Definition: Role


The features, mechanics, situation and purpose which define an element’s function in a game

According to Aristotle, we can claim to have knowledge of something only when we have understood its causes.  These causes come in four types: the material cause – the matter of which the thing is made, the formal cause – the pattern or idea which that matter takes, the efficient cause – the motivation which formed the matter, and the final cause – the purpose for which it is used.  Once we understand all four causes, we know an object fully.  In game design terms, once we can explain all four causes, we know an element’s role.

The Material Cause

Video games are not physical objects, so technically they don’t require a material cause.  However, they do have underlying components that make their existence in the game possible, like models, textures, effects and sounds.  They also require other engine features like physics, particles, etc.  Some elements even require completely unique features, and explicitly specifying these features is important to defining the role.

The Formal Cause

This aspect of a game element is what we traditionally think of as “design.”  The form of an element is the pattern that it follows and the systems in which it operates – the game mechanics that constrain it.  Aristotle is referring to the Platonic idea of an object, but in-game design this is the Paper Design.  Just as in Plato’s theory, real life cannot match the perfection of the world of ideas; the in-game experience will never realize the paper design exactly, but it does provide an objective standard.  Much like a craftsman making a chair is attempting to create a material version of the ultimate idea of “chairhood”, the designer tunes an experience to get as close as possible to the original game design.

The Efficient Cause

Often called the “moving cause” because it provides the motivating force for an object, the efficient cause is closest to our modern concept of “cause and effect.”  In game design, the efficient cause is always the player and their desires.  A game element that does not have a corresponding player desire will never be used (at least not without coercion) so it is crucial to identify and meet those needs.

The Final Cause

The most important cause, at least to Aristotle, is the purpose for which an object exists.  In a game, this is especially true because games are fundamentally about using tools to solve problems, and game elements are usually classified by the types of problems they solve.  This is why it is so important to limit an element’s power so it is only effective for its designated role; if an element is an effective solution for multiple types of problem it becomes difficult to tell what its purpose is intended to be.  This is also why a problem should be presented before or at the same time as the solution, or else the player will not have a way to categorize the solving element.  This purpose is communicated to the player through affordance and reinforced by rewarding feedback.

Taken together, these four causes define an element’s role.  The features that allow it to exist.  The mechanics that give it a form and constrain its use.  The situation that creates the player’s need for it.  The purpose for which the player will use it.  Once a designer understands all four causes for an element, they understand an element well enough to implement it successfully.


Definition: Verisimilitude


The quality of seeming to be true, of resembling reality

Why is Wii Bowling like a Hemingway novel? (Beside the fact that they are each made better by adding alcohol.) They both benefit from the effects of verisimilitude. Authentic characters and believable dialog enhance the reader’s engagement in a story; they do not call attention to the fact that they are fictitious by violating our expectations about what might really happen. In the same way, the way the player’s movement in Wii Bowling matches the form and timing of real bowling avoids the awkward break with reality many people feel when playing video games.

Verisimilitude is important for many aspects of game design. Poorly tuned physics systems, bone-headed AI behaviors, inaccurate collision tests, unrealistic lighting, and scores of other common problems all result in a game feeling “off” or “fake”. That is why players can complain about an “unrealistic” space marine pulse rifle; even though no such thing actually exists, they have an intuition of what it would be like if it did exist.

Teach me!

Exactly like this...

However, nowhere is a lack of verisimilitude felt more strongly than in poorly designed controls. If an in-game action clashes with the input method to which it is mapped, it will always break the player’s flow and they will never be comfortable with the controls. Ideally, when the player is engaged with a game, the controller fades into the background and they are no longer aware of it, but an awkward or discordant control scheme is a constant reminder that they are playing a game. Here are some guidelines to avoid mismatched mappings:

