POSTED BY DAN YOUNG

People don’t often think about the devices they use and how they interact with them. We run apps, we open websites. Each task is done within the frame of another. Our interactions are nested, much like the Russian Matryoshka dolls.

“Frames of interaction” is a concept I first learned through an article written by Matt Gemmell. In his article, he points out that our mobile devices are devices that are “already task-compromised.” To understand this, let’s take a look at a dedicated device: the calculator.

A desktop calculator is a device that most of us have used. It’s designed to do arithmetic. The user interface is tactile; its design is specific to the task at hand. You interact with the device directly, thus it has one frame of interaction.

Let’s now look at your smart phone. Most devices come with a calculator app. The apps can be simple or complex, replicating the financial or scientific functions of desktop calculators. Regardless of accurate the replication of a desktop calculator the app provides, these apps are still contained within the mobile device.

Along side the function keys and numbers of the app, there is the device with its status bar, clock, signal strength, etc. The calculator app is nested within the device. According to Gemmell, users interacting with the app have “two frames of interaction: the app, and the device.” As he put it, “you're reaching through a window to do whatever you’re doing.”

A web app is an application accessed and run through a web browser. Web apps allow web designers the ability to create web sites that can perform similar functions as a native app without having to write software specific to a device, like an iPhone or Android.

So, if our calculator app is a web app, then it would have three frames of interaction: the app is used from within a web browser that’s used within a mobile device; the user is now three levels removed from the web app.

By reaching through one frame to reach content within another, the user is farther removed from their task. Furthermore, with each frame accessed, the device itself needs to allocate additional resources to run the app. Sometimes this creates latency issues and general sluggishness (think about the new Facebook apps), which can create usability issues that outweigh the cost savings of web-based software.

Tablet apps are starting to go one step further, nesting web apps within web apps—four or five frames of interaction. With each level of nesting, much like the Matryoshka dolls, the functionality of the apps is increasingly constrained until you reach a point where it the apps, like the dolls, become too “small.”

Every instance an app is nested into another app, that app is limited by the function of the superseding level; an app can only do what the device or the web browser allows. Thus finding the right balance between ease of development, cost and usability is a challenge (and the topic for another article).

For now, I’ll leave you with the metaphor of the Matryoshka dolls and nested mobile app.