DMS 546/446INTERFACE DESIGN

MEMORY

PERCEPTION

COGNITION

Lecture based on Ch. 2 of User-Centered Website Development (McCracken and Wolfe)

TOPICS:

human sense, perception, memorymental models, metaphor, perceived affordancedesign guidelines based on the above

Constructivist theory of perception:

1. We don't remember all the information in a scene –

just what is important to us.

Q: How many doors are there on the front of this building?

Constructivist theory of perception:

2. Context plays a major role in what people see in an image

Top

Ace

Constructivist theory of perception:

3. figure/ground

Constructivist ->

Gestalt psychology

ProximitySimilaritySymmetryContinuity

Closure

Proximity: people tend to perceive any closely clustered objects as a group

Similarity: grouping by like kind or like type

Symmetry: the whole figure is perceived rather than the parts

Continuity: groupings created by flow of lines or alignment

Closure: mentally completing a shape

MEMORY:

hierarchy: sensory store, short-term, long term“chunking”advantage of relying on recognition vs recallmemory aids

Q: What was on the last slide?

Hierarchical Model of Memorya model to explain memory

sensory memorysensory input comes in but most is ignored or filtered out

short term memorylimited data held for 30 seconds to two minutes“The Magic Number Seven, Plus or Minus Two” - Miller, 1956

long-term memorygreat deal of effort to transfer from short term to long term

ChunkingMiller discusses the data we can hold in short term

memory in terms of chunks

Chunks can be individual digits...645-4920

ChunkingChunks can be words or syllables...

thanksforthememories.com

thanks for the memories (dot) com

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AutosFinanceWeatherNightlifeGamesMusicMoviesSports

InboxFriend RequestsUpload VideoEdit Profile

Recognition vs Recall

It is usually easier to read a foreign language than to speak it.

...you can recognize words that you may not be able to recall when you want to use them in conversation.

Recognition vs Recall

Multiple choice is easier than essay

...you can recognize the right answer even if you can't recall it

>>>cd lecture_4 >ls -l

Memory aids – managing interruptions

knowledge in the world (external)

give people cues or memory aids for resuming interrupted tasks...

blinking cursor

color of links showing visited and unvisited pages

Memory aids – managing interruptions

response time user reactionless than 0.1 second perceived as instantaneousless than 1.0 second noticed delay but no break in thought streammore than 10 seconds user switches to new task

(Miller 1986)

Mental ModelsWhat will happen if I adjust the thermostat?

MetaphorsLeveraging existing mental models

- using Word is like typing?- using the mp3 player is like using the CD

player?- using video conferencing is like using the

phone?

Perceived Affordances

affordances = the functions or services an interface provides

perceived affordances = affordances that are visible or comprehensible to the user

Perceived Affordances

...how do we know which light switches control which lights?

SOME DESIGN IMPLICATIONS

Reduce memory burden rely on recognition over recall chunk information require as little short-term memory as possible

Consider the user's mental models

Use visual cues or memory aids to manage interruptions

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