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分析休闲游戏进行生物计量测试的可行性

发布时间:2012-12-28 16:26:16 Tags:,,,,

作者:Stefano Gualeni

游戏学讲师和开发者Stefano Gualeni解析他的团队如何运用生物计量技术——被大发行商用于测试动作游戏的技术,改进玩家在独立制作的休闲的iOS游戏中的体验。

“大多数时候,英国和美国的鲸鱼制图师好像完全满足于展现机械式的物体外形,例如空洞的鲸鱼轮廓;就生动形象的效果而言,就相当于画出金字塔轮廓的草图。”

Herman Melville,《白鲸》(《Moby Dick》)——对鲸鱼的更为正确的描述和捕鲸业的真实场景。

这篇文章描写了一头白鲸的历史。当然,是我的白鲸故事:iPad游戏《Gua-Le-Ni》,也叫《The Horrendous Parade》。

Gua-Le-Ni(from mobilegn.com)

Gua-Le-Ni(from mobilegn.com)

2011年到2012年之间,我和意大利工作室Double Jungle S.a.S合作,设计和开发了《Gua-Le-Ni》。我用“我的白鲸”作为这款游戏的一个比喻,是因为我对虚构动物的痴迷,在我幼小的童年时期就开始萌芽了。

我依然记得,妈妈和我一起看绘有神奇动物的版画的书籍,也许就是在这些早期记忆中,关于奇妙的动物的游戏概念就开始酝酿了。我肯定,它与促使我决定首先成为一名设计师的执著是类似的。

Toy cubes(from gamaustra)

Toy cubes(from gamaustra)

(绘有动物侧面的玩具方块组成了《Gua-Le-Ni》的玩家主界面。)

本文讲的是我个人的痴迷和作为独立游戏设计师的偏好,如何与学术研究相结合的经历。准确地说,是关于《Gua-Le-Ni》,以及科学实验如何影响这款游戏的开发。

首先,以NHTV Breda应用科学大学的研究团队的要求,我的游戏制作速度要放慢并组织成特定的模块。意大利开发团队和荷兰研究团队携手合作,以《Gua-Le-Ni》为测试游戏,用于评估是否将心理生理学(或生物测量学)实验与快速迭代的休闲独立游戏开发相结合。

但就个人而言,《Gua-Le-Ni》是爱的产物,是对童年经历的缅怀,是理解创意过程的探索;而对于研究团队而言,它只是不带感情观察其机制和可量化的对象和作品。就像从《白鲸》中引用的文字,这是两种视角描述同一只鲸。

从玩家的角度看,《Gua-Le-Ni》是一款动作–益智游戏,它的故事发生在一个喝醉的老英国分类学家的木桌上。在这个分类学家的桌上躺着一本神奇的书:由不可思议的动物画象组成的图鉴。就像神话和传说中的怪兽,这些不可思议的动物是由现实动物的不同部分组成的。如果你不明白我意思,可以想一想神话中的动物,如狮身人面像、米诺的牛头怪或南方公园的人熊猪怪。

feeding the beasts in Cua-Le-Ni(from gamasutra)

feeding the beasts in Cua-Le-Ni(from gamasutra)

(在《Gua-Le-Ni》中,给野兽们喂食可以暂时使它们停止乱窜,还可以调整野兽的组成或增加正确分类的奖励值。)

我的纸怪物走过旧图鉴的插画。从上图中,你可以看到一只“四不像”:它的头是骆驼的、前半身是兔子的、后半身是秃鹰的、尾巴是龙虾的。玩家的主要目标是,在这只怪物从这页书上逃走以前,识别出它的各个组成部分和它们的相对顺序(如果怪物逃走,则游戏结束)。

为了达到目的,玩家要在老分类学家的指导下,旋转和移动绘有动物部分图象的玩具方块。在游戏中,如果玩家成功地将分类方块上的插图和纸怪物匹配起来,就意味着纸怪物被正确识别,它就不会从图鉴上逃走。

从玩家的角度和另一个角度,也就是我的博士学位研究的学术框架出发,《Gua-Le-Ni》也是一件补充论文的创意作品。它证明了用哲学概念和问题的解释、测试和发展用于电子游戏的可能。在我的游戏这个案例中,可游戏化的哲学概念是David Hume对人类的想象能力的理解。读者们应该感到幸运的是,游戏的哲学方面和无趣的个人设计过程都不会在此讨论。

本文将着重于我的白鲸的一个方面,也就是在短暂的生产周期内开发游戏的现实方面。更具体地说,我会探讨如何用生物计量测试法促进休闲游戏的开发(这种游戏的开发往往会多次推翻重来)。

在《Gua-Le-Ni》中运用生物计量法将作为研究案例,以阐明这种测试法的优势。休闲游戏开发者使用它的益处和可行性也会在本文的结尾处简要地讨论。

什么是生物计量法?

