Transcript HUMAN COMPUTER INTERACTION

HUMAN COMPUTER
INTERACTION
Lecturer
Henry O.Quarshie
DEFINITION
• Human-computer interaction is a discipline
concerned with the design, evaluation and
implementation of interactive computing
systems for human use and with the study
of major phenomena surrounding them.
• From a computer science perspective, the
focus is on interaction and specifically on
interaction between one or more humans
and one or more computational machines.
• Human Computer Interaction is concerned
with the man-machine interfaces. Every
system equipped with a microprocessor
has some kind of user interface for its
operation; this is particularly so for those
systems that require lots of interaction for
its normal operation: i.e. computers and
computer programs.
• In a modern approach of Human
Computer Interaction, the user is the pivot
of the design trajectory. Design methods
are based on this principle and this will be
clear in discussion of task analysis,
prototyping, evaluation and usability.
• Because human-computer interaction
studies a human and a machine in
communication, it draws from supporting
knowledge on both the machine and the
human side.
On the machine side, techniques in
computer graphics, operating systems,
programming languages, and
development environments are relevant.
• On the human side, communication
theory, graphic and industrial design
disciplines, linguistics, social sciences,
cognitive psychology, and human
performance are relevant.
And, of course, engineering and design
methods are relevant.
• The growth of discretionary computing and
the mass personal computer and
workstation computer markets have meant
that sales of computers are more directly
tied to the quality of their interfaces than in
the past.
• The result has been the gradual evolution
of a standardized interface architecture
from hardware support of mice to shared
window systems to "application
management layers." Along with these
changes, researchers and designers have
begun to develop specification techniques
for user interfaces and testing techniques
for the practical production of interfaces.
FORCES SHAPING THE NATURE
OF FUTURE COMPUTING
• Human-computer interaction is, in the first
instance, affected by the forces shaping
the nature of future computing. These
forces include:
• Decreasing hardware costs leading to
larger memories and faster systems.
• Miniaturization of hardware leading to
portability.
FORCES SHAPING THE NATURE
OF FUTURE COMPUTING
• Reduction in power requirements leading to
portability.
• New display technologies leading to the
packaging of computational devices in new
forms.
• Assimilation of computation into the environment
(e.g., VCRs, microwave ovens, televisions).
• Specialized hardware leading to new functions
(e.g., rapid text search).
FORCES SHAPING THE NATURE
OF FUTURE COMPUTING
• Increased development of network
communication and distributed computing.
• Increasingly widespread use of computers,
especially by people who are outside of the
computing profession.
• Increasing innovation in input techniques (e.g.,
voice, gesture, pen), combined with lowering
cost, leading to rapid computerization by people
previously left out of the "computer revolution."
FORCES SHAPING THE NATURE
OF FUTURE COMPUTING
 Wider social concerns leading to improved
access to computers by currently
disadvantaged groups (e.g., young
children, the physically/visually disabled,
etc.).
CHARACTERISTICS OF HUMAN
COMPUTER INTERACTION
• Ubiquitous communication.
Computers will communicate through high
speed local networks, nationally over
wide-area networks, and portably via
infrared, ultrasonic, cellular, and other
technologies. Data and computational
services will be portably accessible from
many if not most locations to which a user
travels.
CHARACTERISTICS OF HUMAN
COMPUTER INTERACTION
• High functionality systems.
Systems will have large numbers of
functions associated with them. There will
be so many systems that most users,
technical or non-technical, will not have
time to learn them in the traditional way
(e.g., through thick manuals).
CHARACTERISTICS OF HUMAN
COMPUTER INTERACTION
• Mass availability of computer graphics.
Computer graphics capabilities such as
image processing, graphics
transformations, rendering, and interactive
animation will become widespread as
inexpensive chips become available for
inclusion in general workstations
CHARACTERISTICS OF HUMAN
COMPUTER INTERACTION
• Mixed media.
Systems will handle images, voice, sounds,
video, text, formatted data. These will be
exchangeable over communication links among
users.
The separate worlds of consumer electronics (e.g.,
stereo sets, VCRs, televisions) and computers
will partially merge. Computer and print worlds
will continue to cross assimilate each other.
CHARACTERISTICS OF HUMAN
COMPUTER INTERACTION
• High-bandwidth interaction.
The rate at which humans and machines
interact will increase substantially due to
the changes in speed, computer graphics,
new media, and new input/output devices.
This will lead to some qualitatively different
interfaces, such as virtual reality or
computational video.
CHARACTERISTICS OF HUMAN
COMPUTER INTERACTION
• Large and thin displays.
New display technologies will finally mature
enabling very large displays and also displays
that are thin, light weight, and have low power
consumption.
This will have large effects on portability and will
enable the development of paper-like, penbased computer interaction systems very
different in feel from desktop workstations of the
present.
