Interaction Design User Experience (UX) topic overview/definition

What is Interaction Design?

Interaction design (IxD), the design of interactive products and services, particularly concerns the way people interact with products and services. While primarily applied to digital products such as smartphone apps, IxD is also used to optimize physical spaces. IxD can be examined through five dimensions: words (1D), visual representations (2D), physical objects/space (3D), time (4D), and behavior (5D).

The five dimensions, created by Professor and Head of Department of Computer-related Design Gillian Crampton Smith and senior interaction designer Kevin Silver, represent the ways in which a person can interact with a product or service. Words (1D) encompass text, such as button labels, that help convey the right amount of information to users. Visual representations (2D) are graphical elements such as images, typography, and icons that aid in user interaction. Physical objects/space (3D) involves the medium through which users interact with the product or service—for instance, a laptop via a mouse, or a mobile phone via fingers. Time (4D) relates to media that changes with time, such as animations, videos, and sounds. Behavior (5D) is concerned with how the previous four dimensions define the interactions a product affords—for instance, how users can perform actions on a website, or how users can operate a car. Behavior is also about how the product reacts to the users’ inputs and provides feedback.

Together, the five dimensions allow interaction designers to consider the interaction holistically between a user and a product/service. This allows the designer to convey meaningful information—in the right amounts and at the right time—so as to optimize the user experience of using the product/service. Good interaction design results in items that mirror users’ expectations and enable ease of use towards action goals—designed works that are intuitive to grasp and that only fail at frustrating users.

Literature on Interaction Design

Here’s the entire UX literature on Interaction Design by the Interaction Design Foundation, collated in one place:

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What is Interaction Design?

What is Interaction Design?

Interaction design is an important component within the giant umbrella of user experience (UX) design. In this article, we’ll explain what interaction design is, some useful models of interaction design, as well as briefly describe what an interaction designer usually does.

A simple and useful understanding of interaction design

Interaction design can be understood in simple (but not simplified) terms: it is the design of the interaction between users and products. Most often when people talk about interaction design, the products tend to be software products like apps or websites. The goal of interaction design is to create products that enable the user to achieve their objective(s) in the best way possible.

If this definition sounds broad, that’s because the field is rather broad: the interaction between a user and a product often involves elements like aesthetics, motion, sound, space, and many more. And of course, each of these elements can involve even more specialised fields, like sound design for the crafting of sounds used in user interactions.

As you might already realise, there’s a huge overlap between interaction design and UX design. After all, UX design is about shaping the experience of using a product, and most part of that experience involves some interaction between the user and the product. But UX design is more than interaction design: it also involves user research (finding out who the users are in the first place), creating user personas (why, and under what conditions, would they use the product), performing user testing and usability testing, etc.

The 5 dimensions of interaction design

The 5 dimensions of interaction design(1) is a useful model to understand what interaction design involves. Gillian Crampton Smith, an interaction design academic, first introduced the concept of four dimensions of an interaction design language, to which Kevin Silver, senior interaction designer at IDEXX Laboratories, added the fifth.

1D: Words

Words—especially those used in interactions, like button labels—should be meaningful and simple to understand. They should communicate information to users, but not too much information to overwhelm the user.

2D: Visual representations

This concerns graphical elements like images, typography and icons that users interact with. These usually supplement the words used to communicate information to users.

3D: Physical objects or space

Through what physical objects do users interact with the product? A laptop, with a mouse or touchpad? Or a smartphone, with the user’s fingers? And within what kind of physical space does the user do so? For instance, is the user standing in a crowded train while using the app on a smartphone, or sitting on a desk in the office surfing the website? These all affect the interaction between the user and the product.

4D: Time

While this dimension sounds a little abstract, it mostly refers to media that changes with time (animation, videos, sounds). Motion and sounds play a crucial role in giving visual and audio feedback to users’ interactions. Also of concern is the amount of time a user spends interacting with the product: can users track their progress, or resume their interaction some time later?

5D: Behaviour

This includes the mechanism of a product: how do users perform actions on the website? How do users operate the product? In other words, it’s how the previous dimensions define the interactions of a product. It also includes the reactions—for instance emotional responses or feedback—of users and the product.

See how 5 dimensions of interaction design come together in the animation below:

Important questions interaction designers ask

How do interaction designers work with the 5 dimensions above to create meaningful interactions? To get an understanding of that, we can look at some important questions interaction designers ask when designing for users, as provided by

  • What can a user do with their mouse, finger, or stylus to directly interact with the interface? This helps us define the possible user interactions with the product.
  • What about the appearance (colour, shape, size, etc.) gives the user a clue about how it may function? This helps us give users clues about what behaviours are possible.
  • Do error messages provide a way for the user to correct the problem or explain why the error occurred? This lets us anticipate and mitigate errors.
  • What feedback does a user get once an action is performed? This allows us to ensure that the system provides feedback in a reasonable time after user actions.
  • Are the interface elements a reasonable size to interact with? Questions like this helps us think strategically about each element used in the product.
  • Are familiar or standard formats used? Standard elements and formats are used to simplify and enhance the learnability of a product.

So what do interaction designers do?

Well, it depends.

For instance, if the company is large enough and has huge resources, it might have separate jobs for UX designers and interaction designers. In a large design team, there might be a UX researcher, an information architect, an interaction designer, and a visual designer, for instance. But for smaller companies and teams, most of the UX design job might be done by 1-2 people, who might or might not have the title of “Interaction Designer”. In any case, here are some of the tasks interaction designers handle in their daily work:

Design strategy

This is concerned with what the goal(s) of a user are, and in turn what interactions are necessary to achieve these goals. Depending on the company, interaction designers might have to conduct user research to find out what the goals of the users are before creating a strategy that translates that into interactions.

Wireframes and prototypes

This again depends on the job description of the company, but most interaction designers are tasked to create wireframes that lay out the interactions in the product. Sometimes, interaction designers might also create interactive prototypes and/or high-fidelity prototypes that look exactly like the actual app or website.

Diving deeper into interaction design

If you’re interested to find out more about interaction design, you can read Interaction Design – brief intro by Jonas Lowgren, which is part of our Encyclopedia of Human-Computer Interaction. It provides an authoritative introduction to the field, as well as other references where you can learn more.

References & Where to Learn More

5 dimensions of interaction design -

Questions to consider when designing for interaction -

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Learn more about Interaction Design

Take a deep dive into Interaction Design with our course Psychology of Interaction Design: The Ultimate Guide.

“It can be helpful to understand and even experience the part of the elephant that others are experiencing.”1 Whatever your “elephant” may be, a deep understanding of human psychology is essential for all designers when creating a user-centered product with great user experience.

While many individual differences will never cease to exist between users, we are united by our shared psychology; the constraints and abilities of the human mind are much the same for all of us. Developing an understanding of these cognitive limitations and capabilities is the key to interaction design and a great user experience. Without an awareness of how we interact with things in the real and virtual worlds, you’ll find that your designs will fall short of their potential.

This course will equip you with the knowledge to relate to your users psychologically, thus allowing you to create stand-out products. Through learning about different aspects of human cognition—and how they relate to interaction design—you will find yourself much better equipped to put yourself in your users’ shoes, shifting their thoughts to the forefront and keeping a firm hold of them there when designing your next creation.

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Interaction Design - brief intro

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