当向不太熟悉生物计量法的人介绍我们的作品时,我发现如果能先解释测谎仪的基本功能,读者会更容易理解什么是生物计量法。当使用测谎仪时,测试对象的身体会与几个传感器相连,这些传感器会记录身体的生理过程的变化幅度,比如心跳、皮肤的导电性、呼吸频率等等。

生物计量法就是通过观察这些变量,对测试对象的内部状态做出一个基本上客观的解释。换句话说,也就是通过测量一个人的身体对某种体验的反应,来决定这个人的压力程度、专注程度、焦虑程度、恐惧程度等。

传统的质量控制过程对研究问题做出的回答往往太过主观,而生物计量法产生的结果可以量化,而且更为客观。

通过观察心率变化、皮肤导电性、呼吸和某个面部肌肉的收缩,这种类似测谎仪的机器可以让我们深入考察关于游戏设计选择和具体化游戏使玩家产生的心理生理效应,这是非常有价值的。

运用生物计量实验和方法论来分析游戏,可以科学地解答游戏如何开发,以及为什么游戏会获得商业上的成功。这些问题都是非常重要的。例如:

我们的游戏初始速度是否对目标玩家过快?

游戏是否让玩家的情绪在预想的地方和时间(通常是在免费试玩版的末尾)上达到高潮?

游戏的指南是否能成功地既吸引玩家的注意力又指导他们操作?

目标玩家对第一次游戏结束的反应如何?

游戏是否让玩家压力太大?是否太严厉?

运用生物计量法在游戏设计、调整和测试领域当然不算新鲜:AAA游戏如Valve的《Left 4 Dead》和EA Sports的《NBA Live 2010》都证明了生物计量法作为一种分析工具和改变产品的参考因素的可行性和有效性。我们的研究项目和测试游戏《Gua-Le-Ni》将充分利用生物计量法和其方法论,旨在确定它们对快速迭代的有效性,探索它们作为开发休闲独立游戏的工作的可行性。

第一轮生物计量测试

为了补充基于问卷、采访、盲测和硬核操作测试的更大范围的质量控制活动,荷兰研究团队在NHTV Breda 运用科学大学对《Gua-Le-Ni》进行了第一轮初期生物计量测试。其目标是构建一个与生物计量学观点相结合的测试方法论。

对《Gua-Le-Ni》进行的第一轮生物计量测试的焦点在于分析游戏开始的前几分钟的速度是否合适。负责这部分测试的研究人员将根据生物计量学来决定游戏的最佳速度,也就是游戏开发者确认目标玩家成功地完成了第一部分指南时,游戏当时的速度。在这一阶段,游戏设计的意图是让目标玩家觉得这款游戏难度不大,可以完成最基本的难度,从而更可能在刚开始玩这款游戏获得积极良好的体验。

从游戏的逻辑来说,游戏的初始速度是由野兽的初始移动速度决定的。因此在第一轮测试中决定的怪兽的行走速度将成为之后调整游戏速度和难度的的基础。

研究团队同时测试了两个存在细微差别的游戏版本:在第一个版本,也是比较难的版本中,怪兽走过屏幕的速度比较快(24秒),而在第二个更容易的版本中,怪兽走得更慢(30秒)。当分析受测者的压力分布图并将其与游戏内的问卷调查一一对应时,我们发现,与第一个版本相比,玩家在第二个版本中显示的压力也较小。

我们同样用生物计量法研究了测试对象在其他成功的休闲游戏中的压力水平,然而,与之相比,测试对象在第二个版本中表现出来的压力水平也高出非常多。因此,我们认为怪兽的初始行走速度仍然太快,毕竟我们希望的是玩家能在轻松的心情下享受游戏。结合生物计量数据和自我报告的数据,我们可以推断出结果,也就是测试版游戏的初始速度应该设定为34秒。之后根据第二轮生物计量测试, 游戏在最终发行时的初始速度被确定为36秒。

