Human Computer Interaction lecture Chapter 2.pptx

1
Lecture 2
HUMAN COMPUTER
INTERACTION

2
Summary
 In previous lecture we learnt about,
Basics of Human Computer Interaction
 Alarm Clock Example
 Dos time versus software application
 Don Norman’s Door Example
The human
 Information i/o …
 visual,
 auditory,
 haptic,
 movement

3
TODAY’S OUTLINE
 The MEMORY
 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

Memory
• Without the capacity to remember and to learn, it is difficult to
imagine what life would be like, whether it could be called living
at all. Without memory, we would be servants of the moment,
with nothing but our innate reflexes to help us deal with the
world. There could be no language, no art, no science, no
culture.’ (Blakemore, 1988)

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
(The Cat Ran Up The Tree)

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

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 ill
vet open
owner has money
Result: dog better
owner poorer
vet richer
Props: examination table
medicine
instruments
Roles: vet examines
diagnoses
treats
owner brings dog in
pays
takes dog out
Scenes: arriving at reception
waiting in room
examination
paying
Tracks: dog needs medicine
dog needs operation

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 he will go to work
It is Friday
Therefore he 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
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
– gender, 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

34
SUMMARY
 Today we learnt about,
MEMORY
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

Human Computer Interaction lecture Chapter 2.pptx

More Related Content

Similar to Human Computer Interaction lecture Chapter 2.pptx

Recently uploaded

Human Computer Interaction lecture Chapter 2.pptx