CHARACTERISTICS OF HUMAN
COMPUTER INTERACTION
• Embedded computation.
Computation will pass beyond desktop computers
into every object for which uses can be found.
The environment will be alive with little
computations from computerized cooking
appliances to lighting and plumbing fixtures to
window blinds to automobile braking systems to
greeting cards. To some extent, this
development is already taking place.
CHARACTERISTICS OF HUMAN
COMPUTER INTERACTION
• The difference in the future is the addition
of networked communications that will
allow many of these embedded
computations to coordinate with each
other and with the user. Human interfaces
to these embedded devices will in many
cases be very different from those
appropriate to workstations.
CHARACTERISTICS OF HUMAN
COMPUTER INTERACTION
• Group interfaces.
Interfaces to allow groups of people to coordinate
will be common (e.g., for meetings, for
engineering projects, for authoring joint
documents). These will have major impacts on
the nature of organizations and on the division of
labor. Models of the group design process will
be embedded in systems and will cause
increased rationalization of design.
CHARACTERISTICS OF HUMAN
COMPUTER INTERACTION
• User Tailorability.
Ordinary users will routinely tailor applications to
their own use and will use this power to invent
new applications based on their understanding
of their own domains.
Users, with their deeper knowledge of their own
knowledge domains, will increasingly be
important sources of new applications at the
expense of generic systems programmers (with
systems expertise but low domain expertise).
CHARACTERISTICS OF HUMAN
COMPUTER INTERACTION
• Information Utilities.
Public information utilities (home banking
and shopping, etc.) and specialized
industry services (e.g., weather for pilots)
will continue to proliferate. The rate of
proliferation will accelerate with the
introduction of high-bandwidth interaction
and the improvement in quality of
interfaces.
Human Information Processing
( cognitive system)
Cognitive Thinking
• One of the most influential theories on the
growth and development of cognitive thinking in
children was proposed by Jean Piaget (18961980).
• Piaget was initially interested in how the child’s
biology influenced the development of the
cognitive processes, based on the concept of
maturation, but he was also interested in
epistemology (the study of knowledge).
• Putting the two together, Piaget argued
that biology influences how children gain
and organise their knowledge of the world.
• Piaget’s main methodology was through
clinical interview, mainly using his own
children as case studies.
• He asked the children a series of
questions to test their knowledge of the
world, but was not interested in the
correctness of the answers, but the
reasoning behind it.
• This method led him to discover a wealth
of information relating to children’s
thinking, but his method cannot be
classified as being of scientific rigour.
• Piaget divided schemes that children use to
understand the world through four main stages,
roughly correlated with and becoming
increasingly sophisticated with age:
• Sensorimotor stage (years 0-2)
• Preoperational stage (years 2-7)
• Concrete operational stage (years 7-11)
• Formal operational stage (years 11-adulthood)
Sensori-motor Stage
0-2 years
It is at this stage that children develop their
senses of the world in general through
movement such as sucking, grasping,
crawling, standing and walking.
Children also use their senses of touch,
taste, smell, sight and sound in order to
develop schemata of the world. In this way
children put together a picture that
incorporates these elements.
• Piaget sees the adult as being important
during this stage in terms of providing the
stimulus needed to help the child gain a
variety of experiences.
• According to Piaget, this stage marks the
development of essential spatial abilities
and understanding of the world in six substages:
• The first sub-stage occurs from birth to six
weeks and is associated primarily with the
development of reflexes. Three primary
reflexes are described by Piaget: sucking
of objects in the mouth, following moving
or interesting objects with the eyes, and
closing of the hand when an object makes
contact with the palm (palmar grasp).
• Over these first six weeks of life, these
reflexes begin to become voluntary
actions; for example, the palmar reflex
becomes intentional grasping .
• The second sub-stage occurs from six
weeks to four months and is associated
primarily with the development of habits.
Primary circular reactions or repeating of
an action involving only one's own body
begin. An example of this type of reaction
would involve something like an infant
repeating the motion of passing their hand
before their face.
• The third sub-stage occurs from four to nine
months and is associated primarily with the
development of coordination between vision and
prehension. Three new abilities occur at this
stage: intentional grasping for a desired object,
secondary circular reactions, and differentiations
between ends and means.
• At this stage, infants will intentionally grasp the
air in the direction of a desired object, often to
the amusement of friends and family.
• Secondary circular reactions, or the
repetition of an action involving an external
object begin; for example, moving a switch
to turn on a light repeatedly. The
differentiation between means also occurs.
This is perhaps one of the most important
stages of a child's growth as it signifies the
dawn of logic.
• The fourth sub-stage occurs from nine to
twelve months and is associated primarily
with the development of logic and the
coordination between means and ends.
This is an extremely important stage of
development, holding what Piaget calls the
"first proper intelligence." Also, this stage
marks the beginning of goal orientation,
the deliberate planning of steps to meet an
objective.
