When you hear the words “interaction design” what do you think? I know plenty of people will immediately go and look it up on Wikipedia so here’s a link to save you some time.

Robert Reimann defines interaction design as

a design discipline dedicated to:

• Defining the behavior of artifacts, environments, and systems (i.e., products)

…and therefore concerned with:

• Defining the form of products as they relate to their behavior and use
• Anticipating how the use of products will mediate human relationships and affect human understanding
• Exploring the dialogue between products, people, and contexts (physical, cultural, historical)

We interact with things every day. Whether it’s a door knob, our car, or Facebook. These have to be designed by someone to (hopefully) provide the best experience to the user as possible. A doorknob is probably a simplistic example but if a knob is the wrong size or is hard to turn (or unpredictable in its behavior), people might have a hard time getting used to it.

Human-computer interaction has historically been a tough challenge to conquer, so kudos to Douglas Engelbart for inventing the mouse.

When it comes to the Web, interaction design is closely related to interface design. The key difference is that interaction design focuses on the behavior of the interface and how it responds to the user; interface design focuses more on layout and positioning. Take for example our navigation on this site. Interface design determines that there’s a navigational bar and that it is collapsed. The interaction design delves into how the user experiences our site. Roll over any element and the list expands to allow you deeper access into our site. The user interaction has determined how the site reacts to accommodate what the user wants to do.

Truly great interaction designs provide a rich user experience that is appealing, informative, and functional. “Web 2.0″ and the age of powerful JavaScript libraries has caused good interaction design on the web to become more prevalent and there are some websites that just “get it.”

Take for example Netflix. Aside from their great service, their ratings system and suggestion features meet all three of the above criteria. Rating movies you’ve seen in the past doesn’t require filling out a form and hitting submit, but simply moving your mouse over a graphic of 5 stars and as you move closer to the 5th, they turn yellow. No explanation, no in-depth dissertation of how you should rate the movie according to what the stars mean. It is just intuitive.

What about Netflix’s recommendation engine? I know the movie suggestions are not always great, but the fact that it offers me more choices based on my past behavior is fantastic! From an interaction standpoint all I have to do is pick a movie and they automatically recommend similar movies. I can add movies to my queue from right there if I want. There’s no hassle and minimal clicks to find what I want.

It is important to remember that interface and interaction design are not the same. Take into consideration the cognitive processes that a user will be going through while using your site or application. Focusing on usability through interaction design will naturally flow from understanding what the user wants… but that’s the ultimate question: what does the user want? Sometimes you have to guess. Let’s hope the guesses are right.

• Interaction design -The blog about interaction design and usability
• Thoughts on Interaction Design
• So You Want To Be An Interaction Designer