Human Role in Larger System, Human Capabilities, Project | CS 6750, Study Guides, Projects, Research of Computer Science

Download Human Role in Larger System, Human Capabilities, Project | CS 6750 and more Study Guides, Projects, Research Computer Science in PDF only on Docsity! 1 Human Abilities John Stasko Spring 2007 This material has been developed by Georgia Tech HCI faculty, and continues to evolve. Contributors include Gregory Abowd, Al Badre, Jim Foley, Elizabeth Mynatt, Jeff Pierce, Colin Potts, Chris Shaw, John Stasko, and Bruce Walker. Permission is granted to use with acknowledgement for non-profit purposes. Last revision: January 2007. 26750-Spr ‘07 Agenda • Human role in larger system • Human capabilities – Senses – Information processing – Motor systems • Project 2 36750-Spr ‘07 Human Role • How is human viewed in HCI – What is human role? • Different roles engender different frameworks 46750-Spr ‘07 Human Roles • Human considered to be a… • 1. Sensory processor – Experimental psych, sensory psych • e.g. Model-Human Processor (Card, Moran & Newell) • 2. Interpreter/Predictor – Cognitive psych, AI • e.g. Distributed cognition (Hutchins) • 3. Actor in environment – Activity theory, ethnography, ecol psych • e.g. Situated action (Suchman) • e.g. Activity theory (Vygotsky, Nardi) 5 96750-Spr ‘07 Human Capabilities • Why do we care? (better design!) • Want to improve user performance • Knowing the user informs the design – Senses – Information processing systems – Physical responding Time and effort expended to complete tasks 106750-Spr ‘07 Overview I. Senses A. Vision B. Hearing C. Touch D. Smell? III. Motor systemII. Information processing A. Perceptual B. Cognitive 1. Memory a. Short term b. Medium term c. Long term 2. Processes a. Selective attention b. Learning c. Problem solving d. Language C. Motor system 6 116750-Spr ‘07 I. Senses • Sight, hearing, touch important for current HCI – smell, taste ??? • Abilities and limitations affect design 126750-Spr ‘07 Key concepts for Senses Just noticeable difference (jnd) How much of a change in stimulus is needed before can be sensed Tends to be logarithmic - Weber’s Law Magnitude of physical stimulus versus perceived magnitude (Doubling number of photons does not double perceived intensity) 7 136750-Spr ‘07 Vision • Visual System – Eye – Retina – Neural pathway • ~ 80% of brain’s operation 146750-Spr ‘07 Visual Abilities • Sensitivity – luminance: 10-6~107 mL • Acuity – detection, alignment, recognition (visual angle) – retinal position: fovea has best acuity • Movement – tracking, reading, vibrations • Note: Vision decreases with age • Implications (??) – Font size & location depends on task – Much done by context & grouping 10 196750-Spr ‘07 Color Surround Effect • Our perception of a color is affected by the surrounding color 206750-Spr ‘07 Color Surround 11 216750-Spr ‘07 Hearing • Capabilities (best-case scenario) – pitch - frequency (20 - 20,000 Hz) – loudness - amplitude (30 - 100dB) – location (5° source & stream separation) – timbre - type of sound (lots of instruments) • Often take for granted how good it is (disk whirring) • Implications (??) 226750-Spr ‘07 Touch • Three main sensations handled by different types of receptors: – Pressure (normal) – Intense pressure (heat/pain) – Temperature (hot/cold) • Sensitivity, Dexterity, Flexibility, Speed • Where important? – Mouse, Other I/O, VR, surgery 12 236750-Spr ‘07 Smell Joseph Kaye, “Making scents: aromatic output for HCI” ACM Interactions Volume 10, Number 1 (2004), Pages 48-61 Solenoid-controlled scent bottles 246750-Spr ‘07 II. Information Processing • How do people think? 15 296750-Spr ‘07 Memory • Four “types” – Perceptual “buffers” • Brief impressions – Short-term memory • Conscious thought, calculations – Intermediate • Storing intermediate results, future plans – Long-term • Permanent, remember everything ever happened to us Chess 306750-Spr ‘07 Perceptual Store • Visual and auditory impressions – visuospatial sketchpad, phonological loop • Very brief, but veridical representation of what was perceived – Details decay quickly (~.5 sec) – Rehearsal prevents decay – Another task prevents rehearsal 16 316750-Spr ‘07 Short-term memory • Use “chunks”: 4-5 units (not 7±2) • Display format should match memory system used to perform task • New info can interfere with old info • Exercises – My name is John, I like … – Numbers 326750-Spr ‘07 Long-term Memory • Seemingly permanent & unlimited • Access is harder, slower – -> Activity helps (we have a cache) File system full 17 336750-Spr ‘07 LT Memory Structure • Episodic memory – Events & experiences in serial form • Helps us recall what occurred • Semantic memory – Structured record of facts, concepts & skills • One theory says it’s like a network • Another uses frames & scripts (like record structs) 346750-Spr ‘07 Memory Characteristics • Things move from STM to LTM by rehearsal & practice and by use in context • We “forget” things due to decay and interference Unclear if we ever really forget something Lack of use Similar gets in way of old Exercise 20 396750-Spr ‘07 Learning • Facilitated – By analogy – By structure & organization – If presented in incremental units – Repetition • Hindered by – Previous knowledge (move from Mac to Windows) • ---> Use user’s previous knowledge in interface 406750-Spr ‘07 Observations • Users focus on getting job done, not learning to effectively use system • Users apply analogy even when it doesn’t apply 21 416750-Spr ‘07 3. Problem Solving • Storage in LTM, then application • Reasoning – Deductive- – Inductive- – Abductive- If A, then B Generalizing from previous cases to learn about new ones Reasons from a fact to the action or state that caused it 426750-Spr ‘07 Reasoning about a UI • Deductive: If I want to delete something, I must first select it. Facilitate by animating the disappearance of selected object • Inductive: I could make text bold by selecting it and then using the Bold command. Maybe I could italicize in the same way. Facilitate by putting bold and italic commands together • Abductive:Timeout on the web browser if not connected. Facilitate by telling the user why the timeout occurred 22 436750-Spr ‘07 Observations • People are more heuristic than algorithmic – Try a few quick shots rather than plan • Resources simply not available • People often choose suboptimal strategies for low priority problems • People learn better strategies with practice 446750-Spr ‘07 Implications • Allow flexible shortcuts – Forcing plans will bore user • Allow multiple ways of doing • Provide active rather than passive help – Recognize dead ends and inefficient methods 25 496750-Spr ‘07 Work Station Ergonomics – to Facilitate I/O 506750-Spr ‘07 Recap I. Senses A. Sight B. Sound C. Touch D. Smell? II. Information processing A. Perceptual B. Cognitive 1. Memory a. Short term b. Medium term c. Long term 2. Processes a. Selective attention b. Learning c. Problem solving d. Language C. Motor system III. Motor 26 516750-Spr ‘07 Project • Part 0 – Topics • Part 1 - Understanding the problem – Work with client – Understand users, their tasks, environment – Informal evaluation of current interface, if it exists – Establish objectives, requirements for design – Implications of what you learn! – No design! No assumptions! – Read project description • Make a nice top co-web page 526750-Spr ‘07 Upcoming • Predictive Evaluation • Understanding Users • Task Analysis & Requirements Gathering