Getting to the Bones

In our attempts so far to define what we mean by a game we have looked at the nature of play and the drivers of fun. We have considered the role of patterns, rules, victory conditions and, of course, social interactions, including the role that play takes in forming excusive social groupings.

All of these are lofty concepts and although they are important to consider they don’t leave us with much structure to leverage. If we are going to actually build a game we have to get under the skin of a game. We have to get thinking about how to deliver a playing experience. Those of us who spent too much of our childhood making up games to play with our friends may have a good instinct for what it fun, but to reliably make great content we need more solid framework to build from. That starts by considering the anatomy of a game.

Celebrate Differences

There are huge differences between different games types and genres. Art-style, controls, genres, even the platform we play that game on, all influence design decisions. These variations allow us to endlessly come up with new concepts and ideas and with each one the designer can communicate something new to their players. However, much of this variation is on the surface and by looking underneath this skin we see a great deal of shared common principles.

In this book the model we use is an attempt to make it easy to consider the flow of play in a game, something that is essential to be successful when creating games as a service.

Where’s Wally?

Before we can start we need some common principles. For this purpose let’s start with the assumption that games essentially break down into a series of patterns which combine to form rules.¹ Pattern-matching seems to have been a critical factor in evolutionary success for humans and as a result it seems unsurprising to me that we gain great pleasure from being successful at this apparently simple activity. Finding a skinny guy in a red and white hat and matching jumper is a game, even if one of limited depth, and it’s about finding a known pattern (i.e., Wally himself) within a complex image.

Humans are also unusual in that we can consider patterns using our imagination. We can work through different scenarios and look for the patterns that give us the best outcomes, a skill that has transformed our survival chances. When we play Go we take turns to place our black or white stones in position so that we capture as many of our opponent’s pieces as possible, while safeguarding our own position.

Stick or Twist?

Of course games don’t just use fixed patterns, they often have some level of randomness. For example, we don’t know the original rules for Senet,² the oldest known game, but it seems likely to have involved random number generation using thrown sticks or knucklebones (the first dice). Some of the most common modern games use cards to generate a level of randomness, from snap to bridge; even Magic: The Gathering uses patterns based on the random selection of individual cards that have different values, suits or rules. We essentially compare our cards with our opponent in order according to the agreed set-up. There are dozens of variations, from Texas hold ’em to Montana red dog, where the winning hands remain largely the same but the betting structure and the process to reveal cards varies. All of these pivot around the principle of players using random results to complete patterns and similar principles apply when we look at dice-based games or traditional board games.

Six to Start

In Ludo³ I roll a dice, attempting to get a six, which allows me to get one of my pieces onto the starting spot. It also allows me to move any other pieces I have in play across the board, and hopefully I’ll get lucky enough to land on my opponent pieces, sending them home. Monopoly uses a similar method for movement, but rather than one die, we roll two and add the total together to find how many spaces I have to move my “avatar” before resolving the actions associated with that space, such as if I land my top hat on Park Place (or Park Lane if you are from the UK) where you have placed a hotel!

The introduction of a second die to determine movement has significance not only on the range of movement of my piece, but also the statistical probability of me travelling a given distance. Monopoly adds to this mechanic further by allowing players to roll again after gaining a double. However, there the game also adds jeopardy by sending you to jail if you happen to roll doubles three times in a row.

Complex Forms from Simple Elements

These patterns form a language allowing us to map the design of game mechanics. At their heart these should be highly repeatable and individually don’t usually require complex thinking to resolve. These simple patterns exist in almost every game and combine in unique ways depending on the decision of each player (or indeed to AI response of the game code).

Even chess, a game renowned for its intellectual demands, has very simple rules governing the behavior of each piece. Games like this have a particular characteristic of play that has a profound impact on the flow of the game. They are “games of emergence,” where all of the rules and available options are defined at the start of the play. They use essentially simple and consistent rules, but the combinations of each piece and their relative position to each other creates an immense range of variation. They are extremely challenging to create as they run the risk of creating unexpected dominant strategies. For example, when you understand the mechanism of tic-tac-toe (or noughts and crosses) you quickly learn how to always force a draw.

