Introduction

Human-Computer Interaction SENG 306

the course (description)

Description of the Course Understanding the concepts of an effective interaction with the computer Aim of the Course 1. 2. 3. 4. 5. 6. Defining the basic concepts of human computer interaction. Understanding the cognitive abilities of human. Understanding the technical capabilities of the computer and the interaction methods. Constructing the concepts for a better interaction using the terms mentioned above. Creating interfaces. Analysing the existing models and methods.

Gains In this course it is intended to understand the basic principles of human computer interaction and construct effective and efficient interfaces intended for the cognitive abilities of human. Students participating this course will learn the cognitive facilities of human and how to use these abilities for a better interaction with the computer. Educational Methodology Implemented In This Course Basic concepts of human computer interaction; Cognitive abilities of human; Characteristics of a computer and how to answer the rich cognitive channels of human with these characteristics; Designing an effective interaction; Critical approach to existing models and theories; Socio-organizational and culturel issues and aspects

the course (resources)

Text Book Human-Computer Interaction, 3rd Edition; Alan Dix, Janet Finlay, Gregory D. Abowd, Russell Beale, Prentice Hall, 2004, ISBN: 0-13-046109-1

Reading List
Sources announced during the course and course notes Suggested Additional Material Dov Teeni, Jane Carey, Phing Zhang, Human Computer Interaction: Developing Effective Organizational Information Systems, Wiley & Sons, 2006, ISBN: 978-0471677659 Douglas Whitman, Cognition, 1st Ed. ; Wiley & Sons, 2010, ISBN: 978-0471715665 Margaret W. Matlin, Cognitive Psychology, International Student Version, 7th Ed., Wiley & Sons, ISBN: 978-0470409473

the course (outline)

Course Outline 1.Week: Foundations of human computer interaction; Human and its cognitive characteristics 2.Week: Human and its cognitive characteristics (cont.); Characteristics of computers and interaction 3.Week: Characteristics of computers and interaction (cont.); Paradigms

4.Week: Interaction design basics

5.Week: Human computer interaction in software process 6.Week: MidTerm 7.Week: Implementation support and evaluation techniques 8.Week: Universal design 9.Week: User support 10.Week: Cognitive models 11.Week: Socio-organizational issues and requirements 12.Week: Communication and collaboration models 13.Week: Task analysis; Dialog notations and design 14.Week: System models and rich interaction 15.Week: FINAL EXAM

the course (evaluation)

Evaluation Procedures and Criteria
Number of Weekly Exam Monthly Exam Midterm Homework Term Paper Project Presentation Implementation/Lab. Studies None None 1 None None 1 None None 50 10 (Total) Percentage

Others
Final Exam

None
1 40

assessment

Final Grades will be determined according to the Yaar University Associate Degree, Bachelor Degree and Graduate Degree Education and Examination Regulation

Responsibilities of the Students

Obtaining the text book(s) Coming to the course with a good preparation Following the rules set by the responsibles for the course and the implementation/lab. studies Participating actively HONESTY !!!

Plagiarism

Plagiarism will not be tolerated Projects without references: a penalty of 20% Submitting your own work that has been earlier submitted to satisfy the requirements of another course is (self)-plagiarism (also called double dipping) Copying a journal article or a section of a book and submitting it as your own is plagiarism

Plagiarism

Using significant ideas from someone else, but putting them in to your own words and not acknowledging the source of the ideas is plagiarism Copying an essay, code, work etc. from another student and submitting it as your own is plagiarism And PLAGIARISM is THEFT So dont steal (Nobody likes thieves)

chapter 0

introduction

some definitions
User: an individual user, a group of users, or a sequence of users in an organization, each dealing with some part of the task or process Computer: any technology ranging from desktop computer to large scale computer systems, or embedded systems and process control systems Interaction: communication between user and computer (direct or indirect)

Human-Computer Interaction (HCI)?

Multi-disciplinary subject, should ideally include knowledge from psychology, cognitive science, ergonomics, sociology, computer science, etc. A successful product should be:
useful: accomplish what is required usable: do it easily and naturally, without danger of error, etc. used: make people want to use it, be attractive, engaging, fun, etc.

