The Human Processing and Memory

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The Human Processing and Memory Powered By Docstoc
					      The Human
 Processing and Memory
Human Computer Interaction, 2nd Ed.
  Dix, Finlay, Abowd, and Beale
             Chapter 1
Model Human Processor + Attention
                           Recall, “purely and engineering abstraction”


•   Sensory store
     –   Rapid decay “buffer” to hold
         sensory input for later processing

•   Perceptual processor
     –   Recognizes symbols, phonemes
     –   Aided by LTM

•   Cognitive processor
     –   Uses recognized symbols
     –   Makes comparisons and
         decisions
     –   Problem solving
     –   Interacts with LTM and WM

•   Motor processor
     –   Input from cog. proc. for action
     –   Instructs muscles
     –   Feedback
           •   Results of muscles by senses

•   Attention
     –   Allocation of resources
                           Overview
• Will look at elements of human information processing from a slightly
  different orientation than “engineering abstraction”

• A bit more fine grained analysis, following from psychological studies
    – But, it is these psychological studies from which the “engineering
      abstraction” is derived

• 3 stage model of human memory
    – Iconic buffer, STM, LTM

• Models of LTM

• Reasoning

• Problem solving
3-Stage Model of Human Memory




•   Sensory (here, iconic) memory – “very” short term memory
     – lasts 1-2 seconds, infinite capacity

•   Short-term memory (Working memory)
     – lasts ~ 18 seconds, holds 1.75 (7+/-2 items)

•   Long-term memory
     – infinite capacity; short of damage is permanent
     – Recall vs. Recognition (Remember vs. Know)
          • Retrieval cues
•   Will demonstrate later in class …                    http://www.if.uidaho.edu/~marbjm/class%202.pdf
              “Executive” - Attention




•   Central “executive” controls tasking
     – Pays, or allocates, attention
     – Bandwidth of attention is limited

•   Tasks that require the same resources interfere with one another

•   Attention is both a low-level and high-level property of vision
                                                                  http://www.if.uidaho.edu/~marbjm/class%202.pdf
          Sensory Memory:
      “Very” Short Term Memory



•   Buffers for stimuli received through senses
     – iconic memory: visual stimuli
     – echoic memory: aural stimuli
     – haptic memory: tactile stimuli

•   Examples
     – “sparkler” trail
     – stereo sound

•   Continuously overwritten – demo follows
A Test – of Visual Iconic Memory
• Will present figure briefly (~1/2 second)

• Try to remember as many elements as you can

• Write them down
             The Phenomenon
• After presentation, did you continue to “see” the
  items?

  – Some purely physiological based “seeing”:
     • Afterimage
     • Bleaching of pigments
     • “bright, or colored, stuff”

  – But also, there is a more “memory-based” image
    (process further downstream in memory system)
     • Iconic memory
     • “dark, or veridical, stuff”
     • Reading from the iconic buffer
Reading from the Iconic Buffer, 1
• Typically can list 3 – 7 items named

• Short lived visual, or iconic, buffer
    – holds the image for a second or two

• Read images and place in STM               Set of miscellaneous symbols
    – 3-stage model

• Can get about 5-7 items until run out of
  short term (working) memory capacity

• Limitation of 5-7 comes from:
    – Decay of iconic memory                 Useful Visual
                                             Field of View
                                                                    Visual
                                                                    Search or
                                                                    Monitoring
    – Rate can read from visual buffer                              Strategy



    – Capacity of working memory                                      Eye
                                                                      Movement
                                                                      Control


• In each fixation between saccadic eye
  movements, image of world captured
Reading from the Iconic Buffer, 2
• Again, Limitation of 7 comes from:
    – Decay of iconic memory
    – Rate can read from visual buffer
    – Capacity of working memory

• From each image,                                 Set of miscellaneous symbols
    – brain must identify objects,
    – match them with objects previously
      perceived, and
    – take information into working memory for
      symbolic analysis

• Search light model of attention (for vision)
                                                   Useful Visual          Visual
    – Visual information is acquired by pointing   Field of View          Search or
                                                                          Monitoring
                                                                          Strategy
      fovea at regions of visual field that are
      interesting                                                           Eye

