Effects of task difficulty and time-on-task on mental workload

The proliferation of sedentary, more cognitively demanding computer-mediated work, calls attention to the need for methods to measure mental work load. The present research describes two experiments in which participants performed a machine paced task of entering five and/or nine digit zip codes into a computer. The zip code data was presented on a computer screen for twelve four minute trials where the rate of zip code presentation varied from trial to trial. Using the psychophysical scaling method of magnitude estimation, participants made a judgment of task difficulty after each trial period. In Experiment 1, four females participated in a repeated measures within-subjects design performing each digit task condition for five consecutive days. In Experiment 2, a between-subjects design was adopted where 42 females performed either the five or the nine digit data-entry for only one testing session. Regression analyses using the independent variable of stimulus presentation rate and the dependent variable of judgments of perceived difficulty resulted in R2s of .90 or better for both digit conditions in both experiments. T-tests were conducted to see if different task parameters would affect difficulty judgments; these were statistically significant to the .001 level in both experiments. The results support the notion that magnitude estimation is a reliable method for scaling subjective perceptions of difficulty, which may be an important component of mental workload.

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Changes in Mental Workload and Motor Performance Throughout Multiple Practice Sessions Under Various Levels of Task Difficulty

Neuroscience ◽

10.1016/j.neuroscience.2018.09.019 ◽

2018 ◽

Vol 393 ◽

pp. 305-318 ◽

Cited By ~ 8

Author(s):

Kyle J. Jaquess ◽

Li-Chuan Lo ◽

Hyuk Oh ◽

Calvin Lu ◽

Andrew Ginsberg ◽

...

Keyword(s):

Motor Performance ◽

Task Difficulty ◽

Mental Workload

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Psychology of Computer Use: XXXVIII. Compatibility of Task Presentation and Task Structure in Human-Computer Interaction

Perceptual and Motor Skills ◽

10.2466/pms.1996.83.1.163 ◽

1996 ◽

Vol 83 (1) ◽

pp. 163-175 ◽

Cited By ~ 4

Author(s):

Baijun Zhao ◽

Gavriel Salvendy

Keyword(s):

Task Difficulty ◽

Mental Workload ◽

Computer Programs ◽

Subjective Rating ◽

Task Structure ◽

Program Code ◽

Workload Analysis ◽

Graphic Presentation ◽

Task Presentation ◽

And Task

Task presentation concerns how information is presented. Previous studies of differences between the alphanumeric presentation and the graphic presentation of task information have reported inconclusive or inconsistent results because the effect of task structure and its interaction with task presentation have been ignored. This study explored the compatibility between task presentation and task structure. Two forms of task presentation, namely, the alphanumeric presentation and the graphic presentation, were examined. Two types of task structure, namely, linear procedural and conditional branching, were examined. A nested factorial experiment was conducted for a comprehension of computer programs. Program code written in C programming language was used as the alphanumeric presentation of computer programs. Flowchart was the graphic presentation of computer programs. 32 subjects participated, 16 being exposed only to the alphanumeric presentation, while another 16 were exposed only to the graphic presentation. Each subject performed tasks with both types of structure. Four measures were collected, task completion time, number of errors, subjective rating of task difficulty, and subjective rating of mental workload. Analysis indicated significant interaction between presentation and the structure of task on all four measures. On each measure, the graphic flowchart presentation was more compatible with the conditional branching tasks than the alphanumeric program code presentation. On the two subjective measures of task difficulty and mental workload, the alphanumeric program code presentation was more compatible with the linear procedural tasks than the graphic flowchart presentation.

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Multimodal Measures of Mental Workload during Dual-Task Performance: Energetic Demands of Cognitive Processes

Proceedings of the Human Factors Society Annual Meeting ◽

10.1177/154193129203601811 ◽

1992 ◽

Vol 36 (18) ◽

pp. 1413-1417 ◽

Cited By ~ 5

Author(s):

Richard W. Backs ◽

Arthur M. Ryan

Keyword(s):

