[Game Design] [Round Table]
The majority of game design proceeds from a simple assumption - that the worth of a game can be measured by how fun it is, and all other things being equal, a game that is fun will make more money than one that is not.
Except that's not really true, is it?
Surely it's only necessary to make the first few hours of a game fun, so that the player will become invested. After that, you can milk play out of the player for a period of time limited only by the effectiveness of your reward schedule. Building a reward schedule is in many cases cheaper and easier than building fun. And for a very succcessful MMO, that leads to a very important (and very easy) business decision: if you have to choose between your players having fun, or your company making more money, which do you pick?
No prizes for guessing.
But what on Earth am I talking about? I'm talking about behavioural science.
Around 1957, American behavioural scientist BF Skinner was conducting a series of interesting experiments on pigeons. In these trials, pigeons were placed in cages. Within the cage was a disc, which could be pecked and functioned like a lever or button. The pigeons were subjected to one of five different reward schedules.
* Some pigeons were on a continuous reinforcement schedule. When this group pecked the disc, they were rewarded with seed. Every peck immediately produced seed.
* Some were on a fixed ratio schedule. This group would get seed regularly after a certain amount of presses. For example, every tenth peck on the disc would produce seed.
* Some were on a variable ratio schedule. This group would get seed after random numbers of pecks of the disc. That is to say, on average every tenth peck would produce seed, but the specific number from one reward to the next might vary from five to nine to thirteen, and so forth.
* Some were on a fixed interval schedule. Seed would become available through pecking the disc every, say, five minutes. It didn't matter how often the disc was pressed - it would only deliver seed once in any five minute period.
* Lastly, some pigeons were on a variable interval schedule. Seed would become available on average every five minutes, but the specific amount of time between rewards becoming available might vary from two minutes to ten minutes.
Four interesting relationships are indicated by experiments of this sort.
1) A pigeon on a fixed ratio schedule will pause significantly (stop pecking) after each reward before starting the number of presses necessary to achieve the next reward. This pause is not present in variable schedules - the activity is continuous.
2) A pigeon on a continuous reinforcement schedule whose seed supply is turned off will very quickly stop pecking the disc. But a pigeon on an interval or ratio reward schedule, particularly a variable one, takes a very very long time to stop pecking the disc. The less frequent the rewards originally were, the longer it takes the pigeon to stop pecking.
3) No output/reward equation is present in this behaviour; on schedules were rewards come extremely infrequently, a pigeon may actually peck itself to death trying to achieve the reward.
4) Once the pigeons had learned the relevant behaviours, their inclination to peck the disc was to some extent unrelated to whether they were actually hungry.
So what does this mean? It probably means that ratio and interval reward schemes, particularly a variable ratio reward scheme, are able to:
a) produce repeated and prolonged simple behaviour
b) produce behaviour which is not in a subject's best interest
c) motivate subjects to continue seeking rewards after the rewards cease to become relevant or useful to the subject, and
d) motivate subjects to continue seeking rewards for a long time after rewards stop being available.
Which leads me to my point: when was the last time you went grinding for loot?
It seems that fun isn't necessary to make players continue playing a game long after reaching the point of diminishing returns in terms of original content. In fact, fun isn't even the best way to make players continue playing. It's entirely possible it may even be detrimental to the aim of keeping players hooked. So I ask again - if you are developing a massively multiplayer online game, and you're going to be charging players for access by the month, what's going to be your design goal?
(Apologies to Skinner and to behavioural scientists for my horrible layman's version of this area of study.)
John Hopson's article on Gamasutra, Behavioural Game Design.
Chris Bateman's post on Only a Game, Designing Rewards in Games.
More on BF Skinner and operant conditioning is available here.
This is my post for the May Round Table of Bloggers.