COGNITIVE ASPECTS Why, since both displays have the same
density of information?
Why do we need to understand users?
Spacing
Interacting with technology is cognitive
In the 1st screen the information is
Need to take into account cognitive
bunched up together, making it hard to
processes involved and cognitive
search
limitations of users
In the 2nd screen the characters are
Provides knowledge about what users
grouped into vertical categories of
can and cannot be expected to do
information making it easier
Identifies and explains the nature and
Multitasking and attention
causes of problems users encounter
Is it possible to perform multiple
Supply theories, modelling tools,
tasks without one or more of them
guidance and methods that can lead to
being detrimentally affected?
the design of better interactive
Ophir et al (2009) compared heavy
products
vs light multi-taskers
Cognitive processes heavy were more prone to being
distracted than those who
Attention infrequently multitask
Selecting things to concentrate on at a heavy multi-taskers are easily
point in time from the mass of stimuli distracted and find it difficult to
around us filter irrelevant information
Allows us to focus on information that is Design implications for attention
relevant to what we are doing
Involves audio and/or visual senses Make information salient when it needs
Focussed and divided attention enables attending to
us to be selective in terms of the mass
Use techniques that make things stand
of competing stimuli but limits our
out like color, ordering, spacing,
ability to keep track of all events
underlining, sequencing and animation
Information at the interface should be
structured to capture users’ attention, Avoid cluttering the interface with too
e.g. use perceptual boundaries much information
(windows), colour, reverse video, sound
Search engines and form fill-ins that
and flashing lights
have simple and clean interfaces are
easier to use
ACTIVITY
Tullis (1987) found that the two screens
produced quite different results Perception
1st screen - took an average of 5.5 How information is acquired from the
seconds to search world and transformed into experiences
2nd screen - took 3.2 seconds to search
Obvious implication is to design Memory
representations that are readily
perceivable, e.g. Involves first encoding and then
Text should be legible retrieving knowledge.
Context is important in affecting our
Icons should be easy to distinguish and
memory (i.e. where, when)
read
We recognize things much better
Activity than being able to recall things
we remember less about objects we
Weller (2004) found people took less
have photographed than when we
time to locate items for information
observe them with the naked eye
that was grouped
(Henkel, 2014)
using a border (2nd screen) compared
with using color contrast (1st screen) Processing in memory
Some argue that too much white space Encoding is first stage of memory
on web pages is detrimental to search determines which information is
attended to in the environment
Makes it hard to find information
and how it is interpreted
Design implications for Perception The more attention paid to
something…
Icons should enable users to
The more it is processed in terms
readily distinguish their
of thinking about it and
meaning
comparing it with other
Bordering and spacing are knowledge…
effective visual ways of The more likely it is to be
grouping information remembered
e.g. when learning about HCI, it
Sounds should be audible
is much better to reflect upon it,
and distinguishable
carry out exercises, have
Speech output should enable discussions with others about it,
users to distinguish between and write notes than just
the set of spoken words passively read a book, listen to a
lecture or watch a video about it
Text should be legible and
distinguishable from the Context is important
background Context affects the extent to
Tactile feedback should allow which information can be
users to recognize and subsequently retrieved
Sometimes it can be difficult for
distinguish different
people to recall information
meanings
that was encoded in a different George Miller’s (1956) theory of how
context: much information people can
“You are on a train and remember
someone comes up to you and
says hello. You don’t recognize People’s immediate memory capacity is
him for a few moments but very limited
then realize it is one of your
neighbours. You are only used Many designers think this is useful
to seeing your neighbour in the finding for interaction design
hallway of your apartment But…
block and seeing him out of
context makes him difficult to What some designers get up to…
recognize initially”
Present only 7 options on a
Activity
menu
People are very good at
Display only 7 icons on a tool bar
remembering visual cues
Have no more than 7 bullets in a
about things
list
e.g. the color of items, the
Place only 7 items on a pull
location of objects and marks
down menu
on an object
Place only 7 tabs on the top of a
They find it more difficult to
website page
learn and remember
But this is wrong
arbitrary material
e.g. birthdays and phone Why?
