"What's interaction design?"
I have gone through times where I myself hesitate when trying to give an easy definition of interaction design. Usually an example or two helps for it to click, but that's hard to describe in simple sentences sometimes too. I usually try describing that an interaction designer can help create holistic experiences that range from websites and apps to robots and services. People sometimes get it. What follows are my thoughts on the definition.
A few interaction design definitions
Sometimes you see a definition where interaction is a design of the bigger picture and that it borrows from other disciplines. Somewhere in there empathy, listening, the future or positive change is mentioned. It's a nice and fluffy explanation. A lot of videos I have seen marketing or introducing interaction design have this type of definition. Other popular examples are that interaction design bridges the gap between programmer and (insert visual profession). Or involving the end user and stakeholders earlier in the design process. All pretty nice and fluffy. There's some truth to them but I believe these definitions exist to get people interested and only tells a little bit of what it is and could be.
From one of my good teachers Simon I adopted "humanizing technology" as the simplest definition for awhile. But this definition easily applies to the older precedent of interaction design, human-computer interaction (HCI).
I also take to the ATM example, where users are unable to withdraw money without first taking their card from the machine. And the gesture used to quickly look at your bank balance without needing to login on mobile devices.
This is drawn from Bill Verplank.
Bill Verplank states that an interaction designer has three questions they need to answer. How does one affect/interact with the world? How does one get feedback? What kind of knowledge does the user have? Designers design affordances and understand what kind of knowledge users have during their experiences. In a way this is pretty easy to get and shows a simple overview of what an interaction designer is capable of. Though perhaps this oversimplification leaves one to wonder certain things if one isn't already an interaction designer. You can read more about his thoughts on this 1998 lecture page.
More technical definitions
According to Alan Cooper et al. in the book About Face 3, interaction design is the "practice of designing digital products, environments, systems and services". While conceding that there is still concern for form as a design discipline, there is a large focus on designing behavior. It's also not unusual to show a relationship between form, content and behavior just as this book illustrates when talking about user experience.
Saffer in Designing for Interaction makes interaction design about people and the relationship with other people through what they use (of what designers have created).
These explanations feel a bit confused about the actual role of an interaction designer. Really it's just not simple enough. So what does an interaction designer do? Suddenly, I think back to my first classes and introduction to the topic. Interaction designers like to focus on process and they design iteratively. They work with an understanding between multiple disciplines. Interaction designers take the user-centered design approach and process the user's wants, needs and limits.
So what do designers do?
There is one thing which is easily overlooked about what interaction designers do. It applies to all designers really. That the end result is a design that solves a problem. It's not the ideal definition, and I'm sure there's plenty more definitions for interaction design. The following definition is one I propose as quite open and inclusive to the purpose of interaction design:
Interaction designers create (usually digital) solutions catered to the end user's best interests and use cases, through an involved iterative and collaborative process.