HCI (definition and importance)

HCI: is the set of processes and resources that users employ to interact with computers Building the human computer interface requires 50-70% of systems development effort To users, the interface is the system A study by Nielsen (2003) indicates that if corporations spend 10% of their development budget on usability, they can improve usability by 135%

The Importance of HCI

Another study found that 51% of major websites violate the most basic design guidelines. These studies and more demonstrate that there is a need for a more systematic treatment of HCI in the development process and more HCI experts are needed.

When HCI fails, the system fails

The Importance of HCI

Organizations of HCI are growing rapidly There are more new journals dedicated to HCI than any other information systems sub-discipline

Interdisciplinary nature and scope of HCI

Human Factors Software Engineering Computer Engineering Cognitive Science

Physical capabilities Art Theatre Aesthetics Drama Dialog Communications Social Psychology Sociology

Methodology

Hardware Cognitive Psychology Affective Computing

Intelligent interfaces User modeling Collaboration Cost-benefit

Organizational Psychology Management Philosophy

Why study HCI?

To help make IS users more productive, To help IS professionals develop more usable and successful systems, To enhance organizational effectiveness, To provide researchers with cohesive and cumulative knowledge for theory building, and, To apply this theoretical knowledge to enhance real information systems.

chapter 1

the human

the human
Information i/o
visual, auditory, haptic, movement

Information stored in memory

sensory, short-term, long-term

Information processed and applied

reasoning, problem solving, skill, error

Emotion influences human capabilities Each person is different

Model Human Processor

1983: Card, Moran, Newell Simplified view of human processing involved in interacting with computer systems Three subsystems (sometimes also known as processors):
Perceptual system Motor system Cognitive system

Model Human Processor

1983: Card, Moran, Newell Simplified view of human processing involved in interacting with computer systems Three subsystems (sometimes also known as processors):
Perceptual system Motor system Cognitive system

Model Human Processor

(Three) Two types of memory:
(Sensory memories: Iconic, Echoic, Haptic) Working memory (also known as short-term memory, STM) Long-term memory (LTM)

Following figure presents a simplified model of Human Information Processing which includes processors and memories that interact in order to process information.

A Simplified View of Human Information Processing (HIP)

Attention

Verbal Memory Spatial data Processors

Working Memory

Long term Memory

Perception

Cognition

Motor

A simplified model of Human Information Processing (HIP), including memories and processor.

A Simplified View of Human Information Processing (HIP)

Performance: the speed and accuracy of the information-processing task. Automatic behavior: behavior characterized by cognitive processes that are fast and cognitively undemanding. Controlled behavior: behavior characterized by cognitive processes that are relatively slow and cognitively demanding.

A Simplified View of Human Information Processing (HIP)

Processing of Images: processing characterized as spatial, graphic, and holistic. Processing of verbal information: processing characterized as sequential, linguistic, and procedural. Memory Aids
Heuristics: rules of thumb that depend heavily on the content and context of the task. Metaphor: a cognitive process in which an experience is related to an already familiar concept. Mental model: a representation of the conceptual structure of a device or a system.

Major Senses
Sight Hearing Touch Taste Smell First three important for HCI

People remember
10% of what they read

20% of what they hear 30% of what they see

50% of what they hear and see 80% of what they hear, see and say 90% of what they hear, see, say and touch

Vision
Two stages in vision
physical reception of stimulus processing and interpretation of stimulus

The Eye - physical reception

mechanism for receiving light and transforming it into electrical energy light reflects from objects images are focused upside-down on retina retina contains rods for low light vision and cones for colour vision ganglion cells (brain!) detect pattern and movement

The Eye (Anatomy)

The Eye (Anatomy)

1:posterior chamber 2:ora serrata 3:ciliary muscle 4:ciliary zonules 5:canal of Schlemm 6:pupil 7:anterior chamber 8:cornea 9:iris 10:lens cortex 11:lens nucleus 12:ciliary process 13:conjunctiva 14:inferior oblique muscle 15:inferior rectus muscle 16:medial rectus muscle 17:retinal arteries and veins 18:optic disc 19:dura mater 20:central retinal artery 21:central retinal vein 22:optic nerve 23:vorticose vein 24:bulbar sheath 25:macula 26:fovea 27:sclera 28:choroid 29:superior rectus muscle 30:retina