  • The duration of an input should match the duration of the action. If a single button press is mapped to a melee attack, the animation for the attack needs to be short and responsive, just like the button press. If the animation needs to be longer, it should require several presses, or a press and hold, that takes roughly the same amount of time for the player to execute. Rapidly tapping a button during a grapple is a bit cliché, but it works because it extends the duration of the input to match the onscreen action.
  • Do not map discrete actions to analog inputs. A game where the player initiates a melee attack with the throw on a thumbstick is using an analog input (the range of motion of the thumbstick) to trigger a discrete action (punching a Triad thug in the face) which makes the player feel detached and removed from the action. This is often described as “soft” or “unresponsive”.
  • Do not map unrelated actions to integrated inputs. The D-Pad is not a set of four buttons, no matter how many games treat it as such. It physically represents four cardinal directions, and it is virtually impossible for a player to get comfortable with treating them separately. In the same way, a thumbstick is not a an arbitrary number of discrete buttons arrayed in a circle, and using them that way will prevent most players from engaging completely.
  • Do not use two-step inputs for single-step actions. The easiest way to add inputs to the controller is to use chords, two buttons pressed at the same time. This works great for “zoom” and then “shoot” because it is a two-step action, but is jarring when used for actions that appear to happen all at once.
  • If an action cannot be mapped to the controller, it should be cut. This is the hardest rule, but the most important. Some actions conflict with one another on a fundamental level, and though it may be tempting to cram them both on the controller, the game will suffer for it. It’s better to have a single action that players can execute confidently and competently than multiple actions that are confusing and cluttered.

Definition: Cadence


A pattern of beats and rests that describes a recognizable rhythm and creates a sense of repose or resolution

But first, a verse:

Roses are red,

Violets are blue,

Poetry has cadence,

And so should your gameplay.

What a terrible poem! Any second-grader could write a better one. It isn’t the content; if I simply wanted to argue that gameplay, like poetry, should obey rules of meter and form, it wouldn’t offend your sensibilities. The poem is bad because the cadence is wrong. Instead of resolving the contrasts set up in the first half, the second half breaks the rhythm and leads to a jarring and abrupt end.

In the same way, the wrong cadence can take a good game mechanic and make it feel awkward or even abrasive.  A gun that fires slightly too fast and ends up degrading into a buzz.  A melee combo that is a touch too slow and never feels like it flows smoothly from one hit to the next.  The boss monster whose sweeping tail attack is a little too regular, making it feel robotic and gamey.

There are a few basic components to cadence, and usually just taking the time to notice them is enough to know how they should be adjusted.

  • Tempo – The speed of a cadence, often described by the number of beats per minute.  A good rule of thumb for finding tempos that feel good is to use the same ones found in music.  For instance, the rate of fire of the Halo Battle Rifle is almost exactly the same as the BPM of Queen’s Another One Bites the Dust.
  • Regularity – Some cadences need to be extremely consistent, like a metronome.  The ticking of a clock or the firing of a machine gun sounds mechanical and precise because there is no variance in the cadence.  Others need a slightly irregular rhythm, like footsteps or a series of punches.  Slight variations in the timing leave a more organic impression.
  • Acceleration/Deceleration – Known in music as Accelerando and Ritardando, this describes the way in which a cadence changes from one tempo to another.  Very slow changes in tempo create tension, like a train departing a station.  Quick changes in tempo will attract the players attention, and are great for helping them to anticipate an attack or other event.
  • Style – Some cadences have short, crisp beats (called Staccato), while others feel blended, like pulses (called Legato).  Varying the styles of cadences can change the mood or provide contrast between two game elements.  Having one gun that fires short, separated bursts of bullets and another that emits a continuous wavy beam, for instance, would allow players to choose their own style, and give them a deeper array of options.

 If a game mechanic or other element fulfills its intended role, but still feels unsatisfying or mysteriously broken, try changing the cadence to reinforce and amplify the experience.