• The fifth sub-stage occurs from twelve to
eighteen months and is associated
primarily with the discovery of new means
to meet goals. Piaget describes the child
at this juncture as the "young scientist,"
discover new methods of meeting
challenges.
• The sixth sub-stage is associated primarily
with the beginnings of insight, or true
creativity. This marks the passage into the
preoperational stage .
Pre-operational Stage 2-7 years
• At the age of 2 children have usually
developed their ability to express
themselves using language. This means
that they have developed some form of
Symbolic Representation. This is a key
feature of this stage of development.
• Children do not only develop language as
symbolic representation, they also develop
other skills such as drawing, dance,
modeling, number and music.
• At this stage the child develops the
following:
• Symbolic functioning - is characterised
by the use of mental symbols, words, or
pictures, which the child uses to represent
something which is not physically present.
• Centration - is characterized by a child
focusing or attending to only one aspect of
a stimulus or situation. For example, in
pouring a quantity of liquid from a narrow
beaker into a shallow dish, a preschool
child might judge the quantity of liquid to
have decreased, because it is "lower"--that
is, the child attends to the height of the
water, but not to the compensating
increase in the diameter of the container.
• Intuitive thought - occurs when the child
is able to believe in something without
knowing why she or he believes it.
• Egocentrism - a version of centration, this
denotes a tendency of a child to only think
from her or his own point of view. Also, the
inability of a child to take the point of view
of others.
• Inability to Conserve - Through Piaget's
conservation experiments (conservation of
mass, volume and number) Piaget
concluded that children in the
preoperational stage lack perception of
conservation of mass, volume, and
number after the original form has
changed.
• For example, a child in this phase will
believe that a string of beads set up in a
"O-O-O-O-O" pattern will have the same
number of beads as a string which has a
"OO-O-OO-O" pattern, because they are
the same length, or that a tall, thin 8-ounce
cup has more liquid in it than a wide, fat 8ounce cup
Concrete-operational Stage
7 -11years
• It is not until the age of about 7 that Piaget
sees children as being able to think
logically and in the abstract. In the late
pre-operational stage children are only just
developing the idea of class inclusion the
ability to understand that objects can be
grouped together according to type.
• Piaget states that while the child is able to
understand that when playing with
farmyard animals, horses are different
from cows and chickens are different from
pigs, what they cannot understand until
they reach the concrete operational stage,
is that all of the animals belong in a
category of
• farm animals’. Linked with this is the ability
to order objects in a logical series such as
largest to smallest.
• Important processes during this stage are:
• Decentering - where the child takes into
account multiple aspects of a problem to
solve it. For example, the child will no
longer perceive an exceptionally wide but
short cup to contain less than a normallywide, taller cup.
• Reversibility - where the child
understands that numbers or objects can
be changed, then returned to their original
state. For this reason, a child will be able
to rapidly determine that if 4+4 equals 8, 84 will equal 4, the original quantity.
• Conservation - understanding that
quantity, length or number of items is
unrelated to the arrangement or
appearance of the object or items. For
instance, when a child is presented with
two equally-sized, full cups they will be
able to discern that if water is transferred
to a pitcher it will conserve the quantity
and be equal to the other filled cup.
• Serialisation - the ability to arrange
objects in an order according to size,
shape, or any other characteristic. For
example, if given different-shaded objects
they may make a colour gradient.
• Classification - the ability to name and
identify sets of objects according to
appearance, size or other characteristic,
including the idea that one set of objects
can include another. A child is no longer
subject to the illogical limitations of
animism (the belief that all objects are
animals and therefore have feelings).
• Elimination of Egocentrism - the ability
to view things from another's perspective
(even if they think incorrectly). For
instance, show a child a comic in which
Jane puts a doll under a box, leaves the
room, and then Jill moves the doll to a
drawer, and Jane comes back. A child in
the concrete operations stage will say that
Jane will still think it's under the box even
though the child knows it is in the drawer.
Formal Operations Stage
12 years and older
• Once children reach the formal operational
stage, they develop the ability to think
more abstractly. They can usually solve a
problem that is not physically present,
work out an hypothesis and test it out
systematically. This has obvious
implications regarding what children can
be taught at school.
• At the age of 12, most children have
started secondary school and are
embarking on subjects such algebra and
chemistry. But some people do not always
develop the ability to think in this way.
Challenges to Piagetian stage
theory
• Piagetians accounts of development have
been challenged on several grounds. First,
as Piaget himself noted, development
does not always progress in the smooth
manner his theory seems to predict.
Language
• Language has 5 major properties:
• 1. Language is creative, not merely a
learned behaviour.
• 2. Language is structured. It has a specific
form which tends to be unconscious and
specific.
• 3. Language is meaningful and its
structure helps in expressing that
meaning.
• 4. Language is referential — it is used to
describe the world around us as well as
concepts and ideas.
