游戏邦注：本文原作者是Charles L. Mauro，原文发表于2011年2月，所涉数据均以当时为准。

常见问题：在人因工程（游戏邦注：也称为“可用性工程”）领域担任顾问30多年以来，有数百名客户问我为何用户不喜欢他们公司的软件。这个永久性问题的答案很复杂，但并非难以捉摸。解答问题需要经验和专业的可用性分析。

非常见问题：令人惊奇的是，很少有客户会提出相反的问题：为何某种界面会如此吸引玩家与之互动？这是个很麻烦的问题，因为需要用认知反向工程来解释成功界面中有何种从心理上吸引玩家体验的互动。当基于用户体验的设计使某些产品获得巨大成功时，这个问题就会浮现，此类产品有iPhone、iPad、Google即时搜索、任天堂Wii和微软Kinect等。

有趣的问题：近期有客户咨询取得非凡成功的《愤怒的小鸟》这款运行于手机、平板电脑及其他平台的休闲游戏相关情况。这里对该游戏做个简短的介绍，以为那些不甚了解《愤怒的小鸟》的人释疑解惑。玩家在游戏中将炮弹状的小鸟抛向脆弱的玻璃和由绿猪搭建的木屋，目标在于尽量熟练快速地用倒塌的木屋将绿猪砸死。这听起来显然像是个非常简单的概念，但确实引起了轰动。

为何会有超过5000万的用户下载如此简单的游戏呢？许多人还支付数美元甚至更多来购买高级版本。更令人惊奇的是，这款游戏不仅下载量巨大，全球用户每天在《愤怒的小鸟》上花费的总时间数将近2亿分钟，也就是说游戏每年吸引用户投入12亿小时的时间。相比之下，维基百科创立至今，人们创建和更新词条的总时间数为1亿小时（游戏邦注：该数据源于Neiman Journalism Lab）。我觉得《愤怒的小鸟》值得人们细心研究。为何这款看似简单的游戏会有如此大的吸引力呢？制作真正具有吸引力的软件体验比想象中要复杂得多，即便电脑游戏中最简单的方面也是如此。《愤怒的小鸟》成功获取用户体验背后潜藏着某些认知科学。

angry-birds(from slidetoplay.com)

简单却富有吸引力的互动概念：这一点看似很明显，但很少人意识到简单的互动模型在程序上并不简单。简单化指的是相对短暂的体验时间便能够让用户明白和完全接受界面的行为方式。这在技术上称为图式形成。在真正优秀的用户界面中，技能学习的重要阶段发生在称为“第一次用户体验”的特定使用周期期间。如果用户可以迅速构建完整的图式，他们通常会认为此用户界面“简单”。但是，简单不等同于富有吸引力。创造被用户视为“简单”的用户界面解决方案并不难，真正的挑战在于让用户产生持续与系统互动的欲望，我们将其称为用户的“参与度”。

时机恰当时为用户心智模式添加更多细节会让用户界面产生吸引力。《愤怒的小鸟》的简单互动模式很容易为用户知晓，用户很快便会就游戏的互动方法论、核心战略和得分过程形成心智模式。因为游戏细致安排了用户战略成分心智模式的扩展过程并逐渐增加问题及解决方案方法论，所以它富有吸引力，让用户沉迷其中。随着游戏关卡的复杂性逐渐增加，这些有着聪明行为的小鸟不断扩展用户的心智模式。创造简单、富有吸引力互动模式的过程就变得极为复杂。现在多数开发软件的组织认为只有《愤怒的小鸟》才能扩展用户的心智模式，其实你也可以做到。

精巧管理响应时间：用户界面设计的普遍原则是“响应时间越短越好”。对某些应用来说，这项原则确实是真理。比如，Google将此作为系统的黄金法则。但令人惊奇的是，少数软件开发商意识到响应时间管理可用来增加用户界面参与度的质量和深度。这个观点往往为人们所误解，但用户界面中不是每个层面都需要或应该尽量提速。多数程序员对此难以理解，只有少数游戏设计师会利用这个强大的变量。在大部分商业软件界面中，响应时间管理完全被忽略，甚至那些所谓的用户界面设计专家也不例外。《愤怒的小鸟》开发商以某种超乎“越快越好”原则的方式来管理响应时间。