    – Then using a scanning process in which                                Movement
                                                                            Control

      objects are read from an image buffer from
      more extensive processing
                                         Attention
• Spotlight metaphor
    – Spotlight moves serially from one input channel to another
    – Can focus attention (and perceptual processor) on only one input channel at a
      time
         •   Location in visual field, voice in auditory field, …, anything


• Visual dominance:
    – Easier to attend to visual channels than auditory channels


• All stimuli within spotlighted channel are processed in parallel
    – Whether you want to or not
    – Can cause “interference” - demo
    Say the Colors of the Words




• Easy enough – didn’t take too long
    Say the Colors of the Words




• Took longer … Stroop effect
• Choose secondary characteristics of display to reinforce message
  Again, Human Memory Stages




• Sensory (here, iconic) memory
   – lasts 1-2 seconds, infinite capacity

• Short-term memory (Working memory)
   – lasts ~ 18 seconds, holds 1.75 (7+/-2 items)

• Long-term memory
   – infinite capacity; short of damage is permanent
   – Recall vs. Recognition (Remember vs. Know)
       • Retrieval cues                                http://www.if.uidaho.edu/~marbjm/class%202.pdf
         Short-term memory (STM)




•     “Scratch-pad” (or buffer) for temporary recall
       – rapid access ~ 70ms
       – rapid decay ~ 200ms
       – limited capacity - 7± 2 chunks

    • Chunking, recoding, etc.
       – affects amount of information retained, entering LTM
Examples - Chunking


    212348278493202

     0121 414 2626

HEC ATR ANU PTH ETR EET
         Long-term Memory (LTM)




•     Repository for all our knowledge
       – slow access ~ 1/10 second
       – slow decay, if any
       – huge or unlimited capacity

•     Two types:
       – Episodic (episodes): Serial memory of events
       – Semantic (“meanings”): Structured memory of facts, concepts, skills

    • Semantic LTM derived from episodic LTM
LTM – Models of Semantic Memory
 •   Semantic memory structure
      – Provides access to information
      – Represents relationships between bits of information
      – Supports inference

 •   Many models, theories, accounts, schemata proposed
 •   Semantic network model (example next slide):
      – Inheritance – child nodes inherit properties of parent nodes
      – Relationships between bits of information explicit
      – Supports inference through inheritance

 •   Other Models (examples follow):
      – Scripts, frames, production rules
LTM - semantic network
         Models of LTM - Frames
•   Information organized in “memorial data structures”
•   Slots in structure instantiated with values for instance of data
•   Type–subtype relationships


                        DOG                      COLLIE

           Fixed                         Fixed
              legs: 4                       breed of: DOG
                                            type: sheepdog
           Default
             diet: carniverous           Default
             sound: bark                   size: 65 cm
           Variable                      Variable
              size:                         colour
              colour
          Models of LTM - Scripts
• Model of stereotypical information required to interpret situation

• Script has elements that can be instantiated with values for context


                                 Script for a visit to the vet

        Entry conditions: dog ill                   Roles:       vet examines
                          vet open                                   diagnoses
                          owner has money                            treats
                                                                 owner brings dog in
        Result:          dog better
                                                                        pays
                         owner poorer
                                                                        takes dog out
                         vet richer
                                                    Scenes:      arriving at reception
        Props:           examination table
                                                                 waiting in room
                         medicine
                                                                 examination
                         instruments
                                                                 paying
                                                    Tracks:      dog needs medicine
                                                                 dog needs operation
Models of LTM - Production Rules
• Representation of procedural knowledge.
• Condition/action rules
   if condition is matched
       then use rule to determine action.




                IF dog is wagging tail,
                   THEN pat dog

                IF dog is growling,
                   THEN run away
    LTM - Storage of information
•   LTM much studied in psychology:

•   Rehearsal
     – information moves from STM to LTM


•   Total time hypothesis
     – amount retained proportional to rehearsal time


•   Distribution of practice effect
     – optimized by spreading learning over time


•   Structure, meaning and familiarity
     – information easier to remember
                  LTM - Forgetting
• Decay
     – information is lost gradually but very slowly

• Interference
     – new information replaces old: retroactive interference
     – old may interfere with new: proactive inhibition

•   So,may not forget at all, memory is selective …!


