When I bought my first iPhone almost three months ago, I also acquired a new obsession with the role of playfulness in user experience design. Recently, a fortunate coincidence occurred that has allowed me to explore this new obsession deeply. Tw
o iPhone developers each released new measurement unit conversion apps within a week of each other and also documented their design processes on the Web. As if that weren’t enough, both of these applications, taptaptap’s Convert and Tapbots’ Convertbot, were designed with the idea of delightful experience in mind. The two apps are very different despite all these similarities, and those differences got me thinking about the relationship between playfulness and usability in creating delightful interactions. I succumbed fully to my obsession and roped in some iPhone-using coworkers to participate in an informal comparative usability test. What I learned, led me to compelling insights about the relationship between usability and playfulness.
Users interact with taptaptap’s Convert on a single screen using familiar iPhone user interface controls. The designers altered the visual look and feel of these controls slightly to support the purpose of the app. If you have a moment, watch this video about how the design of Convert evolved. It’s entertaining in its own right, not just informative.
The designers at Tapbots took a different and more playful approach to the design of Convertbot. The application responds to user input as if it were a mechanical device. It clicks, whirrs, opens doors, and is overall a more dynamic interface based on these unique interactions. This is consistent with Tapbots’ approach to making “robots,” their term for the applications they make. Here is their write-up on how they designed Convertbot.
I wrote up a very informal usability test plan (okay, fine, I’ll admit it; it was just a data collection sheet) and got one iPod touch-using and three iPhone-using coworkers to sit down with me for 15 minutes each. I didn’t tell them the true purpose of what I was doing until the end, which was to explore the relationship between playfulness and usability. I asked them three questions up front to get a sense of the usual context in which they need to convert measurements:
- Please tell me the story of the last time you needed to convert one unit of measurement to another.
- Is this story representative of the usual sort of situations in which you need to do a conversion? If not, please describe your typical conversion needs.
- How often do you need to do a conversion?
I then asked my co-workers to perform four conversion tasks with each application and timed them. Each participant did the task first with Convert and then with Convertbot and then moved on to the next task. Two tasks represented reasonably common conversion situations, one represented a more academic situation, and one… well, to call this task an “outlier” is an underestimate of inter-galactic proportions.
- Convert 1,500 miles to kilometers
- Convert 3 cups to pints
- Convert 138 degrees Fahrenheit to Kelvin
- Convert 2.54 million light years to astronomical units (How many times the distance from the Earth to the Sun is the Andromeda galaxy?)
At the very end, I asked them to describe their experience using each application.
- Which experience did you enjoy more? Why?
- Which app would you use in your typical conversion situation?
- Which app would you use to show a non-iPhone user how awesome iPhones are?
The results of this evaluation were both expected and surprising.
First off, the purpose of this evaluation was not to determine which was a better app but to explore the relationship between usability and playfulness. That said, three out of the four people I tested preferred Convert to Convertbot. The reason all of them gave was that Convert was more intuitive. That made Convert more useful to them in their typical conversion scenarios and made them choose to use it to show off the iPhone from the perspective of how usable it can be. This
preference makes sense considering that using Convert took (sometimes greatly) less time in 13 out of the 16 total evaluations performed by the four participants. This is pretty much what I expected based on my own experience with the two apps.
The one person who preferred Convertbot was the surprise. She really struggled with it at first. Her comment to me was familiar, “Once I figured it out, I liked that one better. I’m surprised at myself that I like it better.” There’s that phrase again, once I figured it out. That phrase points directly to learnability. As in my last encounter with iPhone learnability problems, this one has also been instructive.
Implications for User Experience Design
In my last article, I declared that fun is the new usable.
My experience with this evaluation has helped me refine that declaration into something a little less dogmatic. Fun isn’t always the new usable. There are situations in which usability is more important than playfulness and those in which it’s the other way around. The delight that playfulness contributes to an experience depends on the context surrounding that experience.
So what does this mean for user experience design? I don’t know for certain, but I’ve come up with three hypotheses.
Hypothesis 1: Usability inspires more delight than playfulness does in situations in which tasks are clearly defined and use is infrequent. Unit conversion is always a very specific task and the most frequently any of the test participants did it was two times a month. In this context, people want to get the information they need quickly without having to learn or re-learn anything. This implies that there is an inherent learning curve in playful interactions (see hypothesis 3).
Hypothesis 2: Playfulness inspires more delight than usability does in situations in which the tasks are amorphous and use is frequent Playfulness also inspires more delight when there is a clear benefit to overcoming the learning curve inherent in playful interactions (see hypothesis 3). Amorphous tasks are those with a destination in mind but perhaps not a particular one. Using the Yelp iPhone app to find somewhere nearby to eat is an example. This is not a step-one-then-step-two kind of task. There are a lot of individual interactions required to arrive at the destination, and they’re not all the same for everyone every time! When you frequently use a system like this that supports amorphous tasks, you begin to develop a relationship with it and maybe even rely on it. As you return to a system again and again, whether it was easy to learn at first becomes more and more irrelevant. What remains relevant (and perhaps even strengthens the relationship) is playfulness, which inspires delight every time you encounter it. The iPhone itself is a perfect example of such a system.
Playful systems require you to learn how to play with them. When there is a clear benefit to users in taking the time required to do so, they will. One of the test participants who preferred Convert told me that games offer that sort of benefit to her. Tapbots’ other application, Weightbot, is a great example of this. Weightbot lets you track your weight, something you do frequently that has clear health benefits. The playful, compelling nature of the application’s interaction design facilitates and actually encourages its use.
Hypothesis 3: The learnability of a playful system is inversely proportional to the level of interaction at which that playfulness occurs. I see three levels of interaction, individual interactions (like a button press), interaction flows (individual interactions flowing into another to complete a task), and systemic (the language of using the system, e.g. game mechanics, gestures, visual vocabularies). Learnability decreases as playfulness becomes more systemic.
An app like Convert is playful at the level of its individual interactions, such as flicking a wheel, and takes very little time to learn. But an app like Convertbot has a more playful, immersive flow and a correspondingly higher learning curve. A device like the iPhone itself that requires you learn an entirely new form of interaction represents the far end of the spectrum. Using the device is delightful in the same manner that playing a game is delightful, but you also have to spend some effort learning and memorizing how to use it because it’s not immediately intuitive.
What all this tells me is that while playfulness is undoubtedly an important new focus in user experience design, it’s not a panacea. User experience designers need to understand when playfulness is more effective than pure usability in inspiring delight and vice versa. The following diagram represents some recommendations on how to use playfulness most effectively.
The next time you design a system, think hard about the context in which people will use it. Are there very specific things they’ll need to do infrequently? Then consider designing playfulness into the individual interactions of that system. Are people going to use the system frequently and in unpredictable ways? Consider designing playfulness into the flow of the system. Is there a clear, ongoing benefit to users in using the system? Then consider making the system as a whole playful in an effort to allow users to build a relationship with it.
Our mission as user experience designers is to make people love the systems they use every day. To complete that mission, we must think consciously about playfulness and balance it with usability in a manner appropriate to the context in which the system will be used.