游戏结束时玩家表现出的一致性也突出了大部分受测者识别某些动物的难度。根据这个难度和测试团队的意见,我们重制了存在问题的动物身体部分。

另外,我们挑选了龙虾(这是让玩家压力最大、失败最多的动物)作为指南中的例子,目的是让玩家在学习玩这款游戏的早期,就能熟悉它们奇怪的样子。

第二轮生物测量实验

这次实验是在第一次实验的两个月后进行的。这次测试的目标是,了解玩家在游戏前10分钟内的表现情况。

我要强调的一点是,在游戏的竞争版本中,在玩家正确识别一定数量的动物后,动物的行走速度将会递增。这种设计之后的想法是,如果玩家没有好好喂养那些奇特的动物,他们的活动就会更疯狂,因为他们在寻找食物的过程中会越来越饥饿。在测试中,开发团队想找到一个介于游戏初始速度和加速率之间的最佳平衡点,因为玩家会随着游戏的进展而慢慢掌握技术。特别是,我们想得出以下问题的答案:

在游戏三四次后,目标玩家是否能够完成5分钟的游戏回合?

游戏让玩家感到兴趣而不是焦虑?

玩家在游戏结束时通常产生积极反应(玩家必须觉得游戏公平,受到鼓励)?

第二轮测试的直观结果

以下直观地显示了14个测试对象在第二轮实验中的测试结果。图上的每一个点代表一只不同的动物。蓝点表示以初始速度行走的动物,红点表示蓝点动物走得更快的动物。

在《Gua-Le-Ni》的测试版本中,每露面四次,怪兽们就会加速。图中的红色直线表示游戏的结束点,直线以右表示游戏重新开始。

subject pp35(from gamasutra)

subject pp35(from gamasutra)

( 这是测试对象35的皮肤导电率图。每一次游戏结束(红直线)对应一个压力峰值。从图上可知,第一次游戏持续的时间是1分钟多,第二次接近2分钟,第三次差不多是3分钟。)

上图记录了其中一名测试对象的皮肤导电性。皮肤导电性通过追踪测试对象的皮肤湿度变化,让研究人员了解测试对象的紧张和兴奋程度。

上图表明,在第一次游戏中,也就是持续了1分钟10秒的游戏过程中,测试对象35能够顺利地归类所有以基本速度水平行走的动物,但不能识别比行走速度大过初始速度的动物。随后两次游戏环节的结果表明,随着难度增加,玩家的兴奋水平增长越来越慢,在游戏结束时达到极限。

从游戏设计的角度看,测试对象35的皮肤导电性图揭示了玩家应对复杂度和速度渐增的能力。特别要提的是,对象35在她第三次游戏时持续了3分钟。这个结果与开发团队的期望相符,可以认为是一个初步成功。

总地来说,测试结果表明,游戏的持续时间和强度基本上符合设计意图,即玩家经过指南后能马上适应慢速的动物,然后在5分钟的游戏回合中能坚持3分钟。尽管如此,将生物计量测试结果与传统的问卷调查结果相结合后,我还是决定让游戏更慢一点儿。在游戏的发布版本中,速度的增加值也更小,且过渡得更平缓。

第二张图记录的是在第二次测试中,同一位测试对象在相同的游戏回合中的颧大肌(笑肌)的电活动变量。

Zygomaticus Major(from gamasutra)

Zygomaticus Major(from gamasutra)

(这是测试对象35在三次游戏中的笑肌活动情况。在皮肤导电性测试中,每一次游戏结束,都对应了一次压力峰值,而这在张图中,对应的则是一次微笑。)

根据上图,游戏结束总是让测试对象微笑。在游戏后采访玩家问到这个问题时,我们发现,玩家微笑是因为玩家直到怪物的尾巴尖儿离开屏幕才终于将怪物分类好。这意味着游戏让玩家产生了积极态度,能够鼓励玩家再次玩这款游戏。这种设计给玩家的感觉是“差一点,好险”。

