Information Input and Processing Chap 3 Information Input

Information Input and Processing Chap 3

Information Input and Processing u Information Theory u Decision Making u Displaying Information u Attention u Coding of Information u u Compatibility u A Model of Information Processing Fig 3 -2 u Perception u Memory u u Age and Information Processing Mental Workload Human Factors in the Information Revolution

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

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

Coding of Information u Coding: original stimulus information converted to a new form and display symbolically u u 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 u u 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 u Characteristics of a Good Coding System • Detectability of Codes • Discriminability of Codes • Meaningfulness of Codes • Standardization of Codes • Use of Multidimensional Codes (end)

Compatibility u u 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 u Meaningful Abbreviations: (ex) commands (computer) u • • • Movement Compatibility Spatial Compatibility Modality Compatibility (cont. )

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

Compatibility u u u 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 u Selective Attention u Focus Attention u Divided Attention u Sustained Attention (cont. )

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

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

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

Attention u Divided Attention: time-sharing • Guideline: p. 74 u Dissimilar: stages, input modalities, . . . u Number of potential sources of information↓ u Relative priorities u Difficulty level ↓ u Learning of the manual task↑(automatic) –– 儘可能降低難度 (cont. )

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

Attention u Sustained Attention • Guideline: p. 75 -76 u 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↓ u 提高 motivation 強調 作的重要性 給予 artificial signal, 並給予回饋 (end)

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

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

Mental Workload u Measurement • Primary task measures u u u 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 作表現無法維持在事先設定的效標水準 u 問題：task-specific, 無法比較不同的 作 (cont. )

Mental Workload u Measurement • Secondary task measures: spare capacity u Maintain primary task at some level 測 2 ndary task 之表現 Loading task technique devote all necessary resource to 2 ndary task 測 primary task 之表現 u 2 ndary task: time-estimation 最有效 (sensitive) attention demand↑→ time estimation (pass of time)↓ u u 缺點：測 primary task or primary task interfered with by the secondary task (cont. )

Mental Workload u Measurement • Physiological measures (single-resource model) information processing 涉及 CNS u u u Pupillary responses difficulty↑→ dilation response↑ Fig 3 -5 P 300 (event-related brain potential, ERP) difficulty↑→ P 300↓ 缺點：bulky equipment not isolate the specific stages being loaded by primary task (except P 300) (cont. )

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

Mental Workload u Evaluation • Moray (1988) Behavioral measure: disorganized u Physiological: no practical use u Subjective: ↑ u Theory: 尚未 u u 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 u Task performance: sensitive to degree of competition for common resources u (end)

Human Factors in the Information Revolution u Expert System u Natural Language Interface (end)