Changing the Rules As We Go Along

The other common type of games are known as “games of progression,” which create an evolving narrative, even if like Tetris the story is abstract,⁴ which is revealed through the playing and which unlocks new behaviors or mechanics over time. These games tend to have lots of stages but only a small range of victory conditions. Quite often the narrative arc is largely fixed by the game designer and merely navigated through by the player. They also tend to require the player to resolve specific mechanics prior to permitting the player to proceed through the story of the game. They need not be entirely linear, however; games such as Deus Ex, Zelda and Heavy Rain⁵ famously used a range of interactive techniques allowing the player to influence the outcome of the story. One simple variation includes “forks” in the narrative, which split the path of the player down a fixed number of different outcomes. These forks might over time funnel the player back to the original narrative by presenting them with unpalatable or self-sacrificing options. Other more complex structures include the “hub and spoke” structure where the player has a range of conditions to complete before they can move forward to resolve the next section of the game. Unlike games of emergence, games of progression will have a fixed number of endings because in order to make progress, specific playing conditions have to have been met. Each playing moment is in effect a node for decision-making resolved through play. I am tempted to suggest that games of progression are actually metagames, linking a series of mini�games, but that would be too sweeping a statement.

Getting to the Core

Of course being practical, we know that many games blur the boundaries between these two models of design. Regardless of which type of game we want to make we can still break down the anatomy of the game in the same way. We determine the conditions at the start of the game, the challenges and methods of resolution as well as what reaching the victory conditions actually means, including whether this unlocks further elements for later repetition of play. This is the heart of the core mechanic of the game and it’s that which determines what actions are available for players to take, how they resolve the patterns of play, and somehow within these we aim to find the fun.

Let’s take some examples. In almost every MMO adventure I have played since Meridian 59 we start out having to go and kill a virtual rat. When we succeed we loot the rat⁶ and then (assuming we have gained enough experience points) we level up. This we repeat, increasing the skill and challenge of the opponent each time to maintain the speed at which we improve our own character. But essentially each of those monsters is simply a bigger rat.

How about a first-person shooter (FPS) game? Well here it’s similar. We identify a target, choose the right weapon to defeat them, then we loot their gear. Looked at this way we see that there are lots of similarities in structure to the MMO, but of course the delivery is completely different.

Possibly the purest loops are simple puzzles games. These games are almost inherently self-contained cycles of play. We see an incomplete puzzle, we complete it and gain whatever rewards we expected before moving onto the next.

Even resource management games have repeatable cycles of play. We plant the seeds we start out with in the fields we start with and wait until we can harvest them to get more seeds and of course some in-game reward or currency. However, there are secondary and tertiary levels of cycle. In order to plant more seeds we need to buy extra fields, but extra fields mean that we need extra storage units, which we can only access by selling the plants we harvest. Those plants we harvest can also unlock new types of seed for us to plant, etc. This idea of loops feeding other loops is extremely important and in later chapters. We will also look at how we can use imbalanced economies to balance the interactions between each cycle.