比如在《愤怒的小鸟》中，程序员固然可以让小鸟的飞行速度变得很快，但他们没有这么做。他们反倒让那些愤怒的小鸟以悠闲的节奏飞翔，在空中划过一道弧线，然后撞向猪的玻璃屋。这种放慢的响应时间与细致勾勒的轨迹（游戏邦注：即小鸟飞行的路径）相结合，解决了所有用户界面面临的巨大问题——误差修正。大量软件用户界面都未曾考虑过系统体验能够以某种方式来教授用户改善其行为。这对基于屏幕的互动系统来说是个巨大且复杂的问题，误差修正不仅必要，而且还可能影响到整个软件。

在《愤怒的小鸟》的玩法中，猪也会在房子被撞塌一段时间后死亡。在某些游戏场景中，猪摇晃、滑落和滚下木板或被缓慢掉落的残骸砸死需要经过数秒钟的时间。3到5秒的响应时间在多数用户界面中会让用户感到恼怒，但《愤怒的小鸟》并未出现这种问题。而且，这种精致的响应时间控制让用户放松，想想与那些已经玩到第26关的4岁小孩相比自己是多么的差劲。这也给予用户构建误差修正战略（游戏邦注：如更大的弧线、更快的速度或其他更好的战略）的时间，使下次射击得到改善。《愤怒的小鸟》管理响应时间的原则是：快速固然好，精巧设计更佳。

短时记忆管理：在认知科学中，短时记忆（游戏邦注：下文简称“SM”）与我们记忆系统的其他类别相比极为有限，这是众所周知的事实。在过去50年里，该事实已引发数千次的研究。科学家挖掘这个人类认知层面，试图弄清SM的运作原理以及影响SM有效性的因素。在日常生活中，短时记忆让你了解到各种技术方法和总体环境。SM是种暂时性记忆，让我们可以在短暂时间内记住数量极其有限的不相关内容、行为或样式。SM让你可以在不将内容转化为长时记忆的前提下做出行动，因为转化是个更为复杂而且费时的过程。这很重要，因为SM快速且易于形成，使用户可以立即适应某种环境，转化为长时记忆的需求可能会产生致命的影响。在人机对话中，人类的短时记忆还极具易变性。这意味着记忆内容可被迅速清除，更为重要的是，内容会被其他进入人类感知系统的信息覆盖。事情产生趣味性的时机正是劣质用户界面设计影响SM需求的症结所在。比如，某个用户界面设计解决方案要求用户观看某个屏幕上的信息并存储在短时记忆中，随后在另一个屏幕的数据区中重新输入相同信息，这似乎是个毫无价值的做法。研究表明精确达成上述要求很难，尤其当第一屏数据记忆和用户在第二屏输入数据之间有某些其他形式的刺激因素流过。这种干扰性数据流可能会有各种形式，但通常是某些具有吸引力的东西，如对话、声音和动作等。最糟糕的情况是三种兼有，很可能完全清除SM。如果你在使用短时记忆完全转移数据之前遇到此类数据流，很可能在你想找回短时记忆中的重要信息时发现它们已经不复存在。

有些人可能会依此推断，任何影响短时记忆的用户界面设计层面都不是好想法。利用短时记忆的降低确实也可以改善游戏可玩性的吸引力，正如上文提到的响应时间那样，深入洞察这种令人惊奇的做法可以找到其中更为精致的观点。《愤怒的小鸟》在玩家短时记忆管理上的做法令人称奇。

通过对用户界面的简单改造，《愤怒的小鸟》设计师营造出重要的短时记忆丧失，这反倒增加了游戏玩法的复杂性。但其所采用的方式不会被玩家当成消极因素，却增加了游戏本身的沉迷性。《愤怒的小鸟》所采用的微妙且强大的概念是将短时记忆扭曲而不是破坏。如果你破坏了SM，要确保向用户提供非常简单且快速的方式精确找回记忆内容。《愤怒的小鸟》多项游戏模式都采用了此类做法。每次开局时对屏幕移动的简单控制可能是最引人入胜的实例之一。当关卡首次在屏幕上装载完成后，用户会在非常短的时间内看到保护猪的建筑结构。随后，建筑也会很快以简单的滑动行为从右侧移出屏幕。

