Fundamentals of Human Computer Interaction PDF

FUNDAMENTALS OF HUMAN COMPUTER INTERACTION (PART 3: MENTAL MODELS) ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1  CONTENTS PART 3: MENTAL MODELS ❑ INTRODUCTION TO MENTAL MODELS ❑ CATEGORIES OF HUMAN ERRS ❑ MAKING MENTAL MODELS ❑ DON NORMANS’ DESIGN...

FUNDAMENTALS OF HUMAN COMPUTER INTERACTION (PART 3: MENTAL MODELS) ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1  CONTENTS PART 3: MENTAL MODELS ❑ INTRODUCTION TO MENTAL MODELS ❑ CATEGORIES OF HUMAN ERRS ❑ MAKING MENTAL MODELS ❑ DON NORMANS’ DESIGN PRINCIPLES ❑ Affordance ❑ Mapping ❑ Feedback ❑ constraints ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 2  INTRODUCTION Mental Model Mental Model ❑ Mental Model ❑ based on belief, not facts ❑ often partial, unstable, internally inconsistent, unscientific ❑ users develop an understanding of a system through learning and application (using it) – perception and linguistic comprehension yield mental models ❑ Knowledge is often described as a mental model ❑ how to use the system (what to do next) Individual users each have their own mental model ❑ what to do with unfamiliar systems or unexpected situations (how the system works) ❑ Thinking and reasoning are internal manipulations of mental models ❑ E.g.: People make inferences using mental models of how to carry out tasks ❑ Errors can occur if mental model of a system differs from the actual operations ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 3  ERRORS AND MENTAL MODELS Example We use ❑ Mental Mental Model to: Model ❑ Make assumption of how things work ❑ Our understanding unconsciously influence our behaviour and decision making ❑ We apply logical rules of universal instantiation and translate those information to predict outcome ❑ For example: ❑ Bicycle handlebars indicate movement ❑ Pedals and seat show affordance telling us how the bicycle could be used ❑ However, the handlebars and seats face each other → it won’t work! ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 4  HUMAN ERRS Slips vs Mistakes vs Lapse ❑ Slips happens due to ❑ Mistakes happens due to ❑ Lapse happens due to error changes in the context of incorrect understanding of in recall of action or user skilled behaviour caused by situation of system omit required action poor physical skills, ❑ Errors in choosing an ❑ Forget to indicate at a road inattention objective or specifying a junction ❑ Errors in carrying out an method ❑ Medical instruments left in intended method for reaching ❑ Have wrong intention when patient after surgery an objective using a tool ❑ Miss crucial steps in a safety ❑ Right intention, but failed to ❑ Why? Humans create mental (critical procedure) do it right models to explain behaviour ❑ Action is not what was – if wrong (different from intended actual system) then errors can occur ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 5  HUMAN ERRS Violations ❑ Routine Violations ❑ Situational Violations ❑ Exceptional Violations ❑ Non-compliance is a norm ❑ Non-compliance dictated by ❑ Person attempts to solve where general consensus that situation / specific factors problem in highly unusual rules no longer apply (such as time pressure, circumstances (often if ❑ Happens due to lack of workload, unsuitable tools & something has gone wrong) meaningful enforcement equipment, weather, etc.) ❑ Takes a calculated risk in ❑ E.g.: Many motorists drive ❑ Non-compliance may be the breaking rules more than 110km/h on the only solution to an impossible ❑ E.g.: Speed excessively with a highway task flat tire to ensure not late for ❑ E.g.: Van driver has no option meeting but to speed to complete day’s deliveries ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 6  We Rely on Mental Model ✓ How do I think? ✓ How do I understand some domain of knowledge? ✓ How do I make sensible decisions? ✓ What triggers me to think? ✓ How do I reason? ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 7  MAKING MENTAL MODELS Uses – Techniques - Constructions resulting into through USES TECHNIQUES CONSTRUCTIONS ❑ Each model represents a ❑ The use of metaphors ❑ The mind constructs Mental possibility ❑ Novice and expert studies Models as a result of: ❑ Model are iconic (unique) ❑ Comparing user ❑ Perception – becoming aware as far as possible performance on a system of something through senses ❑ Imagination – forming new ❑ It represents what is true ❑ Field observation ideas, images or concepts of ❑ Reliance on counter ❑ Comparison across culture external objects examples and historical ❑ Knowledge – perceptual experience and reasoning ❑ Content analysis ❑ Comprehension of discourse – ❑ Card sorting the action of understanding through written / spoken communication ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 8  DON NORMAN & MENTAL MODELS Norman’s Principles of Design INTERACTIVITY LEARNING & USING To CONSTRUCT needs ❑ In interacting with the ❑ Users understand system ❑ The target system environment, with others through learning and ❑ Conceptual model of target and with technology using system artefacts, people form ❑ Users need to figure what ❑ System image internal, mental models of to do next when using ❑ User’s mental model of the themselves and of the system target system things which they are ❑ Users need to figure out ❑ Scientist / developer interacting what to do with conceptualization of the ❑ This models provide unfamiliar systems / mental model predictive and situations A good Mental Model enables: explanatory power for ✓ Easy learning to use a system understanding interaction ✓ Better performance ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 9  DON NORMAN & MENTAL MODELS Norman’s Principles of Design Controls on simple car radio VISIBILITY #controls equals to #functions Controls are labelled and grouped ❑ Make the relevant parts visible together ❑ By looking the user should be able to tell the state of the device and the alternatives for action (affordances) How deep is your mental ❑ When functionality is hidden, problems in use occur modal of a VCR remote control? ❑ Occurs when number of functions is greater than number of controls ❑ When functionalities (capabilities) are visible, it does not require memory