We spend a lot of time talking with development teams (and clients) about mental models. When designing a screen, especially if the item is a control of some kind where the user is asked to take action, it’s important that the UI’s conceptual model matches the user’s mental model.

In other words, speak their language, express ideas and directions in ways they’ll readily recognize and understand. That means symbols they’re familiar with, phrases they’d likely use themselves — even slang if appropriate. Not doing so means users have to spend additional time and mental effort to learn how to use your interface.

Brandon Walkin has a great example of this in a blog post titled “Managing UI Complexity“.  I’ve included a snippet here, but do yourself a favor and check out the entire post. It’s a truly insightful read.

Here’s what Brandon says:

The recurrence UI in Windows Calendar, for instance, reflects the developer’s model of the task rather than the user’s model. Take a look at the second set of radio options in this screenshot:


1. What’s the “28th last day of the month”?

2. What’s the “4th last Tuesday of the month”?

3. How long did you spend trying to work that out?

The language used here isn’t written in the same way any of us would ever say these things. As such, the options seem overly complex — we have to think and do some mental calculating to figure out what the heck they mean. That’s a sure sign of a mismatch between mental models: the user’s mental model vs. the designer’s UI model. Decisions like this not only make users feel intimidated and overwhelmed – they increase the app’s learning curve, and present barriers to adoption.