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Human-Computer Interaction

Human-Computer Interaction

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Human-Computer Interaction

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  1. Human-Computer Interaction Chapter 1- An Introduction

  2. Learning outcomes • To define the HCI concept. • To identify what a human can do, perceive, feel and response. • To describe the effect of system interface design to a human or user.

  3. Why Bother? 3

  4. Why Systems Fail? • Inadequate requirements 13% • Lack of user participation 12% • Inadequate resources 11% • Unrealistic expectations 10% • Lack of support at senior level 9% • Changing specification 8% • Lack of planning 8% 4

  5. The Perfect User (every designer ‘s wish)

  6. Why Study HCI? People now expect “easy to use” systems - generally they are not tolerant of poorly designed systems - if a product is hard to use, they will seek other products

  7. What is HCI? Short for human-computer Interaction. A discipline concerned with the study, design, construction and implementation of human-centric interactive computer systems.

  8. HCI Definitions From www.pcmag.com: • The design and implementation of computer systems that people interact with. It includes desktop systems as well as embedded systems in all kinds of devices. • HCI is a large discipline that deals not only with the interface design but with the reasoning for building the functionality into the system in the first place. • It is also concerned with the consequences of using the system over time and its effects on the individual, group and company.

  9. HCI Definitions From ACM SIGCHI (http://old.sigchi.org/cdg/cdg2.html): • Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them. Wikipedia (http://en.wikipedia.org/wiki/Humancomputer_interaction): • HCI involves the study, planning, and design of the interaction between people and computer.

  10. HCI Disciplines Fig 1: HCI disciplines ( source: cs3240hci.wordpress.com)

  11. HCI Disciplines • Cognitive Psychology: Understanding human behavior and mental processes • Neuroscience: Neuroscience enables us to build more accurate and robust models of human cognitive functions. These models may allow us to evaluate usability and predict user behavior. Has potential to close the gap between human and computers. • Ergonomics or Human Factors: User- Equipment Design- Environment • Engineering & Computer Science: faster machines, faster systems, building better interfaces. • Design: Interface layout

  12. HCI Disciplines • Anthropology: User body shape • Sociology: Groupware.Considers introduction of IT in society • Philosophy: Philosophy of technology. Create consistency. • Linguistics: language for commands • Artificial Intelligence: simulating human behaviour

  13. Ergonomics • Physical aspects of interfaces • Study of the physical characteristics of interaction • Ergonomics good at defining standards and guidelines for constraining the way we design certain aspects of systems – to suit the environments/users

  14. Ergonomics - examples • arrangement of controls and displays e.g. controls grouped according to function or frequency of use, or sequentially (mapping) • surrounding environment e.g. seating arrangements adaptable to cope with all sizes of user (movie theatre) • health issues e.g. physical position, environmental conditions (temperature, humidity), lighting, noise • use of colour e.g. use of red for warning, green for okay,awareness of colour-blindness etc.

  15. HCI Interrelationships Fig 2: HCI interrelationship (source: sigchi.org)

  16. Understanding Users Who are they? • Individual user • A group of users working together or a sequence of user in organization each dealing with some part of the task or process. • Limited in their capacity to process information • In order to design, it is important to understand the capabilities and limitations of those we are designing for. 16

  17. The Human • How do you interact with the outside world? • Input-Output channel – Vision, Audio, Touch and Movement • How do you remember things? • Human memory – sensory, short term and long term memory • Example??? • How do you processed and applied information? • Learning, problem solving, reasoning, skill, error, experience, etc. Sensory memories Iconic Echoic Haptic Short term memory Or Working memory Long term memories attention rehearsal Fig 3: A model of the structure of memory (source Dix, et al. 2009)

  18. The Human: Human Memory-Sensory Memory • Sensory Memory • Buffers for stimuli received through senses • iconic memory: visual stimuli • echoic memory: aural stimuli • haptic memory: tactile stimuli/touch • Examples • “sparkler” trail • stereo sound • Continuously overwritten

  19. The Human: Human Memory-LTM 3. Long Term Memory • Repository for all our knowledge • huge or unlimited capacity • Two types • episodic – serial memory of events • semantic – structured memory of fact, concepts, skills • semantic LTM derived from episodic LTM

  20. The Human: Human Memory-LTM • Three main activities related to LTM: • Storage/Remembering of Information • Forgetting • Information Retrieval

  21. Human Factors We look at the human factors that affect how people interact with computers and computer programs: • Physiology - physical make-up, capabilities • Cognition - thinking, reasoning, problem-solving, memory • Perception - how a person perceives what input they get through their senses • Emotions – feelings that affect the human behaviour 21

  22. Human Factors : Physiology • The design of devices are often be affected by the human physiology • Some constraints can be introduced and applied based on the physical built up of the users Examples: • Keyboard keys cannot be smaller than finger size • Smaller machines must use different input facilities • Toilet for toddlers • Specific door widths and heights (home, hospitals) • Anymore? 22

  23. Human Factors : Physiology: Reaction Time Human reaction times: • Audio signal - 150ms • Visual signal - 200ms • Pain - 700ms Examples of use: • Design of video games • Traffic lights • Phone

  24. Human Factors : Physiology: Movement Speed or accuracy of movement are important for interactive systems. Examples: • Mouse - keyboard movement (affects choice of which devices/controls operate which actions of the system) • Time taken to move to a target on screen • Careful arrangement of menu items so that frequent choices are placed first 24

  25. Human Factors : Physiology: Disabilities Designers must design so that disabled users can achieve maximum functionality and usability from computer systems Examples: • Speech input and output systems (useful for blind people and those with severe motor impairment) • Keyboard pressing devices • Eye movement detection devices 25

