This document discusses human information processing and its implications for computer interface design. It covers how humans perceive information through their senses, process information in memory and through reasoning. It also discusses problem solving, skill acquisition and errors. The key aspects of human information processing discussed are: - Humans perceive information through four main channels: visual, auditory, haptic and movement. Visual perception involves factors like size, color and reading processes. - Information is stored briefly in sensory memory and working memory, and longer-term in episodic and semantic long-term memory. - Reasoning involves deductive, inductive and abductive logic. Problem solving uses different theories like reproducing known responses or using operators to

1. Human
Hurriyatul Fitriyah [hfitriyah@ub.ac.id]
Human – Computer Interaction Course
Computer System - Information Technology & Computer Science Program

2. 1. Introduction

3.  This lecture focused on human information processing
that includes:
1.
2.
3.
Human
Information
Processing
Perceiving
Memorising
Processing
 Human are limited to their capacity to process information.
This has important implication for design

4. 2. Human Perceptor

5.  Information is received via a number of human sensory channel:
1.
Visual channel
2.
Auditory channel
3.
Haptic channel
Human’s
X
4 Input channels
for Computer Interface
Plus one additional input channel:
4.
Movement
X

6. 1. Visual Channel
 We see windows, buttons, numbers, alphabets, lights colours, menus, icons in our computer –machine
 We design our computer system by adapting the way the eye
perceive brightness, colour, size, depth and relative distance

7. 1.
Size, Depth & Relative Distance
• Human still can identify objects, even in
various size (law of constancy)
Visual
Perception
2.
Brightness
3.
Colour
• Brigthness is subjective reaction to level of
lights
• Brighness perception is subject to
luminance (the amount of light emiited by
an object)
• colour component: hue (wavelength of
light), intensity (brightness), saturation
(amount of whiteness)
• Cones photoreceptors has three type that
each is sensitive to different colour
(blu, green, red)

8.  Reading process stages:
1. Perceiving visual pattern on the word on the page
2. Decoding the pattern with reference to an internal representation
of language
3. Syntatic and semantic analysing and operate on phrases or
sentence
Reading
 During reading, eyes do saccades followed by fixations, also
regressions (move backwards and forwards over text)
 Words are not recognised character by character, but by word
shape
 Experiment suggest standard font size for legible reading is 9 to 12
points
 Negative contrast (dark character on a light screen) provides
higher luminance, therefor increase acuity

9.  Design Example
What can we
learn and use
from visual
perception to
our computer
design?
??

10.  Sound (non-speech) is used as an addition to visual computercommunication
1.
2. Auditory Channel
Attention
2.
Status information
3.
Confirmation
4.
Navigation
 Sound is also used for visual impaired communcation aid

11.  Touch screen is explored because people dislike to be troubled
with mouse (and it’s more way cool isn’t it?)
 Vibration, give feedback (information, alert) when user don’t
want to use visual and sound
 Haptic application in computer gaming
3. Haptic Channel
 Now we seek a technology that allow user to feel surface
(texture) and shape such for e-commerce application

12.  Speed and accuracy of movement is important in computer design
primarily to hit a target on a screen
 The time taken to hit a target = a + b log2 (distance/ size +
1), where a & b is empirically determined constants
 Movement in gaming application:
4. Movement
To direct the input

13. 3. Human Memory

14.  Information is stored in memory
1.
Sensory memory
2.
Short-term (working) memory
3.
Long-term memory

15.  There are 3 sensory memory:
1.
1. Sensory
memory
Iconic memory for visual stimuli
2.
Echoic memory for aural stimuli
3.
Haptic memory for touch stimuli
 It’s constantly overwritten by new information coming
 Example: moving fingers in front of eyes, seeing firework

16.  Working as ‘scratch-pad’ for temporary
recall
 Example: during multiplication like in
35x6
2. Short-term
Memory
 Example of human STM adapted in
computer design:
Early automatic teller machines (ATMs)
gave the customer money before
returning their bank card. On receiving
the money the customer would reach
closure and hence often forget to take
the card. Modern ATMs return the card
first!

17. 3. Long-term
Memory
 It’s our main memory, here we store factual
information, experimental knowledge, procedural rules of
behaviour, everything we know
 2 type of long-term memory:
1. Episodic memory for events and experience
2. Semantic memory for facts, concept and acquired skill

18.  Imagine we have to memorise all important number and
code, such: postal code, phone number, password
Security: arch
enemy of
memory
 Now it has to be alphanumerical (plus symbol)
 Now it has to be more than 6 numbers
 The worst of all: we have to keep them secret, in mind. It can’t be
written!
 Network engineers suggest us what they called a solution for this:
nonsense password but still meaningfull to user (eg. Initial of
names, number of significant dates)

19. 3. Human Think
Reasoning and Problem Solving

20.  Information is prosessed and applied:
•
•
•
•
Reasoning
Problem solving
Skill acquisition
error

21. Reasoning is a means of inferring new information from what is
already known
1.
Deductive: derive conclusion from given premise/s
 Example: It is FRIDAY then he WILL GO TO WORK
2.
3.1. Reasoning
Inductive: generalising from case we have seen to infer
information about cases we have not seen
 Example: we have seen several elephant have trunks, we conclude
that all elephant have trunks
 It’s unreliable, but usefull for constanlty learning new environment
3.
Abductive: it reason from a fact to the action or state that
caused it
 Problem in interactive system: if an event always follow an
action, the user will infere that the event is caused by the action

22.  Problem solving is process of finding solution to an unfamiliar
task, using the knowledge we have
3.2. Problem
Solving
 There are 3 main theory how human solve problem
1.
2.
3.
Gestalt theory: problem solving is a matter of reproducing
known response or trial and error
Problem soace theory: problem has initial state and a goal state
and people use the operator from the former to later
Analogy in problem solving: people use current knowledge as an
analogy to solve novel problem

23.  Three basic level of skills:
3.3. Skill
Acquisition
1.
2.
3.
The real uses general-purpose rules which interpret facts about a
problem. This is slow and demanding on memory access
The learner develops rules spesific to the task
The rules are tuned to speed up performance

24.  Imagine you are learning to cook. Initially, you may have general
rule to tell you how long a dish needs to be in the oven
Example of
skill acquisition

25.  Gradually your knowledge becomes proceduralized and you have
specific rules for each case
proceduralization

26.  Finally, you may generalize from these rules to produce generalpurpose rules
Generalization

27. The difference
between
Human &
Computer
 Example: chess play

28.  Some error are trivial, some maybe serious and requiring
subtansial effort to correct
3.4. Error
 If a pattern of behaviour has become automatic and we change
some aspect of it, the familiar pattern may break throught and
becomes error
 Others is from incorrect understanding (mental models)
 The mental models might be a partia incorrect understanding, or
internally inconsistent

29. 4. Human Emotion

30.  Emotion influences human capabilities
 It suggest that in situation of stress, people will be less able to
cope with complek problem solving or managing difficult
interface.

31. 5. Individual Difference

32.  Users share common capabilities but are individuals with
differences, which should not be ignored
 Difference including sex, physical capabilities and intellectual
capabilities