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

Information Revolution 

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)