This is part of my RPG series of entries here at SOB. See the inaugural entry in the series for more details.
In Shackleton’s Maligning Alignment, he discusses his Motivations system in some depth. It’s a somewhat complex replacement for the Alignment system of D&D in some respects, but in others it represents a significant difference in many other aspects of the game as well.
One comment to Maligning Alignment at reddit reads:
I cannot say enough good things about this idea. It’s brilliant, and I will incorporate it into every house game I play!
I won’t be incorporating the idea into every game I run, but it’s certainly a good idea for some games at least. I’ve come up with different ways to use interactions between principles to determine the chance of success on given actions, rather than discrete (and largely arbitrary) character stats, for a long time — and I like this particular implementation of the idea.
A much more limited form of the idea is one that I intend to use more often in the future for Pathfinder games — the idea that skills should not be tied to a particular attribute. Instead, skill ranks and other modifiers are maintained separately from attribute modifiers, and what attribute modifier applies depends on what exactly you’re doing with your skill.
For instance, in Pathfinder RPG (as of Alpha 3) you now have a Perception skill. That skill combines Listen, Search, and Spot into a single skill — which makes sense. Like Listen and Spot before it (but unlike Search, which was Intelligence based), Perception is a Wisdom based skill. Thus, if you have a Wisdom of 12, one rank in Perception (being a first level character), and a +3 to Perception because it’s a class skill, all checks that would previously have been made with Listen, Search, or Spot are now made using the Perception total of (+1 for Rank, +1 for WIS, and +3 for Class Skill) +5 to your d20 roll.
With the flexible attribute associations idea in play, however, that might change based on circumstances. Instead of always rolling a d20 and adding the same number, if you said you were reading a book about Abyssal architecture and the GM decided there was a possibility you might make a connection between something said in the book and something said to you by a demon in the heat of battle the other day, thus providing a clue, he might have you roll for your character with a 17 Intelligence (+1 for Rank, +3 for INT, and +3 for Class Skill) d20 + 7 instead. After all, making those associations would certainly be more Intelligence based than Wisdom based — it’s a matter of analysis, rather than judgment.
What attribute applies to a given skill check might also depend to some extent on how your character thinks. A highly analytical character (such as me, if I were a PC rather than a player) might use INT + Sense Motive to detect the ill will some NPC bears him, while a more empathetic character might use CHA + Sense Motive or WIS + Sense Motive (depending on how the GM interprets “empathy” in relation to Wisdom and Charisma, I suppose).
As for how the Motivations system fits into enchantment/charm based spellcasting — I think that’s an incredibly slick system for adjudicating the effects. It works beautifully, at least in theory, for applying a novel and effective means of handling emotion and mind control and detection magic. The only caution I might offer Shackleton is to be careful about imposing too much restriction on the way PCs play their characters via the Motivations system, outside of magical controls of course. While that kind of deterministic restriction on NPCs can ease the burden on the GM in determining how interactions proceed, employing the same restrictions on PCs might just make the game less fun.
I may at some point describe here at SOB some of the game systems I’ve created over the years that involve interactions between principles of character rather than discrete stats, including one I came up with a year or so ago but haven’t used yet that employs elemental constitution (earth, air, etc.) rather than more typical attributes.