• 5. Language is interpersonal. It is used in
social settings and reflects the society
around us. It expresses values and beliefs.
• Infants vocalise from the moment they are born
— deaf infants vocalise and babble in the same
way that hearing infants do.
• Early language development involves turn taking
— children become socialised linguistically.
• Adults help children to learn language through
the use of ‘Motherese’ Motherese is
characterised by a special tone of voice that
exaggerates the sounds.
• Most children begin talking in one word
sentences at about one year of age. At about the
age of two, children use telegraphic speech —
putting together two words, but without any
functional grammatical structure.
• Language learning takes place successfully in
many radically different environments. It only
fails in cases where children are not raised in
human company.
• Children who are isolated from learning
around them, invent some of it for
themselves. Deaf children will make
pantomime-like gestures in order to be
understood.
• In children with brain abnormalities or with
deficits, there is a marked alteration of
ability to learn language.
• Language learning therefore results from
the interaction between a young human
brain and various social and cognitive
experiences provided within a given
environment. It could be argued that
language is what makes us uniquely
human.
PERCEPTION
• DEFINITION:
• The process of organising, interpreting,
and integrating external stimuli received
through the senses, the mental, process
involved in identifying and subjectively
interpreting objects, concepts and
behaviour, the attainment of awareness,
insight and understanding.
• Thus the concept of perception appears to
encapsulate a mental or cognitive activity that
receives processes and interprets the host of
external stimuli that impinge on our everyday
lives. This process usually takes place instantlywe see something and jump to some immediate
conclusions about it.
• Phrases such as “First impressions are often
misleading!’ and “Don’t jump to conclusions!’
suggest that whatever we see is often not the
truth, not the reality before us.
• In other cases, it is not so much a question
of misunderstanding reality, but merely
seeing a different truth in it! So, for
example, a man looks out over the
countryside towards the sunset, and says
‘just look at the view’, and his companion
says ‘yes it is amazing how dark it gets in
the early evening at this time of the year!’
• Or, take two people listening to a brass
band playing in the park, one enraptured
by the sound, the other restless and
wanting to move on. Same stimulus, but
different perceptions and different
responses.
• The extent to which an individual’s
perception (i.e. the subjective reality) of
the event matches what is truly there (i.e.
the objective reality) depends on:
• 1: Factors at work in the perceiver, such
as the individual’s physical health,
intelligence level, degree of openmindedness, and general level of
emotional well-being.
• 2:The factors at work in the external
situation, such as whether this is a new
experience or a repeat of a past event, the
extent of the involvement of others,
especially those who bring strongly
positive or negative messages.
REASONS WHY PEOPLE SEE
EVENTS DIFFERENTLY
• Their physical senses vary (e.g. colour
blindness , less-than-perfect vision, poor
hearing, imperfect sense of smell etc)
• Health differences
• Their general intelligence levels vary (i.e.
some people size up their situation far
quicker than others)
• Nature and effects of past experiences are
different for individuals (e.g. an
experienced birdwatcher will see the
camouflaged bird well before a less
experienced colleague)
• Innate abilities and learned skills are
different between individuals
• Individual values and attitudes cause
people to see things differently.
• Personalities differ, and thus individuals tend to
adopt particular stances towards outside events
(e.g. some get very intense, ascribing all sorts of
motives and feelings to the perceived event,
while others are cool and detached about the
same event)
• Individual aspirations and goals also differ
widely, and these affect the relative importance
attached to outside events.
ATTENTION
• This is what enables us to process information
about the world around us. We can only be
aware of things around us if we pay attention to
them.
• We can think of attention as a spotlight that we
shine on things in the world around us to make
them stand out. When something "stands out,"
we notice it, bringing it into our awareness, and
then process or interpret it. Attention can change
rapidly, switching from one thing to another.
• It can be steered by our intentions ("topdown"), as when we look for a particular
face in a crowd, or it can be steered by
features of objects in the world ("bottomup"), as when our attention is grabbed by
a police car's flashing lights in our rearview
mirror. Preattentive processes help us
decide what to pay attention to and what
to filter out and ignore.
• Attention filters and feeds information
about the world around us into our minds.
• It is ability to focus on a task and the
ability to concentrate.
Different Aspects of Attention
1:Selective attention: trying to attend to one task
over another requires selective attention
2: Divided attention: trying to attend to two stimuli
at once and making multiple responses rather
than making one response to multiple stimuli.
3: Automaticity:does not require attention, e.g.
driving a car & listening to the radio.
Type of Things that draw attention
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Colour
Size
Motion
Sound
Factors that can make
website/program more accessible to
children.
• Children tend to explore websites because
they seek to have fun as well as to learn.
Thus, websites should try to be playful
and exploit their general curiosity by
making the site's content attentiongrabbing and, to a small degree,
challenging in order to entice them to go
through the site.
