barbara white : interaction design

Understanding users

cognitivesocial

affective

barbara white : interaction design

IssuesIssues

• What is cognition?

• Design implications of cognitive processes

• Cognitive frameworks:– Mental models– Information processing– External cognition

barbara white : interaction design

Understanding usersUnderstanding users

Why do we need to understand our users?

barbara white : interaction design

cognitive psychology & HCIcognitive psychology & HCI

What is cognition?

What goes on in the mind?

Reflective

Experiential

barbara white : interaction design

Core cognitive aspects Core cognitive aspects

What are the core aspects of cognition?

barbara white : interaction design

Activity: Find the price of a double room at the Holiday Inn in BradleyActivity: Find the price of a double room at the Holiday Inn in Bradley

barbara white : interaction design

Activity: Find the price for a double room at the Quality Inn in ColumbiaActivity: Find the price for a double room at the Quality Inn in Columbia

barbara white : interaction design

ActivityActivity

• Tullis (1987) found that the two screens produced quite different results– 1st screen - took an average of 5.5 seconds to search

– 2nd screen - took 3.2 seconds to search

• Why, since both displays have the same density of information (31%)?

• Spacing– In the 1st screen the information is bunched up together, making

it hard to search– In the 2nd screen the characters are grouped into vertical

categories of information making it easier

barbara white : interaction design

Attention Attention

• Selecting things to concentrate on from the mass around us, at a point in time

• Focussed and divided attention enables us to be selective in terms of the mass of competing stimuli but limits our ability to keep track of all events

barbara white : interaction design

What is this demonstrating no to do!What is this demonstrating no to do!

Our Situation

State the bad news

Be clear, don’t try to obscure thesituation

barbara white : interaction design

Design implications for attentionDesign implications for attention

Information at the interface should be structured to capture users’ attention, e.g. use perceptual boundaries (windows), colour, reverse video, sound and flashing lights

Make information salient when it needs attending to

Avoid cluttering the interface – keep it crisp, simple design

Avoid using too much because the software allows it

Use techniques that make things stand out like colour, ordering, spacing, underlining, sequencing and animation

barbara white : interaction design

Is color contrast good? Find italianIs color contrast good? Find italian

FindFind italianitalian

barbara white : interaction design

Are borders and white space better? Find Are borders and white space better? Find frenchfrench

Find frenchFind french

barbara white : interaction design

ActivityActivity

• Weller (2004) found people took less time to locate items for information that was grouped – using a border (2nd screen) compared with using

color contrast (1st screen)

• Some argue that too much white space on web pages is detrimental to search– Makes it hard to find information

• Do you agree?

barbara white : interaction design

Which is easiest to read and why?Which is easiest to read and why?

What is the time?

What is the time?

What is the time?

What is the time?

What is the time?

barbara white : interaction design

Perception and recognitionPerception and recognition

• Perception is how information is acquired from the environment from the senses (eyes, ears, fingers) and transformed into experiences

• implication is to design representations that are readily perceivable, e.g.– Text should be legible– Icons should be easy to distinguish and read

barbara white : interaction design

Design implicationsDesign implications

• Representations of information need to be designed to be perceptible and recognizable

• Icons and other graphical representations should enable users to readily distinguish their meaning

• Bordering and spacing are effective visual ways of grouping information

• Sounds should be audible and distinguishable• Speech output should enable users to distinguish

between the set of spoken words• Text should be legible and distinguishable from the

background

barbara white : interaction design

Remember? Remember?

Try to remember the dates of all members of your family or your closest friends birthday

Try to describe what’s on the cover of the latest book or DVD/CD you brought?

What’s easiest? Why?

barbara white : interaction design

MemoryMemory

• Involves encoding and recalling knowledge and acting appropriately

• We don’t remember everything - involves filtering and processing

• Context is important in affecting our memory

• We recognize things much better than being able to recall things– The rise of the GUI over

command-based interfaces

• Better at remembering images than words– The use of icons rather than

names

barbara white : interaction design

Recognition versus recallRecognition versus recall

• Command-based interfaces require users to recall from memory a name from a possible set of 100s

• GUIs provide visually-based options that users need only browse through until they recognize one

• Web browsers, MP3 players, etc., provide lists of visited URLs, song titles etc., that support recognition memory

barbara white : interaction design

barbara white : interaction design

The problem with the classic ‘7The problem with the classic ‘72’2’

• George Miller’s theory of how much information people can remember ( 7 +/- 2)

• People’s immediate memory capacity is very limited

• Many designers have been led to believe that this is useful finding for interaction design

barbara white : interaction design

What some designers get up to…What some designers get up to…

• Present only 7 options on a menu

• Display only 7 icons on a tool bar

• Have no more than 7 bullets in a list

• Place only 7 items on a pull down menu

• Place only 7 tabs on the top of a website page

But this is wrong? Why?

barbara white : interaction design

Personal information managementPersonal information management

• Personal information management (PIM) is a growing problem for most users– Who have vast numbers of documents, images,

music files, video clips, emails, attachments, bookmarks, etc.,

– Major problem is deciding where and how to save them all, then remembering what they were called and where to find them again

– Naming most common means of encoding them – Trying to remember a name of a file created some

time back can be very difficult, especially when have 1000s and 1000s

– How might such a process be facilitated taking into account people’s memory abilities?

barbara white : interaction design

File managementFile management

• Facilitate existing memory strategies and try to assist users when they get stuck

• Help users encode files in richer ways – Provide them with ways of saving files using colour,

flagging, image,

flexible text,

time stamping

barbara white : interaction design

Is Apple’s Spotlight search tool any good?Is Apple’s Spotlight search tool any good?

Is Apple’s Is Apple’s Spotlight Spotlight search tool search tool any good?any good?

barbara white : interaction design

More appropriate application of memory researchMore appropriate application of memory research

• Research on information retrieval can be usefully applied

• Memory involves 2 processes– recall-directed and – recognition-based scanning

• File management systems should be designed to optimize both kinds of memory processes

barbara white : interaction design

Core cognitive aspects Core cognitive aspects

Core aspects of cognition?

Problem-solving, planning, reasoning & decision-making, learning

Reading, speaking & listening

Perception & recognition

Attention

Memory