从数据中得出的另一个有趣的结论是,头身比例差别大的怪物组合会让玩家微笑更多次。玩家认为这种组合是更怪异的。“猪鹫”和“兔章鱼”是引起玩家微笑最多的组合。尽管我们没有对这方面做测试,但回顾时,我们觉得原本可以让这些组合在游戏中多露几次面的。

总结

尽管在电子游戏界,最高层次的游戏(硬核游戏)已经成功地运用生物计量测试,但根据最近发表的心理生理学文献,休闲游戏尚未使用这种实验技术。也许是因为进行生物计量实验所需的成本太高,只有高端游戏开发商才支付得起,但《Gua-Le-Ni》的例子证明,事实不是这样的。

我们只投入相当少的工作和金钱就将一间简单的空调房变成一间测试实验室。另外,随着Nintendo的Wii Fit平衡板的发行和它计划中但还未发布的生命传感器的问世,生物计量设备将很快变成一种消费性产品——也就是说,更廉价且更便携。

如果说生物计量测试确实不是因为经济原因而不能普及,那么为什么休闲游戏开发商至今没有采用这种技术和方法论呢?

原因之一可能是,AAA游戏的关注焦点在于动作类型,如射击、赛跑和模拟运动。这类游戏的属性导致容易观察到生理反应特征,但是,休闲游戏如益智、寻找隐藏物、点击冒险等就通常不是这么回事了。

在这里,我要说的是,休闲游戏不采用生物计量实验和方法论是有实际原因的,而非受制于开发成本。因此,休闲游戏开发商采用生物计量法来测试动作类休闲游戏或投入于更多相关研究,并不存在真正的阻碍。

在不久的将来,生物计量方法论大概也能追踪玩家的内心状态,这与不断成长的休闲游戏的市场更有关系。所谓的内心状态就是,比如玩家对手头任务的专注程度、由超过玩家能力的识别任务引起的困惑感或完成任务的成就感等。

专门知识的普及和实用的解释框架也在增多,不只是在晦涩的学术领域:有几个游戏设计专业的大学生正在做一个毕业设计,即设计他们自己的生物计量实验、执行测试和孤立分析数据。

正如我的开头引文暗示的那样,我并不认为心理生理学是游戏分析的终极工具,我也不希望、不相信它能取代所有的传统的游戏设计和质量控制方法。将生物计量法奉为休闲游戏开发的“圣杯”的想法,简直就是乐观得近乎天真,是盲目于它具有的部分优势(尽管是有深度的)。

除了上述提到它具有的客观性外,生物计量法还提供大量数据。将数据与心理生理学理论相结合,我可以有根有据地了解受测对象的心情和感觉,无论是在引用某个游戏事件时还是在比较不同受测者的结果时。从人类学的角度看,生物计量法使我的设计过程更充实更准确更有趣,进一步增加了我对游戏设计的热情和好奇心。就我个人而言,这是一次新鲜又深刻的体验,我希望下次设计游戏时也能进行这种奇特的实验。

从外行人的角度看,在休闲游戏开发中使用生物计量法和生物反馈技术,是很有希望的。人们在生物计量学的应用研究上还会不断投入资金。甚至在当前的经济水平上,生物计量技术也已经证明,它能为游戏开发提供深入而客观的信息。例如,我们的测试案例《Gua-Le-Ni》就广受好评,好评率达83%。

虽然心理生理学并不总是提供标准答案,但它确实能帮助我们更透彻地理解玩家,更有效地改进游戏——因此,我认为它在将来的所有类型的游戏开发中将发挥越来越重要的作用。

test subject wearing the complete set of sensors(from gamasutra)

受测对象戴着全套传感器进行第二轮生物测量实验(from gamasutra)

鲸在潜入海洋深处时,生理活动会放缓;而放慢我们的测试游戏《Gua-Le-Ni》的开发进程时,研究人员就能观察到玩家的生理活动,从而更深入地考察游戏体验。

NHTV Breda应用科学大学现在有了更高效的方法,开发进程却不必放缓,这样就使得这种方法能够更好地与休闲游戏开发迭代相结合。但愿我们在研究和设计游戏这两方面的努力,能够为休闲和独立游戏开发者们引入一片清闲的蓝色大海:生物计量学游戏设计。

除了从测试中收获大量有价值的信息和灵感以外,研究人员和测试对象们共度了一段快乐的时光。(本文为游戏邦/gamerboom.com编译,拒绝任何不保留版权的转载,如需转载请联系:游戏邦

The Case for Casual Biometrics

by Stefano Gualeni

Lecturer and developer Stefano Gualeni explains how his team employed biometric testing — once the purview of big publishers and chiefly used to test action games — to improve player response to a casual, indie iOS game.