Angry Birds(from chrisvitas.com)

用户在左侧看到的是一群健壮且叽叽喳喳的小鸟，身边有个弹弓。这些小角色产生的吸引力清除了玩家对结构设计的大部分记忆内容，而后者正是制定摧毁猪房屋战略的关键。不出所料，用户将界面滑回右侧，再看下建筑结构。游戏允许用户简单且快速地重获短时记忆。你会看到几乎每个玩《愤怒的小鸟》的人都在不断重复这种行为。在iPad上玩《愤怒的小鸟》的主要优势在于玩家可以缩小界面尺寸，这样你就能一直全视野观看整个游戏场景（游戏邦注：包括小鸟和房屋中的猪）。保持全视野观看游戏界面所有层面可防止短时记忆丢失，提高你获得必要通关技术、玩更高关卡的概率。如果你想要在《愤怒的小鸟》中获得更高层次的体验，可以在使用iPad缩小界面尺寸查看整个游戏场景的前提下用上POGO笔。这会使你的控制得到提升，更加精准地命中目标并迅速改变游戏的可玩性。但是，你也会渐渐发现游戏变得不那么有趣。为什么会出现这种情况呢？

神秘感：你可能不知道如何找到游戏的神秘感，但《愤怒的小鸟》确实有这方面的特征。所有我们觉得极为引人入胜的东西都带有神秘感，这便是该想法的背景。所有优秀的艺术作品、广告、电影和产品都带有神秘感元素或特性，毫无疑问，互动游戏也是如此。用户体验的神秘感想法潜藏于广义的神秘感想法中，该特性可增加用户的参与度。当我们观看立体派艺术家毕加索的画作、想起1984年苹果公司著名的超级碗广告或倾听Miles Davis音乐时，都在体验神秘感带来的冲击。神秘感存在于你首次拿起iPad之时。为何屏幕上的图标可以集中得如此紧凑以节省空间呢？为何默认屏幕保护程序看起来就像是位于屏幕中的水波？

神秘感属于特性的第二层次，存在但不甚明确，然而却能通过某些方法来营造，使其足够以微妙且引人入胜的方式来消耗心智资源。从最基础的层面上来说，在互动过程中体验神秘感会让你产生如下问题：“为何他们要这么做？”。我们的意思是，思考“为何他们要这么做？”是件好事，而“他们在想什么？”却不是个好问题。如果你仔细想想自己的生活经历，就会意识到最具吸引力的是那些迫使你长期且努力思考其做法缘由的事物。比如，为何Frank Gehry要将Guggenheim Museum Bilbao建成那样？这位著名的建筑师本可以建造出其他风格，为何他要选择那一种？这便是神秘感，我们无从知晓答案，或许连他自己也不知道。我们所知道的是，他的作品被称为当代最重要的建筑作品之一。建筑可以迷住数百万游客，那么神秘感同样也能让简单的互动游戏卖出数百万套。

《愤怒的小鸟》处处充满小神秘感。比如，为何有时场景中会洒满小香蕉，有时却没有？为何每次游戏开始时，猪的房屋会出现轻微晃动？为何游戏场景中会出现地下岩石和尘土的横断面？为何有时小鸟会翻跟斗跳上弹弓，有时却不会？人们会有意无意地花上大量时间来整理这些小线索。如果用户以这种方式来整理信息，就很可能更深层次地参与到游戏之中。

