Transcript Chapter 5 – Cognitive Engineering
Cognition, Memory, and Attention
ITM 734 Fall 2006 Dr. Cindy Corritore
Through all of this ….
limited cognitive resources analogy flawed plans (heuristics) simulations (cognitive/mental models) goal – to minimize complexity through improved fit (between user, computer, and task) Copyright 2006 Corritore 2 of 52
memory types
sensory memory short-term memory long-term memory Copyright 2006 Corritore 3 of 52
sensory memory/store (multi-store theory)
buffers for incoming data via senses different one for each sense types iconic store – visual store; fades rapidly – can operate on this store echonic store – auditory store short-lived and space-constrained persistence (fireworks in vision after the fact) some processing even if not attended attention brings it into STM cocktail party phenomenae Copyright 2006 Corritore 4 of 52
STM characteristics
quick access and quick decay (volatile) limited in size chunking (experts vs. novices) - phone number 402-111-5555 forgetting time decay? interference with new items? (eg. similarity) attention moves off item?
Copyright 2006 Corritore 5 of 52
STM
gateway to sensory and LTM? no – conversation goes directly to LTM role of rehearsal exaggerated (moving from STM to LTM) lots in LTM that is not rehearsed (eg. snapshot of a birthday celebration) Copyright 2006 Corritore 6 of 52
STM characteristics
recency - last few items in list recalled better than middle - holding most recent items in STM negate with interference?
visual and auditory channel - no interference if different channel primacy - first few items in list recalled better than middle (more rehearsal) Copyright 2006 Corritore 7 of 52
LTM characteristics
Slow but variable access speed Permanent (little decay) Infinite capacity Copyright 2006 Corritore 8 of 52
LTM characteristics
Retrieval depends on ….
recency expectations similarity of information connectedness rehearsal richness & nature of processing at learning level or depth or processing (shallow vs deep perceptual analysis) distinctiveness of processing amount of processing elaborate far better Copyright 2006 Corritore 9 of 52
Richness
paragraph – listen and remember …..
Copyright 2006 Corritore 10 of 52
Types of LTM
Explicit and Implicit conscious recollection, top-down retrieval from multiple systems with massive integration (E) unconscious recollection, bottom-up from single system (I) – more automatic Copyright 2006 Corritore 11 of 52
Types of LTM
Episodic and Semantic self-awareness component, things that happen to you, complex (E) stuff we know, knowledge about the world, relationships, implicit - dictionary, thesaurus likely stored the same way Copyright 2006 Corritore 12 of 52
Types of LTM
Declarative and Procedural knowing that, explicit primarily, relationships, integration of information (D) – knowing things and their relationships knowing how, mostly implicit, not relational – how to do things Copyright 2006 Corritore 13 of 52
Memory structures for stories, events …
Schema - framework that includes frames & scripts basis for expectations Bartlett’s Schema Theory become chunks for expanding memory framework for stories that affects comprehension told American Indian stories, then recall readjusted story elements and themes to fit their model Chunking in experts Helps make it easier to recall, group information Experts have great, robust schema and chunks Copyright 2006 Corritore 14 of 52
Everyday memory
little studied appears to have a lot of variability eyewitness memory flashbulb memory Copyright 2006 Corritore 15 of 52
Eye-witness memory
Effects post-event memory - questioning right after the fact can distort (retroactive interference) verbal overshadowing - talking about it right after happens over-writes visual memory memory in the world sketchy (Normal) confirmation bias - affected by what you expect Copyright 2006 Corritore 16 of 52
Flash bulb memory
what were you doing when heard about 911 disaster?
Richness …..
Copyright 2006 Corritore 17 of 52
LTM processes
Storage rehearsal Retrieval Forgetting Recognition vs recall Frequency and recency effects Copyright 2006 Corritore 18 of 52
Storage- Rehearsal
Memorization involves storing the information and one or more access paths Good memories are rich semantic networks with many (unique) access paths Learning is aided by meaningfulness, structure, familiarity and concreteness Active memorizing requires effort, motivation Passive memorizing - unpredictable, often episodic, context sensitive Similar items interfere if they are not separated during memorizing - learning transfer effects - old interfere with new; new overwrite old Copyright 2006 Corritore 19 of 52
Facilitating Memorization
Structure information to help chunking - use categories, ordering, associations Encourage reasoning during memorizing active memory Help access by multiple pathways memorizing tricks e.g. keywords, cognitive aids, mnemonics, link to image memory (rooms) Make associations clear and keep them consistent Copyright 2006 Corritore 20 of 52
Facilitating Memorization
Make separate and recognizable contexts for recall - important for script / skill memory Increase depth of encoding Richness Visualization Uniqueness Interaction Recognition Copyright 2006 Corritore 21 of 52
Facilitating Memorization: Mnemonics
cognitive mnemonics ABC’s with tune on old olympus mountain tops a finn and german viewed some hops (12 crainial nerves: OOOMTAFAGVSH) seems to be more to remember?