Dual Task ◽

Visual Memory ◽

Task Difficulty ◽

Mental Workload ◽

Cognitive Task ◽

Processing Load ◽

Processing Resource ◽

Central Processing ◽

Cognitive Components ◽

Energetic Model

Fifteen male volunteers participated in a dual-task study in which the central processing load of visual memory and tracking tasks and the physical load of the tracking task were orthogonally manipulated to produce varying levels of task difficulty. Multiple modes of assessment were used to measure mental workload (MWL) across difficulty levels, including: performance, subjective, cardiovascular, and metabolic. To our knowledge, this study is the first to demonstrate metabolic change with manipulations of cognitive task difficulty; others have found only baseline-to-task changes. The relation of the metabolic demands of the task to central processing resource utilization provided support for a structural energetic model of attention that may help to explain measure dissociations. The results of the present study indicated that heart period was only sensitive to central manipulations of task difficulty that affected energetic resources. Performance and subjective MWL were sensitive to all cognitive components of the tasks. We suggest that cardiovascular measures will associate with other measures only when the manipulations of task difficulty require energetic adjustment, and would expect these measures to dissociate when energetic adjustment is not required.

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Optimized EEG–fNIRS Based Mental Workload Detection Method for Practical Applications

10.21203/rs.3.rs-683529/v1 ◽

2021 ◽

Author(s):

Hongzuo Chu ◽

Yong Cao ◽

Jin Jiang ◽

Jiehong Yang ◽

Mengyin Huang ◽

...

Keyword(s):

Task Difficulty ◽

Detection Method ◽

Mental Workload ◽

Systems Design ◽

Detection Methods ◽

Complex Signal ◽

Detection Accuracy ◽

Signal Acquisition ◽

Detection Techniques ◽

Channel Configuration

Abstract Background: Mental workload is a critical consideration in complex man–machine systems design. Among various mental workload detection techniques, multimodal detection techniques integrating EEG and fNIRS signals have attracted considerable attention. However, existing EEG–fNIRS-based mental workload detection methods have certain defects, such as complex signal acquisition channels and low detection accuracy, which restrict their practical application.Method: The signal acquisition configuration was optimized and a more accurate and convenient EEG–fNIRS-based mental workload detection method was constructed. A classical MATB task was conducted with 20 participating volunteers. Subjective scale data, 64-channel EEG data, and two-channel fNIRS data were collected.Results: A higher number of EEG channels correspond to higher detection accuracy. However, there is no obvious improvement in accuracy once the number of EEG channels reaches 26, with a four-level mental workload detection accuracy of 78.25±4.71%. Partial results of physiological analysis verify the results of previous studies, such as that the θ power of EEG and concentration of O2Hb in the prefrontal region increase while the concentration of HHb decreases with task difficulty. It was further observed, for the first time, that the energy of each band of EEG signals was significantly different in the occipital lobe region, and the power of 𝛽1 and 𝛽2 bands in the occipital region increased significantly with task difficulty. The changing range and the mean amplitude of O2Hb in high-difficulty tasks were significantly higher compared with those in low-difficulty tasks.Conclusions: The channel configuration of EEG–fNIRS-based mental workload detection was optimized to 26 EEG channels and two frontal fNIRS channels. A four-level mental workload detection accuracy of 78.25±4.71% was obtained, which is higher than previously reported results. The proposed configuration can promote the application of mental workload detection technology in military, driving, and other complex human–computer interaction systems.

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The Roles Of Cognitive Load and Appraisal Of Task Difficulty In Predicting Subjective Fatigue And Subsequent Task Disengagement

10.32920/ryerson.14661270.v1 ◽

2021 ◽

Author(s):

Nicole E. Carmona

Keyword(s):

Task Difficulty ◽

Central Fatigue ◽

Task Demands ◽

Future Research ◽

Cognitive Resources ◽

Time On Task ◽

Subsequent Effect ◽

Almost All ◽

Subsequent Task

Central fatigue refers to an inability to sustain mental or physical performance in self-initiated tasks and an increased perception of effort (Chaudhuri & Behan, 2000), suggesting that fatigue results from a mismatch between the perceived resources needed to initiate a task and the availability of cognitive resources available to complete it. Consequently, fatigue may be considered a “stop-emotion” to preserve cognitive resources, resulting in task disengagement (Meijman, 2000). This study investigated: 1) the role of perceived cognitive resources in the development of mental fatigue by manipulating the task demands and appraisals of task difficulty, and 2) the subsequent effect of fatigue on task engagement. Fatigue increased and cognitive resources decreased with time on task, rather than as a result of the task demands × instruction of task difficulty interaction. Increases in fatigue did not predict measures of engagement in almost all cases. Implications and suggestions for future research are discussed.

