Workload Flashcards
(28 cards)
When applying Models of Attention… what are they used to solve?
HFE issues especially with measurement of mental workload.
The two types of measurement of models of attention?
Workload and Mental workload.
What is workload?
refers to the total amount of work or effort that a person, or group of people, is to perform within a time limit
What is mental workload?
is the amount of mental effort necessary to perform a task within a time limit
What happens as task demands increase or the time allowed to perform a decreases?
The mental workload increases.
What happens when the mental workload is too high?
Performance may suffer if the mental workload is too high (overload)
What happens when the mental workload is too low?
Performance may suffer if the mental workload is too low (under load)
How is mental workload assessed?
Used to maintain the workload at a level that will allow acceptable performance of operator’s tasks
What factors contribute to workload?
The types of tasks that the user must perform
The number of tasks to perform
Accuracy requirements
Time demands
Work load can be assessed into two techniques..
Empirical techniques: used to measure and assess workload directly in a system or simulated system
Analytical techniques: used to predict workload demands early in the system development process
What are the four major types of empirical techniques in workload measurement?
Primary
Secondary
Physiological
Subjective
A situation may require using one or more depend on the task and environment.
What is a Primary Task Measure?
Evaluate the mental workload requirements of a task by directly examining performance of the user or of the overall system
Assumes that as task difficulty increases, so does workload, and that performance deteriorates when workload exceeds capacity
Commonly used measures include reaction time, accuracy
What is primary task measure not good for?
No diagnostic of mental resources that are being overloaded nor measuring different in mental workload conditions
What is Secondary Task Measure?
Based on the logic of dual-task performance
User is required to perform a secondary task in addition to a primary task
Workload is assessed by the degree performance deteriorates on either task when performed simultaneously compared to individually
Provides a measure of the workload caused by particular combinations of tasks
What do secondary task measures do?
Workload can be assessed by manipulating the primary or secondary task difficulty and observing changes in performance of the other task
Deciding which type of secondary tasks to use depends on the HFE specialist
What should the secondary task do?
It should draw on the processing resources required for primary tasks
What are commonly used secondary tasks?
Reaction time
Choice reaction time
Monitoring for the occurrence of a stimulus
Mental arithmetic
What is the downside to inducing secondary tasks?
It is the artificiality or lack of external validity (no one randomly adds numbers while driving)
How to avoid lack of external validity?
An embedded secondary task can be used (listening to a radio while driving a car)
Doe secondary tasks restrict how much information about workload can be extracted?
People may be used to the secondary task
Limited in how difficult we can make that task
What else can be used instead of using behavior observations?
Psychophysicological Measurments
What is the benefit of using Psycophysiological measurements?
It can provide online measurement of the dynamic changed in workload as an operator is engaged in the task without requiring a second task.
What is the downside of using Psychophysiolocial measures?
require sophisticated equipment and the equipment may interfere with the primary task you’re trying to measure
Can psychophysiological measures be used to measure arousal in users?
Yes, As arousal increases, workload is assumed to increase.
