This is the part 3 of 4.
As the popular saying goes, there is always an easy solution to every human problem: neat, plausible, easy to understand and wrong.
It's now widely accepted that the graphical and behavioral presentation of an interface should be have some conformity to what we evolved to expect (as i talked about in the previous post: transitions, rounded shapes possibly textured, direct manipulation of objects are just some aspects of it), however this brought a very easy answer that introduces a whole new range of problems: skeuomorphism.
A skeuomorph design tries to mimic as much as possible real objects that are an analog version of the tool implemented by the interface, a typical example is an address book application that looks like a leather address book or an ebook catalog application that looks like an actual library.
This is the design direction Apple taken since a while, and now from mobile is starting to percolate in the desktop as well (and being Apple is influencing a whole lot of developers now).
This approach has several problems:
- It kills consistency: the boundary between different applications becomes extremely evident, too evident, condemning to remain forever in the application based paradigm, while "application" is a technical detail, is not much really something that should be very evident in the user facing semantics. Every application has a completely different graphical language, even tough it was designed to ease the transfer of learning from the "real" world it ultimately hinders the transfer between learned part of the system.
- Imposes artificial limits: by copying a real object you copy also its limitations. To stay in the example of the book browser that looks like a library, the mapping to the real object suddenly drops (and thus it starts to look unfamiliar, magical) when you perform functions like sorting or searching books. You can't certainly make magically disappear from the library all books that aren't from a certain author, with a snap of the fingers. This makes quite hard to create innovations, like in this case a more powerful intuitive way to browse books that leverages indexing and metadata extraction.
- It's uncanny: the application will mimic the real object, but not perfectly: it will always feel fake, there always will be something out of place (even if just because of the features it offers that are impossible in the real world just as a simple search), creating a cognitive dissonance: yes I am looking to something that looks like a leather address book, but I can't use exactly like that, i have to use a completely different set of skills.
- It's expensive: last but not least, it's extremely expensive and labor intensive to redo from scratch every single pixel of every application: not everybody that are not Apple can afford to deliver a complex product with quality good enough to be presentable. If the cost of this enormous amount of work was justified by a big benefit could be worth it, but as we seen causes more problems than what it solves.
Finding the balance
The debate between an hyper-realistic, application based design, and a more classical UI approach is very polarizing lately, with good arguments from both sides.
Problem is the detractors of skeuomorph UIs, as gets natural in every polarizing debate, advocate from stuff that looks like it comes out from some 80's science fiction movie, with Windows 8 Metro or Android 4 Holo as examples (especially in the Android case, the similarity with Tron is quite again, uncanny)
As I said, I think Skeuomorphism is the easy and wrong answer to the need of interfaces that feels more natural (where natural doesn't mean there isn't need to learn it), easily learnable to make the machine being a desktop or a phone an extension of your arm rather than a weird machine that you have to dialog in a strange arcane dead language with.
There should be a natural looking language, natural looking (or even reality copying) materials to build the UI elements, with a correct lighting, but yet not trying to copy real objects in the end, what you have to construct is a new machine that looks realistic but yet doesn't copy a library or an address book.
You want something that looks and behaves more "analog" than "digital" (even if is something quite hard to quantify) for the same reason the piano replaced the harpsichord very quickly.
The UI must "flow": as square edges and shapes with spikes should be avoided, the movement of everything should be as smooth as well, nothing that just appears or disappears, everything that is obvious where it comes from.
Remote controls should be avoided, everytime you have to use a UI to configure another UI, rather than directly manipulating it, you are doing something wrong.
In one sentence, design a visual language that is new, consistent, rigurous, looks natural and stick to it.
A button that looks like a button, with the correct lighting, drop shadows to tell the brain what is the most important and secondary things are ok, replicating a fully functional rotary phone is not.
Also, small breaks from the visual grammar can sometimes enhance the value of a particular feature, but only if used extremely rarely.
Next and last, boundaries between applications and workspace, boundaries between devices (or, why they don't exists)