Definition: Habituation


The gradual reduction in sensitivity to a repeated stimulus

I got my teeth professionally cleaned this morning.  (One cavity, apparently I need to floss more.)  Now I cannot stop running my tongue back and forth over the newly polished enamel.  When I woke up today, my teeth were the farthest thing from my mind, unnoticeably insignificant.  But now I am obsessively, subconsciously, exhaustively exploring every crevice and gap.  This is a side-effect of a neural process called habituation.  As a stimulus (like “I have teeth”) is repeated, the electrical and chemical impact of the experience physically decreases to the point where it drops out of conscious thought, and then subconscious awareness, and eventually it is not felt at all.

You can get used to anything

As a human, this is a very good thing.  Imagine trying to have a conversation while consciously aware of the sound of your own heart pumping, the movement of your lungs breathing in and out, every blink interrupting your train of thought, unable to stop noticing the pressure of the chair into your back or ignore the ambient noise of other conversations.  It would be impossible to function.  Habituation allows you tune out the vast majority of unimportant details and focus on what is new and interesting, like how smooth your molars have become.  It’s a miraculously efficient process that allows our embarrassingly under-powered brains to filter enormous amounts of sensory information.

As a player, habituation is what allows us to learn to play a game and subsequently master it.  Our ability to predict future events based on current conditions is inseparably dependent on our habituation to past events.  A chess master learns to ignore the thousands of poor, but still possible, potential moves and consider only the strategically significant ones.  A skilled Halo player moves through a multiplayer map without thinking about it, using all of his attention to scan for his opponents.  When Mario reaches the edge of a ledge, pressing the “A” button always makes him jump.  If chess pieces could move randomly, or a Halo map suddenly had a dead-end instead of a corridor, or the “A” button threw a fireball, the player would be unable to play the game effectively.

Watch out for the Queen!

Alternative ways to make chess more interesting

But as a game designer, habituation is your mortal enemy.  A tireless, inexhaustible foe, mindlessly obviating the best efforts of your craft, which you can only hope to delay, but never defeat.  Fun gameplay is an interactive experience, and habituation inevitably reduces every experience to meaningless static.  To some extent, the purpose of every design trick and tactic is to disrupt habituation, to resensetize players to the fun experience and help them continue to enjoy the game.  We are hacking our own mental hardware, making it less-efficient.

The truly nefarious nature of this enemy lies in how sneaks into the design process itself.  Designers can learn to ignore glaring problems that would annoy or aggravate a new player.  Or they can overlook logical loopholes that will wreck the game balance because they are familiar with how the game is “supposed” to be played.  Or they might wrongly believe an element has been properly tuned because they are no longer sensitive to the effect it has on gameplay.  Understanding and controlling habituation, both their player’s and their own, is a crucial design skill.

Definition: Game Mechanics

Game Mechanic

A single constraint on the possible gameplay actions that determine a part of the player’s experience.

According to our working definition of gameplay, the purpose of a game mechanic is to constrain a game’s interactivity so that it guides the player toward a fun experience.  Tuning these contraints is one of the most important game design processes.  However, in order to tune game mechanics, it is necessary to understand what mechanics are and how they combine to form gameplay.

First, let’s look at how a single game mechanic constrains the possible actions a player can take.  Often these constraints are explicit rules like “If the King is put in check and cannot legally escape, the king is checkmated and the game ends in a loss for that player.”   Sometimes they are limits enforced by the simulation; there are some gaps that Mario can only jump while running.  The most important constraints are usually determined by the game’s control scheme.  After all, the player can only perform actions which are mapped to available inputs.

Another common type of constraint is the player’s objective in the game.  For instance, a goal in Pac-Man is to eat all the dots.  This limits the player’s behavior because any interaction that does not involve eating dots is irrelevant to the game.  This mechanic divides all the entire spectrum of possible actions the player can take into two halves, actions that are permited and those that are prohibited.

More DoTs!  More DoTs!

Pac-Man suffers from OCD

Game mechanics guide the player experience by removing some alternatives and emphasizing others, but by itself, a single game mechanic is not a game and cannot lead to a fun experience.  In fact, a single game mechanic by itself is barely even interactive.  With only one constraint, there is only one option.  There is no room for choice or skill or expression.  To demonstrate this point, I built a “game” based on a single dot-eating game mechanic.