numbers
Inappropriate application of the theory
People can scan lists of bullets, tabs,
Recognition versus recall menu items for the one they want
Command-based interfaces They don’t have to recall them from
memory having only briefly heard or
require users to recall from
seen them
memory a name from a possible
set of 100s Sometimes a small number of items is
GUIs provides MP3 players good
visually-based options that users But depends on task and available screen estate
need only browse through until
they recognize one Digital content management
Web browsers, etc., provide lists Is a growing problem for many users
of visited URLs, song titles etc.,
vast numbers of documents,
that support recognition
images, music files, video clips,
memory
emails, attachments,
The problem with the classic ‘72’ bookmarks, etc.,
where and how to save them a wearable device that intermittently
all, then remembering what takes photos without any user
they were called and where to intervention while worn
find them again
digital images taken are stored and
naming most common means of revisited using special software
encoding them
Has been found to improve people’s
but can be difficult to memory, suffering from Alzheimer’s
remember, especially when
Design implications of memory
have 1000s and 1000s.
Don’t overload users’ memories with
Memory involves 2 processes
complicated procedures for carrying
recall-directed and recognition-based out tasks
scanning
Design interfaces that promote
File management systems should be recognition rather than recall
designed to optimize both kinds of
Provide users with various ways of
memory processes
encoding information to help them
e.g. Search box and history list remember
Help users encode files in richer ways e.g. categories, color, flagging, time stamping
Provide them with ways of saving files
using colour, flagging, image, flexible
text, time stamping, etc. Learning
How to learn to use a computer-
Digital Forgetting based application
When might you wish to forget Using a computer-based
something that is online? application or YouTube video to
When you break up with a partner understand a given topic
Emotionally painful to be reminded of People find it hard to learn by
them through shared photos, social following instructions in a
media, etc., manual
Sas and Whittaker (2013) suggest new
ways of harvesting and deleting digital Design implications of Learning
content
Design interfaces that encourage
e.g. making photos of ex into an
abstract collage
exploration
helps with closure Design interfaces that constrain and
guide learners
Memory aids Dynamically linking concepts and
representations can facilitate the
Sense Cam developed by Microsoft
learning of complex material
Research Labs (now autographer)
Reading, speaking, and listening Problem-solving, planning, reasoning
and decision-making
The ease with which people can
read, listen, or speak differs All involves reflective cognition
Many prefer listening to reading e.g. thinking about what to
do, what the options are, and
Reading can be quicker than
the consequences
speaking or listening
Often involves conscious processes,
Listening requires less cognitive
discussion with others (or oneself),
effort than reading or speaking
and the use of artefacts
Dyslexics have difficulties
e.g. maps, books, pen and
understanding and recognizing
paper
written words
May involve working through
Applications
different scenarios and deciding
Speech-recognition systems which is best option
allow users to interact with them
Design implications
by asking questions
e.g. Google Voice, Siri Provide additional
Speech-output systems use information/functions for users who
artificially generated speech wish to understand more about how
e.g. written-text-to-speech to carry out an activity more
systems for the blind effectively
Natural-language systems enable
Use simple computational aids to
users to type in questions and
support rapid decision-making and
give text-based responses
planning for users on the move
e.g. Ask search engine
Dilemma
Design implications of Reading,
Speaking, Listening The app mentality developing in
the psyche of the younger
Speech-based menus and instructions
generation is making it worse for
should be short
them to make their own
Accentuate the intonation of artificially decisions because they are
generated speech voices becoming risk averse (Gardner
and Davis, 2013)
they are harder to understand than
Relying on a multitude of apps
human voices
means that they are becoming
Provide opportunities for making text increasingly more anxious about
large on a screen making decisions by themselves.
