to present non-critical information using peripheral visualisation with minimal distraction. The utility of Ambient Displays relies on providing useful, well-designed information in a way that does not increase the users cognitive load. Assessing the cognitive load of an Ambient Display is thus an important part of the development process. In this paper we review the key design dimensions of Ambient Displays and consider how they impact on cognitive load. We then examine various approaches for measuring cognitive load before describing a study that investigates a novel use of a dual-task measure to evaluate the cognitive load of a specific Ambient Display. A between-subjects design with 40 participants was used, with the Ambient Display active for half of these participants. All participants completed three different primary tasks (n-back, visual digit span, and auditory digit span) alongside the secondary, Detection Response Task. The results show that the n-back task is the most appropriate for manipulating primary task load when evaluating such displays and that the dual-task paradigm can be used to provide an objective measure of workload. Analysis of the participants primary and secondary task performance indicates that the evaluated Ambient Display imposed no additional cognitive load.

Comparing touch-based and head-tracking navigation techniques in a virtual reality biopsy simulator

Recently, virtual reality (VR) technologies started gaining momentum in surgical simulation-based training by allowing clinicians to practice their skills before performing real procedures. The design of such simulators is usually focused on the primary operative tasks to be taught, but little attention is paid to secondary tasks that the user needs to perform, such as changing his/her point of view when manipulating the surgical instruments. More particularly, it is not clear how to design appropriate interaction techniques for those tasks, and how the fidelity of these interactions can impact the user’s performance on such systems. In this paper, we compare two viewpoint changing techniques having two different levels of interaction fidelity during needle insertion in a semi-immersive VR (SIVR) biopsy trainer. These techniques were designed based on observing clinicians performing actual biopsy procedures. The first technique is based on tracking the user’s head position (high interaction fidelity), while the second technique is touch-based with the user utilizing his/her non-dominant hand fingers to manipulate the point of view on a touch screen (moderate interaction fidelity). A user study was carried out to investigate the impact of the interaction fidelity of the viewpoint changing task (secondary task) on the user’s performance during the needle insertion task (main task). Twenty-one novice participants were asked to perform several trials of a needle insertion task while using the navigation techniques (within-subject design). Objective and subjective measures were recorded to compare the task performance (time to accomplish the task, precision of the tumor sampling, and errors) and user experience for both techniques. The results show that the touch-based viewpoint changing technique improves the users’ task completion performance during needle insertion while maintaining a similar level of needle manipulation accuracy as compared to the head-tracking technique. These results suggest that high interaction fidelity is not always necessary when designing surgical trainers. This also highlights the importance of designing appropriate interactions for secondary tasks because they can influence the user’s primary task performance in VR simulators.

Effects of social stress on performance and strain in complex multiple task environments

While stress has been an important research area in the field of ergonomics, research on social stress and on the combination of stressors is largely lacking. This study examined the effects of social stress on psychological and physiological strain and performance. As an exploratory research question we looked at the combined effects of social stress and noise. Fifty-one male student participants were tested for 2 h using a computer-based simulation of a process control environment with multiple tasks. Social stress (TSST) and noise (80 dB) were varied experimentally. During the task, we repeatedly measured primary and secondary task performance, subjective strain, and psychophysiological strain (cortisol, heart rate). We found a main effect of social stress on physiological strain, both on cortisol and heart rate, but no main effects of social stress on subjective strain and performance. These results suggest that maintaining performance under stress comes at the cost of physiological strain. Practitioner summary: Although the presence of social stress is common at work, little experimental work has been done. Our experiment provides empirical evidence for negative effects of social stress on physiological stress responses while subjective strain and performance decrements could not be detected. Abbreviations: ANOVA: analysis of variance; b/min: beats per minute; CAMS: cabin air management system; CO2: carbon dioxide; dB: decibel; Df: degrees of freedom; ECG: electrocardiography; h: hours; Hz: hertz; M: mean; min: minutes; N: sample size; nmol/l: nanomol per liter; O2: oxygen; pm: post meridiem; SD: standard deviation; SE: standard error; sec/s: seconds; TSST: trier social stress test

Loads of unconscious processing: The role of perceptual load in processing unattended stimuli during inattentional blindness

