Workload

Question 1

When applying Models of Attention… what are they used to solve?

Answer 1

HFE issues especially with measurement of mental workload.

Question 2

The two types of measurement of models of attention?

Answer 2

Workload and Mental workload.

Question 3

What is workload?

Answer 3

refers to the total amount of work or effort that a person, or group of people, is to perform within a time limit

Question 4

What is mental workload?

Answer 4

is the amount of mental effort necessary to perform a task within a time limit

Question 5

What happens as task demands increase or the time allowed to perform a decreases?

Answer 5

The mental workload increases.

Question 6

What happens when the mental workload is too high?

Answer 6

Performance may suffer if the mental workload is too high (overload)

Question 7

What happens when the mental workload is too low?

Answer 7

Performance may suffer if the mental workload is too low (under load)

Question 8

How is mental workload assessed?

Answer 8

Used to maintain the workload at a level that will allow acceptable performance of operator’s tasks

Question 9

What factors contribute to workload?

Answer 9

The types of tasks that the user must perform
The number of tasks to perform
Accuracy requirements
Time demands

Question 10

Work load can be assessed into two techniques..

Answer 10

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

Question 11

What are the four major types of empirical techniques in workload measurement?

Answer 11

Primary
Secondary
Physiological
Subjective

A situation may require using one or more depend on the task and environment.

Question 12

What is a Primary Task Measure?

Answer 12

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

Question 13

What is primary task measure not good for?

Answer 13

No diagnostic of mental resources that are being overloaded nor measuring different in mental workload conditions

Question 14

What is Secondary Task Measure?

Answer 14

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

Question 15

What do secondary task measures do?

Answer 15

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

Question 16

What should the secondary task do?

Answer 16

It should draw on the processing resources required for primary tasks

Question 17

What are commonly used secondary tasks?

Answer 17

Reaction time
Choice reaction time
Monitoring for the occurrence of a stimulus
Mental arithmetic

Question 18

What is the downside to inducing secondary tasks?

Answer 18

It is the artificiality or lack of external validity (no one randomly adds numbers while driving)

Question 19

How to avoid lack of external validity?

Answer 19

An embedded secondary task can be used (listening to a radio while driving a car)

Question 20

Doe secondary tasks restrict how much information about workload can be extracted?

Answer 20

People may be used to the secondary task

Limited in how difficult we can make that task

Question 21

What else can be used instead of using behavior observations?

Answer 21

Psychophysicological Measurments

Question 22

What is the benefit of using Psycophysiological measurements?

Answer 22

It can provide online measurement of the dynamic changed in workload as an operator is engaged in the task without requiring a second task.

Question 23

What is the downside of using Psychophysiolocial measures?

Answer 23

require sophisticated equipment and the equipment may interfere with the primary task you’re trying to measure

Question 24

Can psychophysiological measures be used to measure arousal in users?

Answer 24

Yes, As arousal increases, workload is assumed to increase.

Question 25

What is Pupillometry?

Answer 25

technique to measure arousal by measuring the pupil diameter.

The larger the pupil, the greater the workload demands
Cannot distinguish between the different resources being overloaded

Question 26

What is the measure of psychophysiological measure of arousal?

Answer 26

Heart rate:
Generally, increased heart rate = increased mental workload
However, this is not always true because increased heart rate can increase with physical exertion .

Question 27

What are EEG, ERPs, fMRI?

Answer 27

Brain activity is a popular subject of psychophysiological measures

Question 28

What is subjective assessment techniques?

Answer 28

evaluate workload by obtaining users’ judgments about their tasks