Lecture 1-The Human

8/2/2019 Lecture 1-The Human

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The HumanThe HumanThe HumanThe Human

HumanHuman Computer InteractionComputer Interaction

--Dix, Finlay,Dix, Finlay, AbowdAbowd, Beatle, Beatle--

Vu,Vu, ThiThi Hong NhanHong Nhan([email protected])([email protected])

Faculty of Information TechnologyFaculty of Information Technology

Vietnam National University, HanoiVietnam National University, Hanoi

((Lecture NotesLecture Notes))
mailto:[email protected]:[email protected]:[email protected]:[email protected]


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ContentsContentsContentsContents

1.1. IntroductionIntroduction

2.2. InputInput--output channelsoutput channels

3.3. Human MemoryHuman Memory

..

5.5. EmotionEmotion

6.6. Individual differenceIndividual difference

7.7. Psychology and the design of interactive systemsPsychology and the design of interactive systems

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IntroductionIntroduction

Information i/o

visual, auditory, haptic, movement

Information stored in memory- -

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, ,

Information processed and applied

reasoning, problem solving, skill, error

Emotion influences human capabilities

Each person is different

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Input-output channelsInput-output channels

In interaction with a computer

The human input is the data output by the computer and vice verse

In humans, input mainly occurs through the senses and output through

the motor controls of the effectors


The most important senses in HCI

Vision, hearing, and touch

The primary effectors

Eyes, ears, fingers, head and body position

Visual perception can be divided into 2 stages

Physical reception of the stimulus from the outside world

The processing and interpretation of that stimulus

Humans Computer

Input Output

OutputInput

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VisionVisionVisionVision

Eye: is a mechanism for receiving light and transforming it into electrical energy

Light is reflected from objects in the visual field and their image is focused on the

back of the eye, where it is transformed into an electrical signal and passed to

the brain

The most important components are the cornea (gic m c) and lens (th y tinh


th / n t ) and the retina (vng m c) with the blind spot and photoreceptors(cc

t bo nh n kch thch nh sng): rods, cones located on the fovea (h vng

m c)


Rods are highly sensitive toRods are highly sensitive to lightlight

and are usable under lowand are usable under low

illuminationillumination

Cones are less sensitive to lightCones are less sensitive to light

and canand can distinguish colordistinguish color

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Vision:Vision: The signal interpretationThe signal interpretationVision:Vision: The signal interpretationThe signal interpretation


Size and depth

Visual angle indicates how much of view an object occupies

(relates to size and distance from eye)

Visual acuit th l c is abilit to erceive detail


Familiar objects perceived as constant size

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

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Vision:Vision: The signal interpretation (contd)The signal interpretation (contd)Vision:Vision: The signal interpretation (contd)The signal interpretation (contd)


Perception of brightness

is a subjective reaction to levels of light emitted by an object

affected by luminance of object


Colour

The eye perceive color because the cones are sensitive to light of

different wavelengths

3-4% of the fovea is sensitive to blue, making blue acuity lower

In reality, about 8% males and 1% females are colour blind

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Vision:Vision: The signal interpretation (contd)The signal interpretation (contd)Vision:Vision: The signal interpretation (contd)The signal interpretation (contd)


The visual system compensates for

Movements

Changes in luminance

The context in which an object appears

the human mind

judges an object's

size based on its

background


allows us to clearly disambiguate the

interpretation of the object

Optical illusions sometimes occur dueto over compensation

illusion

the MullerLyer illusion

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Vision:Vision: ReadingReadingVision:Vision: ReadingReading


Consists of several stages

The visual patterns of the words are perceived

Decoded with reference to an internal representation of

lan ua e


The word is processed as part of the sentence or phrase using

syntactic and semantic analysis

Reading involves saccades(c ng gi t gi t c a m t)and fixations

Perception occurs during fixation

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HearingHearingHearingHearing

Provide information about environment: distances, directions, objects, etc.

The ear receives vibrations in the air and transmits them through various

stages to the auditory nerves

Physical sections


u er ear: pro ec s nner ear an amp es soun

Middle ear: transmit sound waves like vibrations to inner ear

Inner ear: chemical transmitters are released and cause impulses in the auditory

nerves (th n kinh thnh gic )

Features of sound Pitch( cao th p): frequency of the sound

Loudness(c ng ): amplitude of the sound

Timbre(m s c): type/quality of the sound

Amplitude

Frequency

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Hearing (cont.)Hearing (cont.)Hearing (cont.)Hearing (cont.)

