So, illusion of uncertainty is certainly a tool to make a session more fun, but is probably not actually part of the game, excepting where said illusion is actually transmission of information (i.e., alters how the players make decisions within the game).
Poker, I could argue, is to a large degree dependent upon exchange of illusory information, and this exchange is certainly part of the game, as its intent is to influence decision-making. So too with a role-playing game. So long as the decision making is part of the game, then the attempt to influence it is part of the game.
Hmm. I don't think bluffing in poker is quite the same as what I'm trying to convey.
As you point out, bluffing in poker is an attempt to influence the decisions of other players. But in my examples, the GM isn't attempting to influence the players one way or the other. He's simply trying to convey an elevated sense of uncertainty in a case where the actual uncertainty may be less or nonexistent.
Let me put it another way: Have you ever seen players agonize over a decision the GM knows is completely unimportant? Heck, I think we've all been in situations where the GM actually rushed the players along because they were spending too much time on something that didn't really matter.
The point is that the players' perception of how meaningful the decision was differed from the actuality. As with every other element of the subjective RPG experience, there will always be differences in perception between players and the GM. And so long as that difference exists or potentially exists, it's something GMs can and will add to their toolbox.
Not every decision has to actually matter. It's often good enough for it to seem like it matters.
If the decision making is not part of the game, it might be fun, and it might be role-playing, but I would argue that it is part of the framework rather than part of the game per se.
Fair enough. But again I'm not talking about players knowingly heaping extra significance on a decision based on character viewpoint or roleplaying purposes--I agree, that can be fun, but it's not relevant here.
I'm talking about what the
players (not characters) perceive as the level of uncertainty at a decision point. If they are making a decision based on a perception of uncertainty, I think they're playing the game even if the perception isn't accurate. Just like a chess player who moves his piece to head off a gambit he thinks the other player is considering, even if that strategy had never occurred to his opponent.