One of the powers of the Situation Model is to be able to accurately defined the concept of Challenge.
Really, it's fairly simple. First, let us divide the Situation into Domains, each named for the three actions that the player is capable of taking. So there is the Reason domain, the Ability domain, and the Comprehension domain.
But, before we can deal with Challenge itself, we need to define two other terms.
Let Risk be the relative potential for the player's actions in the Situation to produce negative consequences towards achieving the player's goal.
There are two degrees of Risk. One degree is the quality of the negative consequences. IE: how badly does it hurt the player to fail? The other degree is the quantity of the negative consequences. IE: how likely is the player to fail? How much of the Mapping Table is dedicated to paths that lead to failure rather than success? Or, put another way, how many Game Inputs are there that lead to success rather than failure?
Let us define the first degree to be Risk:Pain. The second degree will be Risk:Extent.
Risk, in either degree, is a fundamental quantity of a Situation. It is not affected by the player's skill set or body of accumulated wisdom. As such, it is not enough to be able to define what a Challenging Situation is. After all, what is hard when you first begin to play is not nearly as hard at the end.
Since the player's Reason, Ability, and Comprehension are all fixed by the Situation Model, only Knowledge and Experience can explain the changing nature of Challenge. So, now we introduce Complexity.
A Situation's Complexity is a descrition, for each domain as defined above, of the body of Knowledge and/or Experience needed to feed into the player's attributes to successfully deal with the Situation at hand. The more Knowledge and/or Experience, the greater the Complexity.
Complexity exists in each of the three domains, and it should be looked at separately for each.
Complexity in terms of Reason means that it requires pulling in disperate Knowledge in order to device a correct plan that will create the desired Result. The greater the body of Knowledge required to find a viable solution, the more Complex the task of using that Knowledge becomes.
However, reason has the honor of being the only domain fed by both Knowledge and Experience. So it gets a second pass. Reason must also estimate the likelihood of being able to execute the Player Input into Game Input, and the player's Experience informs this. However, greater Experience serves to decrease this form of Reason-based Complexity. Greater Experience means that the player is capable of doing more, providing more complex input, and doing so more accurately. Thus making more complex input easier for the player to achieve.
This also requires a degree of Risk analysis. The player must use the Knowledge of the Risks (which may not be complete, of course) to determine if the player's Experience is enough to be able to hit one of the correct solutions. Risk:Pain makes one wary of confronting the Situation at all (if the player has a choice), while Risk:Extent puts a stress on evaluating one's Experience for confonting the Situation.
Reason-based Complexity, therefore, has two degrees: Complexity:Reason:Knowledge and Complexity:Reason:Experience.
Ability-based Complexity is fed only by Experience. The decision of what to do has been made, and now it must be effected and transformed into Game Input. This Complexity represents the quantity of Experience one needs in order to properly manipulate the user interface to turn Player Input into Game Input. Or, in simpler terms, it represents how skilled a person must be at using the UI in order to command a particular Game Input. Thus, giving rise to Complexity:Ability.
Comprehension-based Complexity is fed only by prior Knowledge. Complexity in Comprehension means that it requires a large quantity of accumulated Knowledge to properly Comprehend a particular Result. The phrase "properly Comprehend", is intensionally nebulous.
Particularly of the Player Input that was used to produce this Result. From that, the player can actually reduce later Complexity (which we will discuss more later), by being able to apply previous victories in new Situations. Rather than later having to use Reason to cobble together some attempted solution, the player need only take an already proven solution and modify it for a new Situation. This proven solution, of course, is represented as Knowledge and/or Experience.
Which gives us Complexity:Comprehension.
So, what is Challenge? Well, quite simply, Challenge is any and all of these. A Situation is said to have a degree of Challenge when any of the 6 aforementioned degrees is involved to any significant extent.
Challenge therefore has 6 pimary degrees that a designer can theoretically adjust. Each of those degrees can be adjusted in a myriad of ways.
Risk of all forms provides the player with negative Results. The player does not (presumably) want negative results, so the player attempts to avoid them.
A high degree of Risk:Pain means that the player has a strong wish to avoid failure. It means that the player is going to be in a mental state of stress on the possibility of failure. Planning to avoid the pain is therefore very crucial; this degree plays towards the player's Reason and Comprehension, as well as Knowledge and Experience.
A high degree of Risk:Extent means that there are many pitfalls. The player must take extra care to provide the correct Game Input to select the right Result. This degree plays towards the player's Ability and Experience.
Complexity, of all forms, confounds the player. It makes the player's task harder by placing greater demands on the players attributes.
Complexity:Reason:Knowledge means that the player must use a great deal of accumulated Knowledge be successful in this Situation. Devising strategies is one example of this.
Complexity:Reason:Experience is all about stressing the player's accumulated skill at manipulating the user interface. The player must plan for his/her shortcomings if there are degrees of Experience that he/she is missing. The player may choose to play it safe rather than attempting a plan with a greater degree of Risk:Pain or Risk:Extent.
Complexity:Ability requires that the player be able to substantially manipulate the user interface. The player must have a great deal of prior experience in performing the actions that the player is being required to perform.
Complexity:Comprehension requires that the player gather large quantites of Knowledge from other Situations in order to be able to understand what is being presented by the game.
There are also 3 extra degrees of Challenge. And they are pretty obvious when you think about it. For a given Situation, there is a base "quantity" of Reason, Ability, and Comprehension that is required to be able to confront the Situation and/or learn from it. The more the Situation requires from the player in these domains, the more difficult the Situation (or later Situations in the case of Comprehension, due to lack of Knowledge and/or Experience) is. We will call these degrees of Challenge Difficulty:Reason, Difficulty:Ability, and Difficulty:Comprehension.
So, in total, there are 9 degrees of Challenge, each with a virtually infinite number of ways of being expressed to the player.
We will discuss how Challenge changes over the course of multiple Situations in later articles.