“For the most part, the English and American whale draughtsmen seem entirely content with presenting the mechanical outline of things, such as the vacant profile of the whale; which, so far as picturesqueness of effect is concerned, is about tantamount to sketching the profile of a pyramid.”

Herman Melville, Moby Dick; or, The Whale, Chapter LVI – Of the Less Erroneous Pictures of Whales, and the True Pictures of Whaling Scenes.

This article charts the history of a whale. Or rather, it is the story of my whale: the iPad video game titled Gua-Le-Ni; or, The Horrendous Parade.

I designed and developed Gua-Le-Ni between 2011 and 2012 with Italian development studio Double Jungle S.a.S. of Padova, Italy, and I call it “my whale” because one of the main tropes of such game, namely the fascination with mythological creatures, captured my curiosity since my early childhood.

I still remember my mother going through books with etchings of fantastic animals with me, and perhaps it is going through these early memories that the conception for a game involving fantastic beasts was first formed. I am sure it was a similar fascination that drove my decision to become an architect in the first place.

Toy cubes with animal parts printed on their faces constitute the main player-interface for Gua-Le-Ni.

This article tells the story of how my obsessions as an individual, as well as my inclinations as an independent game designer, became entangled with academic research. Specifically, it is about Gua-Le-Ni, and about how the development of the game was influenced by scientific experiments.

To begin with, the production of my game was slowed down and structured in a specific modular to accommodate the needs of the research team at NHTV Breda University of Applied Sciences. The coordinated effort of the Italian development team and the Dutch research team made Gua-Le-Ni the benchmark to assess the possibility to integrate psychophysiological (or biometric) experiments in the quick iterative production cycle of casual and independent game development.

Whereas on a personal level, Gua-Le-Ni is a work of love, a way to embrace my childhood experiences and to explore my understanding of the creative process, for the research team working on my game, it was an object of dispassionate observation reduced to its mechanical and quantifiable workings. Analogous to Melville’s pyramid in the quote from Moby Dick, both perspectives are sketches of the same whale — my whale.

From the point of view of a player, Gua-Le-Ni is an action-puzzle video game that takes place on the wooden desk of an old, befuddled British taxonomist. On his desk lies a fantastic book: a bestiary populated by impossible, finely drawn animals. Just like the monsters of myths and folklore, the impossible creatures in my game are combinations of parts of real animals. To understand what I mean, it might help to think of legendary creatures like the sphinx, the Minotaur, or South Park’s Manbearpig.

Feeding the beasts in Gua-Le-Ni does not only temporarily stop their relentless stampeding, but can also modify the beasts’ composition or increase their value in terms of points awarded upon their correct cataloguing.

My paper abominations walk across the illustrations of the old bestiary. Above, you can see a CA-BIT-DOR-STER: a four-module beast with the head of a camel, one body part of a rabbit, another of a condor, concluded with a lobster’s tail. The main goal of Gua-Le-Ni is to recognize the components of the fantastic creatures and their relative order before one of them manages to flee from the page (which is the Game Over condition).

Mentored by the old taxonomist, the player pursues this purpose by rotating, moving and spinning toy cubes with pictures of animal parts printed on the six faces of the cubes. A paper beast is correctly recognized, and thus prevented from escaping the bestiary, when the player manages to match the illustrations on the top faces of the taxonomic cubes with the paper beast currently in play.

Departing from a player’s perspective and taking yet another point of view, namely the academic framework that underlies my doctoral studies, Gua-Le-Ni is a creative artefact that complements my dissertation. It exemplifies the potential of video games for the explanation, the testing and the development of philosophical concepts and questions. In the specific case of my game, the playable philosophical notion is David Hume’s understanding of the imaginative capabilities of the human mind. Luckily for you, neither this aspect of the game nor my sickeningly personal design process will be discussed here.