Copyright 2006 Corritore 22 of 52
Facilitating Memorization: Mnemonics
check out: http://human-factors.arc.nasa.gov/cognition/tutorials/index.html
mnemonic for Norman principles: visibility, feedback, cognitive/conceptual model, affordance, mapping My Fat Cat Ate Veggies Copyright 2006 Corritore 23 of 52
Retrieval - Theories of forgetting
repression (Freud) - bad experience interference (proactive or retroactive) previous learning/memories interrupt espc if similar stimuli – belong to same category eye-witness and post-incident questioning doesn’t explain how it works cue-dependant forget because info not there anymore or *can’t access it encoding specificity principle (cue-dependant) retrieval a func. of overlap between information present at retrieval and info stored in memory includes contextual info Recognition dependant on internal cues only (not external context) 24 of 52
Recall vs. recognition
Knowledge in the World Theory is GUI’s - Alan Kay developed in 1960’s Steve Jobs in late 1970’s from Xerox Parc keep knowledge in world to supplement head knowledge recall vs. recognition remember just enough detail to get by exceptions rather then norms experts not expert in knowledge in the head as much as expert in how to locate needed knowledge in the world (Norman Ch 2) Copyright 2006 Corritore 25 of 52
Design implications
Reduce cognitive load!!!
Type of user novice, expert, intermittent user Copyright 2006 Corritore 26 of 52
Design implications
Mental models natural extensions of schema support schemas metaphors - desktop/office match system information structure with familiar memory structures so user can use their schema Copyright 2006 Corritore 27 of 52
Design implications
Design interfaces that help users ‘grow’ good mental models meaningful and familiar command names (eg. from task world) balance this with existing conceptual models of item names (ie. cut, copy) Incorporate closure (finish) on tasks helps build mental model helps identify chunks for memory when become an expert Consistency to build mental model; don’t have to remember as much Copyright 2006 Corritore 28 of 52
Design implications
Rich encoding multimedia interaction context?
May just be to ‘remember your site’ http://www.pulse3d.com/pulse/ http://www.jordans.com/roomplanner.asp
Copyright 2006 Corritore 29 of 52
Design implications
Focus on recognition rather than recall interface contains prompts/information studies on computer experts found they don’t have better recall, but high recognition of what is and isn’t available on interface and where to find it (mental maps) GUI’s combination of recognition (menu’s) and recall (quick keys) Copyright 2006 Corritore 30 of 52
Design implications
Place the burden of remembering on the machine, not the human
Don’t require user memory (eg. between screens) Don’t have computer ask for info it can derive Copyright 2006 Corritore 31 of 52
Design implications
Design minor messages, alerts, warning to be minimally disruptive prevent user from forgetting data stored in short term memory Copyright 2006 Corritore 32 of 52
Evaluate these
http://happydeluxe.com/ http://www.google.com
vs http://www.yahoo.com
http://www.northcantonmedical.org/ http://www.enchantedharp.com/ Copyright 2006 Corritore 33 of 52
Attention
Humans can focus mental resources on a single event/object helps to simplify environmental input (filter) works with perception - perceive what attending to can divide attention (multiprocessing, not parallel) problem distraction on second task, don’t return to first task in right place.
often use world reminders to hold place in first task (post-it note) Copyright 2006 Corritore 34 of 52
Attention
examples driving a car -must attend to some stimuli, ignore others listening to this lecture - attend to slides and words, ignore other students, physical plant noises Copyright 2006 Corritore 35 of 52
Divided attention
doing two things at once affected by task similarity – similar how?
practice (experience) - automaticity task difficulty – require more resources than are available?
what happens: interference Copyright 2006 Corritore 36 of 52
Success in time sharing attention
four mechanisms account for how well we divide our attention 1. automaticity and resources 2. resource allocation and switching 3. structural factors 4. confusion and similarity Copyright 2006 Corritore 37 of 52
1. automaticity and resources
Automatic vs. Controlled : perform task without thinking about it or require attention, conscious control. Happens over time. Controlled – do something directed by thought.