•   Also, affected by emotion – can subconsciously `choose' to forget
              LTM - Retrieval

• Recall
   – information reproduced from memory can be
     assisted by cues, e.g. categories, imagery


• Recognition
   – information gives knowledge that it has been seen
     before
   – less complex than recall - information is cue
Thinking – Cognitive Processing
•   Humans reason, process information, like, well, humans
     – Recall, any theory is an abstraction and, thus, captures some elements of
       phenomenon, and misses others
     – Question is …
           • Is the account (theory, model) useful in the context and for the purpose for which it is
             used?

•   Basic forms of reasoning, or, forming inferences, are useful in
    understanding broad outlines of human cognition
     – Deduction
     – Induction
     – Abduction

•   Problem solving
     –   Gestalt
     –   Problem Space
     –   Analogy
     –   Skill acquisition
          Induction vs. Deduction
• Induction: make observations first, then draw conclusions
    – organized data survey (structured analysis, visualization) of the
      raw data provide the basis for the interpretation process
    – the interpretation process will produce the knowledge that is
      being sought
    – experience of the individual scientist (the observer) is crucial
    – important: selection of relevant data, collection method, and
      analysis method
    – data mining is an important knowledge discovery strategy here
    – ubiquitious data collection, filtering, classification, and focusing
      is crucial

• Deduction: formulate a hypothesis first, then test the
  hypothesis
    – via experiment and accept/reject
    – data collection more targeted than in induction
    – only limited data mining opportunities

                                                                             Mueller, 2003
                                         Reasoning
•   Deduction:
         –       derive logically necessary conclusion from given premises
                 •      e.g. If it is Friday, then she will go to work - It is Friday, therefore she will go to work
    –     Logical conclusion not necessarily true:
                 e.g.      If it is raining, then the ground is dry - It is raining, therefore the ground is dry


•   Induction:
        – Generalize from cases seen to cases unseen
                 • e.g.      all elephants we have seen have trunks - therefore all elephants have trunks.
    –     Unreliable (but useful):
                 • can only prove false not true


•   Abduction:
    –     Reasoning from event to cause
           e.g.    Sam drives fast when drunk.
                   If I see Sam driving fast, assume drunk.
    –     Unreliable:
             •       can lead to false explanations
          Problem solving - Briefly
•   Process of finding solution to unfamiliar task using knowledge

•   Several theories

•   Gestalt
     –   Problem solving both productive and reproductive
     –   Productive draws on insight and restructuring of problem
     –   Attractive but not enough evidence to explain `insight' etc.
     –   Move away from behaviourism and led towards information processing theories
              Problem solving (cont.)
•   Problem space theory
    – Problem space comprises problem states
    – Problem solving involves generating states using legal operators
    – Heuristics may be employed to select operators
          e.g. means-ends analysis
    – Operates within human information processing system
          e.g. STM limits etc.
    – Largely applied to problem solving in well-defined areas
          e.g. puzzles rather than knowledge intensive areas
          Problem solving (cont.)
•   Analogy
     – analogical mapping:
         • novel problems in new domain?
         • use knowledge of similar problem from similar domain
     – analogical mapping difficult if domains are semantically different

•   Skill acquisition
     – skilled activity characterized by chunking
         • lot of information is chunked to optimize STM
     – conceptual rather than superficial grouping of problems
     – information is structured more effectively
               Individual Differences
•     Long term
          – Sex, physical and intellectual abilities

•     Short term
          – Effect of stress or fatigue

•     Changing
          – Age

•     Dix says ask:
       – Will design decision exclude section of user population?
       – (or, more generally) How does design differentially affect sections of the
         population?

