Announcements
• Tonight: HW #2 (IRB certificate) due at
11:59pm.
• Tomorrow: Project proposal: part 3 due at
11:59pm.
• Read (‘07) all of Ch 3 except omit 3.3.2 and
3.3.3.
1
Cognition:
Memory
CS352
Cognition
• What goes on in our heads when we carry
out activities (eg, use UIs)?
• Book:
– attention, perception, memory, learning,
speaking/reading/listening, problemsolving/reasoning
Memory
• Number activity: try to remember a list of
numbers…
Memory (cont)
• Chunking
• UIs use this.
Memory (cont)
• Number activity
Memory (cont.)
• Number activity: try to remember a list of
numbers…
Structure of memory
• Short term memory (STM)
– a.k.a primary or active memory
– Order of seconds
– 7+2 items
• Long term memory (LTM)
– Everything else.
– Mostly when we say “memory”, we mean
LTM.
– Unlimited capacity
Recognition and Recall
• Money activity #1
• GUI strength: emphasize recognition over
recall.
– But usually slowed down by need for visual
scan in GUIs.
Which is the real penny?
http://www.dcity.org/braingames/pennies/coinBW.gif
People storing/retrieving
knowledge
• Declarative knowledge
– Includes facts and events
E.g., NYC is north of Miami.
E.g., four people brought a laptop to the lecture
E.g., To get key out of ignition, car must be in “park”.
– Easy to teach.
• Procedural knowledge
– For how to do things
E.g., How to spin a basketball on 1 finger
– Best taught by demo, learned by practice.
Encoding and (lack of) precision
• How we encode affects
– what we retrieve (recall or recognize) and
– how we retrieve
• Money activity #2
Which is the penny?
http://mypages.iit.edu/~smart/cesashi/usmoney.jpg
Ways to encode
(and constraints)
•
•
•
•
Appearance attributes
Sound
Rhythm
Rhyme.
Encoding (cont.)
• Retrieval
– E.g., cross words puzzles
• So, reduce and/or facilitate encoding:
– Constraints reduce encoding needed.
– Support external cognition (stay tuned) to
remove need to encode.
• eg: Excel’s arrows make dependencies explicit.
– Provide users a variety of ways to encode
(eg, color, flagging, position).
• eg: forgot filename, but it’s the red folder.
Case study
• The Microsoft Office (past) rearranging of
menus due to recency.
– Think about chunking/grouping
– Think about imprecision of encoding.
– What will do if don’t see what you want?
• Does this mean “most recent” is always a
bad idea in a UI?
Encoding (cont.)
• Different amount of encoding needed for:
– Remembering a bunch of arbitrary things.
– Remembering things with meaningful
relationships.
• Hotel is on north side of town.
– “Remembering” things that can be derived.
• Tied to “mental models” (stay tuned).
Implications for your Project
• Think about user’s memory a lot.
– Quiz system content eg: have I used a question
much like this on an earlier quiz?
– Quiz system UI mechanism eg: how do I print out
the answer key to the quiz?
– Your project examples?
• How can UI help user remember
(store/retrieve) here?
– Think about: recog/recall, practice, chunking,
declarative vs. procedural, encoding, constraints