Repetition is the Soul of Play

The repeatable nature of these game loops is essential to how we create entertainment suitable for services. Interestingly, we find this kind repeatable activity intrinsically enjoyable. The more regularly we repeat them the more compelling they become and we create habits through repeated play. There are some models out there that can help us explain how this kind of repetition is enjoyable. The most common example quoted comes from the experiments on operant conditioning by B.F. Skinner.⁷ This examines the repeated cycle between action and reward, usually a rat or pigeon pressing a lever to obtain food. Various conditions were applied to the release of the food to create “schedules of reinforcement,” which would themselves amend the behavior of the rats. There are of course some apparent comparisons between the ability to manipulate rats using a Skinner Box and the way we affect players’ behavior with our games. Indeed there are some who would argue that, because we use these compulsion loops in games, we are somehow “conditioning” players to repeatedly play that game. It’s a compelling concept but I believe this falls down in practice. Not least because compulsion isn’t the same thing as addiction. One of the key differences is that we aren’t restricting players’ access to real-world necessities, such as food. The stakes involved aren’t equivalent and there are plenty of alternative options for seeking entertainment. On the other hand we never get full of entertainment, unlike our reaction to too much chocolate. However, we do eventually get bored and looking back on our playing history we recognize those games that used operant conditioning too strongly and the resentment that leaves lasting damage for the brand of that game.⁸

Taking Control

Mechanics are more than just the patterns of course. We have to consider the method of play used to resolve those patterns, including the control systems in computer games. In tabletop games we might think about the board and pieces. With a card game we might consider the relationship between the cards we hold in our hand, the remainder of the deck, and the placement of the cards. Computer games—whether on mobile, console, or tablet—have their own considerations. Here we have to think about what the player actually does to move the game forward. Do we move a thumbstick, press a button, shake a controller, type some text, or in some other way direct the movement of an avatar or sprite? If there is some movement involved in the interface, what are the kinetic sensations of the action? How does the game connect the physical movement with the visual and audible feedback? How would that be different if we were to use a touch gesture to slide or spin an object on the screen? How does this action make the underlying experience of play delightful?

The designer has to consider how to communicate the controls system as well as to provide stimulus to inform the player to the actions available to them as well as the feedback from their choices. This has to include any hints, tips or instructions needed to navigate through the game. Will you have pop-up text boxes or “holographic” overlays or perhaps attempt to have all the communication intrinsically contained in the game world itself?

Lights, Camera, Action

We also have to consider what the player sees and how the display responds to their actions. Are we looking at objects in a 2D world? A 3D world? Isometric? You have to consider whether you want the players to be able to direct the camera view or whether you want to fix the camera position within each scene in order to free resources to create the most beautiful visual effects. You might, instead want to have an assisted camera that follows the central character. In some games the designer might also revert to simpler 2D views, perhaps even using parallax scrolling or even Mode7-style effects to create the retro approximations of spatial depth.

The camera view is only part of the visual process. We have to think whether we want our game world to be realistic or perhaps keep it extremely simplified or maybe even quite surreal. The art and audio style we choose will have a profound impact on not only the atmosphere of the game, but to a certain extent the way the players react to specific mechanics and, of course, their emotional responses too.

The Importance of Success and Failure

The core mechanic is like the bones of a game; we can see how a creature might move from its bones, but it’s not the bones that provide the source of movement. It takes an understanding of success and failure to understand the equivalent of the muscles. The motivation to play is a complex balance of push and pull from both of these influences, the lure of success and the pent-up frustration that comes from “good” failure.

As humans we crave challenge and actively need the possibility of failure if we are to value what success we achieve. This is more complicated than first appears especially as we start the process to learn about the game. Failure itself is a great motivator, if we cannot fail then there is no challenge. If there is no challenge, there is no fun to be found. Hard games can be incredibly compelling and a real motivation to continue to play. However, there is a downside. Imagine I start a new game, it’s a first-person shooter and I’m keen to get going. I find how to move my avatar and make it out of the starting spawn point. I see the bright sunlight of an amazing beautiful world (or, perhaps more likely, the dark brown of some unnatural cave system) and turn to see my friends’ avatars charging toward the enemy. Next thing I know, my character receives a head shot. I’m dead. I might get to see a brief replay of my opponent shooting me and perhaps even some obnoxious message to enhance the moment. A few moments after watching one of my team-mates playing the game I have the opportunity to respawn back to the match. OK, that wasn’t great, but I think I know what I did wrong and decide to get back into the game, a process that often requires about a minute of waiting for the level to reload. This time I’m a little more cautious. I wait till I hear its gone quiet before sticking my head out. Bang. I’m dead again. Another obnoxious message. Another humiliating replay I have to watch, then another minute of waiting for the level to reload. How many times does that have to happen before I stop playing this game? This can be a motivation for some players. But this can’t be a good way to build engagement for a mass-market audience.

