Chapter 3Characteristics of

Interaction

1. Input

2. Output

3. Interaction Styles

4. User support

Input

Examples of entering information:

Keyboard

Pointing Devices

Speech Recognition Systems

Handwriting Recognition Systems

Gesture Recognition Systems

Foot-operated devices

Eye Trackers

Data Gloves

Output

Computer screen or other visual display units (as in PDAs, mobile phones, polymers, etc.).

Printers.

Voice output (lifts, London Underground “Mind the Gap”).

Interaction Styles

How much interaction is required in particular applications (ranging from minimal interaction (=batch input where input is made at a particular time and the machine performs the task without further user interaction) to maximal interaction (virtual reality applications)).

Interaction Styles continuedCommon Interaction Styles:

Windows

Menus

Fill-in forms

Spreadsheets

BoxesCommand Languages (preferred by experienced users)

Graphical Interfaces (any interface with windows, buttons, boxes, icons etc. is generally called a graphical user interface or GUI)

Graphical Interfaces

... are considered the most important interfaces.

Eye-tracking studies suggest that people in cultures that read from left to right generally find it easiest if the starting point is the upper-left corner of the screen (this will permit left to right and top to bottom reading).

Cultures who read from right to left would probably find it easiest if the upper right corner of the screen was the starting point.

Graphical Interfaces continued

There is a trend towards asynchronous, multi-threaded dialogue (event-based dialogue) where many tasks are available to the user at the same time and sequencing of each task is independent of the other tasks (e.g. you can run many application programs, open windows in each application program and switch between these applications and their respective windows. Each application program will be able to provide feedback when you perform a particular operation).

Graphical Interfaces continued

Different kinds of graphical user interfaces:

Data and scientific visualisation

Visual databases

Animation

Full-motion video

Multimedia and hypermedia

Graphical Interfaces continued

People tend to have different cognitive styles in general. Moreover, these cognitive styles tend to vary from situation to situation.

This is why icons are predominantly used in paint and photo editing programs (e.g. Photoshop), whilst word processors often have textual menus for actions. The reason for this is because people find it easier to stay in one domain (paint - graphical icons, text - text menu)

Graphical Interfaces continued

A few more words on selecting colour. To express contrast or difference in figures, it is generally recommended to use high-contrast colours. To express similarity, low-contrast colours are generally preferred.

Adjacent colours usually influence one another, e.g. the very same colour will appear lighter on a dark background than on a light background.

Graphical Interfaces continued

9 percent of all people have some form of colour blindness (Marcus, 1992).

User Support

User documentation is seen as part of the user interface.

User documentation should be very high quality and well prepared. The better it is, the less people will need to ask for help.

However, even good documentation does not substitute for a poor user interface design.

User Support continued

Different forms of user support:

1. Online help

2. Hypertext and Hypermedia

3. Printed Manuals

4. Tutorials

5. Expert operated help desk

User Support continued

1. Online Help

Advantages: cannot be lost, does not require desk space, faster to search keywords and better to update than hard copy. Moreover, the user can adaptively control the level of information s/he would like to get.

Disadvantages: Paging might be slower and not as legible as printed material. User cannot add marks.

User Support continued

1. Online Help continued

It is essential that the help system designer understands when users typically get stuck and what the reasons are for the problems they typically encounter.

User Support continued

1. Online Help continued

Many help menus are organised hierarchically.

Problem: As a consequence, users may face problems navigating through the system.

Solution: Reduce menu hierarchy to as few levels as possible and show options at next level once person scrolls over the respective item.

User Support continued

2. Hypertext and Hypermedia

Hypertext consists of a collection of non-linear, text-based nodes that are linked together.

When adding various media such as animations, video, sound etc. to Hypertext, this is typically called Hypermedia.

User Support continued

2. Hypertext and Hypermedia continued

Help provided through hypermedia systems might be better to understand because sequences of actions can be shown as videos.

Too much animation, though, may confuse the user.

User Support continued2. Hypertext and Hypermedia continued

How to avoid confusing the user: provide good tools of navigation and allow users to develop adequate mental models of the system for which help is sought.

Navigation of the user can be enhanced if the designer lets user adopt a “printed magazine” metaphor with a reference section and an exploratory section that lets the user browse the contents.

User Support continued2. Hypertext and Hypermedia continued

The printed magazine metaphor works particularly well for Hypertext, but not necessarily for Hypermedia applications.

User Support continued3. Printed Manuals

Many user manuals are poorly designed, because they often involve loads of technical jargon and are thus difficult to read. This may please experts, but they may not even read user manuals in the first place.

Writing manuals are often left to the most inexperienced people (e.g. summer interns).

User Support continued3. Printed Manuals continued

The poor design of the manuals is also a reason why there is such a variety of commercial literature with titles such as “...for dummies”, “...made simple”...

When writing a manual, it is recommended to be consistent with terminology, style, layout etc. across the chapters.

User Support continued4. Tutorials

Learners are expected through the entire manual from the beginning to the end. This might include teaching and practical sessions. Tutorials should therefore be designed in order of increasing difficulty.

Practical sessions are typically very useful, because they foster direct interaction with the system.

User Support continued5. Expert operated help desk

It is important that the experts have excellent training and communication skills, i.e. they must understand what sort of problems users are likely to experience and they must be able to explain technical problems in a clear way.

User Support continued5. Expert operated help desk continued

This may require specific training of the experts before they operate a help desk. In reality, expert operated help desks not always work as well as they should work.

End of Chapter 3 in Study Guide.

Accessibility issues:

It is important to consider…

 

That some people have monochrome monitors or monochrome printers. Therefore, it is important to check how the website appears on a monochrome monitor or printer, i.e. that the contrasts are strong enough, that the font is dark enough, etc. When displaying graphs on a website, it is important that the lines, bars, etc. within the graphs can be separated from each other.

That 9 percent of the population is colour-blind. Therefore, it is either important to check the colours of the website and to make sure that they can be perceived comfortably by everyone. Alternatively, it is important to make sure that the browser adjustment option is not disabled when developing the website. If it is not disabled, people will be able to change the colour of the font, screen background, links, etc.     

That some people have visual impairments. Therefore, it is necessary to check that the browser adjustment option is not disabled when developing the website. This way people could change the size of the font. It is also important to avoid using buttons as links, because they usually blur when the website is enlarged (whilst text-links can be adjusted without blurring).

That some people are deaf or have switched their speakers off. Therefore, it is important to make sure that necessary information that is provided in acoustic format also exists in text format and can be accessed. For deaf people, it will not be possible to provide a song in text format, but at least they should be informed that a song is played in the background.

    

Some people are blind. It is therefore important to use an ALT-tag that says what is displayed on an image or on a logo. This will enable a screen reader to tell the user what is on this picture or on the logo (e.g. “Goldsmiths, University of London”).

It is important to check the web accessibility guidelines and to run a test whether your website is accessible. This can be done in Dreamweaver or with shareware accessibility software that exists on the web.

It is important to check that the website is accessible and readable in older browsers, because some people do not have the latest equipment.

 

 

More information: http://www.webaim.org/simulations/lowvision