Transcript Human Factors and Systems
Information Input and Processing
Chap 3
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
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.)
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.)
Displaying Information
Selection of Display Modality •
Visual vs. Auditory Tab 3-1 (end)
Coding of Information
Coding :
original stimulus information converted to a new form and display symbolically
分類 : •
Stimulus dimension: single vs. multiple
•
Utility: identify vs. distinguish
Absolute vs. Relative Judgments •
Absolute: identify, comparison in memory
•
Relative: distinguish (same or different) (cont.)
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,
<
product of single
•
Redundant: not independent,
<
orthogonal (cont.)
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)
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.)
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.)
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)
Attention
Selective Attention Focus Attention Divided Attention Sustained Attention
(cont.)
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.)
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.)
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.)
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) ––
儘可能降低難度
(cont.)
Attention
Sustained Attention •
Vigilance decrement 20-35 min (lab), Exponential Fig 3-4
•
Guideline : p.75-76
降低疲勞
work-rest schedules, task variation environmental factors: optimal (cont.)
Attention
Sustained Attention •
Guideline : p.75-76
Detect signal
難度下降
conspicuity of the signal↑(
明顯)
uncertainty: where & what↓ training: make clear the nature of the signal
呈現
signal
之速率
↓
提高
motivation
強調工作的重要性 給予
artificial signal,
並給予回饋
(end)
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.)
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)
Mental Workload
Purpose: •
Allocating functions and tasks between humans and machines
•
Comparing alternative equipment and task designs
•
Monitoring operators to adapt . . .
•
Choosing operators (cont.)
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.)
Mental Workload
Measurement •
Primary task measures
Time required / Time available (e.g.) SWAN
缺點
:
沒考慮
time-shared, cognitive demands
Workload Index (W/INDEX)
考慮
time-shared; conflict matrix
Primary task workload margin changing a parameter of the task
直到工作表現無法維持在事先設定的效標水準 問題:
task-specific,
無法比較不同的工作
(cont.)
Mental Workload
Measurement •
Secondary task measures: spare capacity
Maintain primary task at some level
測
2ndary task
之表現
Loading task technique devote all necessary resource to 2ndary task
測
primary task
之表現
2ndary task: time-estimation
最有效
(sensitive) attention demand↑→ time estimation (pass of time)↓
缺點:測
primary task or primary task interfered with by the secondary task (cont.)
Mental Workload
Measurement •
Physiological measures (single-resource model) information processing
涉及
CNS
Pupillary responses difficulty↑→ dilation response↑ Fig 3-5
P300 (event-related brain potential, ERP) difficulty↑→ P300↓
缺點:
bulky equipment not isolate the specific stages being loaded by primary task (except P300) (cont.)
Mental Workload
Measurement •
Subjective measures
Unidimensional
Multidimensional: time load mental effort load psychological stress (cont.)
Mental Workload
Evaluation •
Moray (1988)
Behavioral measure: disorganized
Physiological: no practical use
Subjective:↑
Theory:
尚未
Lack of: reliability, consistent correlation between different approaches
•
Dissociate:
不同測量方式得到不同結果
Subjective measure: sensitive to no. of current tasks
Task performance: sensitive to degree of competition for common resources (end)
Human Factors in the Information Revolution
Expert System Natural Language Interface
(end)