Don’t Punish Players

It doesn’t just happen with hardcore FPS titles. FarmVille, the classic Facebook social game launched with the infamous “withering” mechanic, where your plants decayed should you fail to harvest them in the allotted time. This on paper is a great concept. We know in advance how long our plants will take to grow and how long they will survive once they are fully grown. It makes sense that if we don’t return to a farm that the harvest might spoil. Our friends can restore any lost plants by simply visiting our farm. But a lot people hated this mechanic, especially where the player had spent money on that farm. Coming back to withered plants was something that regularly happened to me and with my odd work/life balance, it was something I could personally do very little about. So I had to either depend on friends coming back to my farm regularly or to pay to fix it. To me, this felt too much like a punishment for not returning when the game demanded it, rather than when it was convenient for me.

In these examples the overwhelming feeling is that the player is being punished for not meeting the games’ standards. As designers, it’s our job to make sure that we create the conditions where players feel challenged, but not beaten. We want players to be able to reasonably expect that they have a standard to achieve, or they won’t feel success when they reach it. However, we don’t want them to feel hopeless or so badly resent playing that they never return.

Teeter-Totters are Fun Only When Balanced

Getting the balance between the perceived potential for success and the reality of the experience of failure is extremely difficult and can depend on the mechanic. This is especially true with mass-market audiences where the range of game-playing experience or skills may be very broad. We can look to create ways for the game to assess the rate of learning/skill within aspects of the game that are less critical to the flow of the game, or allow players to make decisions that let them opt into higher levels of difficulty. It’s OK to punish a player’s decisions, provided they have the opportunity to change them later. As suggested above, the fear of loss can be an even more effective motivation than the opportunity for gain. Imagine the negative impact of losing $100 compared to the positive value of gaining $100. The same amount of money, but a huge difference in terms of their impact on most people. Because of this effect, loss aversion plays a vital role in decision-making⁹ (not always positively) and we should not ignore its importance in gameplay.¹⁰ Being offered the chance to retry a game, without having to restart or lose some in-game treasure can be a powerful incentive to spend money in a game. However, we also should be careful not to overplay this idea at the risk of spoiling the experience for players.

Playing is its Own Reward

Winning is a great feeling, whether that’s a small win as we complete a puzzle or a big win as we conquer the game world. This is the “intrinsic” reward for success within the very act of play, even if we don’t always succeed obviously. However, we all like to find a way to measure our achievements or to at least be able to find a meaningful comparison so we can feel good about the experience and our abilities. These rewards are highly compelling and provide a lure and motivation to repeat.

Extrinsic rewards, or rewards beyond just the enjoyment of the game, can be very useful to help the game designer demonstrate the players’ achievements. Even the anticipation of these rewards can greatly affect our level of performance in a game. These might be shown through experience points, character levels, in-game currency, etc., all of which enable the player to see that their character, vehicle, system has improved (even if this is just in line with the new increased difficulty). Extrinsic rewards can also include badges, trophies, and achievements that I can brag about to my friends—at least the ones who also play the game. The achievement systems on Xbox Live has been a very effective driver to allow hardcore gamers to brag and to reward those players who are motivated to collect every one.

Success is Never Enough

Rewards methods provide the nervous system for a game. These are the tools that provide feedback and affect our playing patterns. The trouble is that repeated exposure to the same reward stimulus has a diminishing effect. We become satiated by the obvious patterns of play that we have already completed and need something more. Building in progression between each repeat of our core mechanic is important to sustain the interest of the player. Progression can take many forms but essentially involve changing the variables in the mechanic gradually each play. This either builds the challenge level as the player progresses through the game or provides variations that stimulate other aspects of the experience from art style, through genre, even different forms of pattern resolution. Largely this can be done in line with the rate of progress of the player themselves. For many of us, we want the difficulty to increase, ideally just a little faster than our ability to play grows, to respond to that challenge.

