Why is Angry Bird so very popular?
1. Simple yet engaging interaction concept:
This seems an obvious point, but few realize that a simple interaction model need not be, and rarely is, procedurally simple. Simplification means once users have a relatively brief period of experience with the software, their mental model of how the interface behaves is well formed and fully embedded. This is known technically as schema formation.
In truly great user interfaces, this critical bit of skill acquisition takes place during a specific use cycle known as the First User Experience or FUE.
However, simple does not equal engaging. It is possible to create a user interface solution that is initially perceived by users as simple. However, the challenge is to create a desire by users to continue interaction with a system over time, what we call user “engagement”.
What makes a user interface engaging is adding more detail to the user’s mental model at just the right time. Angry Birds’ simple interaction model is easy to learn because it allows the user to quickly develop a mental model of the game’s interaction methodology, core strategy and scoring processes.
2. Cleverly managed response time: Fast is Good But Clever is Better
A universal law of user interface design is “the faster the response time, the better”. The surprising point that is often misunderstood is that not every aspect of the user interface needs to be or should be as fast as possible.
The developers of Angry Birds managed response time in a way that goes far beyond simply “faster is better”.
For example, in Angry Birds, it was possible for the programmers to have made the flight of the birds fast – very fast, but they didn’t. Instead they programmed the flight of the angry flock to be leisure pace as they arc across the sky heading for the pigs’ glass houses. This slowed response time, combined with a carefully crafted trajectory trace (the flight path of the bird), solves one huge problem for all user interfaces – error correction.
In Angry Birds game play the pigs also take a long time to expire once their houses are sent to bits. This response time of 3-5 seconds, in most user interfaces, brings users to the point of exasperation, but not with Angry Birds.
Again, really smart response time management gives the user time to relax and think about how lame they are compared to their 4 year old who is already at the 26th level. It also gives the user time to structure an error correction strategy (more arc, more speed, better strategy) to improve performance on the next shot. The bottom line on how Angry Birds manages response time: fast is good, clever is better.
3. Short-term memory management:
SM makes it possible for you to operate without constant referral to long-term memory, a much more complex and time-consuming process. This is critical because SM is fast and easily configured, which allows one to adapt instantly to situations that might otherwise be fatal if one were required to access long-term memory.
Poor user interface design impacts the demand placed on SM. For example, a user interface design solution that requires the user to view information on one screen, store it in short-term memory, and then re-enter that same information in a data field on another screen seems like a trivial task.
Anything that is engaging, such as conversation, noise, motion, or worst of all, a combination of all three, is likely to totally erase SM. When you encounter this type of data flow before you complete transfer of data using short-term memory, chances are very good that when you go back to retrieve important information from short-term memory, it is gone!
Angry Birds is a surprisingly smart manager of the player’s short-term memory. he subtle, yet powerful concept employed in Angry Birds is to bend short-term memory but not to actually break it.
There are many examples in the Angry Birds game model of this principle in action. Probably one of the most compelling is the simple screen flow manipulation at the beginning of each new play sequence. When the screen first loads, the user is shown a very quick view of the structure that is protecting the pigs. Just as quickly, the structure is moved off screen to the right in a simple sliding motion.
Coming into view on the left is a bevy of bouncing, chatting and flipping birds sitting behind the slingshot. These little characters are engaging in a way that for the most part erases the player’s memory of the structure design, which is critical to determining a strategy for demolishing the pig’s house.
Predictably, the user scrolls the interface back to the right to get another look at the structure. The game allows the user to reload short-term memory easily and quickly. Watch almost anyone play Angry Birds and you see this behavior repeated time and again.
Mystery is that second layer of attributes that are present but undefined explicitly, yet somehow created with just enough context to consume mental resources in subtle and compelling ways.
Angry Birds is full of these little mysteries. Why do the houses containing pigs shake ever so slightly at the beginning of each game play sequence? Why do the birds somersault into the sling shot sometimes and not others?
5. How things sound:
The use of audio effects and carefully varied melodic music lines works to enhance the game play engagement level. Many games do this but few do it expertly. The audio in Angry Birds serves to enhance the user’s experience by mapping tightly to the user’s simple mental model of conflict between the angry birds and the loathsome pigs. This concept, known in film production as “action syncing”, provides enhanced levels of the feedback for users at just the right time. For example, in Angry Birds, we hear the birds chatter angry encouragement to their colleagues as each prepares for launch. The pigs are by no means silent. When the avian interlopers fail, they are often egged on to try just one more time by the snickering, grinning pigs.
6. How things look: Angry Birds has a look. One might characterize the visual style of Angry Birds as a combination of “high-camp cartoon” with a bit of greeting card graphics tossed in for good measure.
To summarize, in the context of Angry Birds, success is bound up in slowing down that which could be fast, erasing that which is easily renewable, and making visual that which is mysterious and memorable.