    • Universal Usability
         - Model Human Processor + Attention
            - Similar to Ware (2004) Model
•   Sensory store
     –   Rapid decay “buffer” to hold
         sensory input for later processing

•   Perceptual processor
     –   Recognizes symbols, phonemes
     –   Aided by LTM

•   Cognitive processor
     –   Uses recognized symbols
     –   Makes comparisons and
         decisions
     –   Problem solving
     –   Interacts with LTM and WM

•   Motor processor
     –   Input from cog. proc. for action
     –   Instructs muscles
     –   Feedback
           •   Results of muscles by senses

•   Attention
     –   Allocation of resources
  A Model of Perceptual Processing
                                                          Quick Overview




What we do is design information displays!




            •     An information processing (the dominant paradigm) model
                     –    “Information” is transformed and processed
                              •   Physical light does excite neurons, but at this “level of analysis” consider information
                     –    Gives account to examine aspects important to visualization
                              •   Here, clearly, many neural subsystems and mapping of neural to ip is pragmatic
                     –    In spirit of visualization as evolving discipline, yet to develop its theories, laws, …
            •     Stage 1: Parallel processing to extract low-level properties of the visual science
            •     Stage 2: Pattern perception
            •     Stage 3: Sequential goal-directed processing
Stage 1: Parallel Processing to Extract Low-level
          Properties of Visual Scene
  • (Very first) neurons fire

  • Visual information 1st processed
    by
      – large array of neurons in eye
      – primary visual cortex at back of brain

  • Individual neurons selectively
    tuned to certain kinds of
    information
      – e.g., orientations of edges or color of
        light
      – Evoked potential experiments

  • In each subarea large arrays of
    neurons work in parallel
      – extracting particular features of
        environment (stimulus)
Stage 1: Parallel Processing to Extract Low-level
          Properties of Visual Scene
  • At early stages, parallel
    processing proceeds involuntarily
      – Largely independent of what choose
        to attend to (though not where look)

  • Is rapid,
      – If want people to understand
        information fast, should present in
        way so is easily detected by these
        large, fast computational systems in
        brain

  • Stage 1 processing is:
      – Rapid and parallel
      – Entails extraction of features,
        orientation, color, texture, and
        movement patterns
      – “transitory”, only briefly held in iconic
        store
      – Bottom up, data-driven
            Stage 2: Pattern Perception
• Rapid processes

• Divide visual field into regions and
  simple patterns, e.g.,
    –   Continuous contours
    –   Regions of same color
    –   Regions of same texture
    –   …

• “Active”, but not conscious
  processes

• Specialized for object recognition
    – Visual attention and memory
        • E.g., for recognition must match
           features with memory
    – Task performing will influence what
      perceived
    – Bottom up nature of Stage 1, influenced
      by top down nature of Stage 3
              Stage 2: Pattern Perception
• Specialized for interacting with
  environment
     – E.g., tasks involving eye-hand coordination

•   “Two-visual system hypothesis”
     – One system for locomotion and eye-hand
       coordination
         • The “action system”
     – One system for symbolic object
       manipulation
         • The “what system”

• Characteristics:
     – Slow serial processing
     – Involvement of both working (vs. iconic)
       and long-term memory
     – Both bottom up and top down
         • More emphasis on arbitrary aspects of
            symbols than Stage 1
         • Top-down processing
     – Different pathways for object recognition
       and visually guided motion
Stage 3: Sequential Goal-Directed Processing

• At highest level of perception are
  the objects held in visual memory
  by demands of active attention

• To use an external visualization,
  we construct a sequence of visual
  queries that are answered through
  visual search strategies

• Only a few objects can be held at a
  time

• They are constructed from
  available patterns providing
  answers to the visual queries
Stage 3: Sequential Goal-Directed Processing

• They are constructed from
  available patterns providing
  answers to the visual queries

• E.g., if use a road map to look for a
  route, the visual query will trigger a
  search for connected red contours
  (representing major highways)
  between two visual symbols
  (representing cities)

• Are other subsystems, as well
    – Visual object identification process
      interfaces with the verbal linguistic
      subsystems of the brain so that words
      can be connected to images
    – The perception-for-action subsystem
      interfaces with the motor systems that
      contril muscle movements
      End

• .

				
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