P.O.E.T

Question 1

what is an affordance?

Answer 1

The affordances of an object are how it can be used (how it can be perceived to be used)

Question 2

What is a perceived affordance? Give an example.

Answer 2

perceived affordances are about how perceptions of an object in a simulated environment operates.

A computer mouse affords clicking, scrolling, pulling, pushing etc.

Question 3

How do we learn conventions?

Answer 3

we learn conventions through:

• clear consistent fundamental design model
• appropriate mappings
• action feedback loop

Question 4

What are the pieces of Norman’s ‘System Image’? and their roles?

Answer 4

Designer:
-creates
User:
-action/use
System:
-feedback

Question 5

How do affordances differ from purposes?

Answer 5

• purposes come from the designer

- affordances are understood by the user

Question 6

Why are labels not considered part of the UI?

Answer 6

• UI is what the users connect to, users do not connect to labels
• labels/instructions/manuals etc are part of the system image and help users to construct a conceptual model

Question 7

How do labels differ from affordances?

Answer 7

• affordances are actual or perceived properties of an object
• labels are not properties of an object

Question 8

Why is visibility important?

Answer 8

• The correct parts must be visible, and they must convey the correct message
• visibility allows for affordances to be perceived.

Question 9

Why can too much visibility be a bad thing?

Answer 9

Too much visibility can be a bad thing. Consider the fancy washing machine with too many settings (discourages people from using it, discourages user from attempting to learn all the functions)

Question 10

What is a conceptual model?

Answer 10

A conceptual model is what the interface tells you about how a system functions.

Question 11

What is a mapping?

Answer 11

a mapping is a clue that relates an interface to an action

Question 12

What is the difference between mapping vs natural mapping?

Answer 12

Mapping implies a relationship between an interface and an action. A natural mapping will use physical analogies and cultural tendencies to create that implication.

Question 13

What is “feedback” in terms of the “system model”

Answer 13

Feedback is sending a response back to the user about what action has actually been accomplished

Question 14

What are the 7 principles for simplifying tasks?

Answer 14

1- Use knowledge in the world(in the system) and knowledge in the head(prior knowledge of the user)
2- Simplify the structure of tasks
3- Make things visible
4- Get the mappings right
5- Explore the power of constraints
6- Design for error
7- Standardize

Question 15

What are some tradeoffs between knowledge in the world vs knowledge in the head?

Answer 15

Retrievability:

• world: easily retrievable
• head: not easily retrievable, requires search or reminding

Learning:

• world: learning not required, instead interpretation is substituted
• requires learning which can have considerable overhead

Efficiency of use:

• world: tends to be slowed up by the need to find and interpret external information
• head: can be very efficient

Ease of use at first encounter:

• world: high
• head: low

Question 16

What are the “gulfs” that the user must bridge when using a system?

Answer 16

Gulf of execution:
-user forms intention, user specifies action, user performs interface action

Gulf of evaluation:
-user evaluates, user interprets display, system displays

Question 17

What are the types of constraints?

Answer 17

• physical constraints: are inherent
• logical constraints: use reason to determine choices
• cultural constraints: a learned convention