Humans can hear sound at frequencies from 20Hz to 15kHz

Can perceive changes at low frequency about 1.5Hz


,

Human auditory system has a filtering system which filter out the

distracting noise to concentrate on important sounds

Cocktail party effect we still can concentrate on the conversation

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Hearing withHCIHearing withHCIHearing withHCIHearing withHCI

Currently sounds are still mainly used to inform some thing, e.g.,

When pressing a wrong button

Welcoming to Windows when booting

Low battery status


Sound research has been carried out

Synthesize speech:Listening to an audio material instead of reading, which

is especially beneficial to blind people & those who have weak visual acuity

Use sounds to create effect in content displaying

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TouchTouchTouchTouch

Provides important feedback about environment

Stimuli are received via the receptors (c quan nh n c m) in the

skin

Thermoreceptors: hot and cold Nocice tors: ain


Mechanoreceptors (c quan c m th c h c): pressure

Kinesthesis (c m gic v s v n ng c a t chi & c th )

Second aspect of haptic perception

Awareness of the position of the body and limbs due to receptors in the

joints

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Touch with HCITouch with HCITouch with HCITouch with HCI

E.g., we can perceive when a button is being pressed

New devices: haptic


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MemoryMemoryMemoryMemory

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

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MemoryMemory

Sensory memorySensory memorySensory memorySensory memory

Act as buffers for stimuli received via each of senses

iconic memory: visual stimuli

echoic memory: aural stimuli

ha tic memor : tactile stimuli


These memories are constantly overwritten by new

information coming in on these channels

Information is passed to sensory memory into short-term

memory by attention

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MemoryMemory

ShortShort--term memoryterm memoryShortShort--term memoryterm memory

Is used to store information which is only required

fleetingly

Can be accessed rapidly: ~ 70ms

Also deca ra idl : ~ 200ms


Has a limited capacity

Humans can store 7 2 chunks of information

E.g.,

212348278493202

0121 414 2626

HEC ATR ANU PTH ETR EET

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MemoryMemory

LongLong--term memoryterm memoryLongLong--term memoryterm memory

Has an unlimited capacity, a slow access time and forgetting occurs

more slowly or not at all

Information is stored here from the STM through rehearsal

2 types of LTM


Episodic (tnh ti t) memory represents our memory of event &

experiences in a serial form

Semantic memory is a structured record of facts, concepts, skills that

we have acquired, derived from the episodic memory

Semantic memory is structured as a network

The more general the information is, the higher is the level on which it is

stored

allows us to generalize about specific cases

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MemoryMemory

LTM:LTM: example of semantic network modelexample of semantic network modelLTM:LTM: example of semantic network modelexample of semantic network model

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MemoryMemory

LTM: FramesLTM: FramesLTM: FramesLTM: Frames

Other models about the organization of LTM

Frames

Information is organized in data structures

Have slots to add attribute values


DOG

Fixed

legs: 4

Defaultdiet: carniverous

sound: bark

Variable

size:

colour

COLLIE

Fixed

breed of: DOG

type: sheepdogDefault

size: 65 cm

Variable

colour

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MemoryMemory

LTM: ScriptsLTM: ScriptsLTM: ScriptsLTM: Scripts

Comprise a number of elements (like slots) which can be filled with

appropriate information

Script for a visit to the vet

Entry conditions: dog ill

Roles: vet examines


owner has money

Result: dog better

owner poorer

vet richer

Props: examination tablemedicine

instruments

treats

owner brings dog in

pays

takes dog out

Scenes: arriving at receptionwaiting in room

examination

paying

Tracks: dog needs medicine

dog needs operation

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MemoryMemory

LTM: Production rulesLTM: Production rulesLTM: Production rulesLTM: Production rules

IF-THEN rules

If information coming into the STM matches one of the

condition in the LTM, the appropriate action is executed


IF a dog is wagging tail

THEN pat the dog

IF a dog is growling

THEN run away

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MemoryMemory

LTM: 3 main activitiesLTM: 3 main activitiesLTM: 3 main activitiesLTM: 3 main activities

Storage of informationStorage of information

Rehearsal of a piece of information from the STM (moved to LTM)

Total time hypothesis (Ebbinghaus 1885)

If the total learning time is increased, information is remembered


better (amount retained is proportional to rehearsal time)

Distribution of practice effect (Baddeley & Longman 1978)

Optimization: the learning time should be well spread over time

Repetition alone is enough?