For the sake of the audience of Gamasutra, instead, this article will focus on one aspect of my whale, namely an aspect which has a practical dimension for people developing video games in short production cycles. More specifically, I will present some of the opportunities offered by biometric testing methods for the development of casual video games (the development of which are characterized by quick iterations).

The practical use of biometry in Gua-Le-Ni will be presented as a case study that clearly demonstrates the advantages offered by biometric testing. The benefits and the viability of a biometric approach for the developers of casual games are extensively discussed in the academic papers that discussed our methods and experiments (see references) and will be shortly presented to the reader in the conclusion of this article.

What is Biometry?

I find it useful, when introducing our work to people who are as yet unfamiliar with biometry, to begin explaining the basic functioning of lie detector machines. When utilizing lie detector machines, the body of a test subject is hooked to several sensors capable of recording changes in a range of physiological processes such as her heartbeat, the electrical conductivity of her skin, the frequency of her respiration, and so forth.

Observing variations in such dimensions, the discipline of biometry is capable of approximating an objective account of the test subject’s internal state variations. In other words, by measuring how one’s body reacts to a certain experience (which could be a set of questions, or the screening of an advertisement, a video game session, etcetera), we can determine one’s level of stress, concentration, anxiety, fear, etcetera.

Whereas traditional quality assurance procedures generate highly subjective answers to research questions, biometry offers a method that produces results that are objective and quantifiable.

By monitoring changes in heart rate, skin conductivity, respiration and the contraction of certain key facial muscles, the lie detector-like setup we utilized was capable of providing valuable insights about game design choices as well as materializing the psychophysiological effects the game has on the players.

Employing biometric experiments and methodologies to analyze a video game, you can obtain scientific answers to several questions that are crucial for its development and commercial success. Examples of such questions include:

Is the initial speed of our video game too high for our target audience?

Did we reach a climax in emotional involvement where and when intended (this is likely to be at the end of our free demo)?

Does the tutorial of our video game succeed in keeping our players engaged while empowering them to perform well?

How does our target audience respond to the experience of their first Game Over?

Is our game too stressful for them? Is it perceived as too punishing?

The employment of biometric measurements is certainly not a new development in the field of video game design, tuning and testing: Triple-A titles such as Valve’s Left 4 Dead and EA Sports’ NBA Live 2010 have successfully demonstrated the viability and desirability of biometry as an analytical tool and as a factor of change for their products. Our research project and its benchmark video game Gua-Le-Ni pioneered and optimized the application of biometric technologies and methodologies with the objective of making them available for quicker iterations, exploring their viability as development tools for casual and independent video games.

The Initial Biometric Tests

To complement a wider quality assurance campaign based on questionnaires, interviews, blind-testing and hard-core performance tests, the Dutch research team at NHTV Breda University of Applied Sciences ran an initial series of biometric tests on Gua-Le-Ni. The aim of these initial tests was to structure a testing methodology incorporating the added perspective of biometry.

The first biometric analysis we ran on Gua-Le-Ni focused on its accessibility during the first few minutes of gameplay. The task that was assigned to the researchers was to determine biometrically the optimal speed of the game for the target audience indicated by the developers as soon as the player successfully completed the first tutorial. The game design goal in relation to the initial set of tests was that of achieving the feeling that the game was non-threatening and manageable at the most basic level of difficulty, hence likely resulting in an initially pleasant and positive experience for the casual audience we were developing for.

In terms of game logic, the initial speed of the game is determined by the initial walking speed of the beasts. In this sense, the results of the first test in terms of the walking speed of our bizarre creatures became a cornerstone for all the subsequent design decisions concerning the tuning of the speed and the complexity of the game.

The research team ran parallel tests on two slightly different versions of the game: In the first and harder version, the beasts crossed the screen rapidly (in 24 seconds), while in the second, easier version they would walk from one end of the page to the other more slowly (in 30 seconds). When the testers’ stress patterns were analyzed and correlated with in-game questionnaires, we found that — compared to the harder version — the easier version showed fewer signs of stress in the participants.

Even in the slower version of the game, however, the recorded stress levels were much higher than expected in comparison with other successful casual games we tested biometrically with the same test subjects. The initial walking speed of the beasts was hence deemed still too high our intended players to simply enjoy the game. We could infer this outcome by combining the biometric data with the self-reported ones. As a result of this observation, the initial speed of the beta game was set — for the tests that followed — to 34 seconds. This value was further refined after the second set of biometric tests to the initial speed value of 36 seconds, with which the game was released.