  26. Human Factors : Cognition • The processes by which we become acquainted with things, how we gain knowledge, familiarity • What goes in our heads when we carry out our everyday activities • Involves understanding, thinking, remembering, reasoning, memorizing, attending, awareness, acquiring skills, creating new ideas. 26

  27. Humanfactors : Cognition • Managing Attention • Process of selecting things to concentrate on at a point in time • Depends on: • Users’ goals • If we know exactly what we want to find out, we try to match this with the information that is available • Information presentation • Greatly influence how easy or difficult it is to digest appropriate pieces of information 27

  28. Human factors : Cognition : User’s Goals • Interface designers need to focus attention on the users’ goals • (If we know exactly what we want to find out, we will try to match this with the information that is available) Try to read the sentences below… Everyday my sister goes to shoocl My two cats lvoe fish I am a KluaLmpr University graduate They are sudtying at UNITEN

  29. Human factors : Cognition : • Information Presentation Interface designers need to focus attention on the right place – plan and structure the information presentation to allow for usability and to suit the task flow : • Structured information VS

  30. Human factors : Cognition : • Information Presentation Interface designers need to focus attention on the right place avoid too much/little information: • Read the following lists and then try to recall as many of the items as possible • 3, 12, 6, 20, 15, 49, 81, 76, 8, 97, 13, 56 • Cat, house, paper, laugh, people, red, yes, number, shadow, broom, rain, plant, lamp, chocolate, radio, one, coin • t, k, y, w, n, o, c, d, e, q, p, r

  31. Human factors : Cognition : • Information presentation • According to George Miller’s (1956) theory, 7 ± 2 chunks of information can be held in short – term memory at any time. • How to apply this in interface design? • Design tips… • Have only 7 options on a menu • Display only 7 icons on a menu bar • Place only 7 items on a pull down menu

  32. Human factors : Perception • How a person perceives what input they get through their senses • Capabilities and limitation of visual processing and understand how we perceive size and depth, brightness and colour

  33. Human Factors : Perception Input from the different senses • Auditory Perception (sound effects) • Haptic (Touch) Perception (game controller) • Visual Perception (pictures/images) We need to understand how the input information is perceived by humans. 33

  34. Human factors - Perception 34

  35. Human factors - Perception

  36. The Human-Emotion • Emotion involves both cognitive and physical responses to stimuli • James-Lange: emotion is our interpretation of a physiological response to a stimuli

  37. The Human-Emotion • The biological response to physical stimuli is called affect Affect influences how we respond to situations • positive  creative problem solving • negative  narrow thinking “Negative affect can make it harder to do even easy tasks; positive affect can make it easier to do difficult tasks” (Donald Norman)

  38. The Human-Emotion • Implications for interface design • stress will increase the difficulty of problem solving • relaxed users will be more forgiving of shortcomings in design • aesthetically pleasing and rewarding interfaces will increase positive affect

  39. The Human- Errors & mental model Types of error • slips • right intention, but failed to do it right • causes: poor physical skill, inattention etc. • change to aspect of skilled behaviour can cause slip • mistakes • wrong intention • cause: incorrect understanding humans create mental models to explain behaviour. if wrong (different from actual system) errors can occur

  40. The Computer • A computer system is made up of various elements • Each of these elements affects the interaction • input devices – text entry and pointing • output devices – screen (small & large), digital paper • virtual reality – special interaction and display devices • physical interaction – e.g. sound, haptic, bio-sensing • paper – as output (print) and input (scan) • memory – RAM & permanent media, capacity & access • processing – speed of processing, networks

  41. The Computer • When we interact with computers or other electronic devices, what are we trying to achieve?

  42. The Interaction • Interaction -> in this context, is a process of information transfer, from the user to a computer and from a computer to the user input output

  43. Understanding interaction • User centric design is the formula for usability • The key to User-centered Design is to understand Interaction • We need to understand : • What Interaction is • What are the elements involved

  44. Interaction Model • The most influential model of interaction is • Donald Norman’s (http://www.jnd.org/) : • Execution-Evaluation cycle • Norman divides interaction into : • Execution • User activities aimed at making the system do something • Evaluation • Evaluating whether the system did actually do what the user wanted 44

  45. Understanding Interaction • Execution • If User cannot make system do what they want • e.g. cannot understand how to do it, unclear icons, unclear indication etc. • Will result in the Gulf of Execution 45

  46. Understanding interaction • Evaluation • If user cannot see what happened to system • e.g. if system has done what they want but no feedback is given to the users etc. • Will result in the Gulf of Evaluation • i.e. difference between the representation of the system state/result and the expectations of the user • E.g ATM • Good Design aims to reduce these gulfs 46

  47. The Interaction Model Donald Norman’s model • Seven stages • user establishes the goal • formulates intention • specifies actions at interface • executes action • perceives system state • interprets system state • evaluates system state with respect to goal • Norman’s model concentrates on user’s view of the interface

  48. goal execution evaluation system The Interaction Model: execution/evaluation loop • user establishes the goal • formulates intention • specifies actions at interface • executes action • perceives system state • interprets system state • evaluates system state with respect to goal

  49. goal execution evaluation system The Interaction Model: execution/evaluation loop • user establishes the goal • formulates intention • specifies actions at interface • executes action • perceives system state • interprets system state • evaluates system state with respect to goal

  50. goal execution evaluation system The Interaction Model: execution/evaluation loop • user establishes the goal • formulates intention • specifies actions at interface • executes action • perceives system state • interprets system state • evaluates system state with respect to goal