Inattentional blindness describes the failure to detect an unexpected but clearly visible object when our attention is engaged elsewhere. While the factors that determine the occurrence of inattentional blindness are already well understood, there is still a lot to learn about whether and how we process unexpected objects that go unnoticed. Only recently it was shown that although not consciously aware, characteristics of these stimuli can interfere with a primary task: Classification of to-be-attended stimuli was slower when the content of the task-irrelevant, undetected stimulus contradicted that of the attended, to-be-judged stimuli. According to Lavie’s perceptual load model, irrelevant stimuli are likely to reach awareness under conditions of low perceptual load, while they remain undetected under high load, as attentional resources are restricted to the content of focused attention. In the present study, we investigated the applicability of Lavie’s predictions for the processing of stimuli that remain unconscious due to inattentional blindness. In two experiments, we replicated that unconsciously processed stimuli can interfere with intended responses. Also, our manipulation of perceptual load did have an effect on primary task performance. However, against our hypothesis, these effects did not interact with each other. Thus, our results suggest that high perceptual load cannot prevent task-irrelevant stimuli that remain undetected from being processed to an extent that enables them to affect performance in a primary task.

The Why, What, and How of Immersive Experience

Assessing and modelling the quality of immersive experience has become a trending topic in QoE. To achieve this purpose, we would firstly want to know why an immersive experience is important to us, what exactly is defined as an immersive experience, and how we could actually measure an immersive experience. This paper aims to answer these questions. We start from the rationales of designing immersive experience, and then briefly go through the definitions of immersion from the system and user perspectives. We also provide our own definition of immersion that fits into the QoE assessment and measurement paradigm. We continue to discuss the pros and cons of four popular measurements of immersion, namely, the psychometric questionnaires, the continuous subjective measures, the primary or secondary task performance, and the neuro-psycho-physiological methods. We also provide a global view of comparing and evaluating these measurements by profiling them along five quality dimensions. Finally, we postulate, briefly, four novel methods of measuring immersion, linking the definitions and theories of immersion with the measurements we have discussed in this paper.

Online and offline contributions to motor learning change with practice, but are similar across development.

Children show motor learning deficits relative to adults across a diverse range of tasks. One mechanism that has been proposed to underlie these differences is the contribution of online and offline components to overall learning; however, these tasks have almost focused exclusively on sequence learning paradigms which are characterized by performance gains in the offline phase. Here, we examined the role of online and offline learning in a novel motor task which was characterized by warm-up decrement, i.e., a performance loss, during the offline phase. In particular, using a relatively extended practice period, we examined if differences between children and adults persist across relatively long practice periods, and if the contribution of online and offline learning is affected by age and by practice itself. Two groups of children, 8-10years and 11-13years old, and one group of young adults (N = 30, n = 10/group) learned a novel task that required control of upper body movements to control a cursor on a screen. Participants learned the task over 5days and we measured movement time as the primary task performance variable. Consistent with prior results, we found that 8-10year olds had longer movement times compared to both 11-13year olds and adults. We also found distinct changes in online and offline learning with practice; the amount of online learning decreased with practice, whereas offline learning was relatively stable across practice. However, there was no detectable effect of age group on either online or offline learning. These results suggest that age-related differences in learning among children 8-10years old are persistent even after extended practice but are not necessarily accounted for by differences in online and offline learning.

Investigating differences in the attention distribution strategies of high and low media multitaskers through a two-dimensional game

The rapid advancement of mobile computing devices and the ever-growing range of infotainment services they enable have cultivated high levels of media multitasking. Studies have considered the effects of this form of behaviour for cognitive control ability, with findings suggesting that chronic media multitasking is associated with reduced inhibitory control. In this study we advance knowledge in this domain by investigating differences in the attention distribution strategies of high and low media multitaskers (HMMs and LMMs) through a simple, two-dimensional game. 1 063 university students completed a web-based survey concerning their media multitasking behaviour and played the 2D game. Contributing to the ecological validity of the study the game was played within the respondent’s web-browser, as part of the survey, at a time and place (and on a computer) of their choosing. During gameplay one of two different banners, both irrelevant to the game, were displayed adjacent to the game. No instructions were provided in relation to the banners. Our analysis considered respondents’ performance in the game in relation to both their media multitasking and the content of the banner displayed. Our findings suggest that while HMMs attend to distracting stimuli independent of their content or salience, LMMs are more selective. This selectivity enables improved primary task performance when distracting stimuli are deemed unimportant. Additionally, we found that LMMs generally recalled banner information more accurately after the game was played.