Measuring Progress

However, we need some way for the game to show us how we have improved and of course our progress in the context of the game. We want small meaningful victories along the way that reassure us of our ability and prove to us that success is not just possible, but something we associate with our own actions. Marking these victories can create anticipation for future stages and show us the measurable value of our investment of time and money in this game so far.

In Candy Crush Saga, they have a simple map showing a winding path with stops representing each of the levels to convey a sense of momentum and at the same time to show you where your friends are on this journey. This approach allows you to measure your progress independently of your specific performance on each of the separate stages, making it more accessible to a broader range of players.

Sometimes however, the player may not use the progression mechanic you thought you had set up. Many games prominently display the in-game grind currency within play and reward player success with increases in that cash. All well and good. However, if you are not careful this becomes the principle way that players determine their progress. With games like Plants vs. Zombies 2 I found this an active barrier to me using that currency to use power-ups like the “pinch,” a mechanic I found highly enjoyable to use in the level that introduced these power-ups, but resented using during normal play. Similarly, I found in games like CSR Racing that this effect reduced my willingness to spend money in the game as for me the purpose to continue to play was to see how quickly I could earn that grind money.

Telling Stories

Building on this idea of progression provides a good reason to think about why we are playing our game. We can’t just have a game mechanic and be able to deliver a great service. There are great products that are simply mechanics that we repeat, however building a service needs more. We need a motivation to continue to play time and again and this often is driven by the context—often the story or narrative of the game.

The context is the circulatory system in anatomy of play. It provides the life and power for the game as well as supplying a sense of purpose for the repeat use of the core mechanic. In Tetris, as we have said, this is quite simple and abstract. We have to place the falling pieces carefully so we can clear them from the screen by completing unbroken horizontal lines, getting a high score along the way which we want to beat each time we play. For Tomb Raider this is a lot more detailed, but essentially involves the survival of a young Lara Croft, shipwrecked on an impossible historic island, facing crazy gangs of cultist and mythical legends, collecting treasures as she tries to save her largely hapless friends.

Games within Games

Context can also evolve over time, sometimes as part of the narrative determined by the developer, such as in Deus Ex Human Evolution for example; do your save the “Thorpe Couple” or not? Do you search to Hung Hua Hotel to find Mei’s friend Ning, who had been taken captive “not long ago?” These don’t belong to the core mechanic, instead they provide their own tier of gameplay as well as the reason for shooting or sneaking your way round the game.

This opens out an important factor. Creating a context for your game, especially in a service, often requires us to think about the patterns of design that also exist at the level of the game mechanic. Here again we find patterns to resolve. However, rather than creating new mechanics to resolve these, we look for ways to encourage repeated use of the core mechanic.

Through this way of thinking your core mechanic can become a loop or perhaps more correctly a cog cycling forward, triggering the movement of another cog for every complete revolution. This could extend for many different cogs making it easy to extend the potential game experience for ever longer periods of time. It’s that thinking that makes it possible for us to create games that can survive not just hours of play, but days, weeks, and even years of play. I’m not suggesting that we shouldn’t introduce variation, but there is value in thinking about game design as a series of layers of engagement.

What’s in a Game?

The use of narrative or context loops can be controversial and largely this comes down to the values designers place on narrative or �gameplay elements. Part of this is the choice of language. The background of the game is part of its narrative, but the flow of play providing context can itself tell a story and it’s hard not to call that the narrative of play. However, there is a core issue here too. Is the “story” a designer wants to tell as important as the game experience the user wants to play? The response is of course “It’s the gameplay stupid!” However, if we are to make better more repeatable games we need to ensure that we create material that supports our context for our repeatable mechanics, that drives repeat play, and entertains in its own right. Players have to care about that story. Indeed I believe they have to consider that the game’s narrative arc as so compelling that they need to return to the game and continue to play because they “have” to resolve that story. Furthermore, I believe that if we are to be a game designer, not just a games player, that we should have something to say about this artform.