• For example, children may seek to explore
certain areas within a site because
exploring it satisfies a curiosity need that is
enticed by the content of the site.
• Children often seek out interactivity with
the site, again to be creative and to have
fun. This can be in the form of coloring
pages that can be printed out. In fact,
coloring pages can be more popular than
games on a site.
• Other popular methods are to allow
children to create music or draw pictures
• In addition, children are much more
attracted to animation than adults.
Animation adds a great deal to the "fun
factor" if it is done well, but too much
animation will distract and disorient them.
children often click visible features on a
screen just to see what would happen.
• If there is a resulting animation or sound,
children often repeatedly click that area of
the screen just to continue the animation
or sound. Therefore, gratuitous animation
or sounds may distract the child from
finding more relevant
• Children do not have the attention span for
longer downloads. A lot of children are expecting
to see a picture when they hit a button, and they
are disappointed if they don't see one.
• children tended to wait for images to completely
load on a page before navigating to another in
the belief that a complete loading was
mandatory. This wait produced signs of
frustration .
• The interest in the site however will last as
long as the contents are innovative and
fun. Thus, it is advisable that websites
geared toward children frequently have
new features in order for the site to be
inventive and interesting to the children.
• It is also recommended that children be
rewarded with different and interesting
features at each level within the site. This
will help draw them deeper within the site.
• Research has consistently shown that
most children under the age of five will
have an attention span of only around 8 to
15 minutes. Many children will have even
less. Thus, the layout and content of a site
should reflect the low attention span of
children by being designed to be accessed
quickly.
• Directions should be very short,
uncomplicated, and easily read (children
tend not to read directions voluntarily), and
games should not take longer than their
attention span.
• Children under eight generally do not think in
abstract terms. For example, children may find it
easier to recognize actual pictures of objects
than to use symbols to represent them.
• It is important to be as 'concrete' as possible
when explaining directions. Moreover, since
children view the world in more concrete terms,
icons should reflect this by being as concrete as
possible.
• Children have different background
knowledge than adults. Children are
typically unfamiliar with many businessrelated concepts.
• Therefore, great care should be taken to
create metaphors that reflect the
understanding, environment, and
language of children.
• Children can make the distinction between
a 'fun' website and a usable one. Buttons
should represent familiar things to
children, easily convey their purpose, and
should be fairly large - the size of a quarter
to accommodate their poorer hand-eye
coordination. Buttons should indicate
when they are being moused over, such
as being highlighted
• Another important concern is the actual
language of the site. For instance, the
website's language should lie somewhere
between being understandable -don't use
computer phrases - and fun, but not too
childish for the intended audience or they
will resent it. Also, the younger the
intended audience, the more concrete the
language should be.
• The font type of the text may also be a
factor in the attractiveness of a website.
For instance, fourth and fifth graders
significantly prefer the 14-point Arial and
the 12-point Comic Sans MS font over the
12-point Times New Roman font and 12point Courier New.
TEENAGERS
• A teenager generally refer to a young
person between the ages of 13 and 19.
• In other words a teenager refers to a
person in his or her early youthful stage.
This is the stage at which they start
maturing physically.
• They generally become aware of their
appearance especially towards the
opposite sex, and also learn to build their
confidence at this stage.
• Female at this stage tend to have a
different kind of perception about things
and even about life itself.
• Most teenage girls also seem to mature
quickly and at a faster rate than their male
counterparts. This can be noticed
whenever a topic is being discussed about
themselves and their environment.
• Teenage girls are fast in picking up sizing
up their situation than their male
counterparts.
• Teenage girls also prefer to be more
thoughtful of things around them. Their
thoughts are based on things that are
mind bugging and very interesting.
• Teenage girls are very emotional and
majority are soft spoken as compared to
their male counterparts.
• Female in their teens pay more attention
to life issues. This is seen in the choices
they make. For e.g. a teenage girl would
prefer to wear clothes that are more
fashionable.
• Teenage girls prefer bright colours. They
prefer colours that brings vibrancy to them
and their environment.
• Teenage boys like huge and big things
while their female counterpart prefer small
and portable things.
• Most teenage girls prefer cool and very
relaxing sound, most teenage boys want it
loud.
• Teenage boys and girls largely surf the
Web for different reasons.
• According to a survey of 1,520
respondents by Jupiter Communications
(2000), boys are more interested in
playing games (62% to 41%), building web
pages (35% to 24%), downloading
software (74% to 48%), and downloading
music (68% to 74%) than teenage girls.
• Teenage girls on the other hand, tend to
read more online magazines (36% to
19%), send e-greetings (75% to 48%), and
do homework online (74% to 63%) more
than teenage boys.
Factors that can make
website/program more accessible to
Adult.
• Older users generally take more steps
than younger users in finding the same
amount of information.
