Information Input and Processing

1
Information Input and Processing

• Chap 3

2
Information Input and Processing

• Information Theory
• Displaying Information ?
• Coding of Information ?
• Compatibility ?
• A Model of Information Processing Fig 3-2
• Perception
• Memory

• Decision Making
• Attention ?
• Age and Information Processing ?
• Mental Workload ?
• Human Factors in the Information Revolution ?

3
Displaying Information

• Direct vs. Indirect Sensing
• Stimuli for Indirect Sensing Display
• Coded stimuli
• Reproduced stimuli
• Types of Information Presented by Displays
• Selection of Display Modality
• (cont.)

4
Displaying Information

• Types of Information Presented by Displays
• Quantitative Information
• Qualitative Information
• Status Information (ex) on/off, TV channels
• Warning and Signal Information
• Representational Information pictorial, graphic
• Identification Information (ex) traffic lane,
  color-coded pipes
• Alphanumeric and Symbolic Information
• Time-phased Information (ex) Morse code, blinker
  lights
• (cont.)

5
Displaying Information

• Selection of Display Modality
• Visual vs. Auditory
• Tab 3-1
• 
  
  (end)

6
Coding of Information

• Coding
• original stimulus information
• converted to a new form
• and display symbolically
• ??
• Stimulus dimension single vs. multiple
• Utility identify vs. distinguish
• Absolute vs. Relative Judgments
• Absolute identify, comparison in memory
• Relative distinguish (same or different)
• (cont.)

7
Coding of Information

• Making Absolute Judgments along Single
  Dimensions Tab 3-2
• Fewer discrimination than relative
• 7 2 (limitation of human memory)
• Making Absolute Judgments along Multiple
  Dimensions
• Orthogonal independent,lt product of single
• Redundant not independent,lt orthogonal
• (cont.)

8
Coding of Information

• Characteristics of a Good Coding System
• Detectability of Codes
• Discriminability of Codes
• Meaningfulness of Codes
• Standardization of Codes
• Use of Multidimensional Codes
• 
  (end)

9
Compatibility

• Compatibility
• relationship of stimuli and responses
  
• to human expectation
• Types of Compatibility
• Conceptual Compatibility
• Meaningfulness of Codes symbols
• (ex) airport aircraft symbol vs. green square
• Meaningful Abbreviations (ex) commands
  (computer)
• Movement Compatibility
• Spatial Compatibility
• Modality Compatibility
  (cont.)

10
Compatibility

• Types of Compatibility
• Modality Compatibility Fig 3-1
• Input Auditory (speech)
• Visual (display on screen)
• Output Spoken response
• Manual response
• Task Verbal A/S
• Spatial V/M
• (cont.)

11
Compatibility

• Origins of Compatibility Relationships
• Intrinsic in the situation (e.g. isomorphic)
• Culturally acquired
• Identification of Compatibility Relationships
• Obvious (e.g. spatial), but check out the
  generality
• Empirical exp.
• Discussion
• Empirically, not self-evident
• Not universal
• Trade-off
• 
  (end)

12
Attention

• Selective Attention
• Focus Attention
• Divided Attention
• Sustained Attention
• (cont.)

13
Attention

• Selective Attention
• Load stress vs. Speed stress
• Guideline p.71
• Few channels
• Provide information relative importance
• Reduce the overall level of stress
• Preview information
• Training optimal scan patterns
• Close together
• Auditory do not mask one another
• Stimuli separated temporally, self-paced
• (cont.)

14
Attention

• Focus Attention
• Proximity of the sources ??
• Distinct ?
• Guidelines attended channel vs. competing
  channels (p.72)
• Distinct
• Separate (in physical space)
• Reduce of no. of competing channels
• Salient larger, brighter, louder, centrally
  located
• (cont.)