声音效果：过去15年间，音乐神经学突飞猛进。这项新研究正开始向我们解释为何音乐能够为电影、广告、喜剧及包括休闲电脑游戏在内的新媒体形式增加如此强烈的感情成分。利用包括音乐在内的音频刺激物通常可以增加所有科技形式用户的参与度。《愤怒的小鸟》的音频效果和音乐看似简单，但实际上非常复杂。音频效果和各种细心编排的音乐旋律有效提高了游戏的吸引力。许多游戏都这么做，但做得如此专业的为数不多。《愤怒的小鸟》中的音频紧紧围绕简单的用户心智模式（游戏邦注：即愤怒的小鸟和令人厌恶的猪之间的冲突）来制作，使用户体验得以提升。这种概念在电影制作中称为“协同动作”，在恰当的时机为用户提升反馈水平。比如在《愤怒的小鸟》中，我们能听到小鸟每次在准备时都会喋喋不休地用鸟语鼓励同伴。当小鸟飞向它们的目标时我们也可以听到叫喊声，命中目标后会听到受害者痛苦地发出回应，因而猪也并非死气沉沉。如果通关失败，游戏用咧着嘴笑的猪来鼓励玩家再试一次。所用的这些音频元素将游戏主角拟人化，使关键的屏幕上行为反馈得以加强，从而增强玩家互动并深化用户参与度。为何音乐旋律毫无理由地从前景转移至背景中呢？这种贯穿于游戏体验中的音乐线索人所共知，在游戏整体主题背景下也很容易理解。有些人觉得好像在其他地方听到过这种旋律。游戏中音频反馈结合的样式和种类恰到好处，使得坐在隔壁房间的家长很少会因为令人分心的重复音乐让孩子关掉游戏。或许这能够解释为何人们花在这款游戏上的时间如此之多！

视觉效果：《愤怒的小鸟》中存在一定的视觉效果。有些人可能会觉得《愤怒的小鸟》的视觉风格结合了“手法高明的低级动画”和许多贺卡般图形。

这产生了某个更为有趣的问题：视觉设计对游戏在市场中获得成功有何影响？我时常会听到那些准备开始重新设计游戏或施行新开发项目的客户提出这个问题。数十年前，视觉设计首先出现于汽车设计中，现在仍是设计扣人心弦用户体验中最容易引起争论的层面。设计师通常说服客户接受的观点是，界面解决方案的视觉设计（游戏邦注：即图形风格）是获得成功的关键因素。从直觉上来说，这种想法似乎确实是对的。但是，真正的制作原则却与直觉想法相反。在多数用户体验设计解决方案中，视觉设计在技术上属于保健因素。视觉设计缺失会给人带来非同小可的消极观，但如果用户界面有着优秀的视觉设计，第一印象便可以产生积极因素。在我们为客户开展用户参与度研究（游戏邦注：与可用性测试并不相同）时，通常使用的便是为此等理论提供强大支持的数据。尽管这个概念不能用来解决所有用户体验设计问题，但多数情况下依然可行。那么，最终的问题在于视觉设计达到何种程度才足够。视觉设计恰当比视觉设计的好坏更加重要。在这个度量上，《愤怒的小鸟》仍然做得恰到好处。视觉设计恰当这个概念本身就很复杂，因为设计师通常会过分侧重于此但工程师却毫不考虑，这会导致项目的发展出现两个极端，用户得到的不是劣质样品就是《魔兽世界》之类的佳作。凭借用户界面设计数十年的经验，通过查看客户产品的用户界面，我就可以相当精确地判断出那些公司的软件开发倾向。我认为Google只不过是个引擎驱动的软件，尽管该公司近年来似乎雇佣了大量UX设计师。

AngryBirds(from gameogre.com)

衡量某些人认为无法衡量的东西：在这种环境下要如何衡量视觉设计呢？目前有许多可供评估项目开发视觉设计适当性的方法。这些调查方法将那些之前被人认为只能主观评估的东西以客观方式呈现出来。视觉设计可以被衡量和评分，扩展后便能够使用户和界面开发人员受益。恰当视觉设计的度量值因应用类型不同而存在差异，但游戏设计中有两种因素显得格外重要。其一，视觉设计必须容易被人记住；其二，视觉设计必须传达游戏模式的特性。

《愤怒的小鸟》令人印象深刻，开发商已经在现实世界中制作出游戏周边产品，包括玩偶、T恤以及各种非同寻常的消费品，为公司带来大量利润。那些小卡通鸟的视觉设计是如此简单又令人印象深刻，它们使用户在游戏体验之外对其产品萌生兴趣。还必须注意到的是，鸟和猪所在的虚拟世界在每个关卡都会有奇怪且微妙的变化。视觉设计是让《愤怒的小鸟》获得成功的另一个关键层面，这又带来了一个问题：《愤怒的小鸟》是否已达顶点，无法再进行改善？如若着眼于长期发展，事实并非如此。

