affordances and signifiers

interaction design

good design

human-centered

discoverability

communication

understanding

affordances

affordances

psychologist, j.j. gibson

relationships between animals and objects

perceptions of use through clues

object qualities and animal abilities

how we can easily make use of everyday things

affordances in
interaction design

engineer turned designer, don norman

appropriation and use in design

discoverability and understanding

popularity and misuse

affordances in this room?

signifiers

signifiers in design

any mark or sound, any perceivable indicator that communicates appropriate behavior to a person

must be perceivable

cursors

mapping

mapping: relationships

relationship between control and action / result

spatial layout

spatial correspondence between controls and actions

make interactions easier to learn

natural mappings

spatial analogies lead to immediate understanding

some mappings are cultural

scrolling and scrollbars

trackpad scrolling

customization

feedback

feedback

response to action

immediate

informative

visual, auditory, haptic, olfactory

consider accessibility and inclusiveness

visual

auditory

not currently visual focus

source?

haptic

poor feedback

miscommunication

inconsistent

latency

too much: inform, not disrupt

response times [nielsen 1993]

0.1 s → limit for feeling instaneous

1.0 s → limit for user's flow of thought

10 s → limit for keeping user's attention

conceptual models

conceptual models

explanation for how something works

can be incomplete

can be inaccurate

but still useful

norman's refrigerator

conceptual models for refrigerator

web browser back / forward

traverse recent history of websites by url

dynamic content (not url-based)

designer's model != user's model

affordances, signifiers, mappings, and feedback → models

how are conceptual models formed?

system image

no direct communication with designer

appearance

similar things

what we are told

documentation

good communication →
good models

burden on system image

good models help users correct mistakes

interaction design

good design

human-centered

discoverability: affordances, signifiers, and mappings

communication: signifiers and feedback

understanding: affordances, mappings, and conceptual models

questions?

reading for next class

Chapter 4: "Knowing What to Do: Constraints, Discoverability, and Feedback"
The Design of Everyday Things