A particular consistency in the Game Over pattern also highlighted difficulties for most testers in recognizing specific creature parts. Responding to the difficulties and the criticism of our test group, the graphics for the creature modules in question were redone.

In addition, we picked the lobster (the beast with the highest rate of stress and failures) as the creature to be used as an example in the tutorial, in order for players to familiarize themselves with its quirky appearance as early as possible in the learning curve of the game.

The Second Set of Biometric Experiments

A second series of tests was conducted two months after the initial experiments. The aim of this second series of tests was to understand how a player’s performance develops during the first 10 minutes of gameplay.

An important point to clarify is that in the competitive version of the game, the walking speed of the paper creatures increases incrementally after a specific number of creatures have been correctly recognized. The idea behind this design parameter is that if our fantastic creatures are not properly fed, their actions become more frenzied as they grow hungrier in their search for food. In this phase of the testing, the development team wanted to find an ideal balance between the initial speed of the game and the rate of acceleration as players progressively gain skills during their advancement of the game. Specifically, we wanted to find answers to the following questions:

Does the game allow players in our target audience to be proficient enough to endure play-sessions of five minutes after three or four games?
Does the game make our players excited but not anxious?
Do players have a generally positive reaction to the reaching of the Game Over state (which needs to be perceived as fair and encouraging)?
Visual Results for the Second Set of Tests
The graphs below visualize the test results of one of the 14 test subjects that was tested in the second phase of experiments. Each dot on the graph represents a different beast. Blue dots represent beasts that were walking at basic speed, and red dots represent beasts that were wobbling faster than the basic speed.

In the test version of Gua-Le-Ni, the paper beasts were accelerated after the appearance of every four specimens. The vertical line on the graph represents a Game Over state, after which the game resets.

Skin Conductivity graph for test subject 35. Every Game Over (vertical red line) corresponded with a stress peak. As readable in the graph, the first game lasted a little more than one minute, the second a little less than two minutes, and the third almost three minutes.

The first graph tracked a dimension called skin conductivity of one of our test subjects. Skin conductivity provides a basic understanding of how tense or excited a test subject is by tracking the variation in moisture of his or her skin.

The results visualized in the graph above show that during the very first game, which lasted for approximately one minute and 10 seconds, Test Subject 35 was able to successfully categorize all of the beasts at the basic speed level, but failed at the first beast that would wobble faster than the initial speed. The results of the two following gameplay sessions show that excitement levels grow slightly as the difficulty level is increased, and reach extremes at Game Over states.

A game design reading of the skin conductivity graph of test subject 35 demonstrates that the ability to deal with complexity and speed progressively increases. In particular, subject 35 reached a three-minute gameplay session at her third game. This result corresponded with the aspirations of the development team and was regarded as an early success.

Overall, the test results showed that the duration and intensity of the game broadly matched the design intention of empowering the player to cope with slow beasts straight after the tutorial and to reach three-minute gameplay chunks within the first five minutes of gameplay. Nevertheless, combining the results of the biometric testing with the results of traditional questionnaires, I decided to make the game slightly slower. In the released version of the game, the rate of acceleration was also lowered and smoothed.

The second graph, by contrast, shows the variations of a second biometric parameter for the same gameplay session and in the same test subject tracked above. The second graph maps the electrical activity in the Zygomaticus Major muscle (responsible for smiling) during gameplay.

The activity of the Zygomaticus Major (smiling muscle) for test subject 35 during the same three games analyzed above. Every Game Over that was associated with stress peaks in the skin conductivity chart corresponds to a smile in this graph.

A combined reading of the graphs shows that the Game Over condition always invoked a smile in the test subject. When players were questioned about this in the post-gameplay interviews, we learned that such smiles were due to the fact that players could manipulate the cubes in an attempt to categorize the beasts until the very last pixel of the beast’s tail is visible on the screen. This feature of the game produced a positive attitude that encouraged players to replay the game. The design feature gave the players a feeling of “almost having made it.”