• Research has found that older users'
success at finding information declined
significantly when they had to follow more
than 3 to 6 hyperlink paths to get to the
desired information.
• It is believed this decline in performance
occurs because older users tend to have
greater trouble remembering their location
within a site because of a decrease in
working memory efficiency.
• Therefore, if the site is geared towards an
older population it is especially important
not to have a very deep hierarchy.
• It is also important that the site's contents
be explicit at the beginning of the site (at
the homepage level) instead of relying on
exploration.
• This could be done by placing a site index
or sitemap at the homepage level. It is
also recommended to use clearly visible
navigational aids to help them visualize
the structure of the site.
• In another study, found that older users were
slower than college-age users in finding
information. In general, older users took the time
to carefully read the text on a web page before
continuing the tasks, which tended to slow them
down.
• This finding is supported by the research who
found that older users tended to carefully read
information before exploring, which further
supports the idea of placing a site index at the
homepage level.
• Older adults also prefer text to have very
clear headings. Clear and large headings
help orientate users as well as help those
who have difficulty reading because of
degraded or impaired vision by giving
them obvious signposts.
• Usually the greatest factor affecting older web
users is their decline in vision. Research has
found that there is a 50% reduction in the
amount of perceived light at age 50 compared to
age 20, and this reduction increases to 66% at
age 60.
• It is therefore recommended that all sites, but
particularly those directed towards older users,
have high contrast between the text and the
background, as well as between darker and
lighter colors in general.
• Older adults also tend to have a reduced field of
view. Consequently, more important information
and links should be placed closer to the center
of the screen in order for them to be more easily
detected.
• This is particularly true if there are many objects
on the screen. That is, older adults generally
have trouble locating a specific object if there
are many other objects on the screen.
• The reading performance of older adults
shows that colored text on a coloured
background typically reduces their reading
performance compared to reading black
text on a white background. Moreover,
research has shown that dark text on light
backgrounds is generally superior to light
text on dark backgrounds.
• However, older adults do have an
increased sensitivity to glare. Thus, it is
recommended that backgrounds not be
pure white, but some form of off-white
color.
• Older adults have reduced attention
spans. older adults have difficulties in
attention over long periods of time. older
adults may be especially distracted by
extraneous visual noise, such as
background graphics.
• Other distractions may include such things
that obscure the screen-even if it is only
temporarily visible. Consequently, items
such as pop-out ads and multiple windows
may tend to distract and disorient them to
a greater extent than younger adults.
Factors that can make
website/program accessible to
international users
• What is needed is an understanding of
how different cultures respond to various
website designs.
• Attention should to paid to regional
languages and customs
• Various cultures respond to layout designs
differently.
• Research on world culture to web design.
stated that world culture consists of five
dimensions, four of which are relevant to
the Web.
• The first dimension, power-distance, refers
to the degree in which individuals with less
power expect and accept unequal
distributions of power within a culture.
Cultures with a high amount of powerdistance (PD) tend to have centralized
political power and deep hierarchies.
• These types of societies emphasize
hierarchical relationships, authority,
experts, certifications and official logos,
leaders, security, and an acceptance for
restrictions to information access. Cultures
with low PD emphasize flatter hierarchies
and greater equality in relationships
• Thus cultures with a high PD may typically
feel comfortable with a greater emphasis
on highlighting the accomplishments of
high-ranking individuals within a
company, as well as providing a greater
hierarchical relationship between different
divisions and positions within the site.
• Low PD cultures, such as Denmark, would
tend to be more comfortable with sites that
showcase 'common' individuals or both
genders. They would also tend to deemphasize hierarchical differences
between individuals within the same
company.
• The second dimension, individualism,
refers to the degree to which a culture
emphasis the self and immediate family
over the society at large. Cultures with
large amounts of individualism (IND), such
as the United States, value personal
freedom and rewards, privacy, and
diversity of opinion. Here freedom of the
press and self-actualization are prized.
• The third dimension, masculinity, refers to
the degree to which traditional masculine
roles of assertiveness and competition are
emphasized. Cultures with high
masculinity (MAS) stress and value these
values, whereas cultures that deemphasize them tend to stress mutual
cooperation and family support.
• Thus Japan, which has the highest MAS
index, may as a society be more
comfortable with sites that promote
traditional male and female roles, as well
as have certain sections of a site
specifically dedicated to each gender.
Countries such as Sweden, on the other
hand, should probably not have sites that
emphasize gender roles because they
have a very low MAS score.
• The fourth dimension, uncertainty
avoidance, refers to the degree to which
individuals have anxiety about uncertain
events. Research points out that cultures
with a high amount of uncertainty
avoidance (UA) tend to be expressive,
have more formal and simple rules, and
desire structure in organizations.
• Low UA cultures tend to desire more
informal business arrangements and are
more relaxed. Thus, individuals within
countries with a high UA, such as Greece,
would tend to prefer sites with limited,
simple, and redundant navigational
devices, whereas individuals in Hong
Kong would tend to prefer greater
complexity and less control over
navigation.
