I’m not avoiding the Far Cry 2/Left 4 Dead/Fallout 3 post.  I’ve played them and am reflecting.  I’ll get there.  Maybe I’m just not inspired enough yet.  I’m considering a Far Cry 2 meets Castlevania: Order of Ecclesia post.  But first…

2.3 is my favorite design number.  It helps me all the time.  This week it gave me a novel reason why players struggle to control the right stick of a controller.  It’s my invisible design friend.  Except it seems kinda like magic.

That’s 2.3.  Slightly more then 2, less then 3.  I first heard about 2.3 from Linked: The New Science of Networks by Albert-László Barabási.  He claimed that network science research has shown that 2.3 is the stable number of connections in a complex system (as opposed to a static or chaotic system).  At 2.3, you can remove a few connections without the graph becoming disconnected, and yet you’re not so dense that each node is flooded with information.  I need to find my copy of his book – I recall him claiming the brain averaged 2.3 neural connections, for example.

Now I see this number all the time.  For example, 2.3 is around the average number of children per family in a stable population.  2.3 exits to your house?  But it’s unusually prevalent in games.  In multiplayer maps, 2.3 is the number of exits per room that flows best.  Don’t believe me?  Look around.  On Starcraft maps, it took a long time but map makers realized that every expansion has to have 2-3 ramps – no more, no less.  I wasn’t surprised that the number of weapons you can carry in an FPS has settled on 2 either.  It’s maybe even 2.5 if you include grenades (of which frequently there’s 2-3 types).  Or that ultimately the Wii settled back again on 2 buttons, A and B, and that everyone struggles with the other ones.  Why are there 2-3 postures in games (run, walk, maybe stealth)?  How many buttons used for the base of a fighting game’s combo tree?  God of War uses 2, maybe 3, if you include grab.  More then that, and those fighting games start becoming a lot harder to learn.

Sure, this could be all coincedence.  I’m sure I could come up with a list of 4s too.  But I don’t think it is.  I think 2-3 things is what a network, and in particular our brain, is best shaped to make choices about.  At 1 or fewer options, there’s no real choice at all.  We just cruise on down the hallway.  At 4+ options, we stop in the maze, paralyzed.  Which one of the 8 hallways should we go down?  Essentially it becomes a random choice (button mashing), or we stop thinking and follow an external rule (go clockwise).  But 2 choices is just right – we can quickly form an opinion, test it, and move on.  A or B, chocolate or vanilla, cats or dogs.  3 isn’t always hard either, in particular when we can make comparisions between 2 extremes (liberal, centrist, conservative, or good, neutral, evil, for example).  These 2 are the simplest most straightforward types of choice there is, and the ones we enjoy making fast and repeatedly.  Given time, we can recall 7-9 things, and make strategic decisions about them.  There’s a reason there’s 9-12 units in Starcraft, for example.  But 2-3 specifically seems like the ideal number of options for tactical choices.

My takeaway: When you want your design to be accessible, and in particular to have flow, focus on giving only 2-3 choices at a time.

Which is how I made a surprising insight about the troubles of the right stick.  The choices around the stick don’t operate in a binary, digital way.  In prototyping, I’ve been reminded analog choices are even more fun then digital ones, and even more important.  Humans seem to love them, the freedom that comes from choosing between small and large differences, the continuous ramping control.  And in game design, we’re almost always dealing in 2 analog axes: distance and time.  Distance is controlled by the left stick.  Time is controlled by when the player makes choices, and conviently provides easy time pressure to make these analog choices tactical ones.  It’s not the right stick that’s the problem – it’s that the design’s adding another analog axes: the camera, where you are looking.  And that third analog axis pushes the problem just over the natural threshold.  2.3 remember?  We can get there if we can mentally treat one of the axes as that ideal .3 of a choice – time say, or (for experienced players) easy camera controls – but the design has to be real careful and massage the player, because we’re over the brain’s natural tactical threshold.

I tried out Auditorium today on Penny Arcade’s recommendation.  I continue to delight in these fun and beautiful little flash games; they are getting good at quickly achieving flow!  I couldn’t help seeing 2.3 again.  In Auditorium there are only 2 types of control – analog position and analog size.  Surprise!  Want to bet the later levels have a simple time mechanic?


4 thoughts on “2.3

  1. Sabre, you may be able to see any number there if you looek for it, but I think the act of puting it in terms of a number can be useful in itself. Thinking about how many choices the player can handle at a time would certainly be a helpful thing to do in designing your game. You don’t have to dogmatically stick to a single number like 2.3 – but I think that posing such a hypothesis can help you see more clearly where it is right and where it is wrong, and end up with the right choice for your particular game.

    Anyway, I love these kinds of blog posts – this one has got me looking at games in a way I hadn’t before. It’s like I just acquired a nifty weapon upgrade for my game-analyzing metagame. 🙂

    Keep it up!

  2. I’d be curious what the 2.3 wrt the brain is all about? Cerebral neurons can have literally hundreds of thousands of connections to other neurons. Even in a bug, there are thousands of connections per neuron…

  3. Yeah, I wish I could find that reference. I even remember thinking at the time it was an odd claim, a little vague, but in context it strike me as interesting. I just can’t remember the details.

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