6. Interface Metaphors

6. Interface Metaphors

6. Interface Metaphors

Metaphors

Metaphors convey an abstract concept in a more familiar and accessible form.

A widely quoted example can be found in Shakespeare's As You Like It: "All the world's a stage...“

Metaphors are widely used to make use of users’ existing knowledge when learning new computer systems.

6. Interface Metaphors

Verbal Metaphors

Verbal metaphors are useful tools to help users to understand a new system.

This perceived similarity activates the user’s ‘typewriter’ schema

Computer has a QWERTY keyboard

Computer has a QWERTY keyboard

Typewriter has a QWERTY keyboard

Typewriter has a QWERTY keyboard

Keys should have same effect as they do on a typewriter

Keys should have same effect as they do on a typewriter

AND

6. Interface Metaphors

Verbal Metaphors

These links provide basic foundation from which users develop their mental models.

Knowledge about a familiar domain (typewriter) in terms of elements and their relation to each other is mapped onto the unfamiliar domain (computer).

Elements: keyboard, spacebar, return key Relations: hit only one character key at a time,

hitting a character key will result in a letter being displayed on a visible medium

6. Interface Metaphors

Verbal Metaphors

Dissimilarities can cause problems for learners. For example, the backspace key on a typewriter

moves the carriage back, while on a word processor it usually deletes a character.

However, as they become aware of the discrepancies, they can develop a new mental model

6. Interface Metaphors

Advance Organisers

Verbal metaphors provided in advance can aid learning.

For example, Foss (1982) studied the effect of describing a metaphor for a system to new users before they start learning.

This is called an advance organiser. In this case file creation and storage were

explained in terms of a filing cabinet metaphor

6. Interface Metaphors

Virtual Interface Metaphors Verbal metaphors try to explain the use of a

computer system in terms of something that it resembles.

Xerox in the late 1970’s realised the potential of deliberately designing interfaces to be more like the real world.

Instead of using verbal metaphors they went further and designed an interface metaphor for the Star system.

The overall organising metaphor on the screen was the desktop, resembling the top of a real office desk.

6. Interface Metaphors

Xerox Star (1980)

6. Interface Metaphors

Apple Macintosh (1984)

6. Interface Metaphors

Windows 1.0 (1985)

6. Interface Metaphors

Windows 2.0 (1987)

6. Interface Metaphors

DR GEM (1988)

6. Interface Metaphors

NextStep (1988)

6. Interface Metaphors

Windows 3.1 (1993)

6. Interface Metaphors

Macintosh System 7 (1993)

6. Interface Metaphors

Windows 95 (1995)

6. Interface Metaphors

Windows XP (2001)

6. Interface Metaphors

MacOS X (2001)

6. Interface Metaphors

Longhorn (2006?)

6. Interface Metaphors

Composite Metaphors

A problem with the ‘metaphor as model’ approach is the difficulty of introducing new functionality which does not fit into the interface metaphor.

Designers have got round this by introducing composite metaphors. These allow the desktop metaphor to include objects which do not exist in the physical office, for example: menus windows

scroll bars (these make use of the concept of unrolling a scroll, or rolled-up document)

6. Interface Metaphors

Composite Metaphors

It might be assumed that users may have difficulty with composite metaphors.

In general it has been found that people can deal with them rather well and can develop multiple mental models.

Some composite mental models can cause confusion. For example, on a Macintosh, you can eject a disk by dragging it to the trash – you retrieve it by throwing it away.

6. Interface Metaphors

Metaphors - Applications

The desktop metaphor has been used successfully for operating systems.

However, other metaphors have been developed for specific types of applications

6. Interface Metaphors

Data Storage

Metaphor: Filing system Familiar knowledge: files, folders, storing

files, retrieving files

6. Interface Metaphors

Spreadsheets

Metaphor: ledger sheet Familiar knowledge:

columnar tables, calculations

6. Interface Metaphors

The Web

Metaphor: Travel Familiar knowledge: going from place to

place

6. Interface Metaphors

Online Shopping

Metaphor: Shopping cart Familiar knowledge: adding items, checking

out

6. Interface Metaphors

Graphics Applications

Metaphor: Toolbox

6. Interface Metaphors

Virtual Reality

6. Interface Metaphors

Web Sites

6. Interface Metaphors

Web Sites

6. Interface Metaphors

Interface Elements

Tabs

6. Interface Metaphors

Interface Elements

Progress Bars Metaphor: progress is to the right (orientational metaphor) Based on direction of reading – highly cultural, as some

cultures read from right to left.

Icons Symbolic icons use metaphors to convey their meaning –

e.g. a globe to represent the World Wide Web or the magnifying glass icon in a photo manipulation program to represent zooming in on an image.

6. Interface Metaphors

Pervasive Computing

Pervasive computing is the trend towards increasingly ubiquitous connected computing devices in the environment

also known as ubiquitous computing In these devices, the computer interface

moves away from the desktop and the interface metaphor is invisible to the user

One user, many computers

6. Interface Metaphors

Pervasive Computing Xerox's Palo Alto Research Center (PARC), for

example, has been working on pervasive computing applications since the 1980s

IBM's project Planet Blue, for example, is largely focused on finding ways to integrate existing technologies with a wireless infrastructure

Carnegie Mellon University's Human Computer Interaction Institute (HCII) is working on similar research in their Project Aura

Massachusetts Institute of Technology (MIT) has a project called Oxygen.

6. Interface Metaphors

Pervasive Computing