我们在上文中从认知层面剖析了吸引人的用户体验，比单纯回答“为何某个用户界面无法发挥作用？”这个问题要有趣的多。总而言之，在《愤怒的小鸟》中，放慢某些可以加快的行为、清除可以简单重新构建起的事物和制作神秘且令人印象深刻的视觉效果让游戏获得了成功。过去10年里，我们公司为数百个用户界面进行过用户参与度研究，如此多的研究依然没有得出通行的原则。《愤怒的小鸟》，你的成功势必让其他人感到愤怒和嫉妒！（本文为游戏邦/gamerboom.com编译，如需转载请联系：游戏邦）

Why Angry Birds is so successful and popular: a cognitive teardown of the user experience

Charles L. Mauro

The usual question: Over the past 30+ years as a consultant in the field generally known as human factors engineering (aka usability engineering), I have been asked by hundreds of clients why users don’t find their company’s software engaging. The answer to this persistent question is complex but never truly elusive. This question yields to experience and professional usability analysis.

The unusual question: Surprisingly, it is a rare client indeed who asks the opposing question: why is an interface so engaging that users cannot stop interacting with it? This is a difficult question because it requires cognitive reverse engineering to determine what interaction attributes a successful interface embodies that result in a psychologically engaging user experience. This question pops up when products become massively successful based on their user experience design – think iPhone, iPad, Google Instant Search, Nintendo Wii, Microsoft Kinect.

The interesting question: Recently clients have asked about the phenomenally successful casual computer game Angry Birds, designed for mobile phones, tablets and other platforms. For those who don’t have a clue what Angry Birds is all about, here is a quick synopsis. The game involves employing a sling shot to propel small cannonball-shaped birds with really bad attitudes at rather fragile glass and timber houses populated by basically catatonic green pigs. The basic thrust of the game is to bring about the demise of the pigs as quickly and expertly as possible by collapsing the pigs’ houses on top of their (sometimes) helmeted heads. Obviously, this sounds like a truly dumb concept. However, there is a catch.

Why is it that over 50 million individuals have downloaded this simple game? Many paid a few dollars or more for the advanced version. More compelling is the fact that not only do huge numbers download this game, they play it with such focus that the total number of hours consumed by Angry Birds players world-wide is roughly 200 million minutes a DAY, which translates into 1.2 billion hours a year. To compare, all person-hours spent creating and updating Wikipedia totals about 100 million hours over the entire life span of Wikipedia (Neiman Journalism Lab). I say these Angry Birds are clearly up to something worth looking into. Why is this seemly simple game so massively compelling? Creating truly engaging software experiences is far more complex than one might assume, even in the simplest of computer games. Here is some of the cognitive science behind why Angry Birds is a truly winning user experience.

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. When users are able to construct a robust schema quickly, they routinely rate the user interface as “simple”. 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. It is engaging, in fact addictive, due to the carefully scripted expansion of the user’s mental model of the strategy component and incremental increases in problem/solution methodology. These little birds are packed with clever behaviors that expand the user’s mental model at just the point when game-level complexity is increased. The process of creating simple, engaging interaction models turns out to be exceedingly complex. Most groups developing software today think expansion of the user’s mental model is for the birds. Not necessarily so.

Cleverly managed response time: A universal law of user interface design is “the faster the response time, the better”. True enough, there are applications where this is patently true. For example, Google has made this a mantra for their systems. However, surprisingly few software developers realize that response time management is actually a resource that can be leveraged to add to the quality and depth of engagement of a user interface. 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. Programmers uniformly have a really hard time with this one and few game designers take advantage of this potent variable. In most commercial software interfaces, response time management is completely overlooked even by those who claim to be UI design experts. 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. The vast majority of software user interfaces have no consideration for how users can be taught by experience with the system to improve their performance. This problem is a vast and complex issue for screen-based trading systems where error correction is not only essential, but also career threatening.