Interpreting the signal

Size and depth
visual angle indicates how much of view object occupies
(relates to size and distance from eye)

visual acuity is ability to perceive detail

(limited)

familiar objects perceived as constant size

(in spite of changes in visual angle when far away)

cues like overlapping help perception of size and depth

Interpreting the signal (cont)

Brightness
subjective reaction to levels of light affected by luminance of object measured by just noticeable difference visual acuity increases with luminance as does flicker made up of hue, intensity, saturation cones sensitive to colour wavelengths blue acuity is lowest 8% males and 1% females colour blind

Colour

Interpreting the signal (cont)

The visual system compensates for:
movement changes in luminance.

Context is used to resolve ambiguity Optical illusions sometimes occur due to over compensation

Optical Illusions

the Ponzo illusion

the Muller Lyer illusion

Reading
Several stages:
visual pattern perceived decoded using internal representation of language interpreted using knowledge of syntax, semantics, pragmatics

Reading involves saccades and fixations Perception occurs during fixations Word shape is important to recognition Negative contrast improves reading from computer screen

Hearing
Provides information about environment:
distances, directions, objects etc.

Physical apparatus:
outer ear protects inner and amplifies sound middle ear transmits sound waves as inner ear
vibrations to inner ear chemical transmitters are released and cause impulses in auditory nerve

Sound
pitch loudness timbre sound frequency amplitude type or quality

Hearing (cont)
Humans can hear frequencies from 20Hz to 15kHz
less accurate distinguishing high frequencies than low.

Auditory system filters sounds

can attend to sounds over background noise. for example, the cocktail party phenomenon.

Touch
Provides important feedback about environment.
May be key sense for someone who is visually impaired. Stimulus received via receptors in the skin:
thermoreceptors nociceptors mechanoreceptors heat and cold pain pressure
(some instant, some continuous)

Some areas more sensitive than others e.g. fingers.

Kinethesis - awareness of body position

affects comfort and performance.

Movement
Time taken to respond to stimulus: reaction time + movement time
Movement time dependent on age, fitness etc.

Reaction time - dependent on stimulus type:

visual ~ 200 ms auditory ~ 150 ms pain ~ 700 ms

Increasing reaction time decreases accuracy in the unskilled operator but not in the skilled operator.

Movement (cont)
Fitts' Law describes the time taken to hit a screen target:
Mt = a + b log2(D/S + 1)
where: a and b are empirically determined constants Mt is movement time D is Distance S is Size of target

targets as large as possible distances as small as possible

Memory
There are three types of memory function:
Sensory memories Short-term memory or working memory

Long-term memory

Selection of stimuli governed by level of arousal.

sensory memory
Buffers for stimuli received through senses
iconic memory: visual stimuli echoic memory: aural stimuli haptic memory: tactile stimuli

Examples
sparkler trail stereo sound

Continuously overwritten

Short-term memory (STM)

Scratch-pad for temporary recall
rapid access ~ 70ms

rapid decay ~ 200ms

limited capacity - 7 2 chunks

Examples
212348278493202

0121 414 2626

HEC ATR ANU PTH ETR EET

Model of STM (Baddeley)

Articulatory Loop

Visuospatial scratch-pad

Central Executive

Auditory imaging system

Long-term memory (LTM)

Repository for all our knowledge
slow access ~ 1/10 second slow decay, if any huge or unlimited capacity

Two types
episodic serial memory of events semantic structured memory of facts,concepts, skills semantic LTM derived from episodic LTM

Long-term memory (cont.)

