1. 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

2. Cognition: Memory CS352

3. 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

4. Memory Number activity: try to remember a list of numbers…

5. Memory (cont) Chunking UIs use this.

6. Memory (cont) Number activity

7. Memory (cont.) Number activity: try to remember a list of numbers…

8. 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

9. Recognition and Recall Money activity #1 GUI strength: emphasize recognition over recall. –But usually slowed down by need for visual scan in GUIs.

10. Which is the real penny? http://www.dcity.org/braingames/pennies/coinBW.gif

11. 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.

12. Encoding and (lack of) precision How we encode affects –what we retrieve (recall or recognize) and –how we retrieve Money activity #2

13. Which is the penny? http://mypages.iit.edu/~smart/cesashi/usmoney.jpg

14. Ways to encode (and constraints) Appearance attributes Sound Rhythm Rhyme.

15. 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.

16. 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?

17. 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).

18. 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