In Angry Birds game play the pigs also take a long time to expire once their houses are sent to bits. In many play sequences, seconds are consumed as the pigs teeter, slide and roll off planks or are crushed under slow falling debris. 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.

Short-term memory management: It is a well-known fact of cognitive science that human short-term memory (SM), when compared to other attributes of our memory systems, is exceedingly limited. This fact has been the focus of thousands of studies over the last 50 years. Scientists have poked and prodded this aspect of human cognition to determine exactly how SM operates and what impacts SM effectiveness. As we go about our daily lives, short-term memory makes it possible for you to engage with all manner of technology and the environment in general. SM is a temporary memory that allows us to remember a very limited number of discrete items, behaviors, or patterns for a short period of time. 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. In computer-speak, human short-term memory is also highly volatile. This means it can be erased instantly, or more importantly, it can be overwritten by other information coming into the human perceptual system. Where things get interesting is the point where 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 reenter that same information in a data field on another screen seems like a trivial task. Research shows that it is difficult to do accurately, especially if some other form of stimulus flows between the memorization of the data from the first screen and before the user enters the data in the second. This disruptive data flow can be in almost any form, but as a general rule, 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!

One would logically assume that any aspect of user interface design that taxes short-term memory is a really bad idea. As was the case with response time, a more refined view leads to surprising insights into how one can use the degradation of short-term memory to actually improve game play engagement. Angry Birds is a surprisingly smart manager of the player’s short-term memory.

By simple manipulation of the user interface, Angry Birds designers created significant short-term memory loss, which in turn increases game play complexity but in a way that is not perceived by the player as negative and adds to the addictive nature of the game itself. The subtle, yet powerful concept employed in Angry Birds is to bend short-term memory but not to actually break it. If you do break SM, make sure you give the user a very simple, fast way to accurately reload. 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. One of the main benefits of playing Angry Birds on the iPad is the ability to pinch down the window size so you can keep the entire game space (birds & pigs in houses) in full view all the time. Keeping all aspects of the game’s interface in full view prevents short-term memory loss and improves the rate at which you acquire skills necessary to move up to a higher game level. Side note: If you want the ultimate Angry Birds experience use a POGO pen on the iPad with the display pinched down to view the entire game space. This gives you finer control, better targeting and rapidly changing game play. The net impact in cognitive terms is a vastly superior skill acquisition profile. However, you will also find that the game is less interesting to play over extended periods. Why does this happen?

Mystery: You probably do not know how to recognize it, but Angry Birds has it. To add context to this idea, mystery is all around us in the things we find truly compelling. The element or attribute of mystery is present in all great art, advertising, movies, products, and not surprisingly, interactive games. The idea of mystery in a user experience as an attribute for increasing user engagement is embedded in the idea of mystery (conceptual depth). We all experience the impact of mystery when we view a cubist period Picasso, recall the famous Apple 1984 super bowl ad, or listen to Miles Davis. He is said to have described jazz as playing the spaces between the notes, not the notes themselves. Mystery is present when you pick up an iPad for the first time. Why are the icons spaced out across the screen when they could be clustered much closer together to save space? Why does the default screen saver look like water on the inside of the screen?

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. At its most basic level, experiencing mystery in what we interact with makes you ask the question, “Why did they do that?”. What we mean here is, “Why did they do that?” – A good thing, not “What were they thinking?” – A bad thing. If you think carefully about the experiences you have in the ebb and flow of life, you realize that the most compelling are those that force you to think long and hard about why a given thing is the way it is. For example, why did Frank Gehry create the Guggenheim Museum Bilbao using the shapes he did? The famous architect could have created any shape concept, but why did he choose those shapes? It’s a mystery – we do not know and probably neither does he. What we do know is that his creation is cited as one of the most important works of contemporary architecture. In the same way that a building can captivate millions of sightseers, the element of mystery (conceptual depth) can help sell a few million copies of a simple interactive game.

