Interface Metaphors: From Architecture to Spectacle
The original GUIs were based on metaphors of architecture and interior design: windows, icons, folders, the desktop, even a trash can. To conceal the virtual nature of the computer, interface designers constructed a physical world inside the screen. This world, exemplified by the original Macintosh, behaves fundamentally like the real one. Files and folders have a location and size that exists independently of our attention. We can manipulate them with the mouse pointer - a proxy for our hand - and they react in natural ways, stretched or dragged across a well-defined space. Their appearances are designed to suggest solidity, with shading, bevels, and other suggestions of depth. These on-screen objects can be created and destroyed, hidden or revealed, but nonetheless they provide a stable embodiment for what are merely scattered bits of data. We take the representation for the reality - as though the icon were the file.
This is not the only possibility. Although the screen is two-dimensional, with fixed resolution and spectrum, it is capable of displaying any image that fits those pixels. One can imagine any number of organizing metaphors for its interface. The main constraint is no longer (if it ever was) the capabilities of the computer, but the limits of our understanding. As we've grown more comfortable with the abstractions of computing, interfaces have begun to represent these abstractions in multiple ways, according to our needs and context. Now that we know what a file is, we can recognize it as an icon, in a list, or as an image of its contents. Interface elements need no longer appear as solid objects, but are often transparent, animated, morphing. The interface becomes not architecture but spectacle.
This new breed of interface is again exemplified by Apple. Its ideas appear to some extent in Leopard, but it's the iPhone that provides the best example. It has no windows, no menus, no pointer - three of the four hallmarks of the old WIMP paradigm. Even the icons have been transformed from physical objects to images: not things but signs. Consider the interaction between applications. Rather than windows overlapping in space, the iPhone shows one at a time, filling the screen. To switch between them, you tunnel back to the home screen and select another. There's no geographic relation between them; each exists in its own parallel universe. Tap on a photo in an album and the thumbnails slide smoothly off to left - but flick the photo to the right and it's another image that enters from the left, not the thumbnails. The flicking motion seems "real", but what physical object behaves in a similar way? This is an interface that draws on basic notions of position, motion, and continuity - but in a way that's unique to the screen and dependent on our acceptance of a more abstract relation to the underlying virtuality. It relates most closely to film and special effects, in which a logical consistency is secondary to visual continuity. We have finally begun to accept the screen as its own medium and design our interfaces according to its logic.