One free interaction

"One free interaction" is a prospective design pattern that gives software and hardware a more humane feel. It exists outside of task flows and the concept of users as task-doers. Instead it sits in the "in between" spaces, suiting users as fidgeters, communicators, and people who play with things.

Snapback pages

When I got my iPhone, I spent time opening up all the applications and playing around. I was keeping an eye open for what new facets of the touchscreen interaction design were fun and useful. When using the Safari web browser, I noticed the funny stretchy-edge pages. Meaning, when you use your finger to scroll above the top of a page or below the bottom of a page, it pulls away from the edge of the browser, revealing a small blank area that sits “behind” the page. When you lift your finger up, the page snaps back into place. It’s kind of hard to describe, so this little video should help.

It was pretty cool, since it provided some visual confirmation of the edges of the page. But honestly I thought it was just a coding oversight. Then I saw it again in the text message page. And again in email menus, and the emails themselves. Nope, I realized, it’s baked into the OS.

I put the feature out of my mind until I found myself fiddling with it. Mulling over an email, or waiting for a text response from someone, I’d sit and idly flick the pages away from the edge just to watch them snap back. Flick-snap. Flick-snap. It was so satisfying, even if it was sort of useless.

Then I started seeing this same pattern in other things.


In the iPhone word-finder application Quordy you’re meant to drag your finger through a grid of letters to create words. But tapping single letters also sets off a little animation of the tapped letter flying into the corner. Since there is no consequence to doing this, it becomes something to do as you look for new words.


I noticed two friends who use their mouse to repeatedly select and deselect text in web browsers as they read pages online. This is absolutely crazymaking for onlookers, but really satisfying for them.


A couple I know so dearly love the “purr” error sound in the MacOS X, that they look for ways to get it to sound without interrupting their work. They found a key command that can only execute when something’s selected on the desktop, so occasionally they’ll deselect everything and play it for one other a couple of times. It's like saying "I love you" in 16Bit/44Khz.

Pearl trackball

This pattern can be seen in industrial design as well. I’ve heard that owners of Blackberries adore just fiddling with the pearl trackball, especially when the device is off.


When I talk to each person about these behaviors, there’s not a lot of conscious decision-making going on here. The web-page-highlighters aren’t intending anything when they do this, it’s just something they enjoy doing. But even though these behaviors don’t help move any tasks or goals along, they’re satisfying. And because they provide a release for nervous energy and/or let us be expressive, they become an extension of ourselves to which we have some small emotional connection.

Free interactivity

This emotional connection is desirable from both a branding and an interaction design perspective, so we should make use of this type of interaction. I’m giving them a name so we can talk about them: free interactions. They’re “free” because they have no consequences. They affect only the interface and don't touch content. It's interactive because there is some small, quick cause and effect.

As we're trying to understand what makes them successful, there are some other important aspects to these behaviors worth noting. Most of them are “natural,” in the sense that they feel more like the natural world than the computer world. The snapback pages feel like they’s connected by rubber bands. The MacOS X “purr” sounds kind of like a cute animal. The pearl is even called a pearl and feels like a little stone under your thumb. Granted, clearly there’s no natural analogue to text selection and deselection, but you see the pattern. When these things have a natural feel they have a pleasant, emotional...humane feeling.

Another aspect is that the feedback loop is very quick. Purr.aiff plays at 0.5 seconds, and that seems like the longest duration before it would become too weighty to keep doing over and over. The snapback, in comparison, feels like it takes about a quarter second, and the Quordy letter animation takes place in even shorter amounts of time.

Free interactions are rare enough right now that I couldn’t find an example in which there were more than one. But I imagine that if there is more than one, it would begin to feel a little hokey and detract from the actual utility of the system. (OK, maybe KidPix has overdone it, but it's right for their audience.) Because of this minimalist constraint, let's ultimately call the pattern one free interaction.

One Free Interaction card

Call to action

Since we want our designs to be humane and, presuming they fulfill their utilitarian purposes well, emotionally satisfying, I suggest that designers begin to include one free interaction in their designs to enable the channeling of energy and simple expression. Design this interaction such that:

  • It's “free,” i.e. having no significance to the task or content
  • It's discoverable in ordinary use of the product
  • It's quick and repeatable (Less than half a second.)
  • It's pleasant

This is a prospective pattern, and one that I'd love to hear if others have encountered or implemented. Where else in the world have you seen this at play?