Everyone has had that experience of someone at the table making a move because of something that occurs in another part of the world. Or you have that player who has memorized the entire Monster Manual from every edition and uses it to their advantage. The term we pin to this kind of play is metagaming. Nearly everyone has done it. Some have moved past it but we all make mistakes early on when learning this whole gaming thing. As a GM and a player there are techniques you can use to mitigate this type of behavior.
Before moving too far forward I'd like to actually clarify the term metagaming. Breaking down the word you get the prefix "meta" which has a whole bunch of meanings, the one we care about is to define something that references or comments on its own subject matter. In this case it is word "gaming" which in this case does mean the act of playing a game. In short this means that metagaming is act of playing a game with reference to its own subject matter.
As you can guess this leads to performing actions one would not otherwise take in the game. Metagaming knowledge is what we use to perform metagaming. So in terms of role playing games we have to break this down even further to help figure out how to combat metagaming.
World knowledge is the player's knowledge of how the world works and things that exist in it. This is commonly seen when playing a game in an established world like the Forgotten Realms in a location that is well know (i.e. Waterdeep). This also pertains to information about creatures and their in-game stats. Knowledge about the world can lead players to conclusions and resources that their character might not otherwise have access to or knowledge of.
In a combat scenario knowing the location of everything can create a win. However sometimes your character is not going to have the full story. They don't know where the invisible teammate is or they are in another section of the dungeon. This is probably one of the most commonly used metagaming knowledge because it can be difficult to block out ones mind. Having this knowledge can lead to enhanced coordination that may not otherwise be possible.
Behavioral Knowledge is one of those subjects that I knew about but never associated it with metagaming. At its core it is using knowledge of how the other individuals at the table behave in regard to their actions or planning. This ranges from what the Ranger's standard approach to attacking is to how forgiving a GM is in regards to failing certain objectives. This one is the toughest to combat as it is not entirely used for metagaming.
Why is Metagaming Bad?
It seems appropriate to address why these can be a problem. After all this is just a game right? Who cares if it doesn't make complete sense in the world, after all we do that in other games? It comes down to everyone's approach to the game. When playing a couch cooperative first person shooter (yes they did exist) we would always get upset when our friends would screen-look to figure out our location so they could kill us with grenades.
Even though a tabletop RPG is not a competitive game there is a level of immersion that we work to uphold. Metagaming is one of the easiest ways to remind us that we are just playing a game, and that ruins immersion. It can make the grand moments that your GM spent time and energy crafting, and just throwing it down the drain. GM's actually have the most amount of metagaming knowledge to filter, because they run every NPC and monster that exists in the world while also keeping track of the players. If a GM uses metagaming knowledge in a situation it can utterly destroy an entire situation and possibly upset players.
How to Combat Metagaming
Each of the knowledge types I listed above has different techniques to counteract, both for players and for GM's. Employ these techniques as need to help reduce meta-gaming in those areas. However none of these technique will work without buy-in from everyone at the table. If there is metagaming occurring at your table you need to address it, either as a GM or a fellow player.
Fighting world knowledge metagaming is the easiest to combat as a GM but requires a bit more leg work. For players it is more of a mindset that you need to get yourself into. The general idea of fighting world knowledge is making everything a mystery.
I will start with players because it is more of a mental exercise. When you sit down at the table for the first session of a campaign, assume your GM has changed absolutely everything. Assume he has put the work into changing every city, NPC, and monster in the game. While your GM may not have actually done so it will be easier for you to just question everything unless your GM strictly gives you (not someone else) information. If you are curious if your character knows a piece of knowledge just ask the GM. The topic of knowledge can be an entire article in itself.
As a GM you pretty much have to mix everything up for your players. This is the easiest to do by creating your own setting to play your game in. If its brand new and only in your head then there is no way for your players to know what to expect. For those players that know the system in and out and know the stats of every creature, throw them for a loop by mixing up a monster. One of my good friends was GMing a game for me and some friends. When we killed a dragonelle, bees came flying out of its corpse. There was no way for us to predict that he was going to do that because it wasn't in a monster manual.
Fighting situational knowledge can be a tricky beast to master. It is also highly dependent on the medium in which you play. In online play this is easier than in person but its not impossible.
Most metagaming reduction techniques for players requires mental discipline. This one is in working on your ability to put yourself in your characters shoes. Pay attention to who your GM is speaking to and ask if you are not sure. Early on in trying to learn this, sometimes it is okay to zone out and wait until your GM asks for your attention or calls your name. This will ease you into being able to separate knowledge in your head.
In online play this is a simple fix until your players are able to start separating the knowledge themselves. Most voice clients have the ability to create separate voice channels. Discord and Mumble have them along with the ability to restrict access. Use these separate voice channels to restrict who hears what information. In addition you should avoid discussing tactics out of character whenever possible.
In offline play this is significantly harder since you are usually in one room and asking people to leave is not a fun experience for that person. This is one of the few times that I would almost recommend the use of technology. Ask your players to come to your game with a pair of headphones and some music, when you need a certain group to not hear something just have them play some music while they wait. As long as they can easily notice when you try to get their attention. When dealing with one or two players for a short scenario walk out of the room with them or pass notes. When leaving the room you need to keep it short so it doesn't seem like those not pulled aside are being forgotten.
In the case you cannot separate your players, kindly remind them when the try to act on this knowledge that their character wouldn't have access to that information. Force the players to discuss tactics in character and cut them short during time sensitive segments. Ask players kindly that are not in an area to refrain from discussing information during segments they are not involved in. As a GM you need to maintain a level of expectations for situational knowledge and be open about it with your players. Establishing this will help newer players learn to separate knowledge in their head.
Since human beings are social creatures this is by far the hardest one to combat. Not only are we social but we are creatures of habit making many of our behaviors predictable. Some of the behaviors at the table can actually be constructive and build better bonds with one another.
As a GM this requires some introspection. When making a decision you need to ask yourself if that is what your players would expect and if mixing it up would actually bring an improvement to the game. If it would then try a different result or best of all, leave it up to chance. More often than not when something could happen I ask my players "high or low" and then roll a die (generally percentile dice) and let the dice decide if it is favorable for my players. I do this for chance things that have nothing to do with skill. Its a 50/50 chance for them and leaves them in suspense. All you can do is try and be as unpredictable as you can.
As a player this is nearly impossible to overcome. I cannot think of any sure fire technique to help you. The best you can do is try to imagine your DM as a completely different person and ignore your preexisting knowledge. However this technique can only do so much and your ability to read people will probably break through.
Why Metagaming is Good
I waited to talk about how metagaming can be a good thing until I expressed a better understanding of how to prevent it, because eventually at the table you and your fellow players will be able to not use metagaming to your advantage. The primary reason metagaming is good is when it helps improve the flow of the game. Having to describe the same room to a group of players multiple times consumes time and can possibly result in misinformation if the information is not repeated correctly.
Improving the flow of the game can increase engagement as the GM can spend less time focusing on separating information and more time focusing on the players and their characters. Having access to world knowledge players can assist the GM when they fail to remember a detail. It also opens the group up open discussion about the game after sessions. At times it can even create tension, just as television shows do sometimes.
Overall you should not be working to eliminate metagaming entirely from your game. It can actually be incredibly helpful to have an experience player join to help set a standard and guide newer players towards a healthy use of metagaming.
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