of how to use ❑ Remind people how to use something “Make relevant parts visible. Make what has to be done obvious” ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 10  DON NORMAN & MENTAL MODELS Norman’s Principles of Design CONCEPTUAL MODEL ❑ Refers to our conception of how something works ❑ People build their own systems of how things work. E.g.: car (conceptual model of how cars work) ❑ Mental “picture” of a device ❑ A conceptual model allows user to simulate the operation of the device ❑ A good conceptual model allows us to predict the effects of our actions ❑ Without a good model, we operate blindly ❑ Simply follow rules without understanding a reason ❑ No understanding of cause or effect ❑ Provide a good conceptual model that can minimize the gulf of interpretation and gulf of execution ❑ Affordance We know the bicycle won’t work! ❑ Mapping Clues from affordance, constraints and mappings Thus, designer can help user foster an appropriate conceptual ❑ Feedback model through the appearance, instructions, behaviour, etc. ❑ constraints ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 11 DON NORMAN & MENTAL MODELS Norman’s Principles of Design CONCEPTUAL MODEL & USER UNDERSTANDING Design Model User’s Model How designer thinks system should Design Model work DESIGNER USER System Image How system works User Model How user thinks system works SYSTEM System Image: the Ideally all should be the same only way to Poor system image = poor understanding communicate the System Image designer’s model! ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 12  DON NORMAN & MENTAL MODELS Norman’s Principles of Design ❑ The perceived properties of the object that suggest how one AFFORDANCE could use it ❑ A good visual affordance ❑ Affordances are an object’s properties that show the possible - No picture, label or instruction actions users can take with it is required ❑ Visual Affordances ❑ Affordances provide ❑ Perceived an actual properties (appearance) of an object “strong clues” to the operation that determine how it could be used of things ❑ For examples: ❑ Affordances should make it Button that appear clickable or push-able obvious what to do Well-designed widgets (resize Door handle for pushing or pulling ❑ Complex things may need handles / crop handles) have Scroll arrow for clicking or dragging explanation clear affordances chairs are for sitting knobs are for turning slots are for inserting buttons are for switch for computer for… table for placing things on handles are for turning pressing toggling ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 13  DON NORMAN & MENTAL MODELS Norman’s Principles of Design ❑ Natural mapping: no explanations needed MAPPING Available actions ❑ Mapping means “relationship between two things” ❑ Natural mappings lead to an immediate understanding User intentions Perceived system state ❑ It is possible to determine the relationships between: ❑ Actions and results Actual system state ❑ Controls and effects ❑ The system state and what is visible ❑ For example: colour, size, shape mapping ❑ User intentions to available actions ❑ Is there a natural mapping between what users want to do and what appears possible? Coins and banknotes ❑ Do users stare at technology for sometimes before they take action? ❑ Or do they immediately know what to do? ❑ Simplicity can help - Things don’t have to be so hard to use Left: Poor mapping (dial and burner arrangement not at all clear) Right: Good mapping ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 14  DON NORMAN & MENTAL MODELS Norman’s Principles of Design FEEDBACK ❑ Sending information back to the user about what has been done ❑ Includes sound, highlighting, animation, change in physical state and combinations of these ❑ For examples: ❑ Home security system How do you know which burner is on? On a gas stove, you see flames! ❑ When armed, system beeps, message is displayed “system armed”, and light glows red ❑ When disarmed, light glows green, message reads “system iPod video shows which song is playing and how many ready” time of the song has been played ❑ When screen button clicked on, provides sound or red highlight feedback “ccclichhk” ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 15  DON NORMAN & MENTAL MODELS Norman’s Principles of Design ❑ CONSTRAINTS Designers are not representative of the user population for whom they are designing ❑ Don’t expect users to think or act like you ❑ Restricting the possible actions that can be performed (limit the ways in ❑ Users have different needs and capabilities which designers may which something can be used) missed ❑ Helps prevent user from selecting incorrect options ❑ Users understand their work environment better and designers ❑ Individual differences: cannot simply assume ❑ People vary in both physical attributes and mental / cognitive ❑ However, designer / developer has technical understanding of how attributes system is implemented or works but users may not ❑ How individuals differ? ❑ Also, designers have knowledge on interaction style and more IT savvy which user may not be ❑ Personality ❑ Physical capability ❑ Anxiety ❑ Long term ❑ Physical and intellectual abilities ❑ Short term ❑ Effect of stress or fatigue Leonid Stadnyk, a Ukrainian man who claimed to have stood at 2.57 m, had difficulty in using ❑ Changing keys on a cell phone ❑ Age ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 16  CONCLUSION Take Heed ✓ Many of the human errors and machine misuse are design errors ✓ Designers help things work with good conceptual model ✓ Things don’t have to be so hard to use ✓ Even the best-trained and best-motivated designers can go wrong when they listen to their instincts instead of testing their ideas on users ✓ Designers decide the target users but they are not the users ✓ Users are different individually – personality, physical capability, intellectual abilities, etc. ✓ Users have lousy memory – don’t see everything, get tired and bored, lack attention, easily distracted ✓ Machines are ever evolving – larger memories, faster, new I/O technology embedded, ubiquitous and multi-use ICT551 HUMAN COMPUTER INTERACTION | TOPIC 1 17 The End of Topic 1… ICT551 HUMAN COMPUTER INTERACTION | TOPIC 2