16 March, 2008 at 10:19 am (rpg theory) (, , , , )

Given that choice is and important part of roleplaying, how do people make choices? There are useful theories out there (including game theory, with which I have a passing familiarity). I’ll try building another one so that it hopefully has something useful to say about roleplaying.

This model is specifically about how people make choices in the context of roleplay and that affect the rp. Extending the model is not particularly hard and is left as an exercise for the reader. The limitation is essentially arbitrary.

I also try out sketching a model for immersion as it is seen through this piece of theory. The threefold model is another example.

Some definitions

Filter is a criterion that assigns a weight to different options people have regarding their play. In case someone in the audience is mathematically inclined, a given filter is a mapping from the decision space (this is the emulation space [emspace] for those familiar with Kuma’s AGE model) to real line; generally speaking, the entire real line is not needed and one can work with a given interval or other subset.

Example filters: What would my character do? Will this result in total party kill? What will this say about me as a person? Is this appropriate to the genre?
Example filters for the more elaborate model: How much will everyone enjoy this? How genre-appropriate is this?

A filter is strong when it makes sharp contrasts between different options; likewise, a weak filter makes little difference. These are not exact definitions and should generally be used as a part of comparative phrases (they imply comparison to some unstated standard if not used in such a way).

A simple model

Every participant has a number of filters. Each filter accepts certain options and rejects others. In math: Filter is an indicator function of a subset of the decision space. It assigns value 1 to any option that is within the subset and 0 to any that is not.

When making a decision, participant applies filters, one at a time, with each application further restricting the possible choices (or at least not adding any). When the remaining options are sufficiently close to each other, the participant makes that choice. “Sufficiently” depends on how important the occasion is, how tired the person is, level of attention, and so forth.

The order filters are applied in is a matter of playing style and other influences.

Assumptions of this simple model

This is not a good model. It makes the following assumption (and others): That people always either reject or accept a given option; essentially, this model assume two-valued logic. This is not very accurate.

A more elaborate model

Filters work as above, expect that they can get values up to an arbitrary positive value on the real line (this can, but need not, be fixed). That is: A given filter assignes some value to all potential options the player has at a decision point (in nontrivial cases the assigned values differ from one option to the next). For desirable (according to that criterion) options, the value is high. For undesirable ones it is low. These are multiplied over all the used filters until one is sufficiently larger than the others. The option with highest value is then implemented and a choice is made.


Character immersion happens when player identifies with a character to great degree. Filter theory sees immersion as a process where the player has one or few very strong filters, so that it seems the player is not making choices at all. Typically this filter is “What does (would) my character do?”. This is clearly distinct from the disruptive behaviour sometimes known as “my guy-syndrome”, in which the relevant players uses the character’s actions as excuses for bad behaviour. In this model, players who disrupt the game and use the character as an excuse don’t make heavy use of the “what would my character do”-filter, but some other, more harmful, one.

The threefold model is a theory about filters. G, D and S all signify emphasis on given (family of) filters: dramatist GM has a strong “does this make a good story”-filter, for example. This is very explicitly not true of GNS: It is not about the way decisions are made, but rather what decisions are thought to be important, which certainly is prone to influencing the strength and priorisation of the filters that are used.

It will do little harm to think about the filters you use and of those that other people you game with use, and the order in which they are likely to be applied. Something might even be learned by such actions.


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It’s all about choices

19 December, 2007 at 11:52 am (rpg theory) (, , , , )

For me, roleplaying is about making choices. I hear there exist alien entitites called other people who disagree. Whatever.

Large heaps of rpg theory are also about choices. More probably, I remember those ones better, but again, whatever. I’ll go through a few from this point of view.


GNS is about the kinds of choices people (in groups) want to make. I am not an authority on the subject, but am fairly likely to get G and N approximately correct. I think these are useful not because they are a tool for putting people in boxes (which they technically speaking are not, but which is a very easy extension of the theory, but instead because you find out that there actually are people who enjoy these kinds of choices, and including them in games to see if people enjoy them might be useful. That’s my opinion.

In a group with a gamist agenda, people appreciate most the kinds of choices that show off your sense of tactics or guts or something like that. These are usually related to winning or beating an obstacle.

A group playing in narrativist way people most appreciate choices that reveal interesting parts about the characters’ inner life. Such decision points often manifest as moral dilemmas and sometimes may involve playing suboptimally from fiction or rules POV (note the qualifiers; they matter).

A group where simulationist play happens most appreciates, well, uh.., I’m not actually quite certain. I’m trying to do a positive definition here. Maybe choices which reveal interesting about the way the fictional reality functions? I guess that is good enough.

GDS aka Threefold

John H. Kim has done a great summary of the threefold model, as has Silvered Glass of From my perspective, threefold talks about the heuristics game masters use when making choices. I will blatantly extend this to players, too. Note that the categories are not mutually exclusive; rather, an overt focus on one will limit the others, because usually there are situations where following a different heuristic would lead to different consequences. I think it is useful to analyse one’s gaming based on these categories. I also think it is useful to check out systems based on thse categories, especially to see if some of the GDS styles will conflict or are congruent in a particular game.

GM with gamist tendencies is someone who tries to make choices so that the game is challenging to the players. My extension is that a player with gamist tendencies wants to make choices which overcome the challenges. Note: Rules and fiction can both be used as the method of presenting the challenges. A courtly intrigue can be as good a gamist challenge as a series of bloody skirmishes even in a game with few to no social rules.

Dramatist GM or player makes decisions that result in the best story (or tries to, anyway). This can be a railroad or a more collaborative exercise (I certainly prefer the latter).

Simulation as a preference means that the participant will make decisions based on “what would really happen”, given the diegetic (in-game) reality.

AGE model

The AGE model by Kuma takes a look at roleplaying from ecological POV, in that the environments that play takes place in are emphasised. This post will not make much sense unless one is somewhat familiar with the model. The six forces are essentially created by players with given decision-making heuristics. Choices are constrained by the different spaces (em, a, game, play) and also affect those spaces by setting precedents and opening new potential interactions.

Original thought

Rules can align some priorities. If, for example, the rules are designed to help in creating a story through challenges, they can be enjoyed by people whose styles of play might normally conflict. Setting likewise; if all characters have a drive to prove themselves by doing the impossible and also want to become as powerful as possible, realistic behaviour in that setting corresponds to facing and triumphing over challenges.

Both of the above effects are achieved by constraining some choices and creating new ones. Rules and setting do both.

In traditional play (huge sweeping generalisation incoming) GM is the one who thinks about the good of the game as a primary filter that removes choices, or such is ideally the case, at least. Personally I don’t see the point of not assuming that players also want the good of the game. I do, as a player, to some degree. Many people who both run and play in games probably think more holistically and act in the best interest of the game.

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