"Hot, hot, hot" reads the caption under Interaction Design on the Core77 discussion boards, and with good reason. Anyone who's been following the creative job market at any point in the last few years is probably aware of the feeding frenzy currently going on, as companies large and small seek interaction designers to do...well...whatever it is that they do. For those of us not in the field, and without much exposure to the IxD (for that's how it gets abbreviated) process, it can seem a bit of an esoteric, shadowy art, attracting the attention of media and employers, but without knowing quite why. We know they work with information (usually), and computers (sometimes), and pay close attention to the users of technology (pretty much always, right?), but that's a vague enough description that it could be applied to web design, graphic design, industrial design, and a number of other disciplines. Determining how one actually becomes an Interaction Designer is an even tougher challenge.

Asking a few working designers about their jobs, the first question that gets answered is why the rest of the questions are so hard. It's a difficult to define field because it's both extremely broad and relatively young--though not as young as you might think: the term dates to the 1980's, meaning there are in fact seasoned interaction designers out there with 15 and 20 years of experience under their belt, in addition to the young cubs we might imagine negotiating six-figure salaries. This puts IxD in an identity-seeking mode that is, if anything, more profound than the one ID has been going through (blog posts and discussion threads asking "What is 'design' anyway?" are approaching mosquito swarm levels of abundance and annoyance), and certainly more frenetic than the academic queries that surface periodically among graphic designers.

What also makes the questions hard is the feeling that Interaction Design is something that happens anyway, with or without the input of Interaction Designers. As an Industrial Designer, the parallel is obvious: many of us are fond of pointing out that every product in the world gets designed by someone, whether or not they know what they're doing. Similarly, every time a user interacts with a piece of technology (there's that broad-ness problem again), someone designs that interaction, and frequently they screw it up. Hence the discipline. Interaction Designers, more than any other group of creative professionals I know, are keenly aware of their own usefulness and their own dispensability.

This probably has something to do with their shared background, or rather the lack thereof. Interaction designers almost never start out that way. Challis Hodge, one of the more prolific writers and thinkers on the subject, has done IxD for Avenue A/Razorfish and IBM Global Services, but started out with an Industrial Design BS from Cincinnati. Interaction designers I spoke with at Intel and Motorola came from Graphic Design and new media backgrounds, and were able to tick off a lengthy list of fields from which their professional colleagues emerged: engineering, programming, motion graphics, psychology, cognitive science, sociology, and perhaps the occasional anomaly who actually started out in an IxD program.

Think about that; it's phenomenal. As if 90% of the world's graphic designers had originally been trained as architects and photojournalists, for example. The typical back-story for an Interaction Designer, as far as there appears to be one, features someone working in one of the above professions, finding certain aspects of a project falling through the cracks. Whether the project is a website being built or a laser printer being designed, it falls to someone to start making the calls about what it feels like to use it: whether the button layout makes sense, whether the next screen in a navigation structure follows logically, how you turn the thing on. In the worst case, these decisions are made by a project manager who justifies decisions with "well this is how I'd do it if I were using it"--a classic recipe for clunky, frustrating interaction. A better scenario is that the choices get made by someone with an innate or learned aptitude for user observation, prototyping and testing. The person gets better at iterating this process, realizes that there is a field devoted to it, and becomes an Interaction Designer.

There are plenty of other ways of attaining that job description, of course, but most of them seem to exhibit some characteristic of gap-filling: advocating for the user, finding out what works in the real world, then applying that knowledge to improve the design. Things that everyone agrees are important, but nobody's quite sure how to do. Mr. Hodge has even gone so far as to diagram the professional progression of the User Experience Designer (a term that encompasses IxD and its siblings, Interface Design and Information Architecture) from the professions that usually feed it:

This particular chart is skewed toward web design, where IxD is growing in importance with whiplash-inducing speed, but the logic behind the progression is clear, and applicable to physical designs too. Interaction exists in the overlap of many related fields, and can potentially draw from any of them.

Once this progression is understood, the ultimate question of "how" seems to diminish in importance. Ask any ten Interaction Designers what they do all day and you'll get nine or ten different answers. The actual tool used to optimize an interaction can range from Visio charts to Flash animations, storyboards to text-only essays. David Malouf, the IxDA's vice president, identified the one crucial skill all Interaction Designers must have as "prototyping." When pressed for greater specificity, none was to be found, and this in the end may be what makes IxD so useful. It is a continually self-evaluating field, but one content to let the process of asking be sufficient. Similarly, it is a field unwilling to cling to any particular tool, knowing that the selection of the right tool--even if it must be learned from scratch--is in fact the most important step.