(My free Flash host can no longer keep up with demand, please click this link to load the example.)

In order to actually define an experience, game mechanics must be placed in opposition to one another, much like the legs of a tripod.  That way instead of creating a single boundary (and therefore no choices) they create a region of interactivity for the player to operate within.  This is what Will Wright calls a possibility space.  It is the sum of all the potential gameplay experiences, sort of the wave function of game design.
Triangle Man hates Pac-Man, they have a fight, Triangle wins

Or maybe the Triforce of Game Design?

Definition: Game


An interactive experience constrained by mechanics designed to reliably satisfy a common teleological aspiration.

Merriam-Webster says a game is “an activity engaged in for diversion or amusement” which is hopelessly broad.  Try pitching “Punching My Younger Brother: The Game” the next time you meet with a publisher.

Raph Koster claims that “fun is just another word for learning” and that therefore “all games are edutainment.”  This is insightful because it attempts to define games by describing the needs they meet, but is obviously too narrow.  Someone that is leveling their fifth World of Warcraft alt is not learning anything, but I dare you to try to tell them they aren’t having fun.  And shouldn’t the tutorial be the most enjoyable part of a game?  This definition commits a logical error called the fallacy of the undistributed middle.  Even if learning is fun, that doesn’t mean that everything fun must be learning.

In Rules of Play, Katie Salen and Eric Zimmerman define games as “a system in which players engage in artificial conflict, defined by rules, that result in a quantifiable outcome.”  Now, it would be unfair to quibble with specific word choices or come up with obscure examples of games that don’t fit this definition.  No definition is perfect.  The real difficulty of this definition, as well as many other similar efforts, is that in dissecting games into pieces they have lost the whole.  It is as if, when asked to define the word weapon, you started listing types of wounds and metallurgy techniques and sources of propulsion and got bogged down trying to figure out if a baseball bat was a weapon or not.  The best way to define weapons is to describe their purpose, committing or threatening violence against someone, and the same is true for games.

Ludwig Wittgenstein famously declared that there is no adequate definition for the word game and we don’t even need one!  But he was not known for being a particularly fun guy, so maybe we can do better.

We’ll start with our previous definition of fun: “the positive emotion associated with fulfilling a teleological aspiration.”  The first definition of game that suggests itself is “something that is fun,” or more specifically, “an experience that fulfills a teleological aspiration.”  However, there are so many ways to satisfy our needs; what makes games special?  Unlike many enjoyable activities, the only purpose of a game is to have fun, and since they have a singular focus, they are able to satisfy these aspirations very reliably.

Additionally, teleological needs like learning or achieving or performing cannot be satisfied passively or by proxy.  They require participation, so they must be interactive and respond to the player’s actions.  This interactivity is not random; it reliably leads to fun experiences because it is limited to specific set of possibilities and actions.  Some games are indeed guided by explicit rules, but many games are constrained by their simulation, or by the objectives given to the player, or even by the story setting in which the game takes place.  In many games the experience is actually constrained by the unpredictable actions of other players.  Ultimately, it doesn’t matter what form these game mechanics take, as long as they constrain the experience in such a way as to more reliably fulfill the player’s needs.

Finally, our definition should acknowledge the fact that in order to ensure that a game’s mechanics lead to an experience that satisfies the player’s needs, they must be carefully designed to do so by a game designer.  Games do not appear naturally in nature.

So, now we not only have a useful definition for the term game, we have also determined the role of the game designer and have a reasonable criteria for evaluating design skill.  A game designer is someone that creates and tunes game mechanics to constrain an interactive experience such that it reliably fulfills common teleological aspirations, and the more reliably these needs are met, the more skillful the game designer.

