Direct Manipulation
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The Direct Manipulation Method
Direct manipulation is the visual representation of the world of actions. For example, the desktop metaphor (Microsoft Windows) which the user can manipulate. Direct manipulation is one of the primary interaction styles which has been used by designers and programmers for their systems. Direct manipulation allows novice users access to powerful instructions without the trouble of learning how to use a complex syntax and/or extensive lists of commands.
Direct manipulation involves three interconnected techniques:
- Provide a physically direct way of moving a cursor or manipulating the objects of interest.
- Present a concrete visual representation of the objects of interest and immediately change the view to reflect operations.
- Avoid using a command language and depend on operations applied to the cognitive model which is shown on the display.
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History
Direct manipulation is considered one of the most significant achievements in human computer interaction (HCI) theory and design. It emerged as a concept in 1980's by Ben Shneiderman.
Shneiderman published a paper in 1983 titled "Direct Manipulation: A step beyond programming languages" in which he noted the appeal of manipulating graphically represented objects instead of formulating complex linguistic commands.
He characterized this style of interaction by three properties:
- Continuous representation of object of interest.
- Physical actions or labelled buttons pressed instead of the use of syntax
- Rapid incremental reversal of actions with an immediate impact on object of interest.
The paper began with two examples of office applications: word processing and spreadsheet. The ability to display the final form on the screen, move a cursor by arrow keys, see the results of an action immediately and to easily reverse commands. Novices would also enjoy using direct manipulation software because they can rapidly master the system with time.
Shneiderman mentioned a few other examples, of which, the most promising example was what is now known as the desktop metaphor.
He also proposed that testing should be done before introducing direct manipulation systems to ensure proper behaviour of the system, specially if uncommon metaphors are being used.
Shneiderman mentioned in his paper that direct manipulation isn't without its faults. He said that using spatial or graphical representation doesn't necessary improve performance. He identified the following four problems with direct manipulation:
- Cluttered presentation, can lead to greater confusion
- Users had to learn the meaning of components of the graphic representation.
- Graphical representation may be misleading.
- Representation might take excessive screen space.
This witnessed a hugely beneficial impact on personal computing and plays a major role in modern interactive software design.
