What does interaction design do?

How can we know if interaction design is successful?


Being an interaction designer, I think about this often. Moreover, I think about how we discuss these questions. Many designers evaluate designs on an instinctive level and when they attempt to externalize their thoughts, it ends up sounding like “I just know users will hate that.”


How then do designers discuss interactions in a credible way? How does one evaluate interaction design? Why do I know users will hate that (whatever that is)?

To answer these questions, I’d first like to talk about what interaction design is and what we think it should do. Of all the definitions of design I’ve come across, Charles Eames’ is my favorite: Design is “A plan for arranging elements in such a way as to best accomplish a particular purpose.”1 (Go here for more definitions than you could ever need) It seems so simple and clear when he says it. And yet this is just as vague as many other definitions of both design in general and interaction design specifically. I find myself giving examples: computer interfaces, the gestures and feelings associated with an iPhone, even door handles2, which all lead to the idea of goals, of purpose as in Eames’ quote. Design needs to either do something or help someone do something well. Interaction design is focused on the intent of a user to accomplish a goal. As an interaction designer, my purpose is not fulfilled unless the user’s goal is achieved and they are satisfied.


Part of enabling users to achieve their goals is making interactions invisible. As Gillian Crampton Smith, said, the main question interaction designers ask is “how can we make sure people don’t have to think about how to interact?”3 Users who have to think about how to work with their tools are neither happy nor productive. Users who don’t have to think about their tools have much more mental capacity to actually work, to accomplish their goals, and to enjoy doing it. Think about driving a car. Very shortly after you learn, driving becomes second nature, almost instinctual. Now imagine all new cars have the accelerator and brake pedals switched. Such a tiny change would have absolutely no effect on the function of the vehicle itself, but the user’s interaction paradigm would be shattered.


The ability to use familiar and/or well-designed tools without thinking about how you’re interacting with them is an essential characteristic designers aim for. One psychologist4 describes the ability to work smoothly without thinking about either the tools or the process as ‘Flow,’ the absolute freedom from distractions and frustrations that well designed tools, objects, and processes can help create. Think about the oft-described “Zone” wherein one’s momentum is incredible, ideas come effortlessly, and you reach a stage of near super-productivity. That is flow, a single-minded immersion that harnesses the emotions in the service of performing and learning5. Interaction designers seek to help users achieve this state.


Interaction design succeeds when it invisibly supports the user’s process. Like a crystal clear wine glass supporting and revealing the palate and bouquet of the selected vintage6; interaction design should create a frictionless channel through which the user’s energy and emotions can flow, toward accomplishment of tasks and goals. How that can be achieved is a topic for another blog post, but these concepts of flow and ease of use give us somewhere to start when evaluating design as good, bad or mediocre. Does the user have to think about how to use their tool? If so, then “I know users will hate it,” because it adds to their cognitive load and prevents them from achieving flow. If using the tool is effortless, than the interaction design has succeeded.



  1. Neuhart, John, Marilyn Neuhart, and Ray Eames. Eames Design: the Work of the Office of Charles and Ray Eames. New York: H. N. Abrams, 1989. Print.
  2. Norman, Donald A. The Design of Everyday Things. New York: Basic, 2008. Print.
  3. Moggridge, Bill. “Interview with Gillian Crampton Smith.” Designing Interactions. MIT, 2007. Foreword – “What Is Interaction Design?”. Designing Interactions. Web. <http://www.designinginteractions.com/interviews/GillianCramptonSmith>.
  4. Csikszentmihalyi, Mihaly. Flow: the Psychology of Optimal Experience. New York: Harper Perennial, 2008. Print.
  5. “Flow (psychology).” Wikipedia, the Free Encyclopedia. Web. 03 May 2011. <http://en.wikipedia.org/wiki/Flow_(psychology)>.
  6. Warde, Beatrice. “The Crystal Goblet.” Print. Rpt. in Sixteen Essays on Typography. Cleveland: University of Chicago, 1956. Print.


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