THE EFFECT OF COLOUR
• Colour has psychological effects on users
that are different across cultures. colour
can present opposite meanings, such as
yellow for cowardice in the United States,
and Grace and Nobility in Japan.
Examples of cultural associations of
color (From Russo & Boor, 1993).
Culture
Red
Blue
United
States
Danger
Masculinity
France
Aristocracy
Egypt
Death
India
Green
White
Cowardice
Purity
Freedom/Peace Criminality
Temporary
Neutrality
Virtue/Faith/
Truth
Fertility/
Strength
Happiness/
Prosperity
Joy
Life/Creativity
Prosperity/
Fertility
Success
Death/Purity
Japan
Anger/Danger Villainy
Future/Youth/
Energy
Grace/
Nobility
Death
China
Happiness
Ming Dynasty/ Birth/Wealth/
Death/Purity
Heavens/Clouds Power
Heavens/Clouds
Safety
Yellow
• The choice of colors on your website is
vital to making your visitors feel welcome
and increasing conversion rates. As Dr.
Morton indicates in The Power of Color,
people base 60% of their decision
regarding whether they will accept or
reject a particular object on its color alone.
• Different colors have different implications
for different markets. It's important to
remember that simply because you
perceive a color to mean something,
people on the other side of the world will
not necessarily interpret the same color in
the same way. Understanding your
website's market is the key to choosing the
right colors.
• One of the first things you should do when
determining colors for your website is to
decide what colors go best with your
particular product.
• Start with a large selection of colors, and
then narrow it down by factoring in your
market age, gender and geographical
location. This may prove to be a difficult
task.
• To understand how color might be used, it
is important to begin by understanding the
response that color elicits within the
average human being.
• Keep in mind, however, that there are
exceptions to every rule. Not every person
responds to color in the same way.
• This information is based on the law of
averages. There will be differences from
person to person, but as a rule
• Yellow is a color that:
• Adults automatically associate with
children.
• Demand attention.
• Is the color of optimism.
• Enhances concentration
• Speeds the metabolism.
•
•
•
•
•
•
•
•
Red is a color that:
Always attracts attention.
Is associated with strength and desire.
Can be used to promote danger as with
emergency exit and stop signs.
Promotes violence and anger in some people.
Stimulates buying action.
In China symbolizes celebration and good luck.
In India is the color of purity and is, therefore,
often used in wedding outfits.
• Pink - - in all shades including mauve - - is
a color that:
• Produces a chemical in the brain that
actually calms people.
•
•
•
•
White is a color that:
Means purity and virginity in the Western world.
Means death and mourning for Asians.
Represents reverence, humility, innocence,
birth, and peace.
• Denotes simplicity and precision.
• Is associated with everything good.
• Represents youth.
• Blue is a color that:
• Is associated with the sky and water; things that
are cool, calm, tranquil, peaceful, and clean.
• Is the color of harmony, unity, and security.
• Is liked by the widest range of human beings.
• Is associated with truth, trust, stability, loyalty,
sincerity, and dependability.
• Helps people be more productive.
• Green is a color that:
• Symbolizes nature and environment.
• Is considered the color of health, youth,
vigor, and renewal because it symbolizes
spring.
• Is viewed by some as the color of jealousy
and envy.
• Orange is a color that:
• Expresses energy,
• Symbolizes warmth, enthusiasm, vibrancy, and
flamboyancy.
• Black is a color that:
• Causes physical fear in some humans while
stimulating anger in others.
• Implies submission, which is why priests and
nuns wear it (to indicate their submission to
God).
• Goes with every other color.
• Is the color of remorse, mourning, and death.
• Purple is a color that:
• Is associated with royalty, nobility, and wealth
and thereby can also denote cruelty and
arrogance.
• Is associated with spirituality and is often used in
religious ceremony.
• In lighter shades, denotes feminism and
romance.
• Brown is a color that:
• Is considered solid and reliable because it is the
color of earth.
• Is confident and casual, as well as reassuring.
• Is a favorite color of men.
• In lighter shades can be sad.
• Gray is a color that:
• Is considered conservative and traditional.
• Denotes intelligence and seriousness.
Implications of Colour from the
physiology of the eye
• Do not use blue for small objects (since
human sensitivity for blue is very low,
particularly in the fovea)
• Blue is a good background color (since
human sensitivity for blue is very low and
since receptors for blue are roughly evenly
distributed over the retina)
• If red and green are used for small objects,
these should be in the center (since the
sensitivity for these colors is far higher in the
center).
• If red and green are used as signals (warnings)
in the periphery, they should have additional
emphasis (like blinking or change in size).
• Black, white, yellow and blue can be used in the
periphery since the sensitivity of the retina is
roughly the same.
