Lecture 10 'Mental Workload'

Question 1

Time-based measures is an example of what type of method to determine mental workload?

Answer 1

Analytic

Question 2

What are the three types of empirical methods of determining mental workload?

Answer 2

> Cooper-Harper scale
NASA Task Load Index
Air Traffic Workload Input Technique

Question 3

Levels of cognitive “occupancy” influences what four factors in workers?

Answer 3

> Prevents performance
Changes control/performance standard
Threatens prospective memory for tasks
Emotional impact

Question 4

(Q 52). Mental workload is usually associated with limits in the amount of time to perform a task. Can we derive reliable and valid workload estimates from a timeline analysis of workers’ tasks?

Answer 4

No, because workers’ covert tasks, task management strategies, and level of skill will affect
performance

Question 5

According to the Contextual Control Model, change of “control mode” as workload changes in what four ways?

Answer 5

1. Strategic = actions chosen after full consideration
2. Tactical = actions are routine but panning limited
3. Opportunistic = actions inefficient and selection incomplete
4. Scrambled = actions seem random and not based on current situation

Question 6

(Q 53) Which of the following is not one of the usual methods of measuring mental workload?

a. Subjective rating scales.
b. Observer rating scales.
c. Secondary task performance.
d. Primary task performance.

Answer 6

b) Observer is NOT

Question 7

(Q55) What is the basis of Nygren’s (1991) critique of the NASA Task Load Index?

Answer 7

Weighting the ratings by the relative subjective importance of the subscales provides no further precision to the scale

Question 8

(Q. 56.) According to Loft et al.’s (2007) review of the mental workload of air traffic controllers, what is the
most effective way of understanding the workload of air traffic controllers (ATCos)?

Answer 8

Investigate how ATCos adapt their work strategies to the current demands of their tasks.

Question 9

(Q. 57.) What is the best description of the current status of the NASA Task Load Index?

Answer 9

Widely used in many countries in many different investigative contexts.

Question 10

Why can’t we just perform a timeline analysis and derive workload estimates, what are six difficulties that need to be considered?

Answer 10

1. Need to measure or estimate duration of tasks
2. Need to know duration of overt and covert tasks
3. Need to take into account task management strategies (priorotisation)
4. Need to know task resource demands + automaticity
5. Need to take into account resource demands
6. Need to consider whether multiple resource demand allows timesharing

Question 11

What are the four empirical methods of measuring mental workload?

Answer 11

> Primary task performance
Secondary task performance
Physiological measures
Subjective rating scales

Question 12

What type of mental workload empirical measure was used to test pilot handling qualities of a new aircraft?

Answer 12

Cooper-Harper Scale

Question 13

What are the two components of the NASA Task Load Index?

Answer 13

1. Optional preliminary subscale RANKING phase

2. Subscale RATING phase

Question 14

(Q. 54) What are the six subscales of the NASA Task Load

Answer 14

1. Mental demand
2. Physical demand
3. Temporal demand
4. Effort
5. Own performance
6. Frustration level

Question 15

How is mental workload calculated in the NASA-TLX?

Answer 15

Multiply ratings by the scaled rankings (result is weighted workload score)

Question 16

In Sperandio (1971)’s study on how ATCo controls their workload, what were the results?

Answer 16

They adaptively controlled their desired workload like a closed-loop process
(desired workload = +/- > strategy > task demands > actual workload