5.7. Emergence¶

Another dynamic that game designers should be aware of is called emergent gameplay (or emergent complexity, or simply emergence). Generally, emergence describes a game with simple mechanics but complex dynamics. In other words - it describes a situation where a small set of rules that seem produce game play that is much more interesting and varied that would seem to follow from the simple rules.

Some examples of emergence from the world outside of games:

• In nature, insect colonies (such as ants and bees) show behavior that is so complex, it appears to be intelligent enough that we call it a “hive mind” (much to the exploitation of many sci-fi authors). In reality, each individual insect is following its own very simple set of rules, and it is only in aggregate that the colony displays complex behaviors.
• Boid’s Algorithm, is a way to simulate crowd and flocking behavior that is used in some CGI-based movies as well as games. There are only three simple rules that individuals in a flock must each follow. First, if there are a lot of your companions on one side of you and few on the other, it means you’re probably at the edge of the flock; move towards your companions. Second, if you are close to your companions, give them room so you don’t crowd them. Third, adjust your speed and direction to be the average of your nearby companions. From these three rules you can get some pretty complex, detailed and realistic crowd behavior. (Link shows flock pursued by predators)

Here are some examples of emergent gameplay:

• In fighting games like the Street Fighter or Tekken series, “combos” arise from the collision of several simple rules: connecting with certain attacks momentarily stuns the opponent so that they cannot respond, and other attacks can be executed quickly enough to connect before the opponent recovers. Designers may or may not intentionally put combos in their games (the earliest examples were not intended, and indeed were not discovered until the games had been out for awhile), but it is the mechanics of stunning and attack speed that create complex series of moves that are unblockable after the first move in the series connects.
• In the sport of Basketball, the concept of “dribbling” was not explicitly part of the rules. As originally written, the designer had intended the game to be similar to how Ultimate Frisbee is played: the player with the ball is not allowed to move, and must either throw the ball towards the basket (in an attempt to score), or “pass” the ball to a teammate (either through the air, or by bouncing it on the ground). There was simply no rule that prevented a player from passing to himself.

Why do we care about emergent dynamics? It is often desired for practical reasons, especially in the video game world, because you can get a lot of varied and deep gameplay out of relatively simple mechanics. In video games it is the mechanics that must be implemented. If you are programming a video game, emergent gameplay gives you a great ratio of hours-of-gameplay to lines-of-code.

It’s important to note that emergence is not always planned for, and for that matter it is not always desirable. Here are two examples of emergence, both from the Grand Theft Auto series of games, where unintended emergent gameplay led to questionable results:

• Consider these two rules. First, running over a pedestrian in a vehicle causes them to drop the money they are carrying. Second, hiring a prostitute refills the player’s health, but costs the player money.

  From these two unrelated rules, we get the emergent strategy that has been affectionately termed the “hooker exploit”: sleep with a prostitute, then run her over to regain the money you spent. This caused a bit of a scandal in the press back in the day, from people who interpreted this dynamic as an intentional design that glorified violence against sex workers. Simply saying “it’s emergent gameplay!” is not sufficient to explain to a layperson why this was not intentional.

• Perhaps more amusing was the combination of two other rules. First, if the player causes damage to an innocent bystander, the person will (understandably) defend themselves by attacking the player. Second, if a vehicle has taken sufficient damage, it will eventually explode, damaging everything in the vicinity (and of course, nearly killing the driver). These led to the following highly unrealistic scenario: a player, driving a damaged vehicle, crashes near a group of bystanders. The car explodes. The player crawls from the wreckage, barely alive… until the nearby crowd of “Samaritans” decides that the player damaged them from the explosion, and they descend in a group to finish the player off!

As you can see, emergence is not always a good thing. Because of the complex nature of the dynamics, emergent games require a lot more playtesting and iteration than games that are more straightforward in their relationships between mechanics and dynamics. A game with emergence may be easier to program, but it is much harder to design; there is no cost savings, but rather a shift in cost from programmers to game designers.