To help learn efficiently, information should be meaningful & familiar

So that, it can be related to existing structures

more easily incorporated into memory

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MemoryMemory


Forgetting: 2 main theories of forgetting

Decay

information held in the LTM is gradually lost but slowly


Inference

New information replaces old one (retroactive interference)

The older information interferes with the newly acquired information

(proactive inhibition)

Forgetting is affected by emotional factors too

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MemoryMemory


Retrieval: 2 types of retrieval

Recall

information reproduced from memory can be assisted by cues (e.g.,

the category in which information can be placed)


Recognition

information gives knowledge that it has been seen before

Less complex than Recall

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Require different amount of knowledge

Some thinking are very directed and the knowledge required is

constrained

Others re uire vast amounts of knowled e from different

ThinkingThinkingThinkingThinking


domains

Thinking can be divided in

Reasoning : deductive(di n dch), inductive(quy n p),

aductive(Truy kch)

Problem solving

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ThinkingThinking

ReasoningReasoningReasoningReasoning

Is the process in which we use the knowledge to draw conclusion or infer

something new about the domain of interest

Deductive reasoningDeductive reasoning

Derive the logically necessary conclusion from the given premises

E.g. If it is Friday then she will go to workIt 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 When the truth and logical validity clash

E.g.Some people are babies

Some babies cry

Inference - Some people cry

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ThinkingThinking


Inductive reasoning

generalizing from cases we have seen to infer information about

cases we have not seen


E.g., all elephants weve been have trunks, therefore all elephants

have trunks

Unbelievable Can only prove False not True

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ThinkingThinking


Adduction

Reasons from event to cause

E. ., Sam drives fast when drunk


If I see him driving fast, assume drunk

Unbelievable

Can lead to false explanation

But still useful

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ThinkingThinking

Problem solvingProblem solvingProblem solvingProblem solving

Is the process of finding a solution to unfamiliar task, using the

knowledge we have

There are different views on problem solving


Gestalt theoryGestalt theory

problem solving is 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 lead towards information processing

theories

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ThinkingThinking

Problem solving (cont.)Problem solving (cont.)Problem solving (cont.)Problem solving (cont.)

Problem space theoryProblem space theory

problem space comprises problem states

problem solving involves generating states using legal operators

People use these operators to move from the initial state to the goal state


heuristics may be employed to select operators

Use of analogyUse of analogy

Problems solved by mapping knowledge relating to a similar knownproblem domain to the new problem

Analogical mapping

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ThinkingThinking

Skill acquisitionSkill acquisitionSkill acquisitionSkill acquisition

Information structure is fine tuned at a deep level to

enable efficient and accurate retrieval


The learners uses general-purpose rules to interpret facts about

a problem

Develop rules specific to the task using proceduralization The rules are tuned to speed up performance, using

generalization

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ThinkingThinking

Errors & mental modelsErrors & mental modelsErrors & mental modelsErrors & mental models

Types of errors

slips

Right intention, but failed to do it right


, .

Changes in context of skilled behaviour can cause error

Mistakes

wrong intention

An incorrect understanding of a situation can cause errors

because humans tend to create mental models , based on

experience, which may differ from the actual situation

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Various theories of how emotion workstheories of how emotion works

James-Lange: emotion is our interpretation of a physiological response

to a stimuli

EmotionEmotionEmotionEmotion


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

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Emotion (cont.)Emotion (cont.)Emotion (cont.)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)

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Emotion (cont.)Emotion (cont.)Emotion (cont.)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

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Individual differencesIndividual differencesIndividual differencesIndividual differences

The principles and properties discussed apply to the

majority of people


But humans are NOT the same at all

Differences should be taken into account in the design

E.g., Divide the users into the target groups

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Some direct applications

e.g. blue acuity is poor

blue should not be used for important detail

However, correct applicationcorrect application generally requires understanding of

Psychology & the design of interactive systemsPsychology & the design of interactive systemsPsychology & the design of interactive systemsPsychology & the design of interactive systems


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)

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SummarySummarySummarySummary

InputInput--output channelsoutput channels

Human MemoryHuman Memory

ThinkingThinking

Individual differenceIndividual difference

Psychology and the design of interactive systemsPsychology and the design of interactive systems

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Lecture 1-The Human

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