Adjustment of cognitive control to the frequency of dual-task interference

ABSTRACTThis study explored whether the control mechanisms recruited for optimising performance are similar for dual-task and interference-task settings. We tested whether the frequency of appearance of a secondary task resulted in an adjustment of anticipatory and reflexive forms of attentional control, as has been observed with other interference tasks (e.g. stroop and flanker). The results of two experiments demonstrated a proportion congruency effect (PCE): when a secondary task frequently appeared, primary task performance was slower. Additionally, there was a relative slowdown of dual-task performance in blocks wherein the secondary task appeared infrequently compared to blocks wherein it appeared frequently. However, this slowdown occurred when the primary task entailed a low level of control (Experiment 1) but was absent when it demanded a high level of control (Experiment 2). Overall, the results suggest that level of control can be adjusted to task demands related to the frequency of the secondary task.

Age-related differences in reallocating cognitive resources when dealing with interruptions

The ability to perform at a high level, even when the task at hand is interrupted by an unrelated secondary task, is central to human information processing. Executive control processes, in particular the reallocation of attentional resources, are crucial for coping with interruptions. Although the age-related decline in cognitive control functions is well described, the consequences of such changes for the ability to deal with interruptions are as of yet unclear. In the present study, we examined behavioral performance as well as electrophysiological parameters associated with executive control processes in older and younger participants using a nested task design: In one third of all trials, an ongoing working memory task was interrupted by a math task. We found that the impact of interruptions on primary task performance was more severe in the older age group. In the EEG, older adults showed stronger frontal midline theta activation and fronto-parietal connectivity in the theta range in response to the cue indicating the relevant attentional set. Younger participants, on the other hand, showed distinct and specific increases in cognitive control as indexed by frontal midline theta in response to the stimulus signaling an upcoming interruption. Overall, the results reveal strategic differences between the age groups, as older participants seem to prioritize the primary task more strongly. The data furthermore indicate that the combination of a rapid succession of events and the decreased ability to shift executive resources renders older adults’ performance particularly vulnerable to the occurrence of interruptions.

Workload and Performance: Associations, Insensitivities, and Dissociations.

The aim of this study was to distill and define those influences under which change in objective performance level and the linked cognitive workload reflections of subjective experience and physiological variation either associate, dissociate, or are insensitive, one to another. Human factors/ergonomics frequently employs users' self-reports of their own conscious experience, as well as their physiological reactivity, to augment the understanding of changing performance capacity. Under some circumstances, these latter workload responses are the only available assessment information to hand. How such perceptions and physiological responses match, fail to match, or are insensitive to the change in primary-task performance can prove critical to operational success. The reasons underlying these associations, dissociations, and insensitivities are central to the success of future effective human-machine interaction. Using extant research on the relations between differing methods of workload assessment, factors influencing their association, dissociation, and insensitivity are identified. Dissociations and insensitivities occur more frequently than extant explanatory theories imply. Methodological and conceptual reasons for these patterns of incongruity are identified and evaluated. We often seek convergence of results in order to provide coherent explanations as bases for future prediction and practical design implementation. Identifying and understanding the causes as to why different reflections of workload diverge can help practitioners toward operational success.

Schema-related cognitive load influences performance, speech, and physiology in a dual-task setting: A continuous multi-measure approach

Schema acquisition processes comprise an essential source of cognitive demands in learning situations. To shed light on related mechanisms and influencing factors, this study applied a continuous multi-measure approach for cognitive load assessment. In a dual-task setting, a sample of 123 student participants learned visually presented symbol combinations with one of two levels of complexity while memorizing auditorily presented number sequences. Learners’ cognitive load during the learning task was addressed by secondary task performance, prosodic speech parameters (pauses, articulation rate), and physiological markers (heart rate, skin conductance response). While results revealed increasing primary and secondary task performance over the trials, decreases in speech and physiological parameters indicated a reduction in the overall level of cognitive load with task progression. In addition, the robustness of the acquired schemata was confirmed by a transfer task that required participants to apply the obtained symbol combinations. Taken together, the observed pattern of evidence supports the idea of a logarithmically decreasing progression of cognitive load with increasing schema acquisition, and further hints on robust and stable transfer performance, even under enhanced transfer demands. Finally, theoretical and practical consequences consider evidence on desirable difficulties in learning as well as the potential of multimodal cognitive load detection in learning applications.

Volitional media multitasking: awareness of performance costs and modulation of media multitasking as a function of task demand.