Effect of Colours in Design
• Remember that the purpose of Web
design is to draw the visitor's eye to
key page elements.
• Ideally your visitors should be able to take
in the page at a glance, with their eyes
locking on the most important things.
Colored table cells, colored text, and
colored graphics are all good ways to draw
attention.
• But colour can get you into trouble too.
Too often you see poorly designed Web
pages where badly chosen colors detract
from the overall design. If you surf the
Web enough, sooner or later you'll find a
page that's almost unreadable because it
sets dark colours on a dark background.
• You can avoid this sort of problem by
applying some basic rules about using
colour.
• 1. Choose colours that contrast. Try to
use colours that play well together.
• 2.Use colour discreetly. According to the
Microsoft resource, black on yellow is a
good colour combination. Does that mean
you should use these as the text and
background colours for your page? Not
really. It means that your eye is quickly
drawn to the bright yellow, and the black
text is easily readable against that
background.
• 3. Avoid fancy tiled backgrounds. noisy
tiled backgrounds too often distract from
the page, making it hard to read.
• 4. When in doubt, use black on white.
Name your three favorite commercial Web
sites. Now take a look at them. Most likely
you'll find they use black text on a white
background. There's a good reason: it's
legible and it keeps the presentation of the
text from distracting from its content.
• 5. What you see may not be what they
get. Keep in mind that, on the Web, you
can never guarantee exactly how a
computer will display a colour. A
Macintosh will render colours a shade
brighter than a PC, and different PC
monitors will likewise vary by a shade. So
don't become fixated on getting a colour
just the way you like it.
• As with most things on the Web, it's best
to test your colours by viewing your page
on several different computers, then chose
the colour that works the best on the most
machines.
Interface Design Guidelines
for Users of All Ages
• The first step to designing for different age
segments and demographics is to
understand
• generational perspectives. From a content
perspective, consider the values of the
target audiences and icons they identify
with.
• Life and world events which connect with
their youth, will posture your site and
products for success.
• Ask yourself how will they use your
product or web site?
• What is important to them?
• What devices(s) will they use?
• How will they be connected(dial up or
broadband)?
• What environment will they be using it
(work, home and / or travel)?
• What physical limitations might they have?
• To reach this audience of consumers, web
designers must understand the dynamics
and the respective natural changes
associated with aging.
• Typically these degenerative effects
include diminished vision, varying degrees
of hearing loss, hand eye coordination and
psychomotor impairments including
difficulty with small motor coordination.
• 1: Layout & StyleT he layout should be
• based on the needs of the user including
the priority of the information as well as
terminology and writing style of the
“typical” user.
• We have observed older users and
novices tend to scroll much slower using
the bar arrows on the right hand scroll bar,
vs. dragging the bar. Further hampering
their navigation is the use of an older
mouse which does not have a built-in
scroll wheel.
• 2. Animation & graphic elements.
Flashing or blinking graphics are highly
distracting. Excessive pop-up windows
and advert banners have this same
impact, distracting the reader and drawing
attention to everything else.
• 3. Avoid distracting background
elements.
• Using any background patterns including
watermarks or embossed logos generally
are distracting and interfere with
readability. As an alternative, a light
complementary background color can be
applied.
• 4.Balance of type and open space.
• Large areas of white space and small
blocks of text increase readability. The
results are your pages are cleaner and
easier to navigate. Bear in mind that larger
(longer) pages can mean more scrolling
for the user.
• 5. Hand eye coordination.
• For those users with diminished motor
capabilities, simple double-clicking a
mouse or scrolling can be difficult. It is
recommended you attempt to make all
graphical links large and static.
• Increasing the size of the area around a
link, making it “hot” or selectable, can
enhance ease of use. Never expect a user
to click on a moving graphic element or
banner.
• 6.Hard coding. Do not use any coding
that will limit a user’s ability to adjust or
change his or her font, font size or colors.
Insure this applies to both the content and
navigation elements on your site.
• 7.Links. Insure your links are consistently
underlined to make then identifiable and
so that “screen readers” can recognize
them. A user should not have to guess or
maneuver the mouse to find a link.
• 8.Page length. Short pages, those
containing one or two screens of text, work
well for the home page and menu pages
when users are scanning for informational
links.
• Avoid creating large pages with multiple
articles and links. Break topics down into
succinct pages for usability and printing.
One larger master document may result in
users having to print out excessive
amounts of material just to get the
paragraph they’re interested.
• 9.Navigation bars & links. Consistency in
navigation is one of the golden rules for all
designers.
Redundancy of links both within a site and
on your navigation bars,(horizontal and
vertical) are helpful as users explore and
learn differently.
• 10.Colour. Colour is a critical
consideration in web and interface design.
Partial sight, aging and congenital colour
defects all produce changes in perception
that reduce the visual effectiveness of
certain color combinations.