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Feedback Loops in Games – What Makes Monopoly, World of Warcraft, and Mario Kart So Much Fun

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We’ve tackled everything from epidemics, labor unions, and skyrocketing rent prices in San Francisco, but today we’re going to nerd out and talk about games. And when we say games, we’re not talking about game theory or a hypothetical model for decision making. We’re talking about real games. Hardcore games like League of Legends and Magic: The Gathering. Casual games like Farmville and Candy Crush. Board games like Monopoly and Risk. Let’s throw sports into the mix too.

What do games have to do with systems? Games are often a compilation of reinforcing and balancing feedback loops that drive the dynamics of player interaction. Take basketball for example, which has the common balancing loop of turn-taking.  After one team scores, possession goes to the opposing team. This is designed to give both sides an opportunity to score. Imagine if instead there was a reinforcing loop which allowed the offensive team to keep possession of the ball after scoring. Points would come in streaks, allowing momentum to build up for the offensive team.

TAKEAWAY 1:
Reinforcing loops reward winners
Balancing loops forgive losers

Sports were designed with fairness in mind- the same rules apply to each player. A point scored at the beginning of the game is just as important as a point scored at the end. In the example above, changing the rules to give possession to the scoring team would increase their opportunities to score, but not their ability to score later in the game.  But imagine if your basket got wider for each basket made by your team. Now we’ve set up a stronger reinforcing loop. The points scored in the beginning of the game are going to be much more important since each point scored makes it easier to score the rest of the game. Many games are designed with these types of behaviors in mind.

Essentially, Reinforcing Loops make it easier for the player to continue scoring against opponents, such as:

  • Increasing your Assets (e.g. In Call of Duty, players who kill multiple opponents in a row are rewarded with special powers like the ability to summon a helicopter)
  • Decreasing Opponent Assets (e.g. in Chess, capturing opponents’ pieces leaves them with fewer options for their future turns, giving you a competitive advantage)
  • Stealing Assets, or simultaneously increasing your assets by taking from opponent’s assets (e.g. in Monopoly, players that land on your properties pay you rent, transferring their assets to you)

moneybags

Not every game has reinforcing loops. Gameplay can be perceived as unfair if reinforcing loops are too strong. For example, most sports avoid reinforcing loops because part of what keeps the crowd entertained is the idea of balance – games are most exciting when both teams have the possibility to win the game with a final clutch play and this requires that no one team gets too far ahead.

fisher
Derek Fisher throws up a 3-pointer with just 0.4 seconds left in Game 5 of the Lakers-Spurs Playoff series in 2004. This shot gave the Lakers the victory.

TAKEAWAY 2:
Reinforcing loops magnify early-game decisions on the outcome of the game
Balancing loops diminish early-game decisions on the outcome of the game

Small reinforcing loops, when activated early on, can have a big impact on the ultimate state of the game. In strategy games such as Settlers of Catan, Civilization, and Starcraft, players race to build up an empire, generating resources which are in turn used to expand the empire even faster. Early on, a decision to focus on resource production can have compounding effects on player’s ability to build, train troops, and overpower opponents later in the game. Player power can grow exponentially in these games as a result of activating these reinforcing loops, and the outcome of the game can be decided very early on.

Conversely, balancing loops can keep a game competitive to the end. Remember how awesome it was to get the blue shell weapon in Super Mario Kart (the blue shell automatically strikes the current game leader)? Mario Kart is designed so that players in the front of the pack get crappier weapons than the stragglers. This keeps the race close until the end of the race, and players often save their most powerful weapons until the last few moments.

blueshell

Another common strategy is for losers in multiplayer games to gang up on the leader, like in Super Smash Brothers when every one attacks the player that still has many lives left.

TAKEAWAY 3:
Reinforcing loops shorten games by creating player inequality
Balancing loops lengthen games by encouraging player equality

The difficulty in good game design comes in striking a balance between Reinforcing and Balancing feedback loops. The existence of reinforcing loops enables players to battle for momentum that keep the game exciting. Players have something to fight for and something to prevent their opponents from obtaining. However, improperly designed reinforcing loops can spiral out of control and make the game end too quickly. Why play a game if the loops favor the leader so decisively that no one has any chance of catching up?

Meanwhile balancing loops keep a game competitive and prevent early game decisions from deciding the rest of the game. But even this can be problematic: If balancing loops eliminate player incentives to compete, the game becomes stale. Equally frustrating are game designs that rely heavily on punishing winners for succeeding or rewarding losers for inferior play. Mario Kart comes to mind: how many have had victory snatched away by a blue turtle shell moments before crossing the finish line?

Ultimately, there is no magic formula for designing games. A good game can have any combination of reinforcing and balancing loops, or neither. They’re powerful tools in the game designer’s toolkit. Used properly, they can make a game fun, engaging, and even addictive. Used improperly, and they’ll spoil the fun.

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Exercise: Think about your favorite game and the rules involved. What positive feedback loops does it have (rules that reinforce a player’s power to make their future successes easier)? What balancing feedback loops does it have (rules that prevent the leader from getting too far ahead)?

If you could change the rules of the game, what feedback loops could you introduce to make the game more interesting? Try playing your game with your newly introduced rules and observe how that impacts your experience.


Essay written by Jenny Zhou & Eddie Hsu

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3 comments

  1. In Jenga, the positive feedback loop lets the tower become higher and while doing this, create new options for picking a piece later in the game.
    The negative loop would be, that after each stone taken, theres one pickable piece less for the opponent.

    Well, the rules apply to both players. So maybe its a bad example?

  2. Counter Strike is an excellent example of feedbacks loops carefully crafted for entertaining competitive play.
    In Counter Strike, at the start of each round you get a sum of money to buy weapons for that round. If your team won the round you get more money (reinforcing loop), but the losing team also gets a certain sum. There is a strong balancing loop in that the losing team amount increases depending on the length of its losing streak. After 4 consecutive losses, you get practically as much money as the winning team.
    This means that a very common strategy is to go “eco” when you don’t have enough money. In essence the team agrees to buy almost nothing, essentially sacrificing the round in order to kickstart their economy again. The beauty of the game is that in such a round, you can still actually win which amounts to a tie-break in tennis. Add to that the fact that many maps are unbalanced (but each teams plays both sides) and it makes the game very enjoyable to watch.

    In chess, you described the obvious reinforcing loop : when you take a piece, you increase your material advantage. But chess is of course much more complicated than that, and the problem is that with each move, you don’t actually know for sure if you are improving or deteriorating your position: If I take your pawn with my knight, this means that my knight no longer controls the same area. Maybe this pawn was actually blocking you from executing a move. Maybe by taking the bait, I lost the initiative. Maybe now my knight is aligned with my queen and you can pin it down.

    In 4X games such as Starcraft, taking ressources early is a key reinforcing loop, but priorizing on ressources means that maybe you have neglected your defenses and that is the balancing loop. Hence the infamous “Zerg rush”, where instead of focusing on ressources, you simply flood the enemy who was too busy planning a long term gain with low level units.

    In board games, probably the oldest balancing loop of all is the “the loser gets to start the next game” rule.

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