Flashcards in P.O.E.T Deck (17)
what is an affordance?
The affordances of an object are how it can be used (how it can be perceived to be used)
What is a perceived affordance? Give an example.
perceived affordances are about how perceptions of an object in a simulated environment operates.
A computer mouse affords clicking, scrolling, pulling, pushing etc.
How do we learn conventions?
we learn conventions through:
-clear consistent fundamental design model
-action feedback loop
What are the pieces of Norman's 'System Image'? and their roles?
How do affordances differ from purposes?
-purposes come from the designer
-affordances are understood by the user
Why are labels not considered part of the UI?
-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
How do labels differ from affordances?
-affordances are actual or perceived properties of an object
-labels are not properties of an object
Why is visibility important?
-The correct parts must be visible, and they must convey the correct message
-visibility allows for affordances to be perceived.
Why can too much visibility be a bad thing?
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)
What is a conceptual model?
A conceptual model is what the interface tells you about how a system functions.
What is a mapping?
a mapping is a clue that relates an interface to an action
What is the difference between mapping vs natural mapping?
Mapping implies a relationship between an interface and an action. A natural mapping will use physical analogies and cultural tendencies to create that implication.
What is "feedback" in terms of the "system model"
Feedback is sending a response back to the user about what action has actually been accomplished
What are the 7 principles for simplifying tasks?
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
What are some tradeoffs between knowledge in the world vs knowledge in the head?
-world: easily retrievable
-head: not easily retrievable, requires search or reminding
-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:
What are the "gulfs" that the user must bridge when using a system?
Gulf of execution:
-user forms intention, user specifies action, user performs interface action
Gulf of evaluation:
-user evaluates, user interprets display, system displays