Semantic memory structure
provides access to information represents relationships between bits of information supports inference

Model: semantic network

inheritance child nodes inherit properties of parent nodes relationships between bits of information explicit supports inference through inheritance

LTM - semantic network

Models of LTM - Frames

Information organized in data structures Slots in structure instantiated with values for instance of data Typesubtype relationships
DOG
Fixed legs: 4 Default diet: carniverous sound: bark Variable size: colour

COLLIE
Fixed breed of: DOG type: sheepdog

Default size: 65 cm
Variable colour

Models of LTM - Scripts

Model of stereotypical information required to interpret situation Script has elements that can be instantiated with values for context
Script for a visit to the vet
Entry conditions: dog ill vet open owner has money Result: dog better owner poorer vet richer examination table medicine instruments Roles: vet examines diagnoses treats owner brings dog in pays takes dog out

Props:

Scenes:

arriving at reception waiting in room examination paying

dog needs medicine dog needs operation

Tracks:

Models of LTM - Production rules

Representation of procedural knowledge.
Condition/action rules
if condition is matched then use rule to determine action.

IF dog is wagging tail THEN pat dog

IF dog is growling THEN run away

LTM - Storage of information

rehearsal
information moves from STM to LTM

total time hypothesis

amount retained proportional to rehearsal time

distribution of practice effect

optimized by spreading learning over time

structure, meaning and familiarity

information easier to remember

LTM - Forgetting
decay
information is lost gradually but very slowly

interference
new information replaces old: retroactive interference old may interfere with new: proactive inhibition so may not forget at all memory is selective affected by emotion can subconsciously `choose' to forget

LTM - retrieval
recall
information reproduced from memory can be assisted by cues, e.g. categories, imagery

recognition
information gives knowledge that it has been seen before less complex than recall - information is cue

Thinking
Reasoning
deduction, induction, abduction

Problem solving

Deductive Reasoning
Deduction:
derive logically necessary conclusion from given premises. e.g. If it is Friday then she will go to work It is Friday Therefore she will go to work.

Logical conclusion not necessarily true:

e.g. If it is raining then the ground is dry It is raining Therefore the ground is dry

Deduction (cont.)
When truth and logical validity clash
e.g. Some people are babies Some babies cry Inference - Some people cry

Correct?

People bring world knowledge to bear

Inductive Reasoning
Induction:
generalize from cases seen to cases unseen e.g. all elephants we have seen have trunks therefore all elephants have trunks.

Unreliable:
can only prove false not true

but useful! Humans not good at using negative evidence

e.g. Wason's cards.

Wason's cards

7 E 4 K
If a card has a vowel on one side it has an even number on the other Is this true? How many cards do you need to turn over to find out? . and which cards?

Abductive reasoning
reasoning from event to cause
e.g. Sam drives fast when drunk. If I see Sam driving fast, assume drunk.

Unreliable:
can lead to false explanations

Problem solving
Process of finding solution to unfamiliar task using knowledge.
Several theories.

Gestalt
problem solving both productive and reproductive productive draws on insight and restructuring of problem attractive but not enough evidence to explain `insight' etc. move away from behaviourism and led towards information processing theories

Problem solving (cont.)

Problem space theory
problem space comprises problem states problem solving involves generating states using legal operators heuristics may be employed to select operators e.g. means-ends analysis operates within human information processing system e.g. STM limits etc. largely applied to problem solving in well-defined areas e.g. puzzles rather than knowledge intensive areas

Problem solving (cont.)

Analogy
analogical mapping:
novel problems in new domain? use knowledge of similar problem from similar domain

analogical mapping difficult if domains are semantically different

Skill acquisition
skilled activity characterized by chunking
lot of information is chunked to optimize STM

conceptual rather than superficial grouping of problems information is structured more effectively

Errors and mental models

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

Emotion
Various theories of how emotion works
James-Lange: emotion is our interpretation of a physiological response to a stimuli Cannon: emotion is a psychological response to a stimuli Schacter-Singer: emotion is the result of our evaluation of our physiological responses, in the light of the whole situation we are in

Emotion clearly involves both cognitive and physical responses to stimuli

Emotion (cont.)
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)

Emotion (cont.)
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

Individual differences
long term sex, physical and intellectual abilities short term effect of stress or fatigue changing age
Ask yourself: will design decision exclude section of user population?

Psychology and the Design of Interactive System

Some direct applications
e.g. blue acuity is poor blue should not be used for important detail

However, correct application generally requires understanding of context in psychology, and an understanding of particular experimental conditions A lot of knowledge has been distilled in
guidelines (chap 7) cognitive models (chap 12) experimental and analytic evaluation techniques (chap 9)