Mechanics

In the field of game studies, the term Mechanics refers to the inner workings of a game, including its rules, goals, and other procedures. Mechanics set games apart from other media (such as novels or cinema) as they work together to create an interactive experience for the player. It is also one of the four elements within Jesse Schell's Elemental Tetrad.

Schell's Six Categories of Mechanics

In chapter 10 of The Art of Game Design: A Book of Lenses, game designer Jesse Schell sets forth a simple taxonomy of game mechanics, a subject he calls "the core of what a game truly is" (130). Schell comes up with six categories:

Mechanic 1: Space

Space is the abstract construction of a game's space; what is left over when all visuals are stripped away. According to Schell, all game spaces:

1. "Are either discrete or continuous
2. Have some number of dimensions
3. Have bounded areas which may or may nor be connected" (Schell 131).

Discrete spaces (like the grid in tic-tac-toe) have a limited number of cells or positions that may be filled or moved into, while continuous spaces (like a pool table) allow for unlimited movement within a limited space. 

By dimensions, Schell means whether a game is played on a 2D or 3D space mechanically, not aesthetically. An improved graphical remake of a sidescrolling platformer, for example, is still only played in two dimensions. Interestingly, verbal games like "Twenty Questions" are still played in a space (the mental construction of the conversation), albeit one with zero dimensions (134).

Schell returns to the idea of Space in Chapter 19 of The Art of Game Design, in which he draws upon the field of architecture in order to explain how to design effective spaces. In it, he sets out five types of game spaces (331-333):

1. Linear -- A player can only basically move forward and backward (Candyland, Monopoly)
2. Grid -- Movement is restricted by discrete, adjacent shapes (Chess, Checkers)
3. Web -- Several points connected by discrete paths (Trivial Pursuit, ToonTown Online)
4. Points in Space -- Several points with no specified connecting path (Bocce, Final Fantasy)
5. Divided Space -- Space carved up into irregular sections (Risk, The Legend of Zelda: Ocarina of Time)

He follows this by listing renowned architect Christopher Alexander's fifteen properties of living structures, which may be used to give game spaces the "nameless quality" essential to good space design (336-337).

Mechanic 2: Objects, Attributes, and States

In addition to space, games need objects to fill those spaces -- characters, items, buildings, props, scoreboards, basically "anything that can be seen or manipulated in your game" (Schell 136).  In computer science terminology, these objects have attributes (position on screen, color, etc.) and states (current speed, maximum speed, etc.) what help define them and how they interact with other game elements.

Schell points out that the game changes depending on who is privy to the states or attributes of certain objects, a useful lens for a designer to look through (138).

Mechanic 3: Actions

Besides objects and states, the "nouns" and "adjectives" of a game, all games need "verbs," which Schell refers to as actions (Schell 140). In combination, multiple actions can lead to interesting strategies and emergent gameplay.

Schell describes two types of actions: operative actions and resultant actions (140). Operative actions are actions the player can make at their most basic levels. In checkers, for example, there are only three operative actions: moving a piece forward, jumping an opponent's piece, and moving a king piece backwards. Resultant actions are a level above operant actions, and involve strategies and situations that arise from operant actions. In checkers, these would be protecting pieces by moving other pieces behind them, forcing opponents into unwanted jumps, etc. Manipulating the number and range of actions can lead to emergent gameplay, an essential aspect in many games. 

Mechanic 4: Rules

According to Schell, rules are the most fundamental mechanic because "they define the space, the objects, the actions, the consequences of the actions, the constraints of the actions, and the goals" (144). Of the multiple types of rules he goes over, the most important in his mind are goals, the objectives the player must acheive. A good goal must be concrete, acheivable, and ultimately rewarding in order to be effective (148-49).

Mechanic 5: Skill

To complete the tasks games present to them, players need skills. In order to create an adequetely challenging experience, designers must balance player skill with game difficulty so that players stay interested and in a state of flow. Schell describes three types of skills within games (151):

1. Physical Skills -- skills involving strength, dexterity, coordination, and physical endurance. In video games, this often includes reflexes and fine motor dexterity.
2. Mental Skills -- skills involving memory, observation, and puzzle solving.
3. Social Skills -- includes reading an opponent, predicting their movements, and coordinating actions with teammates.

In addition, games have the added dichotomy of real versus virtual skills. Real skills refers to a player's skill, while a virtual skill applies to the how good a character is at a certain action (i.e. swinging a sword in many roleplaying games, 151).

Mechanic 6: Chance

The final mechanic Schell is concerned with is the level of chance within a given game. Chance is beneficial because it adds unpredictability to a game experience, increasing replay value and diversifying gameplay (153). Schell notes that the ability to predict probable outcomes is a skill in and of itself, and may be treated like any other skill when it comes to producing flow.