The Intuitive Interface

by Charlie Kreitzberg

Make it Intuitive!

When we design a user interface, creating an intuitive interface is often our number one goal. Everyone wants it. But what does intuitive really mean? How do you do it? And how do you know if you’ve achieved it?

What’s an Intuitive Interface?

Defining an intuitive interface is quite simple although creating one may not be. Here’s the definition:

An intuitive interface is one that works the way the user expects it to.

In other words, we find something intuitive when we don’t have to think about it.

Thinking, as anyone studying for an exam can tell you, is hard. It takes energy and attention. And thinking about two things at once is particularly difficult. That’s why distracted driving is so dangerous.

When someone is using software, they are usually thinking hard about the problem they’re solving. If they also must think about how to work the interface, they’ll have a tough time. Imagine trying to write an important letter while struggling to use the word processing software. It’s exhausting and is likely to result in a poorly-written letter.

We call the mental effort needed to accomplish a task, cognitive load. Intuitive interfaces have low cognitive load. The lower the cognitive load, the more users can focus getting their task done. So, intuitive interfaces have a real advantage in terms of efficiency and the quality of the work. They also have the advantage of requiring less training and support; if an interface works the way users expect it to, they don’t need to learn how to use it.

It’s More Than Just Design

How do you create an intuitive interface? Intuition is not just about the design. What’s intuitive to you may be confusing to me. Like a fine suit or gown, the interface must fit the user. A tailor will use a measuring tape and a dummy to fit the garment to the customer. The UX designer uses research and prototypes to understand the user’s mental model and then designs the interface to fit.

A person's mental model is their internal representation of the situation. It consists of all the concepts, knowledge and beliefs they use to understand the world. To the extent your design aligns with the user’s mental model, (s)he will find it intuitive.

Some of the concepts that comprise a user’s mental model are basic knowledge. If the user encounters a prompt that reads “click to update the database” the user must have concepts for the ideas of clicking a control, what a database is and what the operation ‘update’ means.

Another form of concept is a script. A script defines a user’s expectations for a given situation. Scripts typically include: actors, props, settings and actions.

For example, imagine a person walking into a restaurant. Along with appetite, they bring their mental model of how the experience will play out. Expectations are:

  1. I'll be greeted.

  2. I'll be seated.

  3. I'll be handed a menu.

  4. I'll pick what I want.

  5. The food will be brought to me.

  6. I'll eat it.

  7. I'll pay for it.

This is a bit simplified but should make the point. If the restaurant follows this script, the process is intuitive. The diner does not have to figure out what to do because everything aligns with his or her expectations. A script also enables the user to identify elements that are missing. If the customer is seated at a table but no one brings the menu, she will know to ask for it.

Now imagine that in a certain restaurant, the model is different. Perhaps you are expected to pay before you sit down.

I remember encountering such a place in Italy many years ago. You paid on entry and then were served a cafeteria-style meal. The first time I went to this restaurant I was confused because the process did not align with my mental model; it wasn’t intuitive. Of course, once I learned how it worked, it became easy. But the initial encounter was confusing.

This points out another feature of mental models – they can change based on experience. That’s why, with training and practice, users get adept at working with tools that are not well-designed. But that places a lot of burden on the user. Steep learning curves and training costs add a lot of wasted effort. And as the end result may never match the user’s workflow, the tool may never be efficient.

How to Create Intuitive Designs

A design that does not align with the user’s mental model, forces the user to go into problem-solving mode and work out what the next step is. That requires a lot of mental processing and results in high cognitive load. So, the design goal is to produce an interface or experience that aligns with the user’s expectations and will therefore have the lowest possible cognitive load.

If you want to create intuitive designs, you need to start by understanding the user’s mental model. You can then design to fit the user’s expectations as closely as possible. The problem, of course is that mental models are covert. They exist inside the users’ head so you need to make some guesses about what’s going on. In addition, each user has a different mental model because they have had different experiences.

There are two major ways to assess your users’ mental models:

User research

Talking with users in 1-1 interviews and observing users as they work on relevant tasks can provide you with a lot of information about how they conceptualize their workflow and the steps they envision.

Another powerful technique is contextual inquiry where you observe your users in their own environment, working on the tasks you are seeking to understand.

Usability testing

Observing users working on wireframes and prototypes can help you understand their expectations, especially if you encourage them to ‘think aloud’ as they are working.

Here are some hints for producing an intuitive design:

  • Divide your users into segments. Group users with similar backgrounds and needs together. Pick the segments carefully so that you have as few groups of users as possible. Everyone will not have identical mental models but by grouping them together you will have a fighting chance to identify the commonalities in each group.
  • Try to understand their representations. Ask them to sketch out the steps they would follow or have them write out scripts.
  • Listen carefully to their terminology. An intuitive interface should use the same words as its users.
  • Think about the underlying concepts and knowledge a user must have to understand the UI. Especially consider technical terms and concepts that may not be obvious to the user, Define or explain these when necessary so the user can make meaningful decisions.
  • Organize tasks and information the way the user anticipates them.

Conclusion

Intuitive design creates happy users. It takes effort to build an intuitive design but doing so will reduce training time, lower frustration and increase efficiency. To design intuitively, seek to understand your users’ mental models – the knowledge, beliefs, language and scripts they bring to the interaction. Through usability testing, identify the places where your design deviates from user expectations and modify the design to match them.