Metaphors

Why Metaphors? | How You Can Apply Metaphors | Real-World Metaphors vs. Structural or Abstract Metaphors | Frameworks | Problems with Metaphors

Metaphors can be a very effective means to make software intuitively comprehensible, and thus simple to use. However, metaphors are most useful when they are closely related to the users' tasks or goals. It does not make much sense to locate the processing of a requisition in a maze or in a jungle scenery. Metaphors may also be used to integrate software components into a coherent unit.

Why Metaphors?

Metaphors help users to transfer their real world knowledge to the application. This simplifies learning, relearning, and using an application.

How You Can Apply Metaphors

You can apply metaphors in a number of ways:

Use a terminology that is borrowed from real-world objects and processes, for the objects and processes of your application.
Use graphics that correspond to real world objects (and maybe processes or objects corresponding to processes).
Design the processes so that they resemble or are identical to real-world processes.
Design the desktop or at least the application window so that it resembles the corresponding real-world setting (usually by using graphics).
And, of course, you can combine all of these methods.

Real-World Metaphors vs. Structural or Abstract Metaphors

The most useful metaphors are borrowed from the real world because they are the most direct and intuitive ones. However, objects and processes in an application are often abstract entities and there are no direct correspondences to the real world.

If there is no direct correspondence to the real word, you may:

Use metaphors from the real world that have an abstract, for instance a structural, correspondence to your application
Use abstract models

Note, however, that abstract metaphors may be less useful for users because they are not intuitive, and users have to "translate" the metaphor into their own language.

Frameworks

Frameworks provide a structure that is well known to users and helps to organize an application – that is, they provide an organizational framework for the application. For example, a company or an institution may provide an appropriate structural scheme for an application.

Frameworks are not metaphors in the ordinary sense. Typically, they are fairly abstract but well enough known to be useful. They can be used instead of completely abstract organizational schemes, such as trees, networks, or tables.

Problems with Metaphors

There are two main problems with metaphors:

The metaphor may not be suitable with respect to all software applications that are based on it. There are occasions where people use their real-world knowledge but run into an error because the metaphor is not applicable. Such cases can pose serious problems to users because the source of the error is not obvious to them. Some authors even discourage the use of metaphors for this reason.
The metaphor may be too remote or abstract, so that users have to invest too much effort into translating the metaphor into their world. In this case, the metaphor does not help users. Instead, it forms an obstacle to them.