Build it and They Will Come?

This sensation is vital if we want success for a game as a service. Only a tiny percentage of games succeed in breaking even and even those games that are downloaded, only a few are played more than once. The volume of games available on mobiles, tablets, PCs, and indeed consoles is so large at this point that we cannot assume that players will find our game, let alone that they will be as keen to keep on playing it as we were to make it. As designers we have to give players both a “pull” to want to play the game as well as a “push” to call them back. This is a critical issue, as if we don’t get players back in the game we won’t have an audience and more importantly all our efforts to create a great game will be wasted. Of course if we are using the Free2Play (F2P) model this means that even if we have downloads we won’t be getting any revenue at all. This is why F2P games have (in the end) to be better than other games. It’s a question of survival.

The Gossip Effect

There is a reason why soap operas manage to succeed over decades of daily shows, especially in urban societies. This TV format replicates the human desire to be tapped into the social gossip that we would have experienced in person in the context of village or tribal life. It’s linked to social survival that we are on top of the latest news and indeed this can take the form of a game in its own right. Twitter and Facebook fulfill similar needs in many of us, including those who have no interest in the plots of the soaps.

Am I Missing Out?

Similarly if we wish to create successful games as a service we need them to create a sense of activity or change happening inside the world of that game in order to sustain our players’ attention over extended periods of time. This means we need a “call to action” that reminds the player to return. This can be a simple notification just telling the player to return, however that quickly gets tiring and can actually be a good reason for many to delete your application. It’s much better to have something in the gameplay that we desire that calls us back into play.

One of the most overused mechanics to create a reason to return is the energy mechanic. In this concept, players have a certain amount of energy they can use in any given playing session. Once this has been used up, they have to stop playing and wait till their energy has restored before being able to continue. This model is of course flawed in that we effectively shut players out of the game, requiring them to pay up or wait till they have more energy. However it does offer one really important thing in terms of game design; it created a real sense that the game’s world was “persistent” and that while the player wasn’t in the game, there was still something happening in that virtual space. There are other techniques we can use to replicate this sense of something meaningful happening in the world, including having other players (usually Facebook friends) come into your space to perform some minigame action that rewards both players.

Having a persistent world has other advantages. It creates a context for us to provide regular notifications to the player that relate to changes in that world that become meaningful to the player, rather than just sending sales messages. It also allows us to create stories where the players’ actions can contribute to the state of the game world; indeed they can feel part of the ongoing creation of that narrative.

Telling Better Stories

The interesting thing about the latest evolution of games design is that the focus is increasingly on the relationship between the mechanic and context loops that empower players to experience the story rather than have us tell them what’s happening. There is some classic advice given to writers: “show, don’t tell!” I believe this is just as important in game design. In general, we should avoid exposition and allow players to discover the experiences for themselves, not be told in neat little popup text boxes how their character feels or why they should play more.

Beyond the Context Loop

The concept of cogs driving other cogs doesn’t stop with the context of the game. There are other elements that we have to consider which sit above both the mechanic and the context. This is the metagame and provides the last aspect of the anatomy of a game. However, rather than being a physical analogy to a part of the body, this is more like the psychology of the game “animal.” The elements are not directly part of the game, but they profoundly influence the performance of the other parts. Indeed the metagame can complexly subvert the intentions of the designer as well as the general flow of the game.

It can be found in the social context that the player exists in while they play or from the “mode of use” of the devices that the player uses to experience it. The metagame can form from the behavior of the superfans or even from the physical space surrounding the devices used—think of the shared space around a tablet or television set. All of these things remind us that the game doesn’t exist in isolation, an idea we will return to in later chapters.

