Usability Principles

Question 1

What is affordance?

Answer 1

It is the perceived and actual properties of an object / system that allows an individual to perform an action.

Question 2

What is false affordance?

Answer 2

It has the perceived property of being able to perform an action but does not actually have it.

Question 3

What are signifiers?

Answer 3

It is a signal or an indication that communicates how to use an object. (eg. tab of wet tissue packet, macOS resize corner)

Question 4

What is visibility?

Answer 4

How easily the feature or capability of the object is seen.

Question 5

What is feedback?

Answer 5

It is to send information back about what action has been done or accomplished, can be audio, visual, tactile, verbal, etc.

Question 6

What is mapping?

Answer 6

It is the relationship between the control and the action or result.

Question 7

What are constraints?

Answer 7

Limits to the perceived operation of a device

Can be physical, semantic, cultural, logical.

Question 8

What are metaphors?

Answer 8

Visual, actions, and procedures that exploit specific knowledge that users already have in other domains.

Question 9

What are conceptual models?

Answer 9

Simplified explanation or framework for understanding how something works. Formal, structured & logical.

Question 10

What are mental models?

Answer 10

Models people already have of themselves, others, environment, and things they interact with. Informal, incomplete and sometimes erroneous.

Question 11

What are system images?

Answer 11

Information conveyed by the product and links conceptual models to mental models.

Question 12

What are the differences between conceptual and mental models?

Answer 12

Conceptual: Formal, structured & logical.
Mental: Informal, incomplete and sometimes erroneous.

Question 13

What is the Gulf of Evaluation?

Answer 13

It is the amount of effort a person must exert to interpret the results of their action or state of a system.

The expectations and availability of information specifying the state of the system.

Question 14

What is the Gulf of Execution?

Answer 14

It is the amount of effort a person must exert to tell a system what to do.

Difference between users’ perceived execution actions and the required actions.

Question 15

How do you bridge both gulfs?

Answer 15

Use Usability Principles: FAGGVC

Feedback
Affordances
Good conceptual model
Good mapping
Visibility
Constraints

Question 16

What are Norman’s 7 stages of actions?

Answer 16

GISEPIE

1. Forming the goal
2. Forming the intention
3. Specify a sequence of actions
4. Execution of action sequence
5. Perceiving state of the system
6. Interpret the perceived state
7. Evaluate interpretation

[G]oal
[I]ntention
[S]equence of action
[E]xecution of action
[P]erceive state of system
[I]nterpret state of system
[E]valuate state of system

Question 17

What are Norman’s 7 principles?

Answer 17

1. Use both knowledge in the world and knowledge in the head.
2. Simplify the structure of tasks.
3. Make things visible: bridge the gulfs of execution and evaluation
4. Get the mappings right.
5. Exploit the power of constraints, both natural and artificial.
6. Design for error.
7. When all else fails, standardize.