Automatic: good as
fast
, doesn’t interfere with other tasks (need minimal attention), unconscious bad - unavailable to conscious level, hard to change (driving a shift), can interfere with other automatic processes, harder to unlearn do experiment: Stroup Effect ( http://www.apa.org/science/stroop.html
) Copyright 2006 Corritore 38 of 52
1. automaticity and resources
automatic processing can time-share efficiently doesn't require a lot of cognitive resources eg. walking factor: effort and difficulty of additional tasks if task difficult, requires more resources if have dual tasks, performance will decrease since resources are being shared automatic tends to reduce the difficulty Copyright 2006 Corritore 39 of 52
1. automaticity and resources
can only increase performance so much level equal to ‘full’ resource use on a task, performance data limited (no further benefit from adding more resources) perfect example: no matter how hard I try (invest resources & effort), I won't improve my understanding of a discussion in French beyond a rudimentary level.
also called resource-limited Copyright 2006 Corritore 40 of 52
1. automaticity and resources
bottom line increase effort into a task, improve performance to point if resource limited increase difficulty of task decreases performance unless add resources in dual tasks, if increase resources for one task, will decrease resources for second task and subsequent performance depends on automaticity Copyright 2006 Corritore 41 of 52
2. resource allocation and switching
result of two + tasks co-occuring now look at how you can allocate and switch attention between tasks we don't have elaborate schemes to optimize resource allocation can improve time sharing with these strategies totally depends on the individual
can train
how to control attention Copyright 2006 Corritore 42 of 52
2. resource allocation and switching
optimal allocation schedule vs. actual based on task importance and other factors factors switch cost (so tend to stay with same task even if low priority) cognitive distance of tasks - if close, more confusion when switch (so more costly) faster switch if salient reminders available about task (eg. you can see it vs. just remembering) Copyright 2006 Corritore 43 of 52
3. structural factors
perceptual resources required, brain structures used, info processing required Bottleneck Theory- use same resources, get a bottleneck that shared tasks must wait for bottom line amt. of interference between two tasks depend on degree to which each requires same resources (shared levels on these three dimensions) Copyright 2006 Corritore 44 of 52
4. confusion and similarity
confusion: increasing the similarity of processing material decreases efficiency (too similar) eg. mental math and spelling, Stroup effect semantic value of word interferes with ability to report ink color what happens: responses for one task activated and interfere with second task eg. two verbal tasks, one requiring working memory and the other active processing (eg. comprehension) Copyright 2006 Corritore 45 of 52
Visual attention theories
spotlight vs. zoom lens both correct in part, likely zoom is more appropriate (zoom focus in on what’s imp) how attention works overall gestalt (salient features), focus down on objects and components affected by experience (bananas yellow) Copyright 2006 Corritore 46 of 52
Designing for attention
examine which configurations minimize task interference voice recognition software - may interfere if user has to perform other verbal activities best with spatial activities avoid imposing two tasks using similar materials (confusion) entering digits while others speaking digits Copyright 2006 Corritore 47 of 52
Designing for attention
what about background music?
requires spatial perception decreased performance with lyrics and word processing examine mental workload Copyright 2006 Corritore 48 of 52
Designing for attention
Ways to focus user attention structure information group like things physically, with fonts, with color, spacing, lines, etc.
use same spot for same types of information to help with distractions: system should inform you where you were in task when left let user know position in state space avoid unnecessary information display (KISS) make things easy to use/move thru (so user not 49 of 52
Designing for attention
taking advantage of automatic processing: quick keys across systems standards (like Windows 95 ^c, ^v, ^x) become automatic problem - appears unrelated to task to most people avoid automaticity by interrupting process (eg. put a window up in middle of keystroke sequence) good for deleting urgent info in prominent area; less urgent to specific area(s) Copyright 2006 Corritore 50 of 52
Errors
how design for them? will occur save the user …..
Why? we are satisficing,
not
optimizing always following a plan (heuristics), but most of our plans are flawed Copyright 2006 Corritore 51 of 52
Action slips
activate wrong schema Norman discusses 6 types of slips - a result of different kinds of automaticity errors capture errors – frequently done takes over (same beginning) description errors – intended action fits several possibilities – pick wrong one data-driven – data interrupts automatic behavior and get wrong behavior associative activation – trigger activates wrong action loss-of-activation – forget why doing something mode – more than once state possible slips vs. mistakes (choose inappropriate goals) Copyright 2006 Corritore 52 of 52
Errors ala Te’eni et. al.
Copyright 2006 Corritore 53 of 52
Designing for errors
Schneideman’s guidelines good specificity - what exactly is the problem?
constructive guidance - how can user fix/deal with problem?
positive tone vs. illegal, aborted, fatal… user-centered style - how phrase suggestion appropriate physical format - mixed case, placement on screen?
Guidelines from Microsoft http://msdn.microsoft.com/library/default.asp?url=/ library/en us/debug/base/error_message_guidelines.asp