Defining persistence

Motstandet posted an interesting article on That’s a Terrible Idea yesterday, and it got me to thinking about how we define “persistent” in regards to video games.

I propose that there are two kinds of persistence: character persistence and world persistence.  The former is quite common, almost ubiquitous, while the latter is almost never seen in any mature form.

Character persistence is, at its most basic, the ability for a character to continue to exist over time, with whatever possessions he or she has acquired.  More sophisticated forms of persistence track which quests a character has completed, and how various NPCs or NPC factions have come to view the character based on his or her actions.

Games without character persistence include most multiplayer FPSs; if you log out then start up a new game, you won’t have the same character, with the same weapons and ammo.  Allowing characters to persist in multiplayer FPSs would create an uneven playing field, such that some players would be far more powerful than others.  This defeats the purpose of skill-based games, where the characters are intended to be equal, so the players’ skill will determine outcomes.

Games with character persistence include all RPGs; if you log out then return, you’ll have the same character, with the same items and experience level.  Notably, this persistence implies a persistence in the world itself, but this is a hollow promise as we’ll see.  The fact that the character continues to exist from one play session to the next allows for long-term character development, such that players are motivated to spend their time increasing the power of their character by gaining levels and money and equipment and faction standing.  All of these can of course be time sinks, and naturally often are, since many designers seek to include as many time sinks as possible in MMORPGs.

World persistence is more than just having a world continue to exist between a given player’s play sessions – that is only the simplest and most basic kind of world persistence.  World persistence can also include the continuation of events over time, the persistence of items not in the possession of a PC or NPC, and lasting changes to NPCs or landscape features.  I’ll approach each of these in turn.

The idea that events continue over time is fairly simple and not uncommon, with certain specific limitations.  If two players create a story between them, that event can persist as long as the players involved choose to allow it to.  This is one of the most common facets of roleplaying and will be seen everywhere there is any appreciable RP.  Simpler still and more common is persistence of quest events, wherein a story line will persist for a given player, but will have no impact on other players whatsoever.  E.g. player A could help a villager to find his lost daughter, only to discover upon bringing her back home that she had been cursed by an evil sorceror.  The story could continue, allowing the player to defeat the sorceror and undo the curse, finally freeing the villager’s daughter… but this whole storyline, this persistent series of events, would exist in almost all MMORPGs only for player A.  If player B came to talk to the villager, that same quest would be offered – meaning what player A accomplished has no effect on player B.  This isn’t true world persistence – rather, it’s a specific case of player persistence, since the quest (and the associated series of events) persists only for player A.  For the event to have world persistence, it’d need to be perceivable by other players.  This is obviously incompatible with the static world approach favored in modern MMORPGs, where nothing in the game world truly changes over time except player characters.

The persistence of items not in the possession of PCs or NPCs is a thorny issue.  On the one hand, it’d increase immersion and allow for all sorts of emergent behaviour if items deposited on the ground, or stacked in interesting ways, were to persist over time.  On the other hand, quite obviously this leads to server lag (meaning server CPU cycles committed to tracking the presence of said items; this has nothing to do with latency).  For this reason, items dropped on the ground disappear either very quickly or immediately in MMORPGs.  That includes the corpses of the fallen as well as items dropped from a PC’s inventory.

Lasting changes to NPCs and landscape features are incredibly rare in MMOs, except as noted above in relation to individual PCs.  If I kill an NPC, that NPC will almost always respawn, usually fairly quickly.  If a game allows me to alter the landscape (which is rare), e.g. by setting fire to something, the changes will revert quickly or will only be visible to me.  Changes to NPCs and landscape features can persist for a given character using the technology known as phasing, but again this is merely a type of character persistence, since those changes aren’t shared between players.  One of the only landscape changes allowed in modern MMOs is player and guild housing, and even those are far from ubiquitous.  When a game does allow a player and/or guild to own housing, often only the inside of the structure can be changed, or only very minor external modifications are allowed.  Even in the rare cases where players are allowed to change the landscape in a manner perceptible to other players, their agency to do so is severely curtailed.

A truly persistent world would allow players to change the world over time.  The actions of a given player would affect the world as perceived by all other players, meaning true persistence is completely incompatible with the static designs favored by modern MMOs.  Modern MMOs are designed to give the illusion of persistence but that is all; the only true persistence we see is character persistence, and even that is fairly limited.

1 comment so far

  1. Tesh on

    Perhaps we’re just not there technologically or socially yet.

    The tech may well happen someday, thanks to Moore’s law, but the social issues may be even more troublesome.

    Player-generated content tends to be a considerably thorny issue, especially with the anonymity of the net. Now, if you had private servers, that might be ameliorated a bit, but a mass market game won’t have the luxury of keeping the idiots out.

    Still, a world that had true persistence, and was allowed to evolve and change, may well be a fantastic place to play. It might not be the most profitable, which means we won’t see one for a while, but it sure is interesting.

    Great writeup!

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