Is it possible to give players various degrees of control over the personalities and choices of NPCs?
That question was sparked by my comment in the last blog about novel readers typically having some room for interpretative preference. For example, I just read Frankenstein for a college literature course, and there was debate about the personal nature of Frankenstein's creature. Often, the ability of readers to reasonably interpret a character or action in different ways represents a failure on the author's part. Sometimes, authors want their readers to have great freedom, yes, but all authors should be in the tightest possible control of their story's interpretive possibilities.
Likewise with games. The designer should design their characters and events either so they may be perceived in only one way or so they may be perceived within a controlled range of possibilities.
But that should be old and obvious theory. The bigger question is how might we provide players more interpretative control over NPCs and events? and (the true Frankensteinian question) should we? How might such a system benefit the gameplay?
Something I commonly hear from audiences of movies which have been adapted from novels is, "[such-and-such] didn't look at all like I pictured it". Generally, in this regard, game designers are limited in the same ways as film directors; it's a visual story, so we can't avoid defining the audience's visual experience.
But that's only generally true. Hitchcock, Spielberg and other great directors have commonly hidden characters (human or non) from the audience until the last possible window, or even indefinitely. Sometimes the audience is offered skewed or momentary glimpses, like in Jaws or Predator. Other times, the figure is hidden until the end, like in Alien.
Similar effects have been used in games that are very linear and view-limited (Resident Evil, Eternal Darkness), but the practice should be seized by open RPGs and MMOs as well. Players can be given only shadows and voices (yes, it's ok to force your player to listen to the game, and not just watch it). Camouflage is possible with current technology.
Usually, the best method of this, in my opinion, is footprints. Make a character or event's existence known only through hints at a presence where now there is only an absence.
How about giving players impact over A.I.? I've seen faction score's affect an NPC's behavior toward the player. I've seen dialogue do the same. I haven't seen an NPC change some part of its lasting personality or lifestyle based on player actions.
It doesn't have to be big to make a meaningful impression on the player. It might be as simple as the NPC's weapon or clothing preference.
Ex: The player saves a boy's mother from some thugs, after which he cheers the player excitedly as a personal hero. The player chooses to offer the boy his helmet. The boy jumps with glee, accepts the helmet and may be seen evermore wearing his hero's helmet.
Ex: The player succeeds in a one-shot attempt to convince an NPC that the player's faction (or even favorite in-game sports team; jousting?) is the coolest. The NPC can then-after be seen wearing some cloth or bearing some flag with the emblem of that faction. If this is a multiplayer game, like an MMO, players of opposing factions would later have their own one-shot attempts at converting the NPC away from the first player's faction and toward their own. Any real-world sports fan knows that just seeing the emblem of your team or an opponent can draw a loud "rock!" or "boo!". Speaking of which, Roll Tide! ;)
The tougher challenge (infinitely moreso, it seems, for an MMO or other multiplayer game) is giving players some impact over the story-related decisions of NPCs and accounting for even a small number of ripple effects. It's cool if I can convince an NPC to alter his or her behavior. It's cooler if altering that character's actions draws the attention of other NPCs and affects their decisions. And it's cooler still if I can change an NPC's personality (pattern of behavior...for this purpose), affecting future actions of that character.
Reversibility is a common problem here. Players often have the ability to reverse the affect they've had on an NPC, like earning back faction they lost just as easily as they earned the faction the first time. This is a point in which many gamers desire realism. Some NPCs should be quickly recoverable, some slowly recoverable, and some not recoverable at all.