Angry Birds is full of these little mysteries. For example, why are tiny bananas suddenly strewn about in some play sequences and not in others? Why do the houses containing pigs shake ever so slightly at the beginning of each game play sequence? Why is the game’s play space showing a cross section of underground rocks and dirt? Why do the birds somersault into the sling shot sometimes and not others? One can spend a lot of time on the Acela processing these little clues, consciously or subconsciously. When users of technology process information in this way, it is very likely that they are more deeply engaged than without these small questions.

How things sound: Over the past 15 years, the neuroscience of music has taken a huge leap forward. This new research is just beginning to tell us why music adds such a strong emotional component to movies, advertising, theater, and of course, new media of all types, including casual computer games. Employing the power of audio stimuli including structured music often adds a critical level of engagement for users of all forms of technology. Angry Birds’ audio effects and music seem simple but are, in fact, very complex. 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. We hear avian dialogue as the birds arc toward their targets and hear the pained response from their victims when they strike their targets. 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. These consistently applied audio elements reinforce the player’s interactions and deepen engagement by emphasizing the anthropomorphic qualities of the main characters of the game and providing clever enhanced feedback during critical on-screen behaviors. What about the actual melodic music shifting from the foreground to the background without apparent reason? This musical thread running through the game play experience is mysteriously familiar and easily understood in the context of the overall theme of the game. Where have I heard that melody before? This combination of audio feedback is varied just enough that parents sitting in the next room are rarely prone to demanding an end to game play based on distracting musical repetition. Perhaps this explains the high number of hours spent playing the game!

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.

This leads to a more interesting question: How does visual design impact success in the marketplace? I routinely get this question from clients who are undertaking large redesign or new development projects. Decades after it first surfaced in automobile design, visual design is still the most contentious aspect of designing compelling user experiences. Designers (mostly of the UX stripe) routinely sell clients on the concept that the visual design (graphic style) of a given interface solution is a critical factor in success. This assumption seems to make good intuitive sense.

However, the actual working principle is counter-intuitive. In most user experience design solutions, visual design (how things look) is technically a hygiene factor. You get serious negative points if it is missing, but minimal positive lift beyond first impression, if a user interface has great visual design. When we conduct user engagement studies for clients (not the same as usability testing), we routinely see data that strongly supports this theory. This concept does not apply to all user experience design problems, but in most cases it holds well. The ultimate question is how much visual design is enough? Even more important than good or bad visual design is appropriate visual design. On this metric, Angry Birds again has just the right set of attributes. The concept of appropriate visual design is in itself complex as designers generally apply too much rendering and engineers apply none, which often leaves the actual user staring at the equivalent of an engineering prototype (Google) or alternatively, World of Warcraft. After decades of experience in user interface design, I can predict fairly accurately the corporate software development bias of clients by simply examining the user interfaces of their products. I cannot imagine Google as anything but engineering-driven, despite the apparently large number of UX designers hired in recent years.

Measuring that which some say cannot be measured: How does one measure visual design in this context? There are several well-understood methodologies for assessing the appropriateness of visual design that we employ in development projects. These research methods make objective that which is thought to be only subjective. Visual design can be measured, rated, and scaled to the benefit of users and those who develop such interfaces. The actual dimensions of appropriate and winning visual design vary widely, depending on the application but in game design two factors reign supreme.

First, the visual design must be memorable and second, it must convey the desired attributes of the game play model.

So memorable is Angry Birds that the developers have deals for real world “brand extensions”, including Angry Birds stuffed toys, t-shirts, and all matter of off-the-wall consumer goods that make BIG profits. The simple visual design of those tiny cartoon-ish birds is so compelling and simple, it brings an additional level of continuous interest to the game play experience. Of note too is the world the birds and pigs inhabit which changes in strange and subtle ways with every level. Visual design is another critical dimension of the success of Angry Birds, which leads to the ultimate question: Is Angry Birds the best it can be? Not by a long shot!

We are left with the notion that a cognitive teardown of a truly compelling user experience is vastly more interesting and insightful than simply answering the opposite question: why is a given  user interface dysfunctional? 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. Over the past 10 years, our firm has conducted user engagement studies on hundreds of user interfaces. The vast number did not get one principle right, much less six. You go Birds! Your success certainly makes other Angry and envious. (Source:mauronewmedia)