Module 9

Question 1

Swiss Cheese Model

Answer 1

Accidents must penetrate levels of system defenses

Can reduce accidents by:
- adding more layers
- reducing the size & number of holes
- alerting users when holes line up

Question 2

Root Cause Analysis

Answer 2

Keep asking why to determine causes for erroneous actions and the causes of these actions

Question 3

Deliberate Violation

Answer 3

Error occurred because user intended the erroneous output

Question 4

Types of Deliberate Violation

Answer 4

1. Routine Violation = user always intends to do it; noncompliance is so frequent that it is ignored
2. Exceptional = only in some cases
3. Sabotage = intended destruction

Question 5

Mistake

Answer 5

User formulated the wrong goal/plan => executing action will not achieve goal

Question 6

Types of Mistakes

Answer 6

1. Rule-Based = appropriately diagnosed situation, but chose erroneous course of action
2. Knowledge-Based = does not have correct info

Question 7

Memory Lapse

Answer 7

Failing to do all steps of a procedure, repeating steps, forgetting the outcome of an action, forgetting the goal or plan

Often caused by interruption

Question 8

Attentional Failure

Answer 8

User intended to do correct solution, but did not actually execute action

Type of slip

Question 9

Potential Underlying Causes for Human Error

Answer 9

1. Strong Habit Intrusion
2. Omissions = forgetting intention to act
3. Perceptual Confusion = don’t perform perceptual check to verify that System 1 action is the correct one to take
4. Mistimed Checks = High automated System 1 activity is interrupted; error in resuming activity

Question 10

Image Foraging Theory Perspective

Answer 10

User exploring patches topology in search of prey; always making a decision about whether a patch is the right place to hunt and changing as new info arrives

Question 11

What is an example of a frequent cause of error?

Answer 11

Interruptions

Question 12

Norman’s Key Design Principles

Answer 12

Put the knowledge required to operate the technology in the world

Use the power of natural and artificial constraints

Bridge the 2 Gulfs (Gulf of Execution & Gulf of Evaluation)

Question 13

Direct Manipulation

Answer 13

Rapid incremental reversible operations whose impact on the objects of interest is immediately visible

Question 14

Direct Manipulation Characteristics

Answer 14

• Continuous representation of the object of interest
• Physical actions instead of complex system
• Continuous feedback and reversible, incremental actions

Question 15

Examples of Direct Manipulation

Answer 15

• Google Maps
• GUI Builder
• Spreadsheets