Identifying the Elephant

Throughout this chapter we have tried to break down what makes a game into its component parts. Taken apart, thinking about these elements allows us to get a handle on not only the challenges of game design but also how we can change our thinking to come up with solutions. Thinking of the art-style and game genre as the skin of the game reminds us how important it is for players to see the best of our game and that these concepts allow players to make sense of the shape of the game. Looking at the core mechanic as the bones of the game reminds us that there are “physical” principles at play that have to be highly tuned to support the playing experience. Thinking of success and failure as the muscles is more abstract and perhaps not the best analogy, however I like this way of thinking because it reminds me of what drives the movement of the bones of the game and that, over time, these motivations will tire. That brings us back to the rewards “nervous system,” which provides the stimulus and the context, which supplies the “oxygen” to continue.

However, none of these elements alone are the game. Writing this chapter is like the story of the blind men trying to describe an elephant for the first time, where each one only gets to feel a single part.¹¹ It’s only by pulling these elements together that we truly understand what our game looks like.

Notes

1 Although this is the hypothesis presented by Rafe Koster in A Theory of Fun, not everyone agrees that it’s useful to reduce games to just patterns. However, I think it’s a useful place to start so please bear with me.

2 There are modern rules for Senet that can be found online (http://legacy.mos.org/quest/pdf/senet.pdf), which are based on various tomb paintings and the discovery of playing boxes in various burials.

3 Ludo is based on Pachisi, a game from India around the sixth century, other variations include Sorry! http://en.wikipedia.org/wiki/Ludo_(board_game).

4 The idea that Tetris has a limited narrative is highly controversial. For me the realization that it has an abstract narrative came to me after a long argument with Nick Ryan and Simon Brislin (PlayStation Home), after a great lecture by Richard Bartle at GDC Online in Austin in 2010 (www.gdcvault.com/play/1013804/MUD-Messrs-Bartle-and-Trubshaw). The progression of colors and shapes to complete rows before our inevitable demise is a form of narrative that for me fairly accurately depicts the concept of mutually assured destruction of the late Cold War, not bad considering that the game’s license was allegedly owned by the KGB. For more detailed thought on the argument about the narrative qualities of Tetris check out this article from Jack Post, www.ec-aiss.it/monografici/5_computer_games/3_post.pdf.

5 There is an argument that Heavy Rain isn’t really a game, but is instead is a really advanced form of storytelling; either way its use of narrative flow warrants consideration.

6 I’ve never really understood where a rat might conceivably keep gold or some of the other curious winnings we find when we loot them.

7 American psychologist/behaviorist B.F. Skinner is widely considered to be one of the most influential psychologists of the twentieth century and invented the Operant Conditioning Chamber, known as the “Skinner Box.” Check out www.simplypsychology.org/operant-conditioning.html.

8 There is a great piece on Penny Arcade describing the Skinner effect and making the case against its overuse. I think this underestimates the potential positive use of the technique, however the underlying message is sensible, http://www.penny-arcade.com/patv/episode/the-skinner-box.

9 Daniel Kahneman and Amos Tversky talked about the influence of loss aversion on the decision making process in their 1994 work Choices, Values, Frames, http://dirkbergemann.commons.yale.edu/files/kahnemann-1984-choices-values-frames.pdf. However, it’s also important to note that in recent years the ideas of loss aversion have themselves been questioned. See http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1578847.

10 I talk a lot about using psychological patterns in game design, such as the Skinner Box or loss aversion. This isn’t a cynical thing. It’s a realization that we need to understand human motivations. Actually, I think it’s one of the most amazing things about playing games. We can explore the whole of the human experience and provide a safe way to “practice” our responses. Ignoring how players respond to stimulus would simply impair our ability to make better games.

11 The story of the blind men and the elephant has appeared in many forms but originates from the Indian subcontinent, http://en.wikipedia.org/wiki/Blind_men_and_an_elephant.