Another interesting conclusion that was inferred from the data is that beast configurations in which there was a large size disparity between heads and bodies generated more smiles. These configurations were perceived to be quirkier. The “WART-DOR” (warthog-condor) and the “RAB-PUS” (rabbit-octopus) were the configurations that elicited the most smiles in our test subjects. Although nothing was done with this information, in retrospect, we could have made these types of configurations appear more frequently in the game.

In Conclusion

Despite the successful employment of biometric testing in the highest strata of the video game industry, a review of recent publications on psychophysiology and video games reveals that it has not yet been adopted by the casual sector. It might be assumed that the costs involved in running biometric experiments make it affordable to the developers of high-end games only, but Gua-Le-Ni is proof that this is not the case.

We needed very little work and money to transform a simple air-conditioned research room in a viably neutral testing environment. Additionally, as witnessed by the release of Nintendo’s Wii Fit balance board and its planned but unreleased vitality sensor hardware, biometric equipment is quickly becoming consumer technology — that is to say, trivially inexpensive and more portable.

If biometric testing is really not economically prohibitive, then why have the developers of casual not embraced its technologies and methodologies games yet?

One possible answer lies in the focus of triple-A titles on action-oriented genres such as shooting, racing, and sports simulations. Whereas the qualities of such games give rise to easily detectable physiological patterns, the same is not always true of casual games such as puzzle games, hidden object games, point and click adventures, etcetera.

What I am arguing here is that the notable absence of biometry in the quality assurance methodologies of the casual sector of our industry can be accounted for by practical reasons as opposed to limitations in development budgets. Accordingly, there are no real obstacles that would prevent casual game developers from employing biometrics in testing action-oriented casual games or in investing in pursuing more research.

Biometric methodologies might, in the near future, also offer the capability of tracking internal states that are more relevant to the growing casual market, such as the level of concentration of the task at hand, the bafflement induced by a cognitive task beyond one’s capabilities or the feeling of accomplishment.

The diffusion of expertise and the availability of the interpretative frameworks are also growing, and not only in obscure academic circles: several of our game design undergraduate students are developing graduation projects which involve the design their own biometric experiments, running their tests and the independent analysis of data.

As already hinted in my opening quote, I do not consider psychophysiology to be the ultimate video game analysis tool, nor I ever hoped or believed it could replace traditional game design and quality assurance approaches wholesale. An understanding of biometry as the “holy grail” of casual game development would be naively optimistic and blind to the partial, albeit deep, quality of the insights it provides.

Aside from the objective benefits explained above, and the large quantity of data that are possible to be harvested, working with the added lens of psychophysiology allowed me to talk to my testers about their feelings and intuitions with a more solid ground both when referencing a particular game event and when comparing results with those of other testers in the same target audience. Biometry made my process richer, more accurate, and also more interesting from an anthropological point of view, further fuelling my passion and my curiosity for game design. Personally, it was a refreshing and enriching experience that I am looking forward to repeating with my next, bizarre experiments in combinatorial game design.

From the outlined perspectives, the future of biometric and biofeedback applications in casual game development seems to me to be very promising. Applied research in biometrics is able to continue to attract funds and, even at the current level of economical affordability, the video-ludic employment of biometric technologies has proved capable of delivering both deep insights and objective advantages. Our benchmark case study Gua-Le-Ni, for instance, has received excellent reviews, attaining a current Metacritic score of 83 percent.

Once again, psychophysiology does not universally offer normative answers, but it does grant the possibility to understand players more thoroughly and to better ‘draft’ the games that we make — and on these grounds, I believe that it will play an increasingly important role in the future of game development across all sectors of the games industry.

One of our test subjects wearing the complete set of sensors that were used during the second set of biometric tests.

Where whales can slow down their physiological processes when diving in the ocean depths, slowing down the development process of our benchmark title Gua-Le-Ni allowed the researchers to observe physiological processes in players to gain a far deeper understanding of game play experience.

With the more efficient methodologies now in place at NHTV Breda University of Applied Science, the development process would not even have to slow down, thus making the methodology even more viable to be integrated in casual game development iterations. With our efforts both in terms of research and game design we hoped to have opened a fresh, blue ocean for casual and independent developers: biometric game design.

In addition to the valuable information and inspiration that was gleaned from this method of testing, both researchers and test subjects had a whale of a time.(source:gamasutra)


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