#UX101: Interaction Design and Models

In user experience conversations you will often hear the term “interaction design” bandied about. What does it mean?  Here’s the Wikipedia definition:

Interaction design, often abbreviated IxD, is “about shaping digital things for people’s use”, alternately defined as “the practice of designing interactive digital products, environments, systems, and services.” Like many other design fields, interaction design also has an interest in form but its main focus is on behavior.

Simply put, interaction design involves the creation and definition of how users… interact with a system. What does it do? How does the system “react” to user input? Framed in that way, you can then understand that user interface design is a “sub-discipline” of Interaction Design. The UI is the “platform” that the interaction takes place on, and the objects and elements that users engage with exist on that platform.

This is much less complicated than it may appear, though you shouldn’t be ashamed if you are confused. Interaction design is an abstract conceptual idea that is not easy to grasp for some. Try and think of a blank screen… then, think of placing a couple of thin black and white boxes on those screens, one above the other. Then put a button below the two boxes, and put the word Enter in the box. Add two words to the left of the boxes – Username for the top box and Password for the bottom one. You have just designed a log-in screen. That’s user interface design.

Then think about how you or any other user would engage with the elements. How would they start to enter the information? Using a mouse to click the text box? Through a keyboard shortcut? Do you want the cursor to be in the first box when the screen loads? Do you want to “hide” the characters that are entered in the password field? How should the screen respond if the wrong password is entered? Those details start to go into interaction design – how the interface interacts with users and responds to their input. The line is blurry, but hopefully this explanation helps.

Interaction Models

Part of interaction design involves using or creating interaction models. Interaction models are the “rules” around how users interact with a system. An easy way to understand what interaction models are is to look at them as the “metaphor” of how things work. “This works like…”

Why are interaction models important? Because they help users learn a new site or design, especially if the metaphors are obvious and consistent with how they expect things to work based on their experience. UX Designer Dan Saffer had this to say about interaction models:

“A device without an interaction model will likely seem disjointed and made up of pieces, instead of as a whole. Pieces of functionality will work differently and the overall concept will be hard to grasp. Many mobile phones, appliances, and consumer electronics suffer from this problem.  A solid interaction model is the basis for any great device.” (From his blog)

Good interaction models feels natural and obvious to users. They reflect the real world and align and are consistent with how people see things work and think of how things work. They are thoughtfully defined and internally consistent.  Good interaction models keep things simple and (hopefully) obvious.

The most well-known interaction model is the desktop, which is used by all computer operating systems. The desktop UI reflects the real-world desktop, with files and folders representing storage “places” for information. Since desks have exists for hundreds of years, people can “get” this metaphor quickly and get to work. Another well-known metaphor is in word-processing, where the default UI is a blank page, sized just like a piece of paper.

One site or system can have multiple interaction models present, but they should work together well and not “clash.” A good example of clashing is when an application that “breaks” an existing model – if user are used to scrolling up and down with a mouse in a certain way, don’t change that behavior in an application.

With voice, gesture, and augmented realty new and different interaction models need to be created. Designer are already defining standards and best practices for these new ways of engaging with technology – for one example, check out this article on “New Design Practices for Touch-Free Interactions” from UX Magazine.

Whatever the future will bring, it will need to be designed… and how things work need to align with how users expect them to work. Effective interaction models will help make new technology be more usable and easier to learn.