Michael Cunliffe once said to me "I’d be very interested in a post about whether (or how to) use mechanics to suit setting in RPGs – how do you use dice rolls to provide not only dramatic, but thematic effect for players."
And I obey.
I’ve had an informal maxim in my head for years now as a game designer, and with every year that passes and every design I work on, I’m more and more certain it’s the right one. I’ve never really written it down before, but it goes something like this:
Mechanics drive player behavior.
On the surface, this sounds simple – a game about westerns should have rules about gunfights if it wants to have dramatic gunfights, and so on. But it goes deeper than that, I feel. Games feel different depending on what mechanics they use. This is more explicit with board games, card games, video games, and less flexible genres of game, but even the flavor and tenor of role-playing games are impacted by their choice of mechanics.
Take games of a similar genre, such as Boot Hill and Dust Devils.1 Both are Western games, but each is focusing on something different, whether the design is intended or not, and as a result you get different games. While there is a tried-and-true tradition of hacking or drifting rules in RPGs, what the game focuses on in terms of mechanics will consciously and subconsciously impact how the game is played. While some players can (and will) resist against the tide of mechanics, most will gladly be swept right along, and will indulge in the gameplay the mechanics present and reinforce. And a chunk of the feel and setting for an RPG is created by how the players act within it.
So yes, mechanics should help establish the setting in RPGs. But as a designer, how can you do that?
First, you have to know on a very real level what your setting needs to have enshrined in a mechanic. I believe every version of Dungeons & Dragons has alignment, even if the actual system has gone through various changes. The reason, though, is simple: the difference between "good" and "evil" matters in that game. Even if it doesn’t often come up in the game (and in my experience, it doesn’t come up much at all, aside from the odd "Detect Evil" spell), the fact that it exists and that there are parts of the game that work differently depending on that choice means that in D&D being good or evil is meaningful to the game, and therefore to the setting.
Next, you have to make sure those mechanics matter. Every version of Vampire has had Humanity as a mechanic. And not only a little mechanic, a small number tucked away on a character sheet, but a large ladder of dots. It generally takes up a fair amount of real-estate on a character sheet, and many fans of the game will remark on it being a core element of the game. The actual mechanic isn’t used that often compared to other parts of the game, but when it is, it’s often a significant moment. You can literally lose your character on a bad dice roll, so you’re encouraged to take actions that keep you from having to make that roll. If you make that mechanic matter to the player on a fundamental level, it will impact their game.
(As a side note, I once was in a chronicle of Dark Ages Vampire while I was also playing in a different campaign of D&D. There was a fair amount of overlap in some setting elements, such as "medieval hero uses unusual powers to deal with problems," but each game felt very different at their base because of the different emphasis in mechanics. Similarly, I’ve played an Exalted game under the same Storyteller who ran Dark Ages Vampire, and again they were very different feeling games because of the mechanics.)
Finally, the rest of the game needs to reinforce this mechanic. Paranoia is good at this. Although different editions emphasize different parts of the setting,2 the setting always reinforced and encourages the kind of player-against-player backstabbing and treachery that the rules encouraged. Everything about the game – even the name – backs up and supports this player dynamic.
This is why, I think, small games with a few mechanics and a strong direction are doing well these days – if you have a good vision for the game and everything else supports that vision, the game is stronger as a result.