Human-Computer Interaction - user’s knowledge structure - Prof. dr. Matthias Rauterberg Faculty of...

Human-Computer Interaction- user’s knowledge structure -

Prof. dr. Matthias RauterbergFaculty of Technology Management

Technical University Eindhoven

The Netherlands

© M. Rauterberg, TU/e 2

The fundamental design problem

implementedfunctions

perceivable userinterfaceforms

intendedsemantic

perceivedsemantic

designer’s mental model user’s mental model


What is Human-Computer Interaction about?

systemuser

Working domain

Working system

Goal:Actual Performance=> Desired Performance


Three different function types

Primary functions[application manager]

Secondary functions[dialog manager] Tertiary

functions[dialog manager]

Application object(s)


The User Interface (1)

user

input/output interface

dialog moduledialogstate

applicationstate

perceptionaction

transformation

user interface

applicationobjects

application module

dialogobjects

applicationfunctions

dialogfunctions

presentation


The User Interface

(2)

input-handler output-handler

Long-term memory

actionmodule

output-handler

inputoperation

visual"memory"

visual output

presentation

dialog module

dialogstate

applicationstate

transformation

user interface

applicationobjects (AO)

application module

dialogobjects (DO)

applicationfuncrtions

dialogfunctions

auditory"memory"

auditory output

tactile"memory"

tactile output

perception modulemotormemory

goal problemsolving module

Short-term memory

learningmodule

userexpectationplan

system[further reading]

http://www.ipo.tue.nl/homepages/mrauterb/publications/PhD-thesis95.pdf


Several Notions of ‘Models’[Horst Oberquelle, 1984]

(1) a model of an axiom system(2) a known system with structure and behavior

analogous to the system under consideration(3) a prototypical system in the sense of 'model

farm'(4) an abstract description of the relevant

aspects of a system


User’s Mental Models[Stephan Dutke: Mental Models-constructs of knowledge and understanding, 1994]

mental structure perception

cognition

action

external stimuli

Model:

e.g. visual system

e.g. Action Cycle

e.g. Fitts Law

Interface elements


The Difference between Internal and External Memory

internal memory external memory

• the mental model of the user about the external world is always incomplete

• all necessary information which is not in the internal memory must be provided by the environment (the “external memory”)


Knowledge in the World and in the Head

Property Knowledge in the World Knowledge in the Head

Retrievability: Retrievability whenevervisible or audible or tangible.

Not readily retrievable.Requires memory search orreminding.

Learning: Learning not required.Interpretation substitutes forlearning.

Requires learning, which canbe considerable.

Efficiency of use: Tends to be slowed up by theneed to find and interpret theexternal information.

Can be very efficient.

Ease of use atfirst encounter:

High. Low.

Aesthetics: Can be unaesthetic andinelegant, especially if thereis a need to maintain a lot ofinformation.

Nothing need be perceivable,which gives more freedom tothe designer and can lead tobetter aesthetics.


User’s motor behavior: Fitts' Law

T = k log2(D/S + 0.5) with k ~ 100 msec

T = time to move the hand to a target D = distance between hand and target S = size of target

Fitts' Law is a model to account for the time it takes to point at something, based on the size and distance of the target object.

Fitts' Law and variations of it are used to model the time it takes to use a mouse and other input devices to click on objects on a screen.

Fitts' Law can be applied by designers to suggest moving target buttons closer and making them larger for extremely commonly used buttons. In detail, applying the formula can be extremely useful for exact design of time-critical applications.


The Visual Perception System


Activity Theory: the Complete Action Cycle

physical operation

feedback control of action

goal-, subgoal-setting

mental operation

task(s)

planning of execution selection of means


User’s model: activity cycletask

description

feedback

cognitive process

observable action

goalinstanciation

Goa

l

instan

ciation

level

Actio

n le

vel

Cog

nitive

leve

lF

eed

ba

ckle

vel

[further reading]

http://www.ipo.tue.nl/homepages/mrauterb/publications/CSCW2002paper.pdf


User’s mental structure

Goal

instanciation

level

Action level

M_3 h F_3 1 i hG_2F_10

Main menuMain menu

F-fileStart menuMsDOS

System

levelC

ognitive levelF

eedbacklevel

Regulation-driven goal setting

[further reading]


How to investigate the user’s mental model?

Validation of the functional equivalence, computed by the similarity ratio (SR)

Adding goal setting structure

Reconstructed mental task modelHuman mental model

?

Observation of human behaviour

Folding

Adding sequential and temporal information Model

execution

original behavioural sequence simulated behavioural sequence

Device model

2

G_2

Start menu

M_3

Main menu

F_3

User key press

Automatic transition


MsDOS

G_2

Main menu

F_3

Start menu

M_3



User key press

MsDOS

Main menu Main menu

F-fileStart menu

F_10 M_3 h F_3 1 i hG_2

MsDOS

Main menu Main menu F-file

Start menu

F_10 M_3 h F_3 1 i hG_2

MsDOS

1

3

4

5

6

i


User’s learning process

complex system

operator

beginner

advanced

expert

learning time

interaction

We (1996) found a negative correlation between Behavioral-Complexity and Mental-Complexity

[further reading]


mental activity is like the ‘flow of a river’


Learning means ‘digging’

learning process

[further reading]


User’s Behavior: an example

s0

d h

s1

b

s2 s3F3

F9

CR

_

TAB

F2

"wall" of knowledge about unsuccessful behavior

"dales" of knowledge about successful behavior


User’s real knowledge structure

knowledge about unsuccessful behavior

knowledge about successful behavior


Thank you for your attention

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