Definition: Fun

If you are not a game designer:


(see also: Enjoyable, Cool, I Like It)

Something that I think is cool;

something that I imagine other people would think is cool, if a designer would just listen to my idea

If you are a game designer:


(see also: Blah Blah, Nice)

A completely meaningless term that should never be used;

except when describing the job responsibilities of a game designer to someone over 40

If you are a game designer writing about game design:


The positive emotion associated with fulfilling a common teleological aspiration

 (I realize this definition may itself need some explanation.)

Human Needs 

One way of understanding human behavior is to look at our needs.  If you assume that people are basically reasonable and that they are motivated to act in a way that fulfills their needs, then you can categorize different behavior based on the need that it satisfies.  The most well-known example of this technique is Maslow’s Hierarchy of Needs.  It’s like the Food Pyramid of human desires.  Unfortunately, neither the Hierarchy or the Pyramid are based on solid scientific research, so they tend to be misleading.

A more rigorous categorization of needs has been put forth by Edward Deci and Richard Ryan at the University of Rochester.  They have researched people’s need for self-determination, specifically their needs for competence, autonomy and relatedness.  They have even applied this theory to games with fascinating and practical results.  (If you are interested in this topic or their research, I recommend reading Why We Do What We Do: Understanding Self-Motivation.)

When our needs are being met, we describe the resulting emotion with a variety of terms.  Satisfying, Fulfilling, Relieving, Gratifying, Pleasurable, and Fun.  Each of these emotions is specific to the type of need that is being met, so if we can determine which kinds of needs result in fun we will be closer to defining the word, and have a greater understanding of our goal as designers.

The Need for Fun?

An immediate objection springs to mind against linking fun to needs.  Despite what you told your mom when you were a kid, you can’t die from fun deprivation.  How can fun be related to needs if you don’t actually have to have it to survive?  Well, psychology doesn’t make a distinction between needs and wants, in fact a better term might be desires or appetites.  However, this does bring up an important distinction that will help narrow down what sorts of needs result in fun when they are satisfied.

Some needs produce a negative emotion when we lack them, but are virtually forgotten once met.  These needs are requirements.  Carbohydrates, for example, are a requirement.  If you don’t have any, you will experience wracking hunger pangs, but if you have a sufficient supply you no longer think about them.  Other needs are just the opposite.  When these aspirational needs are not met, they rarely bring themselves to mind, but when they are fulfilled we experience a strong positive reaction.  Pancakes, for instance, are an aspirational need.  Nobody suffers greatly when pancakes are not available, but everyone enjoys them if given the opportunity.

I have a need for charts

Indisputable Proof

Having made this distinction, it’s clear that fun is the result of satisfying an aspirational need.  Much like pancakes, fun experiences are not required for survival, but we still enjoy them when they are offered.  However, this category is still too broad.  Pancakes are delicious, but not necessarily fun.

Even sad Pancakes make me hungry

Sorry Pancakes. We still love you.

The Need for Greek?

One characteristic that is unique to fun experiences is that they require participation.  Many needs can be met by an external source, the way a mother provides for the needs of a baby.  These kinds of needs are often physical objects: food, water, a place to live, a large screen TV.  But they can even be psychological needs like the desire to have the respect of one’s peers, or the need to know how something works.  These needs are ontological needs, meaning they are ends in and of themselves, they exist for the person.

Needs that result in fun are very different.  One person cannot play or learn or rest for another person; they must do it for themselves.  These teleological needs are met when we allow ourselves to be the means for some purpose beyond ourselves.  That purpose may or may not be useful; work can be as fun as play, even though it also provides for many other needs.  They key component is participation.

Every individual values needs differently, but with both of these axis we can arrange all needs into four quadrants: 

I have a need for greek words

Incontrovertible Evidence

The Need for a Conclusion

Now we have a sufficiently narrow range of needs that result in fun, specifically those in the upper-right quadrantThese needs are aspirations because we get a positive emotion when they are met, but do not necessarily suffer when they aren’t, and they are teleological because they allow us achieve some potential end and require our participation.

It remains to be seen if this will prove itself to be a useful definition, but at least it is more specific than “I know it when I see it.”