The invention of the mouse took one mode and moved it to an input device, and context menus took another mode and moved it to a button. Ironically, the advent of touch devices has had the reverse effect, producing multi-modal interfaces:
The traditional WIMP interfaces have the basic premise that the information can flow in and out of the system through a single channel or an event stream. This event stream can be in the form of input (mouse, keyboard etc) where the user enters data to the system and expects feedback in the form of output (voice, vibration, visual, etc) when the system responds. But the channel maintains its singularity and can process information one source at a time. For example, in today’s interaction, the computer ignores typed information (through a keyboard) when a mouse button is depressed.
This is very much different from a multimodal interaction where the system has multiple event streams and channels and can process information coming through various input modes acting in parallel, such as those described above. For example, in an IVR system a user can either type or speak to navigate through the menu.
References
User Agent Accessibility Guidelines working group (UAWG): Keyboard Interface use cases
W3C Multimodal Standard Brings Web to More People, More Ways
Next steps for W3C work on Multimodal Standards
The Future of Interaction is Multimodal
Beyond Mouse and Keyboard: Expanding Design Considerations for Information Visualization Interactions - naturalinfovis_infovis2012.pdf
Setting the scope for light-weight Web-based applications
Jan. 26, 1983: Spreadsheet as Easy as 1-2-3
Multi-modal design: Gesture, Touch and Mobile devices...next big thing? | Experience Dynamics
