Introduction

Human-Computer InteractionSENG 306

the course (description)Description of the Course

Understanding the concepts of an effective interaction with the computerAim of the Course

1. Defining the basic concepts of human computer interaction.

2. Understanding the cognitive abilities of human.

3. Understanding the technical capabilities of the computer and the interaction methods.

4. Constructing the concepts for a better interaction using the terms mentioned above.

5. Creating interfaces.

6. 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 CourseBasic 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 Te’eni, 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 (Total) Percentage

Weekly Exam None

Monthly Exam None

Midterm 1 10

Homework None

Term Paper None

Project 1 50

Presentation None

Implementation/Lab. Studies None

Others None

Final Exam 1 40

assessment Final Grades will be determined according to

the Yaşar University Associate Degree, Bachelor Degree and Graduate Degree Education and Examination Regulation

7

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 don’t 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%

• 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.

The Importance of HCI

When HCI fails, the system fails

• Organizations of HCI are growing rapidly

• There are more new journals dedicated to HCI than any other information systems sub-discipline

The Importance of HCI

Interdisciplinary nature and scope of HCI

SoftwareEngineering

CognitivePsychology

OrganizationalPsychology

Sociology

Communications

ArtTheatre

Human Factors

ComputerEngineering

SocialPsychology

CognitiveScience

ManagementPhilosophy

AffectiveComputing

Physical capabilities Methodology Hardware

Aesthetics Intelligent interfaces

Drama User modeling

Dialog Collaboration Cost-benefit

SoftwareEngineering

CognitivePsychology

OrganizationalPsychology

Sociology

Communications

ArtTheatre

Human Factors

ComputerEngineering

SocialPsychology

CognitiveScience

ManagementPhilosophy

AffectiveComputing

Physical capabilities Methodology Hardware

Aesthetics Intelligent interfaces

Drama User modeling

Dialog Collaboration Cost-benefit

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)

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

MemoryProcessors

Working Memory

Perception Motor

Verbal

Cognition

Attention

Memory

Working Memory

Perception

Spatial

data

Long term Memory

MemoryProcessors

Working Memory

Perception Motor

Verbal

Cognition

Attention

Memory

Working Memory

Perception

Spatial

data

Long term Memory

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

• Colour– made up of hue, intensity, saturation– cones sensitive to colour wavelengths– blue acuity is lowest– 8% males and 1% females colour blind

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

vibrations to inner ear– inner ear – chemical transmitters are released

and cause impulses in auditory nerve

• Sound– pitch – sound frequency– loudness – amplitude– timbre– 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 – heat and cold– nociceptors – pain– mechanoreceptors – 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 timeD is Distance S is Size of target

targets as large as possibledistances 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)

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• Type–subtype 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 illvet openowner has money

Result: dog betterowner poorervet richer

Props: examination tablemedicineinstruments

Roles: vet examines diagnoses treatsowner brings dog in pays takes dog out

Scenes: arriving at receptionwaiting in roomexaminationpaying

Tracks: dog needs medicinedog needs operation

Models of LTM - Production rules

Representation of procedural knowledge.

Condition/action rules if condition is matchedthen use rule to determine action.

IF dog is wagging tailTHEN pat dog

IF dog is growlingTHEN 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

Reasoningdeduction, 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 FridayTherefore she will go to work.

• Logical conclusion not necessarily true:e.g. If it is raining then the ground is dry

It is rainingTherefore the ground is dry

Deduction (cont.)

• When truth and logical validity clash …e.g. Some people are babies

Some babies cryInference - 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

Is this true?

How many cards do you need to turn over to find out?

…. and which cards?

If a card has a vowel on one side it has an even number on the other

7 E 4 K

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)