Secret Goals

One of the basic distinctions in game theory is between games with perfect information, like chess or tic-tac-toe, and games with hidden information, like poker (each player's cards and the deck) or Monopoly (the dice). But I was this evening thinking about games with not only hidden information, but hidden goals like Aquarius (hidden goal card).

Does anyone know about game theory thinking about hidden goals? In some cases (like Aquarius) it may be easy to treat it as ordinary hidden information. But in other situations (like politics), it may change the understanding quite radically. It seems like it would be very hard to develop a predictive model of a player's actions if you don't know what he's going for (e.g., somewhere in emotion-money-ideals space).