In two experiments, we sought to determine whether (a) people are aware of the frequently observed performance costs associated with engaging in media multitasking (Experiment 1), and (b) if so, whether they modulate the extent to which they engage in multitasking as a function of task demand (Experiment 2). In Experiment 1, participants completed a high-demand task (2-back) both independently and while a video was simultaneously presented. To determine whether people were sensitive to the impact that the concurrent video had on primary-task performance, subjective estimates of performance were collected following both trial types (No-Video vs. Video trials), as were explicit beliefs about the influence of the video on performance. In Experiment 2, we modified our paradigm by allowing participants to turn the video on and off at their discretion, and had them complete either a high-demand task (2-back) or a low-demand task (0-back). Findings from Experiment 1 indicated that people are sensitive to the magnitude of the decrement that media multitasking has on primary-task performance. In addition, findings from Experiment 2 indicated that people modulate the extent to which they engage in media multitasking in accordance with the demands of their primary task. In particular, participants completing the high-demand task were more likely to turn off the optional video stream compared to those completing the low-demand task. The results suggest that people media multitask in a strategic manner by balancing considerations of task performance with other potential concerns.

Alcohol increases inattentional blindness when cognitive resources are not consumed by ongoing task demands

RationaleInattentional blindness (IB) is the inability to detect a salient yet unexpected task irrelevant stimulus in one’s visual field when attention is engaged in an ongoing primary task. The present study is the first to examine the impact of both task difficulty and alcohol consumption on IB and primary task performance.ObjectivesOn the basis of alcohol myopia theory, the combined effects of increased task difficulty and alcohol intoxication were predicted to impair task performance and restrict the focus of attention on to task-relevant stimuli. We therefore expected increases in breath alcohol concentration to be associated with poorer primary task performance and higher rates of IB, with these relationships being stronger under hard than easy task conditions.MethodsThis hypothesis was tested in a field study where alcohol drinkers in a local bar were randomly assigned to perform a dynamic IB task with an easy or hard visual tracking and counting task at its core (Simons and Chabris in Perception 28:1059–1074, 1999).ResultsIncreasing the difficulty of the primary task reduced task accuracy but, surprisingly, had no impact on the rate of IB. Higher levels of alcohol intoxication were, however, associated with poorer task performance and an increased rate of IB, but only under easy primary task conditions.ConclusionsResults are consistent with alcohol myopia theory. Alcohol intoxication depletes attentional resources, thus reducing the drinker’s awareness of salient stimuli that are irrelevant to some ongoing primary task. We conclude that this effect was not observed for our hard task because it is more resource intensive, so leaves no spare attentional capacity for alcohol to deplete.

Development and evaluation of a monitoring-aid system for a nuclear power plant in control room system manipulation.

In an advanced nuclear power plant (NPP), the operators are responsible for monitoring a massive number of alarm parameters. To assist the operators, a monitoring-aid system (MAS), that applies four quality control chart methods, was proposed and evaluated. Two types of MAS, namely, text and graph marks, were proposed and compared with the original display. To validate the proposed MAS, 17 professional engineers and operators were invited to join an experiment. Two different system states, normal and abnormal, were simulated. The operators were asked to manipulate the system, monitor the critical parameters, search for operational procedures, and deal with other secondary tasks. The primary and secondary task performance and heart rate were measured. After each task was conducted, three subjective rating questionnaires, namely, mental workload, situation awareness, and preference ratings, were implemented for the proposed MAS and the original system. With the assistance of the MAS, the alarm detection rate, secondary task performance, and subjective mental workload demonstrate significant improvements. The proposed MAS helps the operators monitor critical parameters. Therefore, the MAS should be considered for implementation with the control panel to increase the safety of NPPs. Furthermore, the MAS could reduce the mental workload might decrease the health hazard of the operators.

Effects of Alarm System Error Bias and Reliability on Performance Measures in a Multitasking Environment: Are False Alarms Really Worse than Misses?

Researchers suggest signaling system false alarms damage human performance more than misses, yet the evidence is inconsistent. Therefore, we examined the effects of false alarm and miss rates on concurrent task and detection task performance. Method: Eighty-eight participants interacted with two primary flight simulation tasks and a secondary detection task, with the help of a signaling system that varied by error bias (false alarm-prone, miss-prone) and reliability (90%, 60%). Results: Higher reliability led to better detection task performance and the miss-prone group had higher dependence rates. Misses, however, negatively affected detection task performance more than false alarms and Bayes analyses indicated no differential effect of error type on primary task performance. Conclusion: The frequent alarms in the false alarm-prone group appeared to aid participants in switching from the primary to secondary detection task. Participants may have used the information acquisition function of the aid, but not the information analysis function.