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Task difficulty and physiological measures of mental workload in air traffic control: A scoping review

Ergonomics ◽

10.1080/00140139.2021.2016998 ◽

2021 ◽

pp. 1-54

Author(s):

M. Pagnotta ◽

D. M. Jacobs ◽

P. L. de Frutos ◽

R. Rodríguez ◽

J. Ibáñez-Gijón ◽

...

Keyword(s):

Scoping Review ◽

Traffic Control ◽

Air Traffic Control ◽

Task Difficulty ◽

Mental Workload ◽

Air Traffic ◽

Physiological Measures

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Mental Workload and P300 Component of Event-Related Brain Potentials in a Visual Monitoring Task

Proceedings of the Human Factors Society Annual Meeting ◽

10.1177/154193128803201921 ◽

1988 ◽

Vol 32 (19) ◽

pp. 1404-1408

Author(s):

Hamo Lalehzarian

Keyword(s):

Task Difficulty ◽

Mental Workload ◽

P300 Amplitude ◽

Human Information Processing ◽

Brain Potentials ◽

Visual Monitoring ◽

Monitoring Task ◽

P300 Component ◽

Level 3 ◽

Level 2

The attributes of event-related brain potentials (ERPs) when combined with the information gained from the study of apparent human behavior, can provide valuable information about central nervous system processes. This study illustrates the manner in which these attributes, specifically P300 amplitude, can be used to study human information processing. This research investigated the effects of a systematic increase in mental workload, and the position of the stimulus on the P300 amplitude. The task chosen was a visual monitoring task with four levels of increased task difficulty. A slight increase in the P300 amplitude was observed from level 1 to level 2. At level 3, a significant increase in the amplitude of P300 component was observed from level 2. At level four, no major increase in the P300 amplitude was observed from level 3. At any task difficulty level, the P300 amplitudes were not affected by the position of the monitored cell. Infrequent large changes in the readout value of the monitored cells elicited larger P300 amplitudes than frequent small changes.

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A Comparison of Mental Workload in Individuals with Transtibial and Transfemoral Lower Limb Loss during Dual-Task Walking under Varying Demand

Journal of the International Neuropsychological Society ◽

10.1017/s1355617719000602 ◽

2019 ◽

Vol 25 (09) ◽

pp. 985-997

Author(s):

Emma P. Shaw ◽

Jeremy C. Rietschel ◽

Brad D. Hendershot ◽

Alison L. Pruziner ◽

Erik J. Wolf ◽

...

Keyword(s):

Dual Task ◽

Lower Limb ◽

Task Difficulty ◽

Mental Workload ◽

Cognitive Task ◽

Cognitive Demand ◽

Limb Loss ◽

Alpha Power ◽

Physical Demand ◽

Varying Demand

AbstractObjectives: This study aimed to evaluate the influence of lower limb loss (LL) on mental workload by assessing neurocognitive measures in individuals with unilateral transtibial (TT) versus those with transfemoral (TF) LL while dual-task walking under varying cognitive demand. Methods: Electroencephalography (EEG) was recorded as participants performed a task of varying cognitive demand while being seated or walking (i.e., varying physical demand). Results: The findings revealed both groups of participants (TT LL vs. TF LL) exhibited a similar EEG theta synchrony response as either the cognitive or the physical demand increased. Also, while individuals with TT LL maintained similar performance on the cognitive task during seated and walking conditions, those with TF LL exhibited performance decrements (slower response times) on the cognitive task during the walking in comparison to the seated conditions. Furthermore, those with TF LL neither exhibited regional differences in EEG low-alpha power while walking, nor EEG high-alpha desynchrony as a function of cognitive task difficulty while walking. This lack of alpha modulation coincided with no elevation of theta/alpha ratio power as a function of cognitive task difficulty in the TF LL group. Conclusions: This work suggests that both groups share some common but also different neurocognitive features during dual-task walking. Although all participants were able to recruit neural mechanisms critical for the maintenance of cognitive-motor performance under elevated cognitive or physical demands, the observed differences indicate that walking with a prosthesis, while concurrently performing a cognitive task, imposes additional cognitive demand in individuals with more proximal levels of amputation.

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