15
Attention

• Divided Attention time-sharing
• Single-Resource Theories
• Multiple-Resource Theories (Wickens, 1984)
• Stages Perceptual and central processing
• vs. Response selection and
  execution
• Input modalities Auditory vs. Visual
• Processing codes Spatial vs. Verbal
• Responses Vocal vs. Manual response
• driving a car while talking on the telephone
• (cont.)

16
Attention

• Divided Attention time-sharing
• Guideline p.74
• Dissimilar stages, input modalities, . . .
• Number of potential sources of information?
• Relative priorities
• Difficulty level ?
• Learning of the manual task?(automatic)
• ???????
• (cont.)

17
Attention

• Sustained Attention
• Vigilance decrement
• 20-35 min (lab), Exponential Fig 3-4
• Guideline p.75-76
• ????
• work-rest schedules, task variation
• environmental factors optimal
• (cont.)

18
Attention

• Sustained Attention
• Guideline p.75-76
• Detect signal ????
• conspicuity of the signal?(??)
• uncertainty where what?
• training make clear the nature of the
  signal
• ?? signal????
• ?? motivation
• ????????
• ?? artificial signal, ?????
• 
  (end)

19
Age and Information Processing

• Changes in Information Processing Capacity
• Slowing performance
• central-cognitive, perceptual-motor
• Working memory?(shift of attention)
• LTM (transferring)?
• Difficulty incompatibility, ambiguous stimuli
• 
  
• (cont.)

20
Age and Information Processing

• Guideline
• Strengthen signals
• Reduce irrelevant details
• Compatibility?
• Time-sharing demand?
• Pace (response - next signal) slow
• Initially learn material allow more time and
  practice
• 
  (end)

21
Mental Workload

• Purpose
• Allocating functions and tasks
• between humans and
  machines
• Comparing alternative equipment and task designs
• Monitoring operators to adapt . . .
• Choosing operators
• (cont.)

22
Mental Workload

• Concept
• amount of resources available (within a
  person)
• - amount of resources demanded (by the task
  situation)
• Measurement
• Criteria
• Sensitivity
• Selectivity
• Interference
• Not interfere with the performance of the
  task
• Reliability
• Acceptability
• (cont.)

23
Mental Workload

• Measurement
• Primary task measures
• Time required / Time available
• (e.g.) SWAN
• ?? ??? time-shared, cognitive demands
• Workload Index (W/INDEX)
• ?? time-shared conflict matrix
• Primary task workload margin
• changing a parameter of the task
• ????????????????????
• ??task-specific, ?????????
• (cont.)

24
Mental Workload

• Measurement
• Secondary task measures spare capacity
• Maintain primary task at some level
• ? 2ndary task ???
• Loading task technique
• devote all necessary resource to 2ndary task
• ? primary task ???
• 2ndary task time-estimation ??? (sensitive)
• attention demand?? time estimation (pass of
  time)?
• ??? primary task or
• primary task interfered with by the
  secondary task
• (cont.)

25
Mental Workload

• Measurement
• Physiological measures
• (single-resource model) information
  processing ?? CNS
• Pupillary responses
• difficulty?? dilation response? Fig 3-5
• P300 (event-related brain potential, ERP)
• difficulty?? P300?
• ??bulky equipment
• not isolate the specific stages
  being loaded by
• primary task (except P300)
• (cont.)

26
Mental Workload

• Measurement
• Subjective measures
• Unidimensional
• Multidimensional time load
• mental effort
  load
• psychological
  stress
• (cont.)

27
Mental Workload

• Evaluation
• Moray (1988)
• Behavioral measure disorganized
• Physiological no practical use
• Subjective?
• Theory??
• Lack of reliability, consistent correlation
  between different approaches
• Dissociate ????????????
• Subjective measure sensitive to no. of current
  tasks
• Task performance
• sensitive to degree of competition for
  common resources
• 
  (end)

28
Human Factors in the Information Revolution

• Expert System
• Natural Language Interface
• 
  (end)