Direct manipulation is a human-computer interaction style that was defined by Ben Shneiderman and which involves continuous representation of objects of interest, and rapid, reversible, incremental actions and feedback. The intention is to allow a user to directly manipulate objects presented to them, using actions that correspond at least loosely to the physical world. Having real-world metaphors for objects and actions can make it easier for a user to learn and use an interface (some might say that the interface is more natural or intuitive), and rapid, incremental feedback allows a user to make fewer errors and complete tasks in less time, because they can see the results of an action before completing the action. An example of direct-manipulation is resizing a graphical shape, such as a rectangle, by dragging its corners or edges with a mouse.

Individuals in academia and Computer scientists doing research on future user interfaces often put as much or even more stress on tactile control and feedback or sonic control and feedback than on the visual feedback given by most GUIs. In these cases the term "graphical user interface" seems inadequate. As a result the term direct manipulation interface has been more widespread in these environments.

Direct manipulation vs WIMP/GUI interfaces

Direct manipulation is closely associated with WIMP and GUI as these almost always incorporate direct manipulation to at least some degree. However, direct manipulation should not be confused with these other terms, as it does not imply the use of windows or even graphical output. For example, direct manipulation concepts can be applied to interfaces for blind or vision impaired users, using a combination of tactile and sonic devices and software.

It is also possible to design a WIMP interface that intentionally does not make use of direct manipulation. For example, most versions of windowing interfaces (e.g. Windows) allowed users to reposition a window by dragging it with the mouse, but would not continually redraw the complete window at intermediate positions during the drag. Instead, for example, a rectangular outline of the window might be drawn during the drag, with the complete window contents being redrawn only once the user had released the mouse button. This was necessary on older computers that lacked the memory and/or CPU power to quickly redraw data behind a window that was being dragged.

References

• Frohlich, David M.,"The history and future of direct manipulation," Behaviour & Information Technology 12, 6 (1993), 315-329.
• Hutchins, Edwin L.. James D. Hollan, and Donald Norman.Direct manipulation interfaces. (1985)
• Shneiderman, Ben. Designing the user interface : strategies for effective human-computer-interaction.(2004)
• Shneiderman, Ben. "Direct manipulation: a step beyond programming languages," IEEE Computer 16(8) (August 1983), 57-69.