1. Mental Workload

2. What is Mental Workload?
Why measure it?
Performance limits
Predict top performance
Tasks
Cognitive/perceptual
multiple

3. What kind of tasks have High mental workload?
Air traffic control
Pilot
Military command & control
Nuclear power plant operator
anesthesiologist
N/A
Computer programmer
College professor
Mathematician
Technical writer

4. Key Elements for High mental workload tasks
Stimulus driven not self paced
Large fluctuations in demand
Multiple simultaneous tasks
High stress/High consequence

5. Workload & Arousal Yerkes-Dobson law Low arousal Low performance
Moderate arousal High performance
Over arousal Low performance

8. Basic approaches to measuring mental workload
Analytic
Task difficulty
Number of simultaneous tasks
Task performance
Primary task
Secondary task
Physiological (arousal/effort)
Subjective assessment

11. Analytic Models Tracking models predict based on systems dynamics
Queuing models predict on the basis of task co-occurrence
SAINT / microSAINT best developed queuing models

15. Resources/Attention Some limited capacity
Unitary: task always depletes common pool by a constant amount
Multiple: task depletes pools of resources to varying degrees
Mixed: cost of sharing even for highly dissimilar resources

23. Unconscious/Automatic
Simplified HIP Model S E N O R Y T
Attention
Long
Term
Memory
Working Memory
Unconscious/Automatic
Processes

24. Physiological Measures
heart rate: sinus arrhythmia
blood pressure
respiratory rate variability
tidal volume
ventilation
galvanic skin response
evoked response amplitude
evoked response latency
evoked response latency
electroencehpalogram,
spectral components
time domain,
flicker fusion frequency
pupil diameter
electromyograms
electrooculograms

28. Subjective Workload Measures
Cooper-Harris
Manual control characteristics
SWAT
Dimension based instrument
NASA
6-D assessment scales