Cognition: Memory CS352

Cognition What goes on in our heads when we carry out activities (eg, use UIs)? Our heads do: attention, perception, memory, learning, speaking/reading/listening, problem-solving/reasoning underlined is what I’ll focus on in the next few lectures

Memory Number activity: 347 901 331 7347 89 BRING NUMBER.

347 901 331 7347 89

Memory (cont) Chunking UIs use this.

Memory (Cont.) Number activity: 134 790 133 1734 789 BRING NUMBER.

134 790 133 1734 789 Prev was: 347 901 331 7347 89

Memory (cont) UI implications from these two activities? Leverage to use chunks..

Structure of memory The shortest of short term memory (STM) Demonstration. The Working Memory part of STM. Still volatile and small. Not really a “Place” – more like “pointers”. eg: in book’s warehouse analogy, it’s a small number of searchlights into LTM. Long term memory (LTM) Everything else. Mostly when we say “memory”, we mean LTM.

Recognition and Recall: Money Activity #1 Draw a $1 bill Compare to Recall: How well did they do at drawing one?

Recognition and Recall: Money Activity #1 Recognition: can they recog the right one. Compare to Recall:

Recognition and Recall GUI strength: emphasize recognition over recall. But usually slowed down by need for visual scan in GUIs. UI solution? Solutions: KB shortcuts let people use either one.

People storing/retrieving knowledge Declarative knowledge NYC is north of Miami. To get key out of ignition, car must be in “park”. Easy to teach. Procedural knowledge How to spin a basketball on 1 finger. How to boot a smart phone into recovery mode. 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 (if time permits)

Which is the US penny?

Ways to encode (and constraints) Appearance attributes, sound, rhythm, rhyme. Traveling performers: how did they do that? Thru encoding tied to constraints. (Storage for retrieval). Rhythm Rhymes with Must make sense Example: the Raven

Encoding (cont.) Retrieval So, reduce and/or facilitate encoding: Word guessing activities 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 I do if don’t see what I 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 Avoid burdening long-term memory: Think about: recog/recall, practice, chunking, declarative vs. procedural, encoding, constraints Why consistency matters: reduces LTM burden Ideas: Security problems due to LTM (book p. 103-4) Grocery system content: brand I bought before? Grocery system UI devices: how to get subtotal? Discussion: Your project examples? Passwords: this is why we use obvious passwords, and/or write them down. Security questions: The book points out that we can’t remember which answer – which pet name did I use?