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, problem-solving/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 thingsE.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