Human Computer Interaction
description
Transcript of Human Computer Interaction
Human Computer InteractionHuman Computer Interaction
Study and design of user interfaces and interaction British Computer Society ~“to stress the good design,
documentation and usability” HCI approach – iterative development with focus on
user testing at an early stage HCI is applied engineering with contribution from
Cognitive Psychology Cognitive Science and Engineering Computer Science Ergonomics Artificial Intelligence Graphics and Industrial Design Engineering generally Sociology, Anthropology and Philosophy
HCI is not about ‘looking good’ or ‘making thing pretty’ – It is about making software work for user Good HCI does not grow on trees it has to be
cultivated Owning an aeroplane does not make you a pilot
REALITY Many systems are difficult to use but people are
adaptable There may be conflict between safety and efficiency
Which garage do you prefer – the one which offers you coffee, but does not fix your car, or the one with gruff mechanics who are honest and know their stuff???
Human Computer InteractionHuman Computer Interaction
Selection and design of devices – screen, keyboard, printer, etc. Selection and design of interaction styles Selection and development of tools and methods Design of the environment where a computer is used The tasks to be carried out using a computer Organizational impact of a computer system The training requirements – initial and continuing The design of support material, manuals, on-line
helps, etc. The attitudes and expectations of users Safety issues
Human Computer InteractionHuman Computer Interaction
The need for consistency One of the common causes of problems with
computer based systems Dialogue Design
When interacting with a system a dialogue is in progress between the system and the user – this has to be planned, scripted or choreographed
System Feedback Lack of suitable feedback causes feelings of
discomfort and encourages errors, e.g. pressing RETURN too many times until the response is seen
Human Computer Interaction~ Human Factors Design Issues
Human Computer Interaction~ Human Factors Design Issues
Amount of Feedback Tendency to squeeze too much on to screen
and to show more than is necessary for the current task
Appropriate pacing Too slow – causes frustration Too fast – causes pressure to perform
Human Computer Interaction~ Human Factors Design Issues
Human Computer Interaction~ Human Factors Design Issues
Mismatch between user and computer Often the user has to adapt to the computer Terminology that of computer instead of
user Computer function rather than task oriented
Physical limitations Height Reach Eyesight Sensitivity to lighting condition
Human Computer Interaction~ The Problems
Human Computer Interaction~ The Problems
Human information processing limitations Short term memory limitation Attention highly selective and narrow Long term memory very unreliable Recognition easier than recall Over learning for frequent tasks Reasoning frequently illogical Judgements subject to biases Affected by fatigue and emotion
Human Computer Interaction~ The Problems
Human Computer Interaction~ The Problems
Resistance to Change How is change managed? Who is involved? Technology is search of a solution Disruption of existing social order
Building for whom? Designer build for themselves Poor understanding of users, tasks,
organizations Poorly specified problems Poorly realized solutions
Human Computer Interaction~ The Problem
Human Computer Interaction~ The Problem
looking at how issues in HCI, human-factors engineering, user-centered design, can influence multimedia design use of different media types MM design for vision, hearing, cognition,
memory,attention MM design guidelines design issues for static and dynamic media educational MM
HCI Issues for Multimedia Design
HCI Issues for Multimedia Design
For multimedia, usability has three viewpoints Functional usability
How easy a product is to use GUIs, menus, interaction
Information delivery how well does the product deliver the message
prime concern “multi media “
just because you present the material in a different way doesn’t mean that it will be delivered better
Learnt content how well does someone learn the content delivered by the
product more applicable to educational multimedia but still considered for
movie-style presentations
Types of UsabilityTypes of Usability
Essential Issues of Multimedia
Essential Issues of Multimedia
with MM you have more ways to present information
should be more attractive than standard text and still images
however potential for even bigger ‘mess’ should be about:
delivering information in a novel way enhancing interaction by different techniques
Multimedia ISO Standard TermsMultimedia ISO Standard Terms
message the content of communication between a sender
and received.
medium the means by which that content is delivered (how
the message is represented rather than the technology).
modality the way a message is perceived by a person (e.g.
vision, hearing, touch). Note that this is not technology based but human attributes.
Dynamic MediaDynamic Media
•considerations: how can the media be controlled over time? can the speed of presentation be change? what controls exist over the presentation? how can the media format be changed? can the image be expanded (zoom) can the sound be filtered (amplitude, frequency)? can components of the dynamic media
addressable directly or indirectly?
What you should remember aboutdynamic media
What you should remember aboutdynamic media
dynamic media tend to dominate by attracting attention from static media
dynamic media can easily overload human information processing
retention of detail from dynamic media is poor co-ordination of information presented must allow user control over dynamic media
Static MediaStatic Media
considerations: how can the display be controlled?
standard GUI controls, eg sliders (too much text for window and therefore need to scroll down) etc
how can the media format be changed? depends on the storage format eg text changed in size
(point), and shape (font,bold)
are sub-components of medium addressable? idea of clickable maps where certain aspects of the
image can have different features
What you should bear in mindWhat you should bear in mind
visual images tend to dominate over text images can be scanned quickly (quick look over)whereas reading is more
attention demanding,therefore people will be drawn towards the easier of the two media.
many different messages can be extracted from one image.
interpretation of the message in an image depends on the user’s attention and knowledge of contents.
extraction of information from diagrams requires learning the semantics of a symbolic language
memory of image detail is generally poor unless peoples attention has been drawn to specific facts in the image
• reading is a sequential process. good sentence structure and layout helps reading memory for detail in text generally better that for image, although only the
higher order structure will be recalled accurately
Implications of the eye on MM design
Implications of the eye on MM design
do not expect people to attend to detail in several different areas of an image at once. People will scan around the image, briefly focusing on
different objects, but only one at a time.
in MM systems only one image should be presented at once. Users can not attend to still images and video at the same
time.
movement is a highly effective means of alerting the peripheral vision and drawing the user’s attention. thus change or movement should be limited to one image,
otherwise it will cause stress (due to an inability to attend to both images)
Implications of hearing on MM design
Implications of hearing on MM design
only part of the auditory range is necessary for speech. People tolerate poor sound unless the quality is vital
background noise should be reduced for effective communication although the human ear is good as suppressing noise, we
get distracted
sound is very effective as a means of alerting and warning.
sound is a broadcast medium speech is interpreted by the rules of grammar
Implications of memory on MMImplications of memory on MM
minimise distraction during tasks and memorisation beware of overloading working memory, both in
terms of quantity of information and time span of retention
input from dynamic media rapidly exceeds the capacity of working memory and hence only the high level gist will be retained.
working memory has to be refreshed keeping the information available in persistent media, thus allow to re-view test or image
structuring information (chunking) memorisation of detail from image is limited
Implications of attention to MMImplications of attention to MM
do not use too many competing demands for attention Attention tends to be diverted by change hence temporal
media such as film, animation and sound will dominate over static media such as pictures and text
dynamic media contains change by definition and therefore attract attention more strongly than static
change in static media (highlighting) will attract